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Metalurgy Steel alloy
...
In
addition, the steel also contains manganese, silicon,
sulfur, phosphorus and other chemical elements
...

Steel is the main structural material, because:
exhibit useful properties such as the ability
to gim elasticity and plastic deformation, high
strength, electrical conductivity, thermal
conductivity and other characteristics
...
9%) in the form of iron-containing
minerals and ores called relatively easily extracted
from the ores
...

1
...
In
the development staleplavilngo production of basic
units for steelmaking, production technology has
undergone considerable change: the direct reception
of iron from the ore syrodutnyh furnaces to obtain

ball iron, obtaining steel oxidative melting iron on
the hearth special puddling furnace (from the
English puddle - kneading, stirring)
...
), Ladle treatment of steel
...
The main production
methods are oxygen converter (50%), electric
steelmaking (~ 20%) and open-hearth furnace
(<30%); ~ 2% of steel is produced in electric
furnaces using materials obtained from direct
reduction plants
...
e
...
e
...

1
...
They are classified according to the
method of production, purposes, quality, chemical

composition, nature of the solidification structure
in the ingot molds and the resulting ingot
...

The following main groups of steel can be
distinguished for its intended purpose:
1
...
N
...
Stoke and boiler steel - low-carbon steel, used for
the manufacture of steam boilers and furnaces
...
The steel for railway - rail hearth and BOF steel,
axial, steel bands for railway wheels
...
Bearing steel serves as material for making ball
and roller bearings
...
Tool steel is used for the manufacture of different
tools, cutting tools, roll mills, parts forging and
stamping equipment
...
Differences between these groups are in the
permissible content of harmful impurities
(primarily sulfur and phosphorus), as well as in
special requirements for the content of non-metallic
inclusions
...
010 and even 0
...

In chemical composition are distinguished:
1) The steel with low content of impurities, or a socalled technically pure iron, as the total content of
other elements is only about 0
...
Depending on the
application, this is divided into low-carbon steel
(0
...
25- 0
...
6-2
...

3) Alloy steel - steel containing, in addition to carbon
and other alloying constituents, which in turn are
divided into low-alloy steel (up to 10% PE); medium
(10-20% LE) and high-alloy steel (more than 20%)
...
The
principle of steel marking: the numbers before the
letters mean the carbon content in hundredths of a
percent (if less than 0
...
5% )
...
Allocated
quality structural steel are: 10, 20, 45, etc
...
, Y12,
where the letter U - carbon, and the number carbon content in tenths of a per cent
...

Depending on the microstructure of the steel are
pearlitic, martensitic, austenitic or ferritic
...
The behavior of the metal
in the molds depends on the degree of its
deoxidation - the more fully the steel is deoxidized
(the oxygen is removed), the more easily the ingot
crystallizes (the deoxidation of steel is the process

of removing dissolved oxygen from the metal)
...
On the contrary, the calm
steel crystallizes without visible effects, calmly
...
3 Steel smelters

Slag, which is an alloy of oxides, sulfides, nitrides,
phosphides, carbides and other compounds and is
an inevitable by-product of any modern method of
steel production in open aggregates
...

thirdly, getting into the bath from the outside nonmetallic oxides with the feedstock materials (flux
and solid oxidants), pollution niyami (trash) and
the mixing of scrap or blast furnace slag
...
The products of oxidation of scrap iron and
impurities - silicon, manganese, phosphorus, sulfur,
chromium and other elements (SiO 2, MnO,
P 2 O 5, FeS, MnS, Cr 2 O 3, etc
...
Products fracture lining unit - with corrosion are
the main liner (dolomite, magnesite) in the slag
move CaO, MgO, when corrosion are acidic
(dynasties) - SiO 2
...
Impurities made the charge (sand, clay, slag, the
mixing and the like), -SiO 2, Al 2 O 3, MnS, etc
...
Rust covering the scrap poured into the
steelmaking units, - iron oxides
...
Additional materials and oxidizing agents
(limestone, lime, bauxite, fluorspar, iron and
manganese ore, etc
...
P
...

A positive value of the slag is its ability to absorb
phosphorus (dephosphorization) and
sulfur (desulfurization) from metal
...

In the bottom processes, that is, in the processes
carried out in open-hearth, douche and electric arc

furnaces, the positive role of slags is also expressed
in the protection of metal from harmful impurities
coming from the furnace atmosphere, mainly gases
...
These negative actions of slags on
the course and results of melting are manifested to
varying degrees in any steelmaking process
...

Composition of slag
The structure of slags and their main physicalchemical properties are determined by their
content of various oxides, which conventionally is
called a slag chemical composition
...
Depending on the nature of the slag,
the processes are called basic or acidic (for
example, the main open-hearth process, an acidic
open-hearth process)
...
E
...
In
aggregates having a basic (magnesite or dolomite)
lining, the smelting can be carried out only under
the main slags, the main component of which is CaO
...
Basicity of slag

There are many indices that characterize the
basicity of the slag, but any of them primarily
should allow one to assess the phosphorus and
sulfur absorption capacity of the slag
...

Slag, in which the ratio (CaO / SiO 2) <1
...
6-2
...
5
...
Compositions acidic slags are characterized by
their degree of acidity (or simply "acidity") typically
expressed by the ratio of SiO 2 / (FeO + MnO)
...
The oxidation of slag - is the ability to exert its
oxidizing effect on the metallic phase by passing
oxygen into this phase
...
The
oxidizing capacity of the slag increases with the
increase in the content of iron oxides in it, the
concentration of carbon in the metal and the
temperature and the decrease in the basicity of the
slag to 1
...
8
...

The physical properties of slags determine the behavior of
slags in the smelting process
1
...
e
...
) Hereinafter, the melting point of
slags is referred to) is their main physical
characteristic, which determines other important
physicochemical properties
...
The degree of slag overheating determines
slag behavior, its physical properties (viscosity,
electrical conductivity), and chemical activity
(refining effect on metal, gas absorption from the
gas phase, etc
...
However,
studies have shown that for primary oxidative slags,
the change in the SiO content is of primary
importance
2

(See Figure 1)
...
p
...
As the reduction and increase of
SiO 2 in the slag above the indicated limits leads to
an increase in melting temperature
...
In the course of the melting process in

the main content of SiO 2 is reduced, and rises in
acid processes, so the melting temperature of the
slag during smelting is generally increased
...


...
Viscosity of slags
Slag viscosity is the most important of the
properties
...
The viscosity of the slag depends
on its temperature and composition
...
2, from which it can be
seen that in the region of moderately low melting
temperatures (near the melting point), the slag
viscosity is high and increases with increasing
basicity
...
10
...

TO

Figure 2 - Dependence of slag viscosity (Pa ∙ s) on
temperature and basicity (digits on curves)
The components of the slag, which sharply increase
its viscosity, are primarily MgO (> 10-12%) and Cr
2

ABOUT
3

(> 5-6%); These components, at concentrations
above these limits, enrich the slag with finely
dispersed particles
...

3
...

Some, not excessive foaming of slag in oxygen
converters with the top blowing, plays a positive
role - the absorption of oxygen in the bath increases
and stabilizes, obstacles are created to release
metal droplets from the converter and absorb
nitrogen from the air sucked through the

neck
...
In open-hearth furnaces, even
moderate foaming, which does not lead to slag
emissions, is undesirable, since frothy slag, having a
low thermal conductivity, impairs the heat transfer
from the torch to the metal, which causes
lengthening of the melting and increased wear of
the lining, especially the furnace vault, since a large
part of the heat not absorbed by the metal is
absorbed Lining, and this leads to its overheating
...
A similar effect is due to the presence
in the slag of very fine solids, which increase the
mechanical strength of slag films (serve as a
"frame")
...
If excessive
foaming is caused by an increased content of the
slag SiO 2 and P 2 O 5 , it is necessary to raise the
basicity of slag additive into the lime bath, even
better additive CaF 2 and alkali metal oxides
...
The optimum slag
simultaneous change mode is achieved and the
chemical composition (basicity), and the amount of
slag
...
To meet this
requirement have sufficient basicity final slag of
2
...
4
...
This requirement is consistent
with the final slag basicity of 2
...
3 to 3
...
0, and
the open-hearth process in BOF process
...
Since the guidance of additional
melt and slag extends leads to additional metal loss
will attempt to conduct the process in
odnoshlakovom mode
...
), Particular importance in steelmaking
practice have oxidation reaction
...

2
...
The carbon content as a useful impurities in
steel generally ranges from 1
...
2 to 0
...
10%
...
e
...
As a
result, some of the carbon atoms occupy sites in the
crystal lattice of iron (ferrite), causing its distortion
and leads to stress therein, contributing to the
strength and hardness of the iron
...
This is primarily due to the fact that during
this period the carbon oxidized
...
This outgassing provides intensive mixing
bath (metal and slag), without which the
steelmaking processes in existing embodiments
unrealizable
...

Secondly, the process of oxidation of carbon with
oxygen gas flows to generate heat which is used for
heating the bath
...
e
...

Fourth, the carbon content of the metal and its
continuous oxidation are the main factors
determining the oxygen content in the metal that
affects the oxide content of nonmetallic inclusions
in the finished steel, i
...
its quality
...
Concomitant
oxidation of carbon to form CO 2 is of secondary
importance
...

Possible oxidation of carbon dissolved in the metal:
[ C ] + 1/2 O 2 = sogaz ; Δ G ° = -152570 - 33
...

[ C ] + (FeO) = Fe + sogaz ; Δ G ° = 373 +85 - 83
...


[ C ] + [ O ] = sogaz ; Δ G ° = - 35 630 - 31 T ; - with the
release of heat
...
E
...

Equilibrium constant of the reaction [C] + [O] = {SB}
in general is given by Kc = Pco / (a [c] a [o])
...
08%
oxygen to their activity coefficients are
approximately equal to unity, so Kc = pCO / ([C] +
[O])
...
Then, for any
temperature pCO / ([C] - [O]) = const
...
0025 =
0,0025Rso
...


The theoretically possible maximum oxygen
content (see
...
20-0
...
Taking the
average value of [O] = 0
...
0025 / 0
...
01%, r
...
In the open steelmaking apparatus is
impossible to obtain a carbon content of <0 , 01%
...
10-0
...
02%
...

AT
Figure 3 - Correlation of oxygen and carbon content
in the steel: A - for the decarburization reaction
equilibrium at 1600 ° C; B - in the actual steel; B equilibrium with respect to the steel slag
the modern practice of producing steel containing
<0
...
In these cases,
the outdoor units typically achieve a residual
carbon content 0,025-0,040%
...


General principles for achieving a given carbon
content in the finished steel
...

To achieve the desired content y leroda in the
finished metal must have a certain reserve of
carbon in the starting material (in excess over a
finite initial content), and efficiently consume this
supply during the oxidative refining
...

Bases synchronization processes decarburization and heating of the
metal

When it is operating fusible important not only to
carbon oxidation and receiving predetermined its
content in the final metal, but also carrying out this
process in synchronization with the heating of the
bath process
...

Since See = 0
...
09 kJ / (kgK), and the amount of slag is usually 10-15%, the
equation becomes: Δ t [c] = 0,009Qt
...

The magnitude and sign of the thermal effect of
carbon oxidation process may vary depending upon
the source of oxygen
...
) and hot furnace gases:
Qt, kJ / kg [C] Δ t [c] , ° C /% [C]
Cold blast:
air
...
+ 12500 115
The heated furnace atmosphere
...
carbon
oxidation by oxygen of solid oxidants endothermic
process is dramatically
In actual steelmaking processes quantity Δ t [c] can
greatly differ from the above values of Δ t [c] no
number of reasons: the heat loss occurs in the
surrounding medium bath (heating the liner, and
ambient air, etc
...

2
...
Steels alloyed with silicon, has a
higher yield stress values of elasticity, impact
resistance, good hardenability, heat-resistant, the
ability to retain hardness of the hardened condition
at relatively high temperatures, and others
...
The
course of the existence of the silicon melt in the
batch usually has a positive impact:

This is reflected in the improvement of heat balance
of melting since oxidized isolation among the usual
impurities silicon metal charge it greatest amount
of heat
...

However, silica is formed by oxidation of silicon
metal, it has a destructive effect on the basic
liner
...

Silicon is doped iron binding and in some quantity
in the scrap
...
5-1
...

Dissolved in the metal silicon can be oxidized with
oxygen:
a) contained in the gaseous phase [Si] + O 2 gas =
(SiO 2 ); ΔG = -775670 + 198T, J / mol;
b) contained in the oxides of iron slag [Si] + 2 (FeO)
== (SiO 2 ) + 2Fe; ΔG ° = -300 000 98T;
c) dissolved in the metal [Si] + 2 [O] = SiO 2 ; ΔG ° == 541 + 840 203 T
...
"Plus" sign in

front of the entropy term in the free energy
equation shows that the conditions for recovery of
silicon may be formed at higher temperatures
...

The main processes silica forms in the slag stable
compounds: in the beginning of smelting iron
silicates 2FeO ∙ SiO 2 and calcium CaO ∙ SiO 2 ,
hereinafter dvuhkaltsevy calcium silicate 2CaO ∙
SiO 2 by reacting (SiO 2 ) + 2 (CaO) = 2CaO ∙ SiO 2
...

In acidic processes activity of SiO 2 in the slag is
many times higher than the fundamental processes,
however with increasing the bath temperature to
the end of melting occurs silicon recovery from the
slag by the reaction of
[Si] + 2 (FeO) == (SiO 2 ) + 2Fe,
chegoostatochnoe resulting silicon content of the
metal can reach 0
...
4%
...


Providing a given silicon content in the finished steel

As shown above, in the basic processes that have
currently crucial in the production of steel, the
residual silicon content in the metal at the end of
the oxidation refining is negligible (traces), so
silicon as a useful impurity in the required amount
is introduced into the metal after oxidation
refining
...

2
...
manganese in the
finished steel is in most cases beneficial impurity
serving for deoxidizing and alloying
...
250
...

Main positive effect on the properties of manganese
steel is to reduce the harmful effects of sulfur due to
its binding to the sulfide MnS, which upon
crystallization of metal is released in the form of
solid, randomly placed inclusions, bearing many
times less damage than FeS
...


Manganese as an alloying element
...
Dissolving in ferrite,
manganese improves strength of steel , but
slightly reduces the ductility of steel (elongation and
toughness)
...

Manganese in steel tubs manners
Manganese is introduced into a bath steelmaking
mainly from iron and scrap
...
3-0
...
0-1
...

Manganese dissolved in the metal is oxidized by
oxygen;
a) contained in the gas phase: [Mn] + O 2 gas =
(MnO); ΔG ° = -361 380 + 106T;
b) the iron oxides contained in the slag: [M] + (FeO)
= (MnO) + Fe; ΔG ° = -124 000 56,4T;
c) dissolved in the metal: [Mn] + [O] = (MnO); ΔG ° =
-245 000 109T;
Increasing values ΔG ° with increasing temperature
indicates the possibility of leakage at high
temperatures - reverse process - the recovery of
manganese from iron oxide (MnO) + Fe = [Mn] +

(FeO), as well as carbon and silicon: (MnO) + [ C] =
[Mn] + sogaz; 2 (MnO) + [Si] = 2 [Mn] + SiO 2
...

At the beginning of smelting manganese intensively
oxidized before reaching the equilibrium reaction
(MnO) + Fe = [Mn] + (FeO)
After equilibration, the manganese content in the
metal during the process can remain unchanged for
a constant ambient conditions or change in the
direction of increase or decrease depending on the
nature of changes in external conditions temperature, oxidation of the bath, the amount of
slag, etc
...
when [C]> 0
...
3% by increasing the
temperature of oxidation of the slag at a low
concentration of manganese in the metal at the end
of melting is improved
...
When the [C] <0
...
07%), due to a sharp
increase in the content of FeO in slag in the metal
concentration of manganese decreases (although
additional temperature increase)
...
This reduces the activity of MnO in
the slag and the right shift reaction
...
12% when the
concentration of carbon in the metal is not less than
0
...
20%) values Lmn reduced to 10-20 and the
metal is 20-35% manganese
...
05-0
...

Providing a predetermined manganese content in the
finished steel
In most cases, the residual content of manganese is
significantly less than the
predetermined
...
) At release in the
ladle
...
4 Oxidation and phosphorus recovery

The ores of phosphorus is always accompanied by
iron, often in large quantities
...
Minimum phosphorus
content is 0
...
2% iron, 2-2
...

Increased phosphorus content lowers the ductility
of metal (especially impact strength), also degrades
the strength (tensile strength), flexibility and
weldability of the heated metal
...

In batch furnaces phosphorus falls essentially of
iron
...

Dissolved phosphorus in the metal can be oxidized
with oxygen:
a) contained in the gas phase: 4/5 [P] +
O 2 times = 2/5 (P 2 O 5 ); ΔG 0 = -619280 + 175T;
b) the iron oxides contained in slag: 4
...


"Plus" sign in front of the entropy term in the free
energy equation shows that as the temperature
increases may create favorable conditions for the
reduction of phosphorus
...
However, P 2 O 5 is thermally unstable and at
temperatures of steel bath can not exist in a free
state
...

The acidic slag due to excess SiO 2 formation
phosphates receives limited development and as a
result found that when working under such slags
phosphorus, converted into slag at relatively low
temperatures, at higher temperatures is reduced
and at ordinary temperatures steelmaking (> 1500 °
C) almost all transitions back to metal
...

The basic slags at low temperatures began melting
triphosphates may be formed of iron mainly by the
reaction of
(P 2 O 5 ) 3 + (FeO) = (3FeO
...
In order to remove phosphorus from the
metal and to keep it in the slag, it is necessary to
reduce the activity of P 2 O 5 in the slag
...
Thus the main component, CaO
lime reacts with P 2 O 5 to form calcium phosphate
(CaO) n - (P 2 O 5 ), which in comparison with other
calcium phosphates has the greatest stability and
melting point
...

Combining this equation with the equation of the
reaction of P 2 O 5 , we obtain the equation of the
total metal dephosphorization reaction at the end of
the basic process:
2 [P] + 5 (FeO) +3 (CaO) = (3SaO
...

Thus, it is possible to formulate the basic
conditions, which allows adherence remove
phosphorus from the metal:
1)
...
5-2
...
0-3
...

2)
...
This is due to the fact that,
firstly, FeO takes direct part in the process of
dephosphorization (2 [P] + 5 (FeO) = (P 2 O 5 ) + 5

[Fe]); secondly, FeO accelerates the dissolution of
lime in the slag, ie
...
facilitates the production of a
homogeneous slag
...
The direct effect of
temperature associated with the sign of the effect of
the heat of reaction
...
5 Removal of sulfur (metal desulfurization)

Sulfur is the most harmful impurity, which reduces
the mechanical strength and weldability of the steel
and degrades its electrical, corrosion and other
properties
...
Pure iron sulfide has a melting temperature of
1190 ° C and oksisul fidny-eutectic melt has a
solidification temperature of about 985 ° C, ie
...

