CN114875211B - Method for smelting stainless steel and efficiently desilicating - Google Patents
Method for smelting stainless steel and efficiently desilicating Download PDFInfo
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- CN114875211B CN114875211B CN202210539494.5A CN202210539494A CN114875211B CN 114875211 B CN114875211 B CN 114875211B CN 202210539494 A CN202210539494 A CN 202210539494A CN 114875211 B CN114875211 B CN 114875211B
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- 238000000034 method Methods 0.000 title claims abstract description 38
- 238000003723 Smelting Methods 0.000 title claims abstract description 32
- 239000010935 stainless steel Substances 0.000 title claims abstract description 21
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 21
- 239000002893 slag Substances 0.000 claims abstract description 62
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 58
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 56
- 239000001301 oxygen Substances 0.000 claims abstract description 56
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 56
- 238000007664 blowing Methods 0.000 claims abstract description 54
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 52
- 239000010959 steel Substances 0.000 claims abstract description 52
- 239000000956 alloy Substances 0.000 claims abstract description 36
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 27
- 230000008569 process Effects 0.000 claims abstract description 24
- 239000010703 silicon Substances 0.000 claims abstract description 23
- 238000005261 decarburization Methods 0.000 claims abstract description 14
- 239000000463 material Substances 0.000 claims abstract description 10
- 230000000694 effects Effects 0.000 claims abstract description 5
- 229910000604 Ferrochrome Inorganic materials 0.000 claims description 21
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 20
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 20
- 239000004571 lime Substances 0.000 claims description 20
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 18
- 238000010438 heat treatment Methods 0.000 claims description 18
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 14
- 229910045601 alloy Inorganic materials 0.000 claims description 14
- 229910000863 Ferronickel Inorganic materials 0.000 claims description 12
- 230000002349 favourable effect Effects 0.000 claims description 9
- 239000010459 dolomite Substances 0.000 claims description 8
- 229910000514 dolomite Inorganic materials 0.000 claims description 8
- 229910001080 W alloy Inorganic materials 0.000 claims description 6
- 238000006243 chemical reaction Methods 0.000 claims description 6
- 238000002360 preparation method Methods 0.000 claims description 6
- 230000009467 reduction Effects 0.000 claims description 6
- 238000002844 melting Methods 0.000 claims description 4
- 230000008018 melting Effects 0.000 claims description 4
- 239000002210 silicon-based material Substances 0.000 claims description 4
- 239000003575 carbonaceous material Substances 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 3
- 230000017525 heat dissipation Effects 0.000 claims description 3
- 239000011261 inert gas Substances 0.000 claims description 3
- 230000005855 radiation Effects 0.000 claims description 3
- 239000002699 waste material Substances 0.000 claims description 3
- 239000011819 refractory material Substances 0.000 abstract description 3
- 238000009628 steelmaking Methods 0.000 abstract description 2
- 230000003628 erosive effect Effects 0.000 abstract 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 12
- 229910001356 Nickel pig iron Inorganic materials 0.000 description 8
- 239000011651 chromium Substances 0.000 description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 6
- VNNRSPGTAMTISX-UHFFFAOYSA-N chromium nickel Chemical compound [Cr].[Ni] VNNRSPGTAMTISX-UHFFFAOYSA-N 0.000 description 6
- 229910052742 iron Inorganic materials 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000009529 body temperature measurement Methods 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 238000005070 sampling Methods 0.000 description 3
- 238000010079 rubber tapping Methods 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 241001062472 Stokellia anisodon Species 0.000 description 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 1
- VVTSZOCINPYFDP-UHFFFAOYSA-N [O].[Ar] Chemical compound [O].[Ar] VVTSZOCINPYFDP-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 229910000423 chromium oxide Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000004579 marble Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/072—Treatment with gases
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/005—Manufacture of stainless steel
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0006—Adding metallic additives
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0087—Treatment of slags covering the steel bath, e.g. for separating slag from the molten metal
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/068—Decarburising
- C21C7/0685—Decarburising of stainless steel
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/076—Use of slags or fluxes as treating agents
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master alloys
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention relates to the field of steelmaking, in particular to a method for efficiently desilicating smelted stainless steel. A method for smelting stainless steel and efficiently desilicating the stainless steel comprises the following steps: after high-carbon high-silicon premelt produced by a stainless steel primary smelting furnace is added into an AOD furnace, oxygen blowing desilication and decarburization are carried out by the AOD through a top gun and a bottom gun with high oxygen supply strength, meanwhile, in the blowing process, normal-temperature alloy materials are added through a high-level stock bin or a crown block material groove to control the temperature of molten steel to be in a desilication low-temperature state continuously, slag is added to control the alkalinity of desilication slag, and the aim of rapid desilication is achieved until desilication is completed. The method reduces the erosion of desilication slag to furnace shell refractory materials, and achieves the effect of completely replacing a desilication converter or a desilication electric furnace.