Substantially below the melting temperature of the
metal (usually ~ 1500 ° C)
...
Evolved non-metallic
inclusions are located along the grain boundaries in
the form of thin films
...
This phenomenon is
called became brittleness
...

Not minimal negative impact the sulfur has on the
service, primarily on the strength properties of the
steel, especially at low temperatures <(-30 °
C)
...

Sulfur is a chemically active element and forms
different compounds which are stable at high
temperatures and capable of steelmaking processes
and move into the gas and slag phases
...
This amount of
sulfur is greater the higher the content of sulfur and
oxygen in the metal
...

The bulk of sulfur is removed from the metal
oxidizing slag
It is the traditional scheme:
sulfur, located in the metal in the form of iron
sulfide in respectively Corollary with distribution
law goes into the slag, [FeS] = (FeS)
...

the total (v boiling) desulfurization reaction [FeS] +
(CaO) = (CaS) + (FeO )
...

Effect of temperature on sulfur partition ratio can be
direct or indirect
...
This process is exothermic, so if other
conditions constant, the higher the temperature, the
smaller the Ls, but this effect is negligible, since a
small thermal effect process: -42 kJ / mol
...
The higher the bath
temperature the better metal desulfurization, if
temperature rise is used efficiently to obtain a
homogeneous highly basic slag
...

Sulfur is a surface active element
...
Therefore, the greatest effect is achieved
by the use of such methods of melting, which
provide an increase in the metal contact surface with a
desulfurizing phase (artificial mixing of the metal
with slag, blowing in fine powdery metal reagents
and m
...


However, the major enhancement metal
desulphurization laid down in the changing chemical
composition of the slag
...
This slight acidic slag
sulfur absorption does not occur due to the
formation of simple anions S 2- , and due to the fact
that the sulfur is partially replaces silicon-oxygen
anions:

Basic oxidizing slag conventional chemical
composition (B> 2,0-2,5) provide Ls = 3-7,
sometimes up to 10 m
...
Several times higher than
for acidic slags
...
For guidance
zhidkopodvizhnogo highly basic slag in the slag
bath is carried lime additive (limestone) and
downloading primary slag carried out to remove
silica from the furnace
...
On the one hand, the presence of
FeO in slag CaO accelerated dissolution and
obtaining a homogeneous highly basic slag
(liquefied slag) that improves desulfurization
...

In general, basic slag seropoglotitelnaya capacity
remains low because of high oxidation steel slags
...
In the mode of desulfurization odnoshlakovom R
= [S] n / [S] to may reach 1
...
E
...
5-2 times (40-50%)
that under current conditions it is often insufficient
...

Thus, removal of sulfur from a metal (metal
desulfurization) is facilitated by:
1) the presence of basic slag with a high activity
CaO;
2) low okislennost metal slag (minimum FeO);
3) the low concentration of sulfur in slag
(downloading new slag and guidance);
4) mixing the metal with slag and increasing the
contact surface;
5) Increasing the bath temperature
...
1 History of converter steel production

Converter steelmaking method was proposed in
1855
...
The
method consisted in the redistribution of iron into
steel by blowing molten pig iron by air supplied
through the converter bottom
...
Converter converter) is a rotary vessel about a horizontal
axis, consisting of a metal casing internally lined
acid (earths) firebrick
...

The presence of acidic lining predetermined work
Bessemer converter with acidic slags, so the
Bessemer process was used only for the
redistribution nizkofosforistyh ores
...
Sydney Thomas problem
removing phosphorus from pig iron in a converter
by blowing a basic lining has been solved, in which
was used as calcined dolomite, and in the presence
of a highly basic slag
...
Method for
processing vysokofosforistyh iron by blowing air in
converters with a basic lining called Thomas,
a converter with a basic lining - Thomas converter
...

However, both processes inherent disadvantage - an
increased nitrogen content in the steel (0,0100,025%) due to the fact that the blast air, nitrogen
dissolved in the metal
...
For steel with a low content of
nitrogen in the methods used 1950-65 purging
bottom steam-oxygen mixture, and a mixture of
oxygen and carbon dioxide, and a method by
blowing purge oxygen enriched
...
These processes have the common name of
the oxygen converter process
...
and Thomas
Bessemer process and variations thereof have been
squeezed BOF process with the upper and lower
feed blower
...
2 Apparatus BOF top-blown

BOF process - a steel production of molten iron with
addition of scrap in the converter with a basic lining

and blowing oxygen from above through a watercooled tuyere
...
;
3) less costs redistribution, which include the cost
of electricity, fuel, refractories, replaceable
equipment, salary, etc
...
Heat released by the
oxidation of iron components with an excess
enough to heat steel to a temperature of
manufacture and allows up to 24-28% of the scrap
in the charge
...
Figure 4)
...


1 - support bearing; 2 - pin; 3 - a protective casing; 4
- a support ring;
5 -korpus driven wheel; 6 - mounted motor with a
reducer;
7 - a driven gear; 8 - damper motor coupler;
9 - damper driven wheel housing; 10 - supporting
frame
Figure 4 - Device BOF
Format converter
...

The dimensions of the converter
...
The dimensions of some converters are
shown in the table
...
65

4
...
90

0
...
50

1
...
50

5
...
60

1
...
78

3
...
27

6
...
41

0
...
90

3
...

Specific volume should be in the optimum range
...
However, if the specific
volume excessively large, unnecessarily increasing
the height dimensions of the converter and the
converter plant, the heat-transfer surface of the
casing and the heat loss rate of refractories for the
lining brickwork
...
8-0
...
0 m 3 / t, and this value
should decrease with an increase of the converter
vessel
...
However, the excessive
decrease of H / D , T
...
Decrease converter height
emissions begin as expandable metal reaches the
low-lying mouth
...

For converters 100-400 tons capacity value
projected in recent years H / D taken within 1,81,35, wherein within these limits it is usually
reduced in proportion to increase of the converter
vessel
...


The depth of the bath of liquid metal in the quiescent
state is changed from 1
...
8-1
...
Even for
the small-capacity converter (50 m), it should not
be less than 1 m in order to avoid destruction of the
lining of the bottom oxygen jets
...
9 m it is not
recommended, since this because of insufficient
penetration deep into the bath and oxygen jets
deterioration mixing bath hampered melting of
steel scrap
...
0
to 4
...
When choosing the
value Dg consider that large mouth allows the filling
of scrap steel in one step, reducing the length of the
heat
...
Therefore, the neck
should not be larger than necessary for charging
...
Based on
domestic practice not considered necessary to make
an angle greater than 25 °, since with a greater slope
resistance deteriorates neck liner
...
Converter casing perform
welding of Steel sheet thickness of 20 to 110 mm
and make it either all-welded or with detachable
head, which is bolted or wedge connections
...
Therefore, the top of the neck to protect
the welded or molded helmet that if damaged easily
replaced
...
This form facilitates the circulation at the
top metal blast feeding and reduces liner
wear
...
Detachable bottom may be attachable and
detachable
...
Currency pegs rests on the
roller bearings are fixed in the machine frame of
reference
...

Steering gear
...
Rotation of the converter necessary to perform
the operations: casting of cast iron, scrap filling,
draining steel and slag, and others
...

rotation mechanisms are fixed and hinged
...

Suspended multi-motor drive has the following
advantages: skewed pins does not affect its
performance; in case of failure of one motor drive is
operational; 2-3 times the mass of the drive is
reduced; significantly decreases the area required
for its installation
...
Lining converter operates in harsh
conditions, being exposed to high
temperatures; thermal stresses arising from
temperature fluctuations of the lining; beats batch
of pieces when loading and alternating loads arising
from the rotation of the converter
...

Liner usually made of two-layer
...
The reinforcement
layer is made of magnesia or magnesia-chromite
bricks
...

For masonry working layer refractories are used on
the basis of dolomite (CaO-MgO) and magnesia
bonded from coal tar
...

In order to increase the resistance of converter
lining applied hot gunned lining
...

Duration shotcrete is typically less than 5 minutes,
it is performed after each or after several
batches
...
19
and 1
...

Oxygen lance
...
The oxygen
pressure before the lance is 1
...
6 MPa
...
8- 3
...


The lance is made of three concentric steel tubes
and the copper is provided below the nozzle
head
...

Copper lance head has from 3 to 7 of the Laval
nozzle type nozzle increasing with increasing
oxygen flow rate and the converter vessel
...
In addition, they provide an opportunity
to increase the intensity of the oxygen supply and
cut, thanks to this, the duration of the
heat
...

3
...
Composition irons, processed in different
plants varies widely: 3,7-4,6% C; 0,4-2,6% Mn; 0,32,0% Si; 0,02-0,08% S; <0,3% P
...
6-0
...
At unduly high content of silicon increases
expense for the slagging of lime produced SiO 2 and
the amount of slag in the converter increases, which
leads to an increase in iron loss with slag promotes
occurrence and emissions; resistance decreases as
the converter lining
...
3%)
silica content slows slagging due to the slow
dissolution of lime because of too low content of

SiO 2 in primary slags, and also reduces the heat
coming
...
2-1
...
The
presence in the raw slag manganese oxide
accelerates the dissolution of lime accelerates the
formation of slag, which improves deforsforatsiyu
and desulfurization, and also reduces the amount of
emissions, and increases the resistance of the
lining
...
Therefore it
is desirable to have a converter redistribution
manganese content of the iron is not less than 0
...

The phosphorus content in the iron should not
exceed 0
...
3% because at higher contents it is
necessary to carry out an intermediate slag draining
during purging and new guidance, which reduces
the performance of the converter
...
03-0
...

The temperature of the molten pig iron is processed
into a BOF is typically 1300-1450 ° C
...


The amount of steel scrap reaches 25-27% by
weight of the mixture
...
In addition,
limiting the maximum size of the scrap pieces,
because they are too large chunks may not have
time to dissolve in the metal during the blowing,
and at boot time can damage the lining of the
converter
...

The basic slag forming materials - this lime and
fluorspar, sometimes as slag or coolers also use iron
ore, mill scale, bauxite, agglomerate, calcareous ore
pellets
...

The pieces of lime must have sizes from 10 to 50
mm
...

Fluorspar - effective diluent slag
...
Iron ore,
sinter and pellets should not contain more than 8%
SiO 2 , size pieces of ore should be 20-50 mm
...

3
...
In this case, the
production cycle is usually composed of several
operations, the duration of which is shown below,
m:
filling scrap

3-4

Pouring iron

3-4

blow

10-25

Sampling, analysis expectation

3-4

Drain (release) of the metal

5-10

slag drain

1-2

Inspection and preparation for the converter

0-5

Once melted, in Vol
...
shotcreting
The total duration of the cycle (melting)

25-50

The duration of the individual operations and cycle
(melting), as a rule, does not depend on the capacity
of the converter
...

Before starting the exercise its each
melt blending (planning), i
...
determine the optimal
data quantity terms (cost) of cast iron, scrap, slag
forming materials and oxygen, providing at the end
of the purge receiving metal to a target weight,
temperature and concentration of carbon,
phosphorus and sulfur
...
Melting begins by loading scrap
into the converter
...
E
...
Uniform distribution of
the scrap at the bottom of the converter is achieved
by tilting in the opposite direction from the load
side
...
Pouring
cast in the desired amount, known chemical
composition and temperature is carried out in one
step using iron ladles suitable capacity
...
The cavity is administered
converter tuyere, including oxygen supply - purge
period
...
The first
portion includes
...
These materials are
introduced into portions of 1% of the metal mass to
not cause hypothermia tub and disrupt the normal
course of smelting
...

Due to oxygen introduced oxidize excess carbon,
and silicon, manganese and a small amount of iron,
the oxidation of silicon and manganese ends in the
first 3-4 min purge
...
Its basicity as lime dissolution
increases and the end of the purging is 2
...
7
...

Formed in the oxidation of carbon bubbles CO
foamed metal and slag and substantially enhance
the circulation of slag and metal, which accelerates
the oxidation processes of dephosphorization,
desulfurization, heating metal, etc
...
Hydrogen and
nitrogen
...
The melting of scrap usually complete within
the first 2/3 of the purge duration
...
The presence in the exhaust gases of a large
amount of iron oxides due to the intensive
vaporization of iron and its oxides (smoke
emission)
...

To clean the converter gas dust from 50-200 g /
m 3 each converter is equipped with a complex
system of flue gas cooling and cleaning filters "wet"
or "dry" type
...
At this
point, the metal must be heated to the required
temperature (1600-1650 ° C), and the sulfur and
phosphorus content thereof should not exceed the
admissible for this grade of steel limits
...
In the event of a given composition or
temperature of the metal is carried out corrective
operations smelting:
a) with excess carbon content is held short final
blow providing reception predetermined carbon
content
...

c) when there is insufficient metal temperature is
carried out at an elevated position of final blow
lance, or injected into the converter or
ferromanganese snlikomarganets followed final
blow;
g) carbon content in low produce carburizing the
metal additives of ground coke or graphite on the
metal stream during its release into the ladle
...

After all necessary operations to remedy the
melting converter is tilted, carrying steel
production in the bucket through the tap
hole
...
It depends on the capacity of the
converter, but should not be <5 min
...

Drain slag is carried into the slag through the
converter mouth cup, turning it in the opposite
direction from the tapping direction (Fig
...

Inspection and preparation for the next converter
smelting are reduced to the examination and
restoration of the lining, the elimination of faults
found
...
The
inevitable wear of the lining is reduced gunning
...

3
...

Blow smelting mode can be considered optimal if
provided by the following basic requirements: 1)

high rate of removal of metal impurities (oxidation
of carbon) with the most complete and
approximately constant oxygen uptake; 2) rapid
slagging; 3) no metal and slag emissions; 4)
minimum formation of outstations and smoke; 5)
the minimum concentration of gases in the final
metal
...

Specific consumption of oxygen ranges from 47 to 57
m 3 / t steel, increasing with increasing content of
oxidizable impurities in the iron and decreasing
with increasing proportion of steel scrap in the
charge, as the scrap contains less oxidizable
elements than iron
...
The output de Laval nozzle
lance oxygen gas pressure is converted to kinetic
energy
...
The
oxygen pressure before tuyere thus should be 1
...
6 MPa
...
With excessively high oxygen jet lance's
location will not penetrate into the metal ( "surface
blowout") is low and the degree of oxygen
uptake; at excessively low position ( "hard
blowing") is enhanced removal of metal flue gas
drops and abrasion lance drops metal significantly
slows slagging and others
...
8 to 3
...
In this
range, the height generally increases with
increasing capacity of the converter and also
depends on the specific operating conditions of the
converter
...

Intensity purge (in contrast to the oxygen
consumption per unit time, which increases with an
increase of the converter vessel and converters for
heavy reaches 2000 m 3 / min), independent from
the container; it is mainly determined by the design
of the oxygen lance (number of nozzles therein) at
different factories intensity value J is within the
range 3-5,0 and sometimes reaches up to 7 m 3 /
min-m when applying 7-nozzle lances
...
Communication between the

quantities t and J can be expressed approximately
by the following equation: t = Q / J, where Q specific oxygen flow rate of both above mentioned
47-57 m 3 / t
...
For example, when using oxygen
having a purity of 98,3-98,7% steel contains 0,0040,008% N, and at an oxygen purity 99,5-0,0020,004% N
...
5%
...
6 Behavior iron components while flushing

Oxidation reaction
...

To purge the converter characteristic direct
oxidation of iron in the contact zone of the oxygen
jet with metal (a "primary reaction zone") and
oxidation of other metal components due to
secondary reactions at the interface with the
primary reaction zone in the remaining volume of
the bath
...
g
...

If the sum equation reactions right or left columns
in both cases we obtain a final carbon oxidation
reaction: [C] + 1 / 2O 2 = CO, which thus reflects only
the initial and final states of oxidation
...
Faster their oxidation
as compared with carbon due to the difference in
chemical affinity of various elements to the oxygen
at different temperatures
...

AND of Figure 6 shows that at temperatures below
1450-1500 ° C silicon and manganese have a higher
affinity for oxygen than carbon; at higher
temperatures the high carbon affinity for oxygen
than the affinity of manganese and
silicon
...


Oxidation of Silicon ends in the first 3-5 min Purge
subsequently during melting liquid metal silicon
does not
...

AND
Figure 6 - Dependence of ΔG some of the reactions
on the temperature
Intensity manganese oxidation is observed in the
beginning of blowing, at low temperatures when its
chemical affinity for oxygen is large; 3-5 minutes to
purge oxidized about 70% manganese that records
the in cast iron
...

In accordance with this reaction are noted (see
Figure 5)
...
The final manganese
content of the metal depends primarily on its iron
content and increases with increasing temperature
of the metal at the end of the purge and lowering of

oxidation of the slag
...

carbon oxidation occurs in a basic oxygen furnace
predominantly to CO
...
Figure 5) when intensively oxidized silicon and
manganese, and the bath temperature is low, the
oxidation rate of carbon is comparatively low (0
...
15% / min)
...
Figure 6) and reducing the
oxygen consumption by the oxidation of manganese
and silicon, carbon oxidation rate increases,
reaching a maximum blowdown mid (0
...
45% /
min)
...

Dephosphorization - i
...
removal of metal in the
phosphorus slag, is carried out by the exothermic
reaction
2 [P] + 5 (FeO) + 3 (CaO) = (ZSaO
...

Dephosphorization begins immediately after the
start of blowing (see
...
Since

phosphorus removal reaction is accompanied by
evolution of heat, dephosphorization most
intensively flows into the first half of purge at a
relatively low temperature
...
Typically, when the phosphorus content of
less than 0
...
20% iron metal at the end of
purging comprises 0
...
004% phosphorus
...
However, a part of sulfur
(less than 10%) is removed in the form of SO 2 as a
result of its oxidation by oxygen blowing
...
BOF slag also contains a significant
amount of FeO (7-20% or more), so desulfurization
gets limited development
...


3
...

To slag requirements
...
To this end,
the slag basicity should be sufficiently high (2
...
7) and viscosity is low, as in dense slag retard
diffusion of components involved in the
dephosphorization and desulfurization reactions
...
Due to the short
duration of the purge it is extremely important to
ensure the early formation of a slag as possible
...

Formation of basic slag reduces the dissolution
loaded into the converter lump lime into the liquid
slag phase-oxidation products constituting iron
(SiO 2 , MnO, FeO)
...

To accelerate the slagging to the converter at the
beginning of blowing is usually sits fluorspar
(CaF 2 ), and enrich slag iron oxides by blowing
tuyere at an elevated position, and sometimes at the
expense of additives iron ore, sinter, pellets,
bauxite
...
After the start of blowing in the converter
slag is introduced a first portion - about 1 / 2-2 / 3
of the total
...
Slag
remaining amount is administered one or more
portions during 1/3 purge duration
...

Total lime consumption of 5-8% by weight of the
melt; it is determined by calculation so as to provide
the required slag basicity
...
15-0
...

Furthermore fluor slag breaker primary slag, to
accelerate the formation of slag blowing was started
at an elevated position to saturate the slag tuyere of
iron oxides
...
Markedly reduced FeO content in the most
intense period of oxidation of carbon (blowdown
mid) when receiving strong development of carbon
oxidation reaction due to the iron oxide slag
...

3
...
During additives
solid oxidizers iron is reduced primarily carbonmetal reaction Fe 2 O 3 + 3 [C] {CO 3 =} + 2
[Fe]
...
1%), iron is
oxidized
...
7-1
...
If the
purpose of melting the greatest possible processing
scrap carried out without solid oxidizers, then the
loss of iron as a result of oxidation increased to 1
...
0%
...
The
average yield in the gas is oxygen converters - 70
m 3 / t, and the average content of dust (mainly iron
oxides) 100-150 g / m 3 , therefore, iron loss due to
evaporation averages from 1-1
...

Part of the iron is lost with the wren iron slag
...
The
lower limit applies to cases of melting mild steel
(<0
...
5% [C] nizkookislenny slag)
...
5%
...
In this connection it should provide early slag
formation
...

In general, the total loss of iron during melting steel
in converters with an upper feed blast usually 3-4% ,
but can reach> 5% when blowing and slagging does
not occur optimally
...
The yield of liquid steel ( the yield ) as
BOF process with all the losses of 88-90% by weight
of the metal charge
...
9 Material and heat balance BOF melt

Material balance
...
Given that the molten
iron is supplied with an amount of a domain (the
mixing) slag, scrap and waste usually contains
inevitable in the casting of some loss of metal, for
the case in an actual minimum flow rate of iron is
about 830 kg / m and the flow rate of metal stock
(scrap and pig iron) 1140- 1150 kg / t cast
steel
...
Thus, BOF process differs from the hearth,
not only a high consumption of iron, but also of
metal stock as a whole, ie
...
Greater capacity main
types of material resources
...
Steel discharged from a converter
to be heated to a temperature of 1600-1650 ° C,
while submerged in BOF iron typically has a
temperature of 1250-1400 ° C
...


Calculations heat balance and practice demonstrate
that the total amount of heat released by the
oxidation of iron impurities in any composition,
significantly higher than the heat requirement for
heating the steel and slag to tapping temperature
and to compensate for heat losses
...
Their number depends on the
temperature of pig iron, their content of silicon and
other impurities, as well as the rate of operation of
the converter, since the elongation of the pauses
between purges increasing the heat loss due to
cooling of the converter
...

Typically, as the coolant used steel scrap
...
Increased scrap rate reduces the cost of
steel, but also causes increase in the yield of usable,
since scrap contains less than cast iron impurities
are oxidized while blowing
...

A disadvantage of the scrap is that its filling is
produced in the early melting, whereas the heat
release occurs throughout the purging
...
The drawback is considered also
that its cooling effect does not affect directly the
zone of maximum temperature in the converter podfurmennoy reaction zone as scrap located under
a layer of liquid iron
...

Iron ore as a coolant is relatively rare
...
The cooling effect in the
ore 3
...
8 times the cooling effect of equal amounts
of scrap; ore consumption comes up to 8%
...
; oxygen presence
in the ore reducing (by 10-15%) the rate of oxygen
gas
...
It brings a lot of slag SiO 2 , and
therefore the lime consumption increases and the
amount of slag that normally causes a reduction in
yield of usable
...

Use as coolers sinter, pellets and briquettes gives
the same cooling effect as iron ore
...

When used as refrigerants limestone and dolomite
heat consumed for decomposition content of
CaCO 3 and MgCO 3
...
Rare
use of these coolers is due to the fact that they do
not increase the metal yield
...
10 recycling scrap in converters

The main disadvantage of converter processes is
low consumption of scrap in the charge, usually not
more than 25-28% with an average proportion of
scrap in steelmaking charge of about ~ 45-50%
...
; 2)
techniques for supplying additional heat, primarily

heating the scrap in the converter or cavities in
special devices
...
For carrying
out post combustion in the upper portion of the
cavity of the converter is fed oxygen above the bath
(through tuyere bunk) allowing the reaction: CO + 1
/ 2O 2 = CO 2 ; + 282 980 J / mol, the heat from which
is transferred to the bath, which allows to increase
the coolant flow rate - steel scrap
...

Heating the scrap in the converter by combustion of
solid fuel (coke anthracite)
...

At a flow rate of coal of about 1% by weight iron
decreases the charge rate at 2
...
5% (by weight of
the blend), but at the same time increasing the
duration of melting, which reduces the performance
of the converter by about 6%
...

Injection of pulverized coal
...
Heat released during the oxidation of

injected carbon can increase the scrap rate
...
Lack - complication of
structure
Heating the scrap in the converter by combustion of
gaseous or liquid fuel
...
When this is achieved increase the
amount of steel scrap in the charge on the 4-9% (by
weight of the blend); the duration of heating at
different factories is 8-18 min, 5-13 consumption of
natural gas and oxygen for heating 15-20 m 3 / t
steel
...
These materials are loaded
with scrap are oxidized with considerable thermal
effect during purging
...

Preheating of the scrap is simple converter devices
(shovels and buckets) is ineffective, in that they
manage to heat the scrap to only 500-600 ° C, and
construction of special devices, improved in respect

teplotehnicheskom that increases capital and
operating costs
...
11 converter process with bottom blowing oxygen

The first attempts to replace the air blast in the
Bessemer and Thomas processes have not yielded
positive results due to lack of flushing technology,
which provides high durability underbody
converters
...

Incomplete and inconstant from heat to heat
absorption of the blowing emogo oxygen bath
...

To eliminate these drawbacks have been developed
possibility of using a bottom oxygen injection
...
e
...


Subsequently carried out in a number of countries
in the study have led to the development of suitable
industrial use oxygen injection method below in the
form of jets, surrounded by a ring of the
containment of hydrocarbons
...

Cooling zone okolofurmennoy is because at the
outlet of the lance takes place a number of
endothermic processes: decomposition of
hydrocarbons (CH 4 = C + 2H 2 -Q); carbon dissolved
in the metal heat absorption (C = [C] -Q); incomplete
combustion of hydrocarbons (CH 4 + 1 / 2O 2 = CO + 2
{H 2 } - Q
...

Under these conditions, the bottom of the reaction
zone does not develop very high temperature and
iron oxides are formed, so there is no intensive
wear and bottom tuyeres at a flow rate of fuel
already ~ 5% of oxygen flow (maximum flow rate of
~ 10%)
...
Natural gas
consumption is 6-8, propane about 3
...

converter device

Converters of bottom blowing oxygen are
detachable bottom, but otherwise similar to
converters applied at the top blowing oxygen
...
Each lance comprises
two concentric tubes; at an average tube of stainless
steel or copper with an inner diameter of 24-50 mm
is fed oxygen, stainless steel outer tube forms an
annular gap of 0
...
It is fed
through the nip the protective environment gaseous or liquid hydrocarbons
...
Slag
temperature reduction caused by transferring the
high temperature reaction zone of the upper layers
of the bath in the amount of metal
...

Reduction of iron oxides due to the intensification
of mixing of metal and slag and a reducing nature of
the gas phase (the content of CO 2 in the gaseous

phase at the upper blast - 10%, and not more than
3-4% at the bottom)
...

Therefore, normal carbon steel smelting converters
with bottom feed oxygen only possible using
powdered lime, also its bottom blowing in an
oxygen stream
...

behavior of impurities
During the purge time oxidize excess carbon,
silicon, manganese portion; formed slag, which
removes phosphorus and sulfur; melts steel
scrap; due to the heat of oxidation reaction heats
the metal
...
However,
for the process is characterized by several
differences related primarily to the fact that feeding
the blast through tuyeres below provides several
sharp intensification baths stirring
...
Therefore,
the FeO content in the slag move through the vent
does not exceed 5-6%
...

Oxidation of phosphorus
...

Removal of sulfur
...

A feature of the process is that the hydrogen formed
as a result of thermal decomposition of the injected
hydrocarbons dissolved in the metal and at the end
of blowing hydrogen content reaches 9
...
To remove excess hydrogen before
releasing for a short time (within 10-60 c) purging
with argon metal; wherein the hydrogen content is
reduced to 2
...
metalla
...
4 m 3 / t, propane 1
...
The nitrogen flow rate of the metal and purge
flow in through tuyeres mezhplavochnye periods
for the purpose of cooling is about 15-20 m 3 / t
...
This is due mainly to the fact that
there is incomplete combustion of fuel, the heat
released does not usually compensate for heat
losses to the decomposition of hydrocarbons; In
addition, reduced iron oxidation
...

3
...
5-2-fold decrease of iron loss due to the smaller
slag contains Zhaniya iron oxides in the slag;
increased yield Yid Coy steel 1
...
1-3;

increases and stabilizes the degree of assimilation
kitty loroda bathroom, which facilitates control of
the process;
it becomes possible to enhance the intensity of
blowing therefore converter performance by 510%;
decrease oxygen consumption, better explained by
(5-10%) to its use in connection with the fact that
less oxidized iron and minimal amounts of carbon is
oxidized to CO 2 ( in the
exhaust gas contains <5% CO 2 , then as At purge fro
m the top to 10 - 15%);
reducing the amount of oxidized while blowing
manganese, which leads to savings ferromanganese;
higher degree of dephosphorization and
desulfurization;
uptake decreases due to nitrogen blowing lowering
the temperatures the oxygen contact zone and
metal;
favorable conditions for the organization of
injection into the bath of different inert gases
(argon, nitrogen) and the powder materials (of lead,
graphite, coal, etc
...


However, for a process with bottom blowing with
oxygen characterized by the
following disadvantages :
It requires the use of a powdered lime, which
requires special equipment for its grinding and
injection;
essential metal inert gas purge to remove hydrogen
and also feed through tuyeres an inert gas or air in
mezhplavochnye periods for cooling the tuyere;
complicated construction and operation of bottoms
with an oxygen supply system, the protective
environment of inert gas and pulverized lime;
arise converter downtime when replaced bottoms,
which lasts for 8-20 hours;
2-5% decreases the amount of recycled scrap, which
is associated with the expenditure of heat to the
decomposition of hydrocarbons and the
ability sheniem arrival of heat from the iron
oxidation (dross), and by reducing the fraction of
carbon is oxidized to CO 2 ;
requires special devices to trap smoke and you
are wearable from the converter metal drops when
it is tilted
...
05% C) from any iron
...

3
...

The converter combined with a process (top and
bottom) supply of oxygen has the greatest
technological capabilities, but the design of the unit
and its system software is the most difficult
...

Receives a number of varieties spread combined
purge, which in addition to supplying oxygen
through the top lance may include:

blowing inert gas through the porous refractory
elements in the bottom
injecting oxygen through the bottom tuyeres, and
the mixture of inert gas in the annular shell from
hydrocarbon or inert gases;
blowing air through the bottom tuyeres into an
annular sheath of inert gas;
feeding part of oxygen through the bottom tuyeres
into the annular about span of from hydrocarbon
gases or Neutral
methods listed above with an additional injection of
lime through the bottom
...
This technology is much easier
than with the combined supply of oxygen, but
preserves the main advantage of the bottom
purging - good mixing tubs and related
technological advantages
...
Their
diameter depends upon the number of the received
purge intensity
...
01-0
...
3 m 3 / min-m)
...
As the
neutral gas used is usually nitrogen, as an inert gas

(argon) roads
...
When the minimum intensity purging
nitrogen absorption is insignificant and its contents
can be achieved in the finished steel is not more
than 0
...
004%
...
In
mezhproduvochnye periods bottom tuyeres are
usually transferred to an air blast, since it is
cheaper nitrogen
...
Directional
channels in the refractory blocks have a small
diameter (<2 mm), the metal and slag therein not
numb, so neutral purge gas can be carried out not
during the entire heat, and when it is
needed
...
When the intensity of the specific purge to
0
...
3 m 3 / min-m) provided by reduction of
oxidation of the slag and metal, as necessary
decarburizing depth as well as further
dephosphorization and desulfurization metal
...
However,
such furnaces, even with a high calorific value fuel
combustion when applying cold air could not
maintain the temperature in the melting space over
1420-1460 ° C
...
5% C, may be in a liquid state, but the
casting it into ingots must have a higher
temperature (at 60-80 ° C)
...
In this regard, until the
middle of the 19th century the primary method of
producing high-carbon steel in very small quantities
was crucible process
...
Martin, use waste heat
from the melter combustion space for heating the
fuel gas and air consumed for its combustion (heat
recovery principle)
...

In the late fifties in the USSR and some other
countries it came and was implemented a new
method of using waste heat from the melting space
of the combustion products to heat the scrap
...


4
...
The metal may be heated to this temperature, if
the flame combustion products have an even higher
(at 100-150 ° C) temperature
...
The theoretical combustion
temperature of any fuel determined by the equation
t t = (Qt + Qgf) / Cps Vps,
wherein Qt - heat of combustion;
Qgf - physical heat of heated air and combustible
gas;
Vps - volume of the combustion products;
Cps - their average specific heat
...
This idea is widely used now on most
domestic factories
...
The role of the
heating air in the heat of the furnace is decreased,
although air regenerators remain
...
2 Apparatus OHF

Hearth furnace includes upper and lower structures
(Figure 7)
...
The ends
of the melting space are arranged head serving for
fuel and air supply and discharge of the combustion
space of the melting products
...
The
lower structure of the furnace is disposed below the
working platform management and consists of slag
chambers intended for separating particles from
the flue gases of entrained slag from the melting
space and dust regenerative chambers and boars
with changeover valves
...


P rohodya through preheated nozzle regenerator
air is heated to 1000-1200 ° C and in a heated state
through the "head" enters the furnace
...

P
1 - workspace; 2 - a head; 3 - vertical channels;
4 - slag chambers; 5 - nozzle regenerators; 6 - hog;
7 - reversing and regulating valve; 8 - waste heat
boiler;
9 - gas cleaning; 10 - smokestack
Figure 7 - Scheme OHF
After a certain period of time (5-20 min) after
heating nozzle regenerator and the corresponding
cooling nozzle opposite change in the regenerator is
made of air flow direction is reversed by means of
change-over valves
...


flue gases from the furnace working space with exit
temperature of 1680-1750 ° C, from the regenerator
slag chambers - with the temperature 1500-1550 °
C
...
Usually they tend to use
waste heat, directing them hogs system in the
recovery boiler
...

4
...

Tools hearth furnace space bounded above the arch,
bottom - hearth (or "bottoms")
...
The front wall of the
furnace there are openings - the charging window,
through which a working space is charged with
solid charge and poured (by ladders chute) liquid
iron
...
During filling refractory solid charge
materials from which the workspace is made,
undergo a sharp thermal and mechanical shock,
while they are subjected to smelting chemical attack
of molten metal and slag; in the workspace
maximum temperature
...

By chemical properties applied refractories are
divided into: a) acidic - Silica bricks, quartz sand; b)
basic - magnesite brick, magnesite powder,
dolomite; c) neutral (with properties amphoteric
oxides) - chamotte, hromomagnezit,
magnezitohromit, high alumina grog, forsterite
...
Otherwise, as a result of an energetic interaction
slag refractory furnace hearth Oshlakov, i
...
it goes
into the slag and furnace fails
...
Rear
and acidic hearth furnace front wall spread of silica
brick, the main hearth furnace - of magnesite
...
Filling also subjected hearth
end parts adjacent to the heads of the furnace; they
are called slopes
...
The arches are made of open-hearth
furnaces or heat resistance of silica-magnesia
chromite bricks
...
During operation, a set of Dinas bricks
welded into a monolith that can run as a selfsupporting (as akrki) and ensures reliability even in
case of any piece of the arch will fall
...


Magnesite brick is characterized by higher fire
resistance (allowable heating temperature of 1800 °
C), which increases the furnace
productivity
...
Features of the operation code of magnesiachromite bricks: a) bricks poorly welded together
and form a monolith; b) expansion coefficient
magnesia-chromite bricks higher than that of silica,
whereby on heating the outer roof arch joints
disclosed, but on the inner side having high
compressive stress, which leads to cleavage of the
inner cover; c) an increased thermal conductivity
and large leaks masonry (disclosed joints) cause
higher (almost twice) heat loss from 1 m 2vault
area; g) the bulk density magnesite brick is 1
...
All this eliminates the
possibility of the use of conventional curved
arch
...

However, the ability to increase the temperature in
the furnace roof by using magnesite as well as
increase lifetime arch makes the device complicated
suspension systems cost, however vaults this type
are widely used
...

the furnace head

Bits are used for fuel and air supply and discharge
of the combustion space of the melting
products
...

Heads must ensure that: 1) a good flatness of the
torch across the length of the bath (to a maximum
heat transfer and minimal bath - vault and walls); 2)
minimal resistance during retraction of the
combustion products from the workspace; 3) good
mixing of fuel and air for complete combustion of
the fuel in the furnace
...
Therefore, depending on
operating conditions, intermediate option selected
...


1 - vertical channels; 2 - slag chambers; 3 - nozzle
regenerators 4 - outboard set nadnasadochnogo
space; 5 - podnasadochnye space
Figure 9 - A device slag chambers and regenerators
OHF
Slag chambers serve to trap dust and smelting slag
particles entrained combustion products from the
working area, and thereby prevent the nozzle from
clogging the regenerator
...
This leads to the fact that a significant
proportion (50-75%), melting dust settles in the
slag chambers, wherein the coarse dust settles,
smaller fractions largely carried into the pipe (1025% of the dust settles in nozzles regenerators)
...
This fact has to be taken into account
when selecting materials for laying of vertical
channels and slag chambers
...
If the vertical channels and slag
chambers are lined with silica brick, the basic
oxides, of which the dust energetically interact with
the acidic material to form the liner fusible iron

silicates
...

In this regard, for the laying of vertical channels and
slag chambers are frequently used heat-resistant
magnesite brick
...

Regenerators should provide a more or less
constant high temperature heating gas and
air
...
Therefore,
the upper rows of nozzles spread of heat-resistant
magnesite brick
...

From podnasadochnogo space offgases at a
temperature of 500-700 ° C fall in hog which are
intended to supply gas to the regenerator, and
discharging the air from which the products of
combustion to the pipe or to the recovery
boiler
...

4
...
This predetermined the
main feature - the lack of their own process heat for
melting
...

Combustion of fuel should take place within the
workspace, or it ends up in vertical channels and
regenerators, which greatly reduces the resistance
of these elements of the furnace and increases fuel
consumption
...
151
...
Any fuel combustion products will consist of
oxidizing gases CO 2 , H 2 O, O 2 and a certain amount
of neutral nitrogen N 2
...
This is one of the characteristics of the
open-hearth process
...
The thickness of the slag in the hearth
furnace ranges from 50 to 500 mm, the depth of the
metal bath - from 500 to 1500 mm (depending on
the capacity and design of the furnace)
...
However, some
temperature difference of depth of the bath still
persists, especially between slag and metal
...
Along the length of the
metal furnace temperature also varies
...

The fourth feature of the open-hearth melting
technology - hearth participate in the proceeding
processes
...
Therefore, the effect of
interaction with metal hearth is very noticeable
...
Virtually all additive introduced into the
furnace at the slag fall or pass into the metal

through the slag
...
If we consider that the heat from the flame
to the metal is also passed through the slag, it
becomes clear huge role of slag in the open-hearth
process
...

Direct oxidation of the metal (iron and impurities)
oxygen in the gas phase is observed only in the
open-hearth process during filling, heating and
melting of the charge, and may also occur in the
period of intensive boiling where the metal droplets
are ejected into the gas phase
...
He
becomes a rallying point in the system, the gas
phase metal
...
For the
smelting bath absorbs 1 to 3% oxygen by weight of
metal
...
This difference
primarily depends on the proportion of iron in the
batch, and determines the basic variations (variants)
hearth process: ore, ore process scrap, scrap and
process scrap coal open-hearth process
...
If the oxygen
supply still needs, in this case the process is called
scrap process
...
This process is called scrapore
...

Scrap-ore process is one of the most common
variants of the open-hearth process
...
The
proportion of iron in the charge varies mainly in the
range 50-70%
...
Loading
iron ore before pouring (normally under scrap
layer) and during melting (during polishing)
...
If the
high flow rate of pig iron in the hearth furnace
process intensification solid lead without oxidizing
agents, the melting duration is increased due to
insufficient oxygen supply rate of the gas phase of
the furnace
...
In this case, the main

component of the metal charge is scrap metal
...
Iron ore, and if allowed, then in minor
amounts (typically 1-2%) only during melting
(during polishing), but not during the filling
...

Carburetor (scrap-carbon) of the process is furnace
operation at low flow (10-15%) or only on iron
scrap
...
N
...
5 Basic periods open hearth melting and their meaning

smelting process of steel in an open-hearth furnace
at any of its varieties includes the following main
periods: filling furnace; filling and warming solid
charge materials; pouring molten iron (pig iron
filling of the solid) and the melting; finishing
smelting; deoxidizing and alloying metal; metal and
slag release
...
Best welding filling
material is observed at a high temperature of the
working space, so the back wall above the filling
level of the fusion products produced during the

finishing of the previous heat; filling slopes at slag
level and below is carried out during tapping
...
Procedure for filling and
arrangement of the charge in the furnace affect the
melting rate of the charge, furnace slagging and
durability
...
On hearth evenly charged
portion of iron ore (sinter, pellets), then a layer of
limestone (lime) and the remaining ore
...
During and after filling ore and limestone is
heated, at least for the complete removal of
moisture
...

After filling and warm iron ore and limestone are
charged scrap, having a fine scrap at the bottom of a
big top
...

In operation, the scrap-hearth process for the
lightweight charged scrap, which is charged on top
of limestone (8
...
Then fill up the rest of the
scrap
...
When scrap coal
during filling of the same order as in the process of
scrap, but a scrap layer carburetor layer
...
To ensure successful melting and
reduction of its duration is required heating the raw
materials, particularly when the scrap-ore
process
...
To
reduce the warm-up period bulk layers charged and
stirred for opening unheated mass
...
The heating temperature of
the scrap, at least the upper layers thereof, should
not be below the solidification of cast iron
temperature (1250-1350 ° C)
In the case of iron casting in the preheated charge is
not enough there is its "zakozlenie"
...
Furthermore, during the inactive state of
the bath in the slag accumulates large amounts of
iron oxide to iron by heating zhidkopodvizhnogo
condition which may result in emissions of dross
and even metal from the furnace due to the
intensive oxidation of carbon with oxygen
FeO
...
After heating the raw
materials in the furnace hot metal is poured
...
The duration
is determined by pouring cast iron organizational
capabilities and usually 15-30 min
...

Melting as an independent melting period begins
after pouring molten iron
...

Establishment of optimum slag during melting
mode and oxygen balance allows a major portion of
the metal refining in this period, for example, in
many cases provide the desired degree of
dephosphorization it
...
Duration
melting except to the capacity and thermal capacity
of the furnace depends on the melting of slag regime
period, number of pig iron in the charge, the
temperature of the liquid iron and the degree of
heating of solid charge materials, especially scrap
...
This period should be removed as
possible to reduce the amount of slag slag layer
thickness in the furnace and to improve heat
transfer from the flame to the bath
...
Reducing limestone consumption due to the
fact that the slag basicity, lowered into the melting
period, small (0
...
0)
...
The slag flowing from the furnace
during melting after pouring liquid cast iron,
referred to as "cascading" primary slag
...
Glandular slag and dephosphorization
favor reduced temperature
...
The
average composition of the slag following primary
escapes,%: SiO 2 20-35; A1 2 O 3 3-5; FeO 2535; Fe 2 O 3 3-5; CaO 12-20; MgO 5-9; MnO 1535; P 2 O 5 2-4
...
Therefore, in those cases where a batch little
sulfur and phosphorus slag escaping trying to delay

in the furnace and thereby reduce the metal
loss
...
Slag Descent continues almost until
complete melting of the charge
...
When the
solid iron melting period longer (3-4 hours) since
the heating iron needs additional heat consumption
...

Lapping smelting hearth for different variants of the
process is carried out for approximately one
circuit
...
Lapping generally consists of two steps:
polishing (boiling ore) and pure (free) boiling
...
For this, first download
of furnace slag, and then sits down slag forming
materials: lime, bauxite, fluorspar, etc
...
After melting
bath in the furnace serves a number of iron ore or
bath purged with oxygen or compressed air
...
At this time, cut off the fuel
supply, the pressure falls in the furnace and the slag
to foam and leaves the furnace slag specially
prepared bowl
...
At the moment when the cup filled with
slag slag, fuel is fed again to the furnace, the furnace
pressure increases, the slag settles and becomes
away from the furnace
...
Disable the supply of
fuel when it is not necessary
...
Together with downloadable slag out of the
furnace leaving a significant portion of the
remaining phosphorus in the bath and some sulfur
...
Slag basicity CaO /
SiO 2 thus increases to 2
...
If such a slag is
excessively thick and viscous, it liquefied additives
bauxite or fluorspar
...
This mixing caused favors heat transfer
from the flame to the bath, and the temperature of
the metal gradually increases
...
Oxygen solid oxidant oxidizes carbon
intensively, which ensures good mixing of the bath
and slag formation accelerates
...
For the normal needs of
polishing metal superheat above the melting
temperature at 40-60 ° C
...
5%
...
It should be borne in mind that 1%
solid oxidizer cools bath at 20-25 ° C, lime - at 10-15
° C, bauxite - at 15-20 ° C (in the converting process,
i
...
, without absorption of heat from the flame ,
higher cooling effect, respectively, 35-40, 15-20, 2025 ° C)
...

Furthermore, for the normal period of polishing
requires a certain stock of carbon, which is typically
0
...
5% and depends on the period duration (how

many and how many techniques sit down
materials), the capacity of the furnace (the smaller
the capacity, the greater the required C stock)
...
During this period the
carbon oxidizes essentially only hot oxygen furnace
gas phase with continuous admission of heat in the
flare bath
...
During this period it is not
suitable for a seat in the slag fluxes and solid
oxidants, except smelt low carbon steel when the
carbon to intensify the oxidation reaction is allowed
additive ore in small portions
...
The slag in this period should be normal
zhidkopodvizhnost
...
10-0
...
The manganese content in boiling
pure period when [C]> 0
...


Basic slag during this period should be sufficient to
prevent the phosphorus recovery and a sulfur
removal
...
5
...

The rate of removal of sulfur from the metal, the
greater the rate of oxidation over carbon because,
firstly, the sulfur is partially removed along with the
CO in the furnace gases from metal and
slag; Secondly, the higher the rate of oxidation of the
carbon, the better use of the desulfurizing capacity
of the slag
...

During boiling pure normal state thanks to the bath
(presence of a homogeneous and uniform slag boil)
Incoming rate of hydrogen from the gas phase is
reduced, and its rate of removal of CO increases in
the bubbles
...
According to numerous studies,
the hydrogen content in the metal at the beginning
of boiling pure typically 4-6 cm 3 /100 g, in pure
boiling is reduced by 1-2 cm 3 /100 g
The duration of the boiling to clean metal degassing,
including its removal peroxidation is 20-30 min
...

Task master steelmaker is to the moment when the
metal temperature would be sufficient to release,
good bath prokipela would purified from gas and
nonmetallic inclusions contained in the metal to the
required minimum amount of carbon and sulfur,
and phosphorus
...
If scavengers
introduced into the ladle, the fluidized metal tapped
from the furnace without deoxidation
...
The furnace usually sits refractory and
sparingly soluble ferrous alloys, e
...
,
ferrochrome
...

Release melting is always responsible operation
...
The duration of the
tapping hearth furnaces usually ranges 10-20 min
and depends mainly on the furnace capacity (less
than the capacity of the furnace, the smaller the
release duration)
...

The total duration of the melting in open-hearth
furnaces varies from 5-6 to 10-15 hours and
depends on many factors furnace capacity, type of
iron used (liquid or solid), its proportion in the
charge, the heating system, the degree of
intensification of combustion and oxidation of
impurities , the degree of mechanization and
furnace servicing t
...
The increase in the furnace
capacity, at constant other conditions, leads to an
increase in the smelting duration
...
With increasing iron concentration in the
mixture also reduced the duration of loading and
melting periods
...


When designing hearth furnaces tend to maximize
the heat reception surface (hearth area), and hence
reduce the thickness of the metal layer (the depth of
the bath, which for large furnaces is less than 1
...
0 m)
...
Under these conditions the bath with
oxygen scavenging possible with intensity limited to
a maximum of 10-20 m 3 / (mv), whereas it reaches
converters 5-6 m 3 / (T min) or more
...
Low productivity is a major disadvantage of
open-hearth furnaces
...
Their main advantage - the ability to conduct
the process at any consumption of pig iron in the
charge
...

4
...
The heat of the torch and heated masonry
furnace charge
...

In accordance with the formula Stephan Boltzmann law, the amount of heat Q, the charge
transferred to the cold radiation is:

Q = δε p [(T hot / 100) 4 - (T cold / 100) 4 ],
where δ - coefficient taking into account the optical
properties of masonry and form a working space;
ε n - the emissivity of the flame;
T hot and T cold - flame temperature (hot) blend and a
(cold), K
...
Improve flame
temperatures reach improved degree of heating the
air and gas regenerators and oxygen enriched
air; increasing the degree of blackness torch - flame
carburation
...
To increase the degree of blackness of
the flame, it is necessary to provide a solids content
of "black" particles (primarily carbon)
...
Practically degree flame emissivity ε f must
not be lower than 0
...


At the same characteristic torch difference [(T hot /
100) 4 - (T cold / 100) 4 ], the higher the charge
cooler
...
The emissivity cold solid charge is close to
unity (0,92-0,95)
...

As the heating temperature of its charge T cold is
increased, charge is heated, is covered with the slag
itself starts to reflect heat rays, whereby the charge
absorption heat conditions deteriorate
...

Thus, the fuel supply is changed during
smelting
...
Supplied at this
time is called the maximum heat load
...
The thermal work-hearth furnace
characterized by an average heat load or the heat
capacity of the furnace, which is a quotient obtained
by dividing the total consumption of heat at the time
of melting:
Heat consumption kJ / Prod
...
2 to 125-m to 69
...
The
maximum heat load of 20 - 40% above the average
...
):

wherein Q T - heat of combustion; Q SS - warm flue
gases
...
50 - 0
...

Specific heat consumption (heat consumption of
fuel per 1 ton of steel) dependent on many factors,
primarily on the furnace vessel
...

Fuel OHFs
In Russia most prevalent as a fuel for open-hearth
furnaces, natural gas and fuel oil
...
Usually fuel oil contains 83-85% C and

10-11% H 2 , balance - moisture, ash and sulfur
...
50
...
Sulphurous fuel oil (3% S or more) in the
production hearth is rarely used, since sulfur from
the fuel and passes into the metal impairs its
quality
...
Spraying fuel oil is carried out with
compressed air supplied under overpressure of 0
...
7 MPa or superheated to 300-350 ° C by steam
under excess pressure 1
...
2 MPa
...
Torch
malosvetyaschiysya natural gas and for
simultaneously increasing its luminosity with the
gas in the furnace is introduced a certain amount
(30-40%) oil
...
The methane decomposes when heated (
"reformed") with the release of large amounts of
soot particles (CH 4 = C + 2H 2 ), which provides
luminous flame
Natural gas is a "convenient" fuel: it does not
contain toxic substances and harmful impurities,
cheap, easily transportable number hearth furnaces

equipped with a gas-oxygen burners, through which
gas is introduced into the furnace through the roof,
and a high-temperature flame of natural gas
burning in oxygen, sent directly to the
charge
...

The calorimeter temperature cold combustion of
fuel oil and natural gas in the heated air is 26002650 ° C, and the actual × 0,7 = 1820-1850 ° C
...
7 slagging and slag mode open-hearth

For the open-hearth process mode slag it is
extremely important, since the metal hearth
furnace heating occurs through the slag layer, ie the
slag in an open-hearth melting involved not only in
metal refining, but in its heating
...
); products of
corrosion lining unit (MgO and CaO in the main
furnace and SiO 2 in acid); contamination introduced
by the charge (sand, clay, etc
...
2 ,
A1 2 O 3 ; The mixing slag; rust covering scrap, ie
Fe
...
) - CaO, Fe 2 O 3 , MnO, SiO 2 , A1 2 O 3 and others
...
In the course of melting the slag
composition continuously changes due to the
oxidation of iron impurities from the lower layers of
surfacing baths previously trapped bulk material
and removal of the resulting foamy slag
...

4
...
As the furnace capacity and
improve their thermal performance, the oxygen
entering from the gas phase through the slag layer
into the metal become insufficient, so refining,
especially carbon oxidation lagged behind metal
heating
...
as an additional source of oxygen
began to use iron ore
...

The use of oxygen for intensive bath flushing OHF
oxygen was diffused in the 60s in the XX
...
So there's a new version of
the open-hearth process, which is called scrapoxygen process
...

Scrap-ore process without blowing oxygen bath
Embodiments open hearth melting differ primarily
way to achieve a given carbon content in the metal
bath to the melting point, which determines the
normal holding period finishing and release a
predetermined composition of metal
...
This is the
main feature of the scrap-ore process
...
The formula for
calculating the flow rate of ore obtained from
oxygen balance equation can be written as:

Each of these articles is dependent on many factors,
so the formula is obtained deployed complex and it
in a production environment, you can use only if the
calculations performed by a computer
...

The main factors that significantly affect the rate of
solid oxidants during filling, are as follows:
1
...
The higher the amount of
iron in the charge and oxidizable impurities in it,
the greater the consumption of oxygen on the
oxidation of metal impurities and slag formation on
iron oxides, less intake of oxygen from the bath
furnace gas phase and in the form of dross
scrap
...


2
...

With an increase in the specific load on the hearth
oxygen from the furnace atmosphere decreases
...
Consequently,
with an increase in the furnace capacity with
increasing specific load on the hearth ore flow
during filling increases
...
This causes an increase of oxygen from
the gas phase of the furnace, ie
...
Reduction of the
ore flow during filling
...

3
...
The better the thermal performance of
the furnace, especially when intensifying
combustion oxygen fuel, the higher the specific flow
of oxygen from the gas furnace phase and lower
than the melting duration, t
...
The one hand there
is an increase of oxygen (reducing ore flow during
filling), the other - reducing the duration of the
melting period causes the opposite effect (increase
ore flow)
...
E
...

4
...
The larger
it is, the less oxygen consumption by the oxidation
of carbon and ore flow during the filling
In addition to these major factors for consumption
solid oxidizers during filling affect slag in the
melting regime of descent period and quality of
scrap
...
The finer and oxidation of the scrap, the
greater the amount of oxygen supplied from the
scale and less ore flow during filling
...
This replacement in full its use can
improve the performance of open-hearth furnaces
in the 1
...
Advantages of the scrap-oxygen-hearth
process embodiment: firstly injecting oxygen gas
into the bath can increase several times the rate of
oxidative refining of metal; Secondly, replacement
of oxygen solid oxidizers to decomposition which
consumes a large amount of heat, oxygen gas
improves the thermal balance of the melting and
results in reduced fuel consumption
...
However, these losses
are typically less than a prize that can be achieved
with a decrease in the duration of melting
(increasing furnace capacity) and reducing fuel
consumption
...
This is because the flow rate of
oxygen injected into the bath defining a residual
carbon content of the metal, can easily be changed
(increase or decrease) during the process, e
...
, by
taking a metal sample and determining its carbon
content before the melt bath
...

Thus, scrap-oxygen process is not only the high
performance method hearth redistribution of
charges with a high content of iron, but the most
easily controllable process
...
E
...
The main parameters are the
purge period melting specific consumption of blast
(Wd, m 3 / m), the specific purge intensity [io 2 , m 3 /
(m-h)] and purging duration (τ f , h)
...
7-0
...

Specific consumption of oxygen injected into the
bath in the melting period mainly depends on the
fraction of iron in the batch, its chemical
composition and the carbon content in the metal
melt
...

Typically, when scrap oxygen during oxygen
consumption bath blowing in the melting period
ranges from 15-25 m 3 / t, in the period finishing 510 m 3 / t
...
It usually varies
between 5-20 m 3 / (t h) according to the specific
conditions of plant operation (furnace)
...
P
...

However, the full use of the opportunities of
intensification of the open-hearth process is
restricted by oxygen and
shihtopodache
...
This is
because the decarburization rate is increased to a
greater extent than the metal heating rate, so the
relative change in the bath temperature decreases,
t
...
On heating bath at the same size requires more
carbon
...

In this regard, scrap-oxygen process operates only a
part of the open-hearth furnace, typically having a
specific intensity purge 6-8, rarely 10 m 3 / (t h)
...

Synchronization processes decarburization and
heating of the metal in the scrap-oxygen hearth
process provided much more easily than in

converter processes because, firstly, it is easier to
control the current values of the carbon content and
temperature, and secondly, there is an adjustable
supply of heat from outside
...
9 Indicators and perspectives of open-hearth steel
production

Melting steel in open-hearth furnaces differs from
conventional converter necessity for supplying heat
from the outside and a high scrap rate of the charge,
which results in less overall power consumption
...

Material balance hearth process differs from the
converter, not only a smaller flow rate of pig iron,
but generally of metal stock
...
Total consumption of metal charge in
the open-hearth process typically 1125-1135 kg / t
steel, whereas in the converter process is 10-15 kg /
ton more
...
In open-hearth process of drawing
it is important primarily for determining the
shortage of heat required for the process and fuel
consumption
...
Typically, the fuel utilization factor
(KIT) is 22-27%, so the consumption of fuel varies
between 80-140 kg / t of ore and scrap 160-220 kg /
t scrap process
...
However, the total power
consumption of scrap process considering past
costs significantly less scrap than the ore
...
The larger the capacity of the furnace, the
lower specific fuel consumption
...

Open-hearth process has played a huge role in the
production of steel in the XIX-XX
centuries
...
Firstly,
low productivity, and secondly, greater difficulties
in synchronizing the smelting of steel in openhearth furnaces and casting steel caster, thirdly, the
high consumption of refractory materials and the
proportion of manual labor in the repair of
furnaces, fourthly, more difficult working
conditions
...
The significant volumes of open-hearth
production was preserved in China, Russia and
Ukraine, due to lack of funds for modernization of
steelmaking
...
10 The essence of the work of tandem furnaces

Practice intensive bath flushing OHF oxygen showed
that not achieved theoretically expected
improvement of heat balance and a decrease in fuel
consumption
...
In the normal
course of conventional open hearth process, fully
oxidize CO to CO 2 over the bath, heat the reaction
bath is used for heating, and better than the heat of
fuel
...

A negative consequence of incomplete oxidation of
CO to CO 2 in the working space is also inevitable
overheating of the lower structure of the furnace,
primarily regenerators nozzles and quick exit from
their system
...
By its dimensions the machine should be such
that it can be put instead of the open-hearth
furnaces
...
Figure 10)
...


1 - lances, 2 - arched gas-oxygen burners
Figure 10 - Scheme workspace double-bath furnace
apparatus
In each bath smelting is carried out with an offset of
about half the duration, t
...
End of melting in a
melting bath corresponds to the middle in the
other
...
At this time in the
second bath is carried oxygen scavenging
metal
...
Using the heat of the
reaction is effective because, firstly, there is a
complete oxidation of CO to CO 2 , and secondly, the
heat perceive cold solids
...
Thus, a double-bath smelting furnace may be
carried out using up to 35% of scrap, wherein the
fuel consuming only 10-15 kg / m, and mainly to
maintain the furnace in a working state during its
filling
...
The gases leaving the furnace from the
bath, where there is a first half of smelting, often
called cold period
...

Externally, the double-bath furnace is not very
different from the open hearth
...
During the first half of the melting occurs
intensive heating solid charge of heat supplied from
outside: heat oxidation of CO to CO 2
...

The second half of melting - oxidation refining is
carried out as in a basic oxygen furnace but with a
lower intensity purge
...
It is primarily limited
bandwidth furnace flue tract, as well as the duration
of the first half of melting (the synchronism of the
two baths)
...

4
...
However,
this process is different from the open-hearth and
converter that for the normal operation of the unit
requires constant synchronization works both
baths requires strict adherence to the schedule of
operations in each bath
...


Figure 11 - Graph of combining the smelting
operations in steel printing and double-bath
exemplary duration (% of total melting time)
In the double-bath furnaces (each cage bath 250300 m) the total duration of the cycle in a single
bath 3-4 h, t
...
Melt discharged from the furnace at
intervals of 1
...

Fueling of the furnace is conducted to restore worn
during welding melting bath sections, front, back
and dividing walls
...
In this connection, the duration of
fueling double-bath furnaces somewhat greater
length of filling the open-hearth furnaces
...
The solid part of the raw
materials generally constitute scrap, and fluxes
(mainly lime)
...
Solid oxidants are not applicable or used in
limited quantities in order to reduce the
endothermic carbon oxidation by oxygen of the iron
oxides
...


Warming charge (scrap) in a double-bath furnaces
is predominantly oxidation reaction heat of CO to
CO 2
...
The heating temperature of the scrap, at least
the upper layers thereof, should not be below the
solidification of cast iron temperature (1100-1150 °
C)
...
This
results, firstly, in a lengthening of the second half of
melting and reducing furnace
performance; secondly, it may cause ejection of slag
and metal from the furnace due to possible abrupt
growth of carbon with oxygen in the oxidation rate
of iron oxides in the slag accumulated at the
beginning of blowing, slag and metal when heated
and become normal
zhidkopodvizhnost
...
When pouring the cast iron oxides cause
rapid oxidation of iron carbon, that can also lead to
release of metal and slag from the furnace
...
5-0
...


Pouring iron in double-bath furnaces is a period
corresponding to the middle melting
...
Typically, iron is fed to a double-bath
furnaces in two ladles, pouring therefore its
duration is considerably greater than BOF shops
and normally reaches> 25 min
...
The
double-bath furnaces, scrap iron bath prior to
pouring warmed and there is a certain amount of
liquid iron oxides, iron so casting must be carried
out carefully at a low speed
...
Purge mode is characterized by
intensity and position of the oxygen lances
...
4-0
...
During melting, as a rule, the
intensity of the blast supply do not change
...
However, at certain moments melting one or
two of the lance is raised above the level of the slag

surface and carry out purging
...
Furthermore, the surface purge is used to
accelerate the slagging, since in this case, firstly, the
improved heating and, secondly, increases the
content of iron oxides in the slag, which accelerates
the dissolution of the lime therein, and the heat of
formation of the iron oxide improves heat bath
...
5% purity) can be conducted, and
process (purity 95%) in oxygen
...

Slag mode
...
This allows, if necessary to
provide a high degree of metal dephosphorization
with minimum fluxes
...
The main difference in the slag
mode is that in double-bath furnaces have required
descent primary slag to increase the bath heating,
as during purging bath heated mainly heat of
exothermal reactions of the metal components of
the oxidation, instead of heat torch, in open-hearth
furnaces
...
First, a double-bath furnace slag
MgO content is always higher than in the converter
slag, and is> 10% (greater length and melting
reaction over the slag), in connection with which
fosforo- seropoglotitelnaya ability and
below
...
5 impossible
...
According to the content of basic
components (CaO, SiO 2 , FeO) in the slag formation
of double-bath furnaces it obeys the laws
characteristic of the BOF process
...
During the first 2/3 purge the
residual carbon content in the metal is judged by
the consumption of oxygen
...
0-1
...
In the normal course of melting scrap

to this point it has time to dissolve completely, and
all the metal in a liquid state
...

After melting bath should be ensured synchronism
of carbon oxidation and heating bath
...
Its solution is simplified if there is a bath
overheating since overheating can be easily
removed doped solid oxidizer
...
To do this, one
or two lances raised by placing the end of the bath
and spending part of the oxygen for the oxidation of
CO
...

By this method can eliminate small subcooling
...

Upon reaching the predetermined values of the
carbon content in the metal and the temperature of
heating blowing is stopped
...
Nitrogen content using process
oxygen double-bath furnaces metal does not differ
from the converter and the hearth, and the content
of hydrogen hearth better, so the blow at normal
conditions and slag smelting steel, resulting in
double-bath furnaces commonly not inferior OHF
and BOF
...
As research on the CMI and other plants for the
removal of slag peroxidation enough exposure ~ 10
min
...

Deoxidation and alloying metal as in the BOF
process, is carried out exclusively in the ladle
...
12 Prospects of double-bath furnaces

Double-bath furnace has significant advantages
over open-hearth furnace: double-bath oven is
better suited for purging the oxygen in connection
with what is possible to achieve high performance
with lower fuel consumption
...
0-1
...
M and fuel
consumption of 10-20 kg / t
...
Simplicity of design (no regenerators)
double-bath furnaces reduces the amount of repair
work (and heaviest) and reduces the consumption
of refractories
...
However, due to lower fuel
consumption and refractories smaller volume
repair cost of steel produced in the double-bath
furnaces, usually somewhat lower than open-hearth
steel production costs
...
But the installation of oxygen
converters in open-hearth shops significantly
increases the cost of reconstruction, complicates
the operation
...

However, experience has shown that double-bath
furnace compared with the open-hearth though
they have a distinct advantage in performance, but
the possibility of recycling of scrap they are inferior
to the open-hearth furnaces
...
In addition, the quality of steel produced
and the working conditions at the double-bath
furnaces worse than the open-hearth furnaces and

converters
...


5-furnace steels
Until the mid XX century, teeming ladle served as a
container for the transfer of molten steel from the
melting furnace to the casting mold or mold
caster
...
It may be
significantly reduced duration of the melting
process in a steelmaking unit while improving the
quality of the finished metal
...

5
...
In
the oxidative nature of the gas phase a certain
amount of oxygen is always transferred from the
gas phase to the metal
...
034%, and further while cooling it varies in
accordance with the equation lg [O] = - 12630 / T +
5
...
This lead to the
separation of oxygen from a metal oxide as
dispersed phase
...
At relatively low
concentrations of oxygen in its independent phase
separation occurs already during the life of the
product, which contributes to embrittlement
(aging) steel
...

To eliminate the negative effects of the presence of
oxygen steel deoxidized
...

If the metal contains impurities whose affinity to
oxygen is higher than that of iron, the oxidation of
these impurities occurs and the oxygen
concentration in the metal decreases
...
As such elements,
deoxidizing use manganese, silicon, aluminum,
calcium, rare earth elements
...
Oxygen dissolved in the metal reacts with
carbon, and the reaction of [O] + [C] = CO gas occurs
boiling metal
...
After the operation is called
deoxidation steel deoxidized
...
If not
conduct deoxidation operation, the steel during its
gradual cooling in the mold will flow reaction
between the dissolved oxygen in the metal and
carbon [G] + [C] = sogaz
...
This became
known as "boiling
...
The residual
dissolved oxygen causing transient "boiling" of
metal at the beginning of crystallization
...
"
The following methods are used deoxidation In
modern steel production are: a) the depth

(precipitant); b) diffusional; c) treating the
synthetic slags; d) vacuum treatment
...
2 Processing of metal vacuo

The gas phase is formed during the flow of carbon
oxidation reaction processes in the metal release of
dissolved hydrogen and nitrogen, as well as the
evaporation of non-ferrous metals
...

[O] = pco / K [C]
...

In those cases where the oxygen in the metal oxide
is composed of non-metallic inclusions, decrease of
pressure over the melt leads by reaction with
carbon in partial or complete destruction of these
inclusions by reacting (MeO) + [C] = [Me] + SB T
...

Metalworking vacuo influences on the hydrogen
content of the steel and nitrogen
...

Thus, when processing a metal vacuum therein is
reduced content of dissolved oxygen, hydrogen, and
nitrogen oxide content of nonmetallic
inclusions; resulting in the release of large
quantities of gas bubbles mixed metal becomes
uniform, there is a "homogenization" melt
...

5
...
Each
bubble represents a "vacuum chamber", because
the partial pressures of hydrogen and nitrogen in a
vial zero, so gases dissolved in the metal, moving
into the bladder and removed along with it into the
atmosphere
...

Technically, the purge operation of large masses of
inert gases in the ladle metal easier and cheaper
than treatment vacuo, therefore, where possible, by

long-time purging vacuum processing replaces inert
gases
...

Industrially, the process used purging with argon
three metal: through porous refractory inserts in
the bottom of the ladle; through false stopper, the
refractory stopper ending with radial holes having a
diameter of 1
...
5 mm; lined through lance is
lowered into the metal from above
...

5
...
Such compound is CaS
...
4
...

Steels synthetic slags
Process flow chart: slag portion in an amount of 36% by weight of the steel is poured into the casting
ladle, and then the same bucket produce steel
...
0 m, emulsifies slag, so the surface
"slag-metal" section tenfold greater than the surface
interaction of the metal and slag in the hearth steel
making process
...

Experience has shown that during tapping (10-15
min) sulfur content is reduced to from 0,015-0,033
0,005-0,012% and the ratio of the actual
distribution of sulfur between slag and metal varies
from 27 to 77
...

Thus, the processing liquid became lime-aluminous
slag helps to reduce the sulfur content and oxygen,
as well as contamination of the metal with nonmetallic inclusions
...

Sufficiently high degree of desulfurization (~ 40%)
is also achieved by treatment of steel in the ladle at
release solid powdered synthetic slags or slag-forming
exothermic mixtures
...
, An inert gas jet
...
The particulate
materials can be introduced into the steel in the
form of a specially constructed cored wire
...
One effective way of reducing the
harmful influence of sulfur is to change the
composition of nonmetallic inclusions sulfide by
means of elements forming a refractory sulfur
compounds not soluble in the liquid iron
...

The use of alkaline-earth metals and rare-earth
metals
The steelmaking practice widely used ability
calcium, magnesium, barium, cerium, lanthanum
and other rare-earth metals and alkali-earth metals
and their alloys to form stable compounds with
oxygen and sulfur are not soluble in the liquid
iron
...

Of the alkali-earth metals in the steel production
greatest application received calcium, which
typically is introduced in a well deoxidized steel in
the form of alloys with silicon, aluminum, barium,
etc
...

In the process of floating calcium vapors react with
oxygen and sulfur for the reactions: Ca g + [O] =
CaO tv ; Ca g + [S] = CaS tv ,
Calcium contributes to the formation of nonmetallic
inclusions globular shape
...
REM is
introduced into the steel in the form of mischmetal
or ferrocerium (70- 95% REM)
...


6 Fundamentals crystallization
theory
Smelted steel in a steelmaking apparatus is
produced in a ladle and then poured into a metal
mold - mold or directed to a continuous casting

machine
...

casting technology and organization largely
determine the quality of the finished metal and the
amount of waste in the further redistribution of
steel ingots, from 6 to 18%, and sometimes up to
25% of the smelted steel in the remelting returns
due to defects arising during casting
...
1 Processes at release and aging metal in the ladle

On tilting the converter or the trough of openhearth furnace or double-bath steel flows directly to
the ladle
...

The processes taking place during the release and
casting
...
The ladle deoxidation of steel is produced,
the formation and removal of nonmetallic
inclusions has reduced temperature of the metal
and slag, their composition varies
...
Thus, preliminary deoxidation of the
steel in the furnace, especially mild impractical
...
Catching chute on screens CO stream
from contact with the atmosphere
...
This contributes to higher
than the melting unit, the partial pressure of N 2 and
the lack of protection of the slag layer
...
E
...

Significant sources of oxygen entering the steel
during tapping and exposure of metal in the ladle,
are also slag and the refractory lining
...

After the end of production of steel is maintained in
the ladle before casting
...


Extract steel in the ladle before casting and during
casting contributes from floating particles and
refractory slag inclusions and deoxidation products,
uniform distribution-deoxidizing elements
prisazhennyh the ladle, the temperature
equalization, release gases dissolved in the steel
...

When the temperature began to fireclay linings
actively interacts with furnace slag in the
ladle
...
As a result,
by the end of pouring its contents into the metal
may increase
...
The casting process also
oxidizes to 0
...
03% carbon
...

During the casting of steel in ingots occurs it reoxidation
...
Most prone to

secondary oxidation glubokoraskislenny metal
...

To reduce oxidation of the casting used jet argon
protection, pouring through the elongated glass
beneath the metal level in the mold, the protection
of a metal mirror in the mold and the mold slag or
mixtures of creating a reducing atmosphere in the
mold cavity and m
...

6
...
Casting in a mold casting is
divided into top and siphon
...
Steel directly
from the ladle 1 enters the mold 2 mounted on the
iron plates - 3 pallets
...


Sometimes the casting of top dvuhstopornye used
buckets; This allows you to fill the two molds and
shorten the duration of casting
...

P When pouring siphon (see
...
The liquid steel from the ladle (1) enters
mounted on the pallet (5) lined internally central
sprue (2), and from it on the lined channels pallet
(6) in the mold (4) below
...

T
Figure 13 - Scheme bottom casting (designations in
the text)
mayor, the metal from the ladle enters the mold, a
system of channels passing, lined with refractory
brick
...
P
...
Siphon casting has the following
advantages over the casting from the top:

simultaneous multiple casting ingots reduces the
length telnost melting and pouring allows pouring
into small ingots smelting large mass;
convenient to use metal mirrors protection in the
mold slag Vym mixtures or molten slag;
pure ingot surface is obtained, since a metal
from lozhnitsah rises without splashing;
ladle lining is increased firmness and improved
working conditions of the stopper and the sliding
gate valve due to the smaller The duration NOSTA
casting and reducing the number of opening /
closing;
it is possible to monitor the behavior of the metal in
the mold and adjusting the casting speed
...
7-2
...

The benefits of casting from the top are:
a simple training equipment for casting and pouring
lower cost;
less risk of contamination with non-metallic
inclusion became niyami;
no metal flow in the sprues;
temperature of the metal before casting may be
lower than when pouring siphon
...
Solidified on the walls of the
mold and the oxidized surface of the metal splashes
are not dissolved in the molten steel rising to form a
surface defect - slivers which are not welded to the
metal during rolling;
long duration of casting;
due to the long duration of the casting ladle lining
durability is reduced and due to the large number of

openings and closed vany worsen working
conditions of the stopper or slide gate
...
Due to the
simplicity and the absence of metal loss from the
runner often prefer pouring from above
...
At the same time a high quality
alloyed steel, when seeking to reduce the loss of
expensive metal to sweep and clean surface to
receive the ingot is cast mainly
siphon
...
5 t
...
3 Summary of the crystallization process

SUMMARY crystallization process steel is its
transition from liquid to solid
...
At a certain temperature, called
the crystallization temperature , thermodynamically
equally likely that the system of both liquid and
solid phases
...

From the diagram (Figure 14), which is higher than
the crystallization temperature T 2 > T is a stable
liquid state G w ...

P
Figure 14 - Change in free energy G of pure metal in
a liquid (a) and the solid (B) states depending on
the temperature T
When cooling liquid to the melting point,
crystallization begins immediately
...
For stable formation of primary crystals is
necessary subcooling, t
...
A decrease in
temperature below the melting point
...
The crystallization process
consists of two stages - nucleation and subsequent
growth
...

By homogeneous is meant the formation of crystal
nuclei in the bulk liquid phase
under heterogeneous - available at the interface (on
the surface of solid particles located in the melt such as nonmetallic inclusions, molds and mold
walls)
...
Simultaneously and
continuously occurs destruction of most of them
...
E
...

Terms of homogeneous nucleation
...

The solidification or melting during temperature
changes due to the fact, that at temperatures higher
than the crystallization point, at specific free energy
has a liquid phase, and at lower temperatures solid
...


When the crystallization temperature and the free
energy of the liquid and solid phases are equal
embryo formation is impossible since there is no
source for compensating the formation of
interfacial energy costs
...

P When this value supercooling thermodynamically
stable, ie
...
capable of further growth, the embryos
are those whose size exceeds the so-called
"critical"
...

The critical radius of nucleus determined from the
relation:

Figure 15 - Change in free energy G of pure metal in
the homogeneous nucleation of a crystal
where σ - the interfacial tension at the interface
between the liquid and solid phases;
T cr - onset temperature of crystallization;
? T - subcooling;
Q Kp - the latent heat of crystallization
...
By
increasing the degree of supercooling critical radius
of nucleus decreases, t
...
The thermodynamically
stable become smaller embryos
...

Approximate calculations show that homogeneous
nucleation at a number of metals may supercooling
equal to 0,2 • T cr , r
...
About 350 ° C for
iron
...
However, the magnitude of hypothermia
in the steel strip usually does not exceed 10 °
C
...

In real conditions of solidification mechanism has a
heterogeneous nature, when the formation and
growth of the embryo occurs on existing interface crystallization centers
...

In the formation of the structure of the ingot is not
smaller role plays the subsequent crystal growth,
which is determined primarily intensity oriented
and heat dissipation
...
The nascent crystal has a regular
shape, defined by the type of crystal lattice of the
solid metal
...
The dendrite
branches
...
From the vertices of the crystal grow axis of
the first order (dendrite trunks) for them
perpendicularly directed second fold axis
(branches), which likewise develop threefold axis
and r
...
The proliferation of the axes and their
gradual thickening lead to the formation of a solid
crystal ( dendrite)
...
When directional
heatsink crystals have an elongated shape
...
The qualitative relationship
between the speed of nucleation V 0
...
toand the amount of
subcooling is shown in Figure 16
...
In this case, a
fine-grained structure
...
The crystals will grow to a
large size
...

The crystal growth rate is primarily determined by
the intensity of the heat sink; the greater rate of
heat transfer and the greater the subcooling the
liquid metal, the greater will be the growth
rate
...

Crystallization range
...
At a
temperature corresponding to the beginning of the
interval of crystallization are formed and begin to
grow crystals axis depleted in carbon and other

components of steel, and in the remaining of the
liquid metal content increases
...

The magnitude of the crystallization interval,
determined by the composition and conditions of
the steel ingot solidification
...
By increasing the crystallization interval
increases the degree of chemical heterogeneity of
the ingot
...
When steel
solidification in the mold, heat is removed through
its wall, thus nucleation and growth of crystals
begins in the mold walls and the solidified layer
thickness increases continuously towards the
middle of the ingot
...
1 Equipment for the casting of steel

The equipment for casting include: teeming ladle, a
pouring nozzle, the stopper or slide gate, the
intermediate funnel and buckets, the mold trays,
the feed head, runner system, and others
...
Capacity ladle is in the range 5-480
m; addition to the molten steel ladle slag must
contain little (2-3% by weight of metal), which
prevents the metal from the rapid cooling during
casting
...

For steel casting ladle out of the mold is a glass with
the stopper or slide gate, and sometimes turning
gate
...
"The diameter of the glass" is 25- 120 mm,
height of glasses, depending on the capacity of the
bucket is equal to 120- 440 mm
...
It is a metal stubble with a diameter of 40-60
mm, protected from exposure to molten steel and
slag chamotte tubes (coils)
...
When casting long
stopper rod loses strength and can bend, so the aircooled stoppers sometimes used
...
Stopper serve one casting
...

Gate valve operates at less severe conditions than
the stopper (stopper is within the scope of molten
steel), and therefore more reliable in
operation
...
In domestic practice for manufacturing slide
gate plates are used corundum and periclase
allowing to pour three batches
...

Tundish serve buffering capacity, allowing
continuous pouring steel from two or more ladles
method "melting smelting", and most importantly
keep constant the ferrostatic pressure and metal
casting speed
...

The bucket has a steel jacket and is lined inside with
fireclay bricks
...
To reduce heat loss

bucket covered with a lined lid
...

Intermediate funnel used for pouring killed steel to
reduce the metal top jet spraying; It has a metallic
casing which is lined refractory body of refractory
powder and refractory clay water glass with
addition of graphite; the bottom of the funnel is set
nozzle diameter of 18 to 40 mm
...

molds
Molds of cupola cast iron of the following
composition,%: 3,3-4,0 C; 0,9-2,2 Si; 0,4-1,0
Mn; <0,20 P and <0,12 S
...
Mass ingots cast for rolling mills varies
from 200 kg up to 30 tons, and the rolling blooming
cast ingots of up to 13 m, and for rolling on slabbing
-up to 30 m
...

More economical casting of steel into large ingots,
since this reduces the duration, reduced labor costs,
consumption of refractories and casting equipment,
the metal losses are reduced in the form of scrap
and sprues increases performance rolling
mills
...


TO onfiguratsiya molds, characterized by the form
of transverse and longitudinal sections is
determined and steel product mix further
processing of the ingot
...
Figure
17)
...
5 for both the sheet
and rolled; flat bars with a ratio b / h in the range
from 1
...
0 - for rolling on the sheet
...
The multi-faceted molds cast ingots for
forging forgings
...
) and broadening
downwards for pouring boiling and balanced steel
(see Figure 18b
...


Figure 18c), which upper opening after filling the
mold steel or stoppered cap
...

The mold is broadened downward, making crosscutting (without bottom), and the mold is
broadened up - usually the bottom
...
When pouring siphon is
inserted in it a cup firebricks through which the
steel flows into the mold, and the casting of the top a steel liner (tube), protecting the bottom of the
mold from the metal jet erosion
...
This increases the surface of contact with the
ingot mold faster growing thickness of the solidified
crust at the initial time of crystallization and
reduces affection ingots outer longitudinal cracks
...
The increase in H
/ D value allows to increase the productivity of
rolling mills, as well as reduce the duration of the
solidification of the ingot, which contributes to
reduction in segregation
...
The
optimal value of H / D ratio is relaxed for carbon
steel ingots 3
...
5, and for alloy and high-quality
carbon steel 2
...
3
...
E
...
In this case, to increase the density of the core
of the ingot mold walls taper increases
...
0-3
...
Increasing the H / D
ratio as compared with the steel ingots relaxed
acceptable due to the fact that boiling bullion and
balanced steel is formed an axial looseness
...
Too
big height increases the ferrostatic pressure at the
bottom of the solidified ingot, making it difficult to
boil the metal and helps to reduce the thickness of
healthy crust
...
The more
mold walls taper and the taper of the ingot, the
higher the density of its structure and the less
developed axial looseness
...
Therefore

taper for mold walls killed steel is selected in the
range of 2-4% per side
...
The sheet molds for killed steel taper wide
sides is taken equal to 3-3
...

In the absence of boiling and bullion balanced steel
axial shrinkage looseness walls taper downwardly
expanding molds is smaller than that for the killed
steel molds
...
9-1
...

The thickness of the mold wall is selected based on
the conditions for ensuring the mechanical strength
of the mold and it is usually taken to be
approximately 20% of the transverse dimension of
the ingot
...
03
...

P
and, - stationary; in - floating;
1 - pin; 2 - lining adapter; 3 - frame extension; 4 mold; 5 - heat-insulating liner; 6 - hake
Figure 19 - the hot-top
ribylnye extension
mounted on the upwardly widening of the mold
during casting killed steel; they can be fixed (Figure

19 a, b) and floating (Figure 19, c)
...

Lining the feed head made of refractory bricks or
refractory masses based powder with a refractory
clay
...
Mass lucrative part and head trimmings,
respectively the quantity of large ingots of ordinary
steel is the use of such extensions 12-16 weight%
sheathe ingot
...
Due to
the low thermal conductive inserts with adapter
inserts compared with lined have a smaller height
and volume and their use quantity head trimmings
ingots is reduced to 2-5%
...
Figure 19, c) is used in the
casting of large ingots
...
The advantage of
these extensions is the ability to move in the mold
together with the ingot during its shrinkage, which

eliminates podvisanie ingot and formation of
transverse cracks
...
A pallet is a cast iron plate 100-200
mm thick
...

AT pallets for bottom casting (see
...
If the casting mold from above is used
without a bottom, the pallet making a recess in
which is placed a removable liner made of steel and
sometimes of refractory bricks, preventing erosion
of the metal pan spray
...
Pallet
consumption is 0
...

Siphon brick prevents erosion of the pallet, center
and bottom molds in the casting of molten steel
...
Hole size diameter
siphon bricks stacked in the pallet is typically 30-50
mm; diameter holes pivot tube is 70-100 mm
...

7
...
The
composition prepared with mold release before the
steel from the furnace is fed into the pouring
passage steelmaking shop
...
Further, the
composition is sent to the stripping separation
plant equipped with special cranes to remove
feeder heads and the release of the ingot molds, and
then the building of the rolling mill soaking pit
...
After release
from the ingot mold is cooled to a temperature of
80-110? C either by prolonged exposure to air or in
dushiruyuschih devices providing soft cooling by
supplying to the surface of the mold sprayed water
...
Clean the mold metal brushes
or jets of water supplied to the inner surface of the
mold under high pressure
...

The lubricant prevents sticking of spatter during
casting to the walls of the mold and the ingot to the
welding mold
...

In contact with the liquid metal lubricant is
burnt
...
Furthermore, gases generated by the
combustion of lubricant, the mold was removed
from the walls of the oxidized metal film that
improves the purity of the ingot surface
...
At higher temperatures, the
grease will burn out before the start of casting; at a
lower - layer of grease is obtained excessively thick
and uneven
...
"Paint" to
prevent welding of the lining extension to the
ingot
...
Preparation extensions with thermal
insulation inserts is to install in new housing
extension inserts
...
Trays for bottom casting molds and
after removal from the ingot scrap is purified, and
from the sump channel removed sprues and
exhaust siphon brick
...
Sump
temperature before naborkoy should be not less
than 80 - 100 ° C to ensure rapid drying of the
refractory mass
...

Prepare trays on top of the casting is that after
removing the pallet ingots and molds are cleaned
from scrap, slag and debris and purged with
compressed air
...
The pallet is cleaned of debris and scrap,
then recess for stars and fall asleep dry sand
channels and set the siphon brick, center collected
on racks in a special place
...

Build structures for casting the top : on the cleaned
trays greased molds and set them, if necessary, the
hot-top
...
3 Structure of steel ingots

Classification of steel according to the degree of
deoxidation
Steels according to the smelting technology, and
mainly on the degree of deoxidation is divided into
a relaxed, semi-killed and boiling
...
wherein the oxygen activity is lowered
so that completely stops the reaction of carbon
oxidation
...
Boiling steel
deoxidized with manganese only partially and in the
process of casting and curing in the mold is actively
carbon oxidation reaction process [G] + [C] SB =
{}
...
Semi-killed steel according to the degree of
deoxidation and, respectively, gas evolution during
solidification rate is intermediate between the
boiling and calm
...

Ingot killed steel
The structure of the ingot killed steel shown in
Figure 21
...
A
sharp metal overcooling causes the formation of a
very large number of nuclei and their rapid growth,
and therefore the crystals can not grow to a
considerable size and take a definite
orientation
...

Subsequently the heat sink and the cooling rate
falling significantly, since the heat dissipation slows
crust of solidified metal, the mold wall heating and
air gap formed between the mold walls and the
ingot due to its shrinkage
...
Crystal growth continues cortical zone,
wherein growing crystals main axis directed
perpendicular to the wall of the mold (cooling
surface)
...
In large ingots
with large cross section is observed deviation
crystals to the head portion of the ingot (ingot to
heat the center)
...

In the central part of the ingot heat directed almost
non-existent because there is low heat extraction
rate, and in addition, metal is removed from the
solidifying of the mold walls by the same
distance
...
Due to slow heat removal and absence of
appreciable supercooling number of newly formed
crystals is small, therefore, the coarse metal
structure
...
This lowering of the crystals is due
to the difference in density of the solidified and
liquid metal
...
This is the area where the
growing crystals coexist axis and unhardened metal
mezhosnyh spaces
...

It should be noted the presence of a solidifying ingot
convective flows of the molten metal
...
Downward movement
occurs because the solidification front supercooled
liquid metal and has a higher density than the rest
mass
...
35 m / s; it is the greater,
the higher the superheat of molten steel, since it
increases the difference in temperature and density
of the metal in the bulk of the ingot and the
solidification front of the ingot solidification As the
quantity of liquid metal superheat, and with it the
intensity of the flow is reduced
...

Shrinkage cavity in the ingot killed steel

In the upper part of the ingot is a cavity - the socalled shrinkage cavity (see Figure 12
...
E
...
The magnitude
of shrinkage depending on the composition of steel
varies in the range 2,0-5,3%
...
The shell is closed, if the
feed head due to insufficient insulation solidifies
upper metal layer; when applying fillings
exothermic and heating the ingot top open
shrinkage cavity is obtained
...
Shrinkage
value, determined by the nature of steel, can not be
reduced
...
For this purpose it is common
practice to resort to the following measures
ensuring the later solidification of the ingot upper
portion:
1) killed steel is generally poured into the mold is
broadened upward
...
Typically this is set on the hot-top casting

mold, which in the casting mold is filled as the liquid
metal
...
As used asbestos insulating fillings,
calcined vermiculite, coke, slag, etc
...
Lyunkeritov
which constitute the powder mixture of
combustible and neutral components
...
Lyunkernta consumption of
0
...
0 kg / t steel
...

Ingot steel boiling
In the process of casting steel boiling and after the
steel in the mold "boils", ie
...
Carbon oxidation
occurs according to the reaction [C] + [O] = CO with
the generation of carbon monoxide bubbles
...
Much of the CO bubbles

evolved at reflux remains in the ingot
...

To reduce the heterogeneity of the finished steel
boil shortly after the filling of the mold is stopped,
covering massive ingot metal cap (mechanical
occlusion) or deoxidizing metal in the top of the
mold with aluminum (chemical clogging)
...
Shrinkage is dispersed across
multiple gas cavity
...
Since the ingot is no shrinkage cavity is not
necessary to use a mold, expanding upward
...
This simplifies the process of
undressing ingots - simply remove the mold with
the solidified ingot
...
Structure mechanically
occluded ingot rimmed steel, is shown in Figure 22
as well
...
2 to 40 mm and depends on whether or not
removed from the metal formed during its
solidification CO bubbles
...
Their
floating creates a stream whose intensity is
sufficient for the separation of bubbles getting stuck
between the axes of the growing crystals, which
ensures the formation of the metal layer
bespuzyristogo
...
Under these conditions, bubbles
formed in the spaces mezhosnyh crystals remain in
the metal, ie,
...

Thus, the lower okislennost steel and the higher the
rate of filling the mold, the lower the intensity of the
boiling and less thickness bespuzyristoy peel
...
There is a
comparatively rapid growth of the principal axes of
the columnar crystals, which accumulates between
the released carbon monoxide
...

In the upper part of the ingot cellular bubbles have,
as they are washed away by gas flow rising from
below
...

Termination cell growth of bubbles due to the fact
that after the formation of vesicular
maloteploprovodnoy zone heat removal rate is
significantly reduced and slows down the growth
rate of the principal axes of the columnar crystals,
which delays between the CO bubbles
...

After the ingot covering cap (freeze its top) boiling
ceases, since CO bubbles can not be formed due to
increase of pressure inside the occluded
ingot
...

Solidification of the ingot central portion is no
noticeable gas evolution and metal circulation
...
Accumulation of the top of the ingot due to
higher content of oxygen and carbon is due to phase
separation, and the buoyancy of bubbles from the
bottom
...

The top of the ingot bubble and accumulation of
sulfur and phosphorus is cut off due to their
segregation during rolling; head trim value is 5-9%

by weight for an ordinary steel ingot reaches 1013% and for high-quality steel
...
See figure 22b) has in
the lower part of the short cell zone of bubbles at
the top and - accumulation shrinkage voids and
bubbles over which usually is a dense metal
bridge
...
The thickness of the Healthy
peel is the same as in the ingot mechanically
stoppered 2-40mm and determined by the level of
oxidation of steel and metal in the mold lifting
speed
...
Injectable aluminum binds oxygen
dissolved in the steel, so the stops boiling and cell
growth bubbles
...

alumina clogging consumption is selected so that
upon further solidification was a slight gas
evolution, which should compensate for the
shrinkage of the steel and preventing the formation
of shrinkage cavity concentrated
...
Depth tapered downward
bubble accumulation zone and shrinkage voids can
reach 30-45% of the height of the ingot
...
It isolates the void from the
atmosphere, whereby the latter are welded during
the rolling
...
56%
...

In case of insufficient deoxidizing metal breakouts
occur bubbles SB ingot surface
...
If the metal pereraskislen then formed
deep enough isolated top shrinkage cavity crowded
likvatov and nonmetallic inclusions
...

The thickness of the crust healthy - an important
quality criterion of boiling steel ingots
...
More thin crust can be oxidized by
heating before rolling ingots
...
As a
result, flaws are formed on the rolled surface
...
The intensity of
the boiling and the thickness of the Healthy peel will
greater the higher okislennost molten steel and the
lower rate of filling the mold with metal
...
Because carbonmanganese reduce the amount of oxygen dissolved
in the steel (its oxidation), to obtain a sufficiently
thick cover healthy in steels with a high content of
these elements is difficult
...
27% C and 0
...

As shown by experience, the oxidation of the molten
steel, obtained by melting under existing methods
allows to pour boiling steel at a rate not exceeding
1
...

If it is necessary to pour the steel at a higher rate,
then they resort to the use of so-called boiling
intensifikaterov
...
Coming from the intensifier to the steel

enhances the boiling oxygen intensity and allows to
obtain an ingot with a thickness sufficient healthy
peel at casting speeds up to 2
...
5 m / min
...
e
...
Due to early chemical
plugging dimensions and small bubbles during
heating for rolling the outer layer of the ingot
bubble oxidized, whereby flaws are not formed on
the rolled surface
...
It is usually deoxidized in the ladle
by injecting silicomanganese, ferrosilicon and
ferromanganese in an amount as to obtain a
predetermined content in the steel of manganese
and administering 0,06-0,13% Si
...
During solidification in
the mold there is a "sparking" - the formation and
isolation of a small amount of carbon monoxide
...


In the upper part of the ingot balanced steel (see
...
Bubbles are located
at the surface of the ingot, since oxidation of the
metal and the boiling intensity insufficient to form
appreciable bespuzyristoy peel thickness
...


Figure 23 - the structure of semi-killed steel ingots
scheme with different degree of deoxidation:
and - nedoraskislennaya;
b, c - normal deoxidized;
g - pereraskislennaya
Location shrinkage voids in the ingot depends on
the degree of killed steel
...
The magnitude of the head trimmings thus
constitutes 2
...
In case
pereraskisleniya (duration of "arcing" in the metal
mold is less than 10 seconds) are obtained from

ingots thinner "bridge" and insufficiently insulated
shrink sink, leading to an increase in magnitude of
the head trimmings
...

Depending on the degree of deoxidation balanced
steel ingot structure approaches the boiling or
relaxing structure ingot
...
Figure 23, a)
...

Needless to complete deoxidation (see
...
3 to 5
...
At low speeds gassing conditions

ameliorated increases cellular bubbles height zone,
and their length is 30-40 mm, which greatly
enhances the prevalence rolled flaws
...
Therefore, it is recommended balanced
steel pouring from above at an increased rate
...
E
...
Therefore balanced steel
oxidation during the casting process is controlled:
after the filling of the first metal mold fixed arcing
duration and if it is large (> 40 s), the next mold is
added small amounts of aluminum which reduces
the oxidized metal
...
4 Chemical heterogeneity ingots

Liquid steel is a homogeneous solution of carbon,
silicon, manganese, phosphorous, sulfur, oxygen,
and gases in the liquid iron, but the content of these
impurities in different points of the steel ingot
differently
...

The cause of segregation is that the solubility of a
number of impurities in solid iron lower than that

in the liquid
...

The tendency to segregation of the various elements
contained in the steel varies
...

Distinguish two types of segregation: dendritic and
zonal
...
The greatest propensity to exhibit
dendritic segregation sulfur, phosphorus and
carbon
...
The size of the dendritic phase
separation, ie, the difference between the content of
individual elements in the axes of the dendrites and
mezhosnyh spaces reaches significant values, for
example for a 3-ton ingot%: sulfur about 200,
Phosphorus 150, 60 carbon, silicon 20, manganese
15
...

Zonal segregation - is the heterogeneity of the steel
composition in different parts of the ingot
...
By
formation zonal segregation prone sulfur,
phosphorus, carbon and oxygen
...

The zonal segregation causes heterogeneity of
properties in different parts of the steel product
and metal can cause rejection due to metal
composition deviation from the set
...
These processes are: diffusion of
impurities from the two-phase region in the
remaining volume of the liquid metal; convective
flows in the metal mold resulting in removal
likvatov the upper and middle portions of the
ingot; floating volumes of contaminated metal

impurities due to the fact that their density is less
than the density of the rest of the metal
...

Manifestation zonal segregation depends inter alia
on the degree of metal deoxidation
...
The outer
cortical zone and no segregation of the ingot
composition metal is not different from the
composition of molten steel because of the rapid
crystallization of the surface layers of the ingot
liquation processes herein do not have time to
develop
...
Negative
segregation at the bottom of the ingot explain
buoyancy and displacement of impurities in the
upper part of the ingot
...

Formation of V-shaped segregation explain
lowering shrinkage voids in the axial part of the
contaminated metal alloy ingot of profit
...
When
moving interested likvatami and contaminated
liquid from the adjacent two-phase region, which
fills gaps arising during shrinkage, being located in
a funnel shape
...

P richina education Λ-shaped segregation not fully
understood
...

H

1 - Λ -shaped segregation;
2 - V-shaped segregation;
plus - positive segregation zone;
negative - negative segregation zone
Figure 24 - Scheme segregation in the ingot killed
steel semi-killed steel at a different degree of
deoxidation:
and - nedoraskislennaya;
b, c - normal deoxidized;
g - pereraskislennaya
cities account for major amount segregating
elements found in podpribylnoy axial portion of the
ingot where the metal solidifies in the last turn and
in the "whiskers" area
...
5-4
...
Typically, this portion
of the ingot is cut off during rolling
...
Zonal segregation develops the
stronger, the greater the mass and cross section of
the ingot and the longer the duration of its
solidification
...
5 m)
...
factors, in
turn causing increase in the rate of cooling and
crystallization of the ingot would reduce
development Λ-shaped segregation
...
The
ingot is mechanically sealed outer cover layer
healthy due to the very rapid solidification of the
composition is different from molten steel
...
This is due to the fact that
the active boiling likvaty are carried to the top of
the ingot
...
The content of sulfur, phosphorus,
and carbon increases in the direction from the
surface towards the axis and from the bottom to the
top of the ingot
...

The zonal segregation in the steel ingot boiling due
to the intensive metal circulation is considerably
stronger than killed steel ingots
...
In
this connection, in the production of high quality
steels boiling for removing harmful impurities
cluster headache trimmings must be increased to 10
to 13% by weight of the ingot (instead of 5
...

Due to the strong development of phase separation
by mechanical plugging it actively replace
chemical
...
5
min box closure mold filling and mechanical - 7-15
min
...
The remaining volume of the ingot is
noted slightly noticeable increase in the content of
impurities in the direction from bottom to top and
from the surface to the axis of the ingot
...

The balanced steel ingot character segregation is
approximately the same as a chemically sealed
rimmed steel ingot
...
5 The temperature and the casting speed

Steel discharged from the furnace must be heated at
100-150 ° C above the melting temperature, which
depends on the steel composition and usually
decreases with increasing carbon content and
alloying elements
...
5 h
...

Normal start temperature casting consider a
temperature higher than the melting temperature
of the steel at 90-120 ° C at a casting siphon and 70110 ° C in the casting of the top
...
Superheated steel longer solidifies in the
mold, so in the ingot growing stronger chemical
heterogeneity
...
With increasing temperature
also increases the amount dissolved in the steel of
harmful gases, which degrades the properties of the
finished metal
...
Cool Metal more viscous, making it
difficult to crystallize floating LMW ingot and leads
to an increased contamination of steel with nonmetallic inclusions
...
When pouring siphon
cold metal on its surface in the mold forms a crust,
which is a serious defect inversions ingot
...
Excessively high casting speed
increases the number of longitudinal cracks on the
surface of the ingot during casting and causes a
reduction in the boiling steel healthy outer crust
thickness in the ingot
...

For these reasons, the casting speed is linked to the
metal temperature
...
Optimal temperature and casting
speed are chosen empirically taking into account
the casting method, an ingot mass, composition and
properties of the steel
...
It is controlled by changing the nozzle
diameter, and also partial overlap resulting from
the jet nozzle by means of a stopper or sliding
shutter
...
6 casting technology of steel into molds

7
...
1 Features killed steel casting
Killed steel is poured from above and siphon and, as
a rule, in the mold, expanding upward from the feed
head
...
To avoid
spattering when hitting the bottom of the mold
during casting start slowly fully open stopper
...
The casting speed thus
determined by the diameter of the nozzle (4055mm)
...

top casting speed until recently selected within 0
...
1 m / min
...
5 m / min - 80 mm diameter glass) steels
are not prone formation of longitudinal
cracks
...
5-8 minutes
...
Subsequently the casting speed is
controlled depending on the metal surface in the
mold
...
Formation and growth
of peel intensified at low casting speed, insufficient
metal temperature and especially in the presence in
the steel easily oxidized elements (aluminum,
titanium, chromium)
...
"
The magnitude of the siphon steel casting speed is
usually in the range 0,15-0,7 m / min
...
Duration body filling ingots from 1 to 13 m
varies from 1
...

After closure of casting metal ingot killed steel
surface in the hot-top is filled exothermic or
insulating mixtures
...
The
need for long exposure prior to transport caused by
the fact that the shake crystallizing ingot increases
sharply off-axis (zonal) segregation
...

Casting a layer of molten slag
...
Slag particles also absorbs oxides, pop-out
metal
...

Casting a heat-insulating materials and
mixtures
...
The former include the
disks and plates obtained by compression of mica,
asbestita, graphite, sawdust, etc
...
Drives during filling of the mold to float on
the surface of the rising metal
...
Sol-graphite mixture
comprises fly ash of thermal power stations, which
is based on SiO 2 and A1 2 O 3
...
In contact with the
liquid metal mixture podplavlyaetsya and forms a
viscous slag does not adhere to the mold
wall; nerasplavivshayasya upper portion of the
mixture acts as a heat insulator
...


Flow sol-graphite mixture is 2-3
...
0-1
...
5-2
...

Metal stream protection with argon
...
The annular cavity fed argon, protects
the metal from oxidation
...
Due to the complexity of the
method is only applicable when casting steel
containing easily oxidizable elements
...
These include a number of
ways of which the most widely used are wooden
frames casting and casting with petrolatum
(petroleum refining byproduct) which was charged
in an amount of 0
...
0 kg / ton lubricated mold
prior to casting, and the mold was sealed cover
...

1
...
Inserts in the
form of plates fixed in the hot-top wall or in the top
of the mold along its walls, in the latter case, the
mold was used without feeder heads
...

2
...
Inserts made of
exothermic mixtures in the form of plates
...
Exothermic mixtures thereof, of
which the bundle (waterglass) is prepared as
inserts contain combustible material (aluminum),
oxidant (scale) and neutral fillers (chamotte, clay,
vermiculite)
...
As a result, heating is reduced
penetration depth into the ingot shrinkage cavity
and head trimmings reduced by 5-8%
...
Arc heating
...
The
method allows to increase the yield by 5-8% at a
flow rate of electricity of 15-40 kWh per 1 ton of
steel
...
Gas heating
...
Heating for
15 - 20 minutes by burning natural gas or coke in
oxygen improves the metal yield by 6-8%
...
Electroslag makeup
...
The slag is immersed top
electrode of steel of the same composition as the
cast ingot
...
The
method allows to obtain ingots without shrinkage
cavity and increase the metallic yield of 15% or
more
...
6
...
In both
cases, in order to prevent the splash of the metal on
the walls of the mold and formation captive on the
lower surface of the lower ingot mold part is filled
slowly
...
When the siphon superheated steel
casting and excessive okisleniosti it can occur from
metal splashes centerline
...
When casting steel
boiling important factor is the rate of rise in the
metal mold, which determines the thickness of the
Healthy peel ingot
...
5-1
...
0m / min produced a
healthy crust minimum allowed thickness (8-10
mm)
...

After closure of the mold filling metal therein boils
for some time and then to reduce the development
of chemical heterogeneity boiling stopped, using
mechanical or chemical blockage of the
ingot
...

Mechanical blockage
...
The thickness of
this layer is about 1/6 of the thickness of the ingot
(60-100mm) and a boiling time of 7-15
minutes
...
The cover is
removed from the ingot after 20-30 minutes after
occlusion
...
Experience has shown that
mechanical clogging provides satisfactory quality
ingots weighing less than 6
...
In larger ingots due
to prolonged boil (7-15 minutes), phase separation
is developed so strongly that for the removal of
noxious impurities clusters requires a substantial
increase in the rolling head trimmings
...

In chemical plugging to stop the boiling and
accelerate solidification of the top of the ingot in the
mold is introduced scavengers
...
5 min after closure of the mold
filling
...
Aluminum is given as a fraction or a liquid
...

Ways of increasing the casting speed steel boiling
The level of oxidation boiling steel during its
smelting existing methods is that it can be poured
from the metal recovery rate in the mold is not
more than 1 m / min because at greater speeds
healthy crust thickness obtained ingot insufficient
(<8-10 mm)
...
Application boiling intensifiers - powder mixture
containing oxides of iron and capable of easily
transmit oxygen of oxides of the molten steel
...

Application boiling intensifier produces healthy
crust sufficient thickness (10-20 mm) with
increasing casting speed to 2
...
5 m / min, and
increased contamination by nonmetallic inclusions
became not observed
...
A rinsing jet steel with oxygen
...

3
...
When casting steel boiling with such a large
metal mold lifting speed bubbles begin to form at
the surface of the ingot and owing to rapid clogging
they are unable to grow to a considerable size
...
The thin outer metal layer with
blisters oxidized by heating an ingot for rolling
passes in scale and rolled surface without defects is
obtained, despite the lack of healthy crust
...
6
...
Good results are obtained by using highspeed casting of top-linear metal recovery rate of
not less than 1
...
In this case, due to the

rapid growth ferrostatic pressure is possible to
suppress or at least weaken the formation
subcortical bubbles
...

Semi-killed steel is cast in the bottle and a
downwardly through the mold is broadened
...

Defects 7
...
By
first include piping, axial looseness, chemical and
structural heterogeneity, cell bubbles, endogenous
non-metallic inclusions; among the second - cracks,
slivers, inversions peel, bubbles subcortical bullion
killed steel, "Shaft" and riser bars boiling steel,
thinness in them a healthy crust and some
others
...

Axial looseness
...
When
crystallization unhardened metal ingot axial zone

narrows and kept in separate locations occurs
fusion of crystals growing from the opposite sides of
the zone
...

Increasing axial looseness contribute to lowering
the temperature of the cast metal, the increase in
weight of the ingot, the presence of elements in the
steel to increase the shrinkage during solidification
(in particular carbon), the presence of elements
(chromium, titanium), which increase the viscosity
of the liquid steel,
Improved heating the upper part of the ingot
decreases the axial porosity
...
This defect ingot surface formed
predominantly at the siphon casting due to
oxidation and the cooling surface of molten steel in
the mold
...
Solidifying metal under the film forming
with it a crust, which also absorbs from the pop-up
molten steel and non-metallic slag inclusions
...
The location in the

ingot peel bloat detected congestion nonmetallic
inclusions and gas bubbles resulting from the
interaction of oxides contained in the cake with
carbon steel
...

Intensity peel ingot growth and porazhennost bloat
increases at low temperature cast steel and the
casting speed and, in particular, the presence in the
steel easily oxidized elements (chromium,
aluminum, titanium)
...

Cross-hot crack
...
The most common fractures are
caused by local hang ingot mold
...

Longitudinal outdoor hot crack
...
Their width is 3
...

Cracks are formed as follows
...
The liquid

metal as it appears in the vessel wall which serves
as a crust of solidified metal
...
the Probability gap higher than
the above temperature of the steel and the casting
speed, since in these cases due to excess heat builds
slowly peel thickness of the solidified
metal
...

The measures to combat the formation of
longitudinal hot cracks generally are: preventing
overheating of steel, reducing the casting speed, the
use of molds with concave and wavy walls
...
They are formed
during the cooling of the solidified ingot at its edges
at temperatures lower than 600 ° C
...
Cooling bars should be carried out
slowly in order to prevent their formation
...

Slivers
...
As
a result, the metal jet hitting the bottom of the steel
mold is sprayed
...
Slivers not welded to the metal and during
rolling, whereby the surface of the rolled billets
have to expose the mopping
...
In order to reduce
plenoobrazovaniya also applied via intermediate
casting ladles and funnel
...
The ingots killed steel are
sometimes found gas bubbles located at the surface
of the ingot
...
One of them - too thick layer of grease the
mold
...
Sublimates trapped between the
solidifying metal crystals, forming bubbles
...
5%) Moisture Content
lubrication as a result of evaporation, as well as the
casting insufficient killed steel because of the
formation at its crystallization CO
bubbles
...
Adhering to the
walls of the metal droplets (spray) with oxidized
surface
...

When rolling ingots bubbles locations arise hairline
- small fine cracks
...
The cause of this defect killed steel ingot is
increased content of hydrogen in steel
...
This defect is typical for steels
with high silicon content
...
When excessive oxidation boiling boiling
steel during filling of the mold is very rapidly,
bubbles strongly CO foamed metal
...

Riser bars boiling steel
...


8 Continuous casting
8
...
Partially solidified ingot is
continuously pulled therethrough, and further
cooled in a so-called secondary cooling zone
...

Assemblies for casting steel this method is called
the continuous casting machine (CCM) or a
continuous casting machine (UNRS)
...
Figure 25) of steel ladle
enters the tundish, and from there into the
mold
...
The partially solidified
billet by a conveying system - pulling the cage
enters the secondary cooling zone where complete
solidification blanks
...

R
1- tundish;
2-mold;
3, the secondary cooling zone;
4-pulling stand; 5-cutting;
6-primer;
7-crystallized metal
Figure 25 - Scheme casting steel caster (a) and the
effect of primer (b)

azlivku lead to exhaustion of the metal in the ladle
or dispensed without a break of several metal ladle
(the casting method "melting smelting")
...
Thus,
to obtain killed steel blooms or slabs by continuous
casting instead of pouring into molds followed by
rolling enhances the yield of usable 10-15% by
weight of the cast steel
...
Applying continuous
casting eliminates the production cycle of
operations to prepare the casting composition,
stripperovaniyu ingots, rolled in the roughing
mill
...
That is simplified production of the plant
as a whole and improve the technical and economic
performance, reduced energy costs, labor
requirements and the area of the plant;

3) because of the small transverse dimensions of
the steel ingot and high crystallization rate limited
development phase separation, i
...
improved
quality metal;
4) create opportunities for full mechanization and
automation of casting, improve productivity and
better working conditions
...

The solidification of a continuous ingot
The approximate heat balance of a continuous
ingot: mold - 16-20%; ZVO - 23-28%; Air cooling 51-61%
...

Metal poured into the mold in contact with its
water-cooled copper walls is supercooled and
solidified, forming an ingot crust desired
configuration
...
3-0
...
In this zone, due to possible deformation

flimsy crust and the walls of the mold may occur
dense portions and loose contact, which, due to
differences in the heat sink temperature and the
thickness of the solidified shell will vary
...
The thickness of the
cake at the exit of the mold must be sufficient to
withstand the pulling force and the pressure of the
molten steel
...

In the secondary cooling zone on the moving surface
of the ingot is fed water spray and set the
supporting devices (e
...
, rollers) which prevent
possible buckling peel ingot under the influence of
head pressure of molten steel
...
g
...
Therefore, the atomized water is used (
"mild cooling")
...

The length of the secondary cooling zone is 80 100% of the depth of liquid metal in the ingot wells
...

Education structural zones in a continuous ingot, as
well as in the ingot cast into the mold, is determined
mainly by the composition and temperature of the
steel as well as thermal conditions of
solidification
...

Chemical heterogeneity in a continuous ingot
develops to a lesser extent than in the ingot cast
into the mold
...
At higher crystallization speed
isolation impurity diffusion extends less completely
and correspondingly smaller effect and the

difference in the impurity concentration of the axes
of the dendrites and mezhosnyh sites
...
It is found that
when the speed of advance of the solidification front
more than 1
...
In a continuous ingot even large
sectional crystallization speed exceeds the critical
value, therefore in continuous ingots no significant
zonal segregation
...

8
...
All these varieties of
plants are classified according to the following
criteria
...
The preforms are cast in slab machines,
have a cross sectional shape of a rectangle with a
long side to a short ratio> 3
...
On bloom caster
and high-grade cast billet in the form of a circle, a
square or a rectangle with a smaller aspect
ratio
...


According to the principle of the distinction of the
continuous casting and semi-continuous casting
...
When polunepreyvnoy
molding preform length due to the design features the course of the drawing mechanism, which is
selected from the consideration of simplification
and cheapening of the machine in the data
production conditions
...
Increasing the productivity
of the plant is achieved from the metal casting ladle
in several crystallizers
...
Recently manufactured slab machine with
four streams
...
);
- with a reciprocating motion; crystallizer certain
period moves simultaneously with bars or ahead of
it, and then returns to the initial position; to this
type of machine relates major amount continuous
casting of steel;
- with the mold, moving at a speed of the ingot; it
ensures the absence of the ingot shell slide relative

to the mold and hence the friction between them,
which reduces the probability of rupture of the shell
at high casting speeds; to this type of caster is the
so-called rotor (roller) caster
...
Figure 26 a-d), and machine process axis on
the plot solidifying ingot variable curvature (see
...

The most widely used following types of caster:
vertical, curved and radial, with a bend of the ingot
and horizontal
...
Pouring,
crystallization and cooling NLZ carried out by
standard techniques
...
Since
hardening should end before entering the ingot in
pulling the cage and the cutting zone, the increase in
depth of the molten metal wells with increasing
speed (or section) makes it necessary to increase
the metallurgical length CCM - high altitude
...
To 25-27 m below the level of the shop
floor, or the construction of tall buildings
...

Operating experience vertical caster indicates that
they should be applied in the metallurgical
installation length not exceeding 12
...
This, in
turn, means that the machines can not be a vertical
type pouring melting with heavy aggregates, such
converters SADC 300-400 m
...
The yield ingot reaches 95-98% of the liquid
metal
...

Curved and radial caster

In machines of this type are radially curved mold is
formed by a certain radius of the ingot
...
Its value is
determined so as to provide a path length sufficient
to complete solidification of the ingot at the time of
a predetermined linear extension of the pulling
rate, and does not exceed the allowable amount of
deformation in extension, which could lead to
cracks and ruptures in the ingot
...
Normally
bending radius is selected in accordance with a
ratio R = (30-40), where a - ingot thickness, m
...
After passing
through the arc fully solidified ingot unbend lowest
point, turning it into a horizontal position
...
E
...
Dispersal is to reduce the deformation
arising from this ingot in the peel stress and the
probability of cracks
...

For these reasons, in recent goals almost
abandoned the construction of vertical continuous
casting machine and build mostly curved and radial
...
first variant of the machine (see
...
Next, a moving bar is bent, in a horizontal
position
...
Similar
machines used for the casting of ingots small
thicknesses (<150 mm), since at greater thickness
due to the need to have a large bending radius not
achieved significant height reduction compared to a
vertical caster
...
) a
vertically disposed crystallizer and a small height (3
- 4 m) vertical section with supporting rollers for
which there is a section of the bending rollers,
bending poluzatverdevshy ingot, and more radial
roller wiring
...

Installations of this type are used less frequently
than the curved due to a greater height
...

In general, with curved caster axis technology has
some significant advantages compared to vertical :
high speed casting and the ability to take heavy
melting; less 3-4 times the height of the
installation; possibility of obtaining unlimited
length of the ingot; capital costs 30-50% less than
the same productivity; It facilitates maintenance of
CCM, as the main technological equipment is located
above the level of the shop floor; issuing blanks in
horizontal possible to perform rolling immediately
after casting blanks
...

Therefore, when choosing the type of machine in a
high-performance plants preference should be
given radial and curved continuous casting
machine, and casting quality steel with particularly
complex profile a number of advantages reserved
for the vertical continuous casting machine
...
For continuous casting of billets of small
cross-section and a wide assortment in shops with
aggregates of small and medium size designed and
implemented horizontal caster
...
Scheme horizontal caster shown in
Figure 28
...
mold 3 - copper or combination (copper-

graphite) refrigerator, a water-cooled; secondary
cooling zone 4 in the form of roller conveyors; a
pulling device 5, providing a periodic elongation of
the ingot; device 6 for cutting the ingot
...
Figure 28)
into the lined hearth, is rigidly connected to the
mold through a refractory glass
...
Next is a mechanism for periodic drawing
of the ingot
...
The number of cycles varies from
20 to 100 per minute
...
For pulling mechanism is gas cutting and
roller table with driven rollers
...
The main advantages of horizontal
machines - low height, weight and a smaller amount

of equipment and, consequently, lower the cost of
their construction
...
3 Key components of CCM

Modern caster consists of the following elements
and components: steel teeming
stand; tundish; trolley or stand for the
tundish; mold; postupalnogo mechanism for
reciprocating motion of the mold; support elements
and devices of the secondary cooling zone; Device
for the transport of the ingot; seeds; a mechanism
for inputting and harvesting the seed; Device for
cutting continuous casting ingot to billet cut
length; Device for cleaning and transporting
preforms to a rolling shop and office finishing
workpieces; devices for supplying the solid or liquid
lubricant; equipment for supplying water into the
mold; secondary cooling zone and cooling elements
caster; electrical equipment; means of control and
automation
...
6-1
...
"
P

1 - submerged nozzle; 2 - the stopper; 3 - an
intermediate ladle; 4 - a protective tube; 5 - cover; 6
- mold; 7 - jet portion (Boyne place); 8 - Emergency
drain
Figure 29 - The apparatus tundish
KSR ladle executed welded (see
...
To reduce
heat losses it is provided with a cover lined with
bricks or refractory ramming mass
...

Figure 29)
...
Protective pipes are used to protect the
metal from contact with air on site casting ladle tundish and are made of fused silica or
shamotografita
...
A olzhen provide
rapid formation of a sufficiently thick and strong
peel ingot without defects
...

The inner wall of the mold is working in difficult
conditions (exposed to the high temperature melt,
the ingot grinding action, the effect of ferrostatic
pressure, and so on
...
In order to increase the

softening temperature of copper is sometimes
doped with chromium or silver, and for improving
the wear resistance on the working surface a thin
layer of abrasion resistant materials
...
10 m / s
...

On CCM used three types of molds: prefabricated,
block and the barrel
...
The most widespread prefabricated
molds, consisting of four copper workers walls, each
of which is secured by pins to the rigid steel plate
(see
...
Blue wall made of a thick (50-70
mm) copper plates (with a small thickness of 10-20
mm of warpage occurs, leading to the formation of
longitudinal cracks in the crust of the
ingot)
...


Figure 30 - Scheme precast mold (designations in
the text)
A characteristic feature of the precast mold is
possible to change the strand width
...

Block molds are made of solid copper billets, the
sleeve - of copper seamless pipes
...

Ingot quality is largely determined by primary peel
strength
...
Usually
its thickness at the exit from the crystallizer is 1525 mm
...
However, in the
former case it reduces plant productivity, and in the
latter increases the friction between the ingot and
the mold walls, and also increases the risk of mold
warpage
...
To the ingot for a
longer time in contact with the walls of the mold,
the inner profile of the mold sometimes operate
with reverse taper (ie
...
The lower section
somewhat smaller than the top)
...


Operating experience of CCM found that by sticking
to the peel ingot mold wall, and also due to warping
may hang in the ingot mold
...
To prevent bridging ingot
facilitate ingress of oil between the ingot and the
mold wall, and most importantly, provide sealing
(healing) ruptures crust crystallizer communicates
reciprocates via mold oscillation mechanism
...
Rotating motor or eccentric
cam via a lever system provide swing frame on
which is mounted a mold
...
The amplitude of oscillation varies from
1 to 40 mm, frequency - from 10 to 600 cycles per
minute
...
On the vertical and horizontal machines, the
seed is a metal rod, and a curvilinear axis machines
it is made of articulated links
...
); seed head
section corresponds to the cross section of the cast
ingot
...
Poured metal solidifies in
the mold in a recess of the head, providing adhesion
primer with the ingot
...
After the
release of the seed from its pinch rollers are
separated from the ingot
...
The main technological function of the
secondary cooling zone (secondary cooling) is to
create optimal conditions for complete
solidification of the cast ingot, ensuring the desired
quality of the metal
...
40 m Throughout this section together
with the metal solidification occurs impact force on
it numerous factors: the thermal stresses depend on
the cooling conditions,
...

Secondary cooling zone most often operate as a
system of nozzles, feed the ingot to the surface
water spray, and supporting rollers
...

Figure 32) or bars in one, two or three rows along
the direction of ingot movement depending on its
width
...

AND
1 - ingot;
2 - support roller;
3 - an atomizer;
4 - a tubular collector;
5 - valve
Figure 32 - a secondary cooling section curved
caster
Intensity cooling should decrease as the distance
from ingot mold
...


The intensity of secondary cooling is dependent on
the properties of cast steel (susceptibility to
cracking) and the casting speed, with an increase
which increases the intensity of the water inlet
...
4-1
...
0-1
...
The length of cooling zone direct water on the
ingot can be up to 10-12 m
...
Cooling mode in secondary cooling of the
ingot should ensure minimum duration of complete
solidification of the ingot and the continuous
absence of surface and internal
defects
...

Supporting device
...
To prevent this,
in the secondary cooling zone is set to a frame
supporting the rollers (Figure 32)
...
For ease of
replacement during repair group of neighboring
upper and lower rolls combined into a single
section where the frame is mounted generally from
2 to 7 pairs of rollers
...
Thus when casting the
ingots 300 mm thick diameter rollers from 150-200
mm at the mold is increased to 480-600 mm in the
horizontal section
...
Commonly used oxygen gas cutters or
shears
...

ABOUT
Figure 33 - Stand-rotary lifting (in text notation)
borudovaniya for a quick change of buckets

...
According to the design and function
steel-smelting stands divided into two types - bridge
and revolving
...
Most modern lifting and
turning stand (
...
In the console hangers 4 can
be installed two bucket (5a, b); vertical movement
of the bucket reach swing console, the rod 3 ensures
translational movement suspensions and ladles
...
4 continuous casting technology

To reduce the axial porosity, the degree of center
segregation, staggered ingot cracks sizes zone of
columnar crystals with a reduced strength and
ductility, as well as to reduce the erosion of
refractories (cup, detents) metal superheat the feed

to the crystallizer, above the liquidus temperature
should be minimal
...

After pouring closure previous heat (or series of
heats during casting by the "melting smelting") CCM
is prepared for the next casting
...

Before beginning casting establish heated to 10001200 0 C
...
Metal
tundish filled to a height of 0
...
6 m, and then,

opening the stopper, begin feeding metal into the
mold
...
5 to 2
...

After a predetermined time when the mold is not
completely filled, include ingot pulling
mechanism; at the same time, the mechanism
automatically mold oscillation
...
The casting speed is chosen empirically,
considering that its increase increases plant
productivity but decreased the thickness of the
strand shell at the output of the mold casting speed
varies depending on the cross section of the ingot
brand cast steel, condition caster equipment,
typically falling by increasing the cross section of
the ingot and the degree of alloying of steel
...
4- 2
...
4 m / min,
M
Figure 34 - A method of supplying metal into the
mold

Ferrous materials fed into the mold or open jet (see
...
Feed "level under the" carry vertical (Figure 34b)
or horizontal or inclined jets (Figure 34, c)
...
The feed streams used in vertical casting of
ingots that are similar in cross section to a circle or
a square; flow through submersible glasses with
side openings - for slabs
...
As a
lubricant often use paraffin oil and rapeseed oil,
paraffin flow rate of 0
...
7 kg / t steel
...
The
composition of the mixtures is varied, they may
include CaO, SiO 2 , A1 2 O 3 , Na 2 O, K 2 O, GaP 2 , MgO,
sometimes 20-30% of powdered graphite
...

When the metal is fed into a crystallizer can not
allow the jet breaks and abrupt change the amount
of supplied metal
...
Changing the flow
of metal causes the metal level fluctuations in the
mold and the appearance of veining on the ingot
surface
...

8
...

The continuous ingot due to the low thickness and
consequently the rapid solidification has a smaller
development of chemical heterogeneity, more
uniform distribution of non-metallic
inclusions
...

These are the basic defects ingot obtained by
continuous casting
...
Centerline porosity
noticeably enhanced when increasing the superheat
of the metal and increased casting speed,
sometimes going into axial shrinkage
voids
...

The curved bars and particularly horizontal
continuous caster, there is some asymmetry of the
structure and distribution of the components of
steel, since solidification zone last portions of the
metal, and hence shrinkage porosity and
accumulation liquidating impurities are displaced
to the upper face of the ingot; at the top face is also
observed increased content of non-metallic
inclusions due to their buoyancy
...
For
ingots of square section is characterized
by orthorhombic - distortion of the profile of the
ingot in the mold when a square section is deformed
into a rhomboid
...
The blow-up
of the ingot (the bulge of its cross section) occurs
under the action of the ferrostatic pressure of the
liquid column in the steel ingot; appearance defect

contributes to the casting speed and the
temperature of the metal, which reduces the
thickness of the solidified shell; insufficient
intensity of secondary cooling; deviation setting
support rollers; increased distance between the
support rollers
...
The longitudinal surface cracks on the faces of
the ingot have a length of up to 1-1,5 m or more and
a depth of 10-15mm
...
g
...
An effective means of
dealing with this casting defect is coated with a
protective slag as formed between the crust and the
walls of the mold a thin slag layer substantially
reduces the unevenness of the heat sink
...

Figure 35, 7) are formed as a square profile bars for
the distortion in the mold
...


The transverse surface cracks (see
...
Such cracks may occur
upon bending or straightening the billet continuous
caster to a curvilinear axis
...

1 - central fissure; 2 - diagonal cracks; 3 - Axial; 4 internal cracks perpendicular to the wide faces of
the ingot;
5 - longitudinal surface cracks on the faces of the
ingot;
6 - a crack perpendicular to the narrow faces of the
ingot; 7 - longitudinal cracks along the edges
(corners);
8 - and arachnids reticulated cracks;
9 - transverse cracks in the corners of the ingot;
10 - transverse surface cracks (tears peel)
Figure 35 - The main types of cracks in pulling out of
the mold ingot caster
Arachnids and crack mesh (see
...
Arachnids cracks occur in the mold
with uneven peel adhesion to its walls in places

tight fit, ie
...
The prevalence of these cracks during
casting decreases with coated slag in the
mold
...
The number of these cracks is
greatly reduced in the transition from water to a
soft water-air secondary cooling
...
Distributed internal
cracks perpendicular to the wide faces of the ingot (see
Figure 35, 4)
...
Such
cracks can also occur due to nonuniform thermal
stresses during the secondary cooling
...
) - clusters of small,
cracked similar type 4 and are arranged closer to
the center of the ingot formed in extension bar with
liquid core
...
Figure 35, 3) are arranged in the
slabs at their major axis in the clamping zone of the

crystallization front
...
The
bars of square cross section, where the shrinkage,
the shape is different axial cracks is concentrated in
the center of the ingot (see
...

Cracks perpendicular narrow faces (see
...
E with not
maintaining the ingot shell supporting devices
...
Figure 35, 2) at the junction of
crystals growing from the two adjacent faces are
found predominantly in ingots with a square section
profile in distortion obtuse angles
...
A
number of surface defects associated with a poor
ingot casting organization
...
Veining (transverse grooves on the
ingot surface) result from abrupt changes in the jet
and the metal level fluctuations of pressure in the

mold at a local erosion peel metal jet and gapping
portions crust to the walls of the mold
...
6 Casting and Rolling Complex

In the construction of these units utilize the
principle of the combined casting and rolling
processes blanks great length, i
...
two technologies continuous casting, the cross section of which is
approaching the parameters to the size of the
finished product, and of direct alignment with the
casting process by rolling a thin strip
...

Another embodiment of obtaining rolled sheet are
at Settings continuous strip casting
...

direct strip casting technique possesses many
advantages, but above all, it excludes the
conventional process operations such as casting and
stripping slab reheating and hot rolling
...

Of all rolling machines are currently in operation
only two roll machine (Figure 36)
...
The liquid steel enters the
space between the rollers and in contact with the
roll surface crystallizes, forming a crust, which
move together with the surface and out of the rolls
in the form of a sheet whose thickness is
determined by the distance between the rolls and
the width - the side walls of the mold
...
Initially, rolls made from steel, then
copper, is now the most widely used alloy of copper
and chromium, in some cases, the coated surface of
the roll with nickel, which provides a high thermal
conductivity, and sufficient mechanical strength of
the tool
...

A serious problem is the design of the side walls,
which must retain the liquid steel to prevent
breakouts from its mold and ensure uniform metal
temperature near the walls and in the middle part
of the mold, to prevent deformation of the sheet

edges
...

Research is being conducted on the retention bath
of molten steel by an electromagnetic field
...
Expanding upon heating rolls leads to a
reduction of the gap
...
It should, of course, to avoid
the formation of cracks and wrinkles on the sheet
surface, since the thin sheet casting crack depth of 1
mm may be through
...
Recent nonwettable made of steel composite
materials
...
5 and 1
...
8

mm) and thick (4
...
The maximum
period, respectively 100 and 129 min (90 m pouring
melting)
...

T
Figure 37 - The energy consumption (MJ / m) for
producing a thin sheet according to different
technological schemes
Tehnological scheme for producing a thin sheet
using a two-roll caster 8-10 times allows to reduce
the costs of energy resources 40-50 times to reduce
metal loss in scale, 5-10 times increase productivity
by 10-20 times to reduce greenhouse gas emissions
while substantially reducing the cost of capital
construction, which provides an economic
motivation in terms of its further development and
improvement
...


Recommended reading
Metals steel
...
Yavoyskogo VI and Kryakovskogo
Y
...
: Metallurgy, 1984
...
125-187
...
M
...
- S
...


Metallurgy steel
...
Bige
...
- S
...

Dyudkin, DA Modern technology of production of
steel
...
Dyudkin, VV Kisilenko
...
: Heat, 2007
...

Metals steel / Yavoysky, VI, Kryakovsky, YV,
Grigoriev, VP et al -
...
: Metallurgy, 1983
...

Kudrin, VA The theory and technology of steel:
Primer vuzov
...
: "Mir", OOO "Izdatelstvo AST",
2003
...

Chalmers, B
...
M
...
- 280 p
...
Replacement
equipment for casting steel
...
320C
...
M
...
- 464s
...
Liakishev, NP, Shalimov, AG M
...
- 208 p
...
- M
...
- 143c
...
- M
...
- 216c
...
Ferrous
metallurgy, 1990, №4
...
23-31

---

Title: Metalurgy Steel alloy
Description: Metallurgy is a domain of materials science and engineering that studies the physical and chemical behaviour of metallic elements, their intermetallic compounds, and their mixtures, which are called alloys. Metallurgy is also the technology of metals: the way in which science is applied to the production of metals, and the engineering of metal components for usage in products for consumers and manufacturers. The production of metals involves the processing of ores to extract the metal they contain, and the mixture of metals, sometimes with other elements, to produce alloys. Metallurgy is distinguished from the craft of metalworking, although metalworking relies on metallurgy, as medicine relies on medical science, for technical advancement. Metallurgy is subdivided into ferrous metallurgy (sometimes also known as black metallurgy) and non-ferrous metallurgy or colored metallurgy. Ferrous metallurgy involves processes and alloys based on iron while non-ferrous metallurgy involves processes and alloys based on other metals. The production of ferrous metals accounts for 95 percent of world metal production.

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