Description
Technical Field
The invention relates to the field of steelmaking, in particular to a method for efficiently desilicating smelted stainless steel.
Background
With the change of stainless steel smelting technology and the use of cheap high-carbon high-silicon materials, the carbon-silicon content of the steel-doped steel for AOD smelting is gradually increased, and the C content and the Si content of the steel-doped steel for AOD smelting by using an intermediate frequency furnace or submerged arc furnace premelt at present reach more than 3.0 percent and more than 2.0 percent.
The conventional production process of the AOD furnace for smelting stainless steel requires that the Si content of the steel-doped premelting solution is less than 0.6 percent, if the AOD uses the high-carbon high-silicon premelting solution (the C content is more than 3.0 percent and the Si content is more than 1.0 percent) for smelting the stainless steel, slag pouring operation is needed after the desilication is finished, but the silicon oxidation temperature rise speed is high, the high temperature is unfavorable for the desilication reaction, the desilication time is long, the desilication efficiency is low, the desilication end temperature is high in the general smelting process, the problems of serious corrosion of materials, splashing at the desilication end and the like occur in the desilication process, and the continuous production is influenced.
In practical production, in order to realize smelting of high-carbon high-silicon premelt, a desilication converter or a desilication electric furnace is added in the middle of a primary smelting furnace and an AOD furnace for desilication treatment and then is used for AOD, but the construction cost and the production step cost of the desilication converter or the desilication electric furnace are high, so that the enterprise benefit is seriously influenced, and therefore, the high-carbon high-silicon premelt is realized under the condition that the silicon content of the AOD premelt is very high, and the high-carbon high-silicon premelt is obtained through rapid and high-efficiency desilication.
Disclosure of Invention
The invention aims to solve the problems and provides a method for efficiently desilicating smelting stainless steel.
The purpose of the invention is realized in the following way: a method for smelting stainless steel and efficiently desilicating the stainless steel comprises the following steps: after high-carbon high-silicon premelt produced by a stainless steel primary smelting furnace is added into an AOD furnace, oxygen blowing desilication and decarburization are carried out by the AOD through a top gun and a bottom gun with high oxygen supply strength, meanwhile, in the blowing process, normal-temperature alloy materials are added through a high-level stock bin or a crown block material groove to control the temperature of molten steel to be in a desilication low-temperature state continuously, slag is added to control the alkalinity of desilication slag, and the aim of rapid desilication is achieved until desilication is completed.
The high oxygen supply intensity aims to improve smelting efficiency, shorten smelting time and reduce stay time of desilication slag in a furnace, and the air supply parameters in the blowing process of the top gun and the bottom gun are as follows: the top gun adopts a low gun position of 2.0-2.5m, the oxygen supply intensity of the top gun is 1.4-1.8Nm3/min t, the oxygen supply intensity of the bottom gun is 1.0-1.5Nm3/min t, and the inert gas supply intensity of the bottom gun is 0.25-0.40Nm3/min t.
The normal temperature alloy material is high carbon ferrochrome, ferronickel and scrap steel, the addition amount of which is calculated according to the formula (1) to calculate the effective temperature T of molten steel at the end of desilication 1 Selection of effective temperature T at the end of the desilication period 1 : according to the steel adding condition, referring to the decarburization desilication heating rate formulas (2) and (3) and the alloy material cooling quantity T Alloy Controlling the temperature of molten steel at 1500-1550 ℃ after desilication, and selecting the adding time of normal-temperature alloy materials to preferentially add high-carbon high-silicon materials and then add low-carbon materials; all normal temperature alloy materials are added as early as possible, and a stripping and melting mode is adopted,the molten steel is kept in a low-temperature state which is favorable for desilication, and the utilization rate of desilication oxygen is improved;
T 1 =T 0 +(t Si +t c )*t-b-T alloy ①
T 0 For the initial temperature of the premelt, DEG C,
t Si for the desilication heating rate, DEG C/min,
t c for decarburization heating rate, the temperature is increased at the temperature of/min,
t is the oxygen blowing time, min,
b is the radiation heat dissipation constant, DEG C,
T alloy The temperature reduction value of the ton alloy for the ton melt is as follows: high-carbon ferrochrome 1350 ℃, high-carbon ferrochrome 1450 ℃, high-carbon ferronickel 1550 ℃, low-carbon ferronickel 1650 ℃, various waste steels 1650 ℃ and ordinary lime 1850 ℃;
t Si =I*0.8/10*M Si *X Si ②
i is oxygen supply intensity, nm 3 /（min*t），
M Si Is 1wt% of silicon heating amount, DEG C,
X Si is the desilication oxygen utilization coefficient,%;
t C =I*0.933/10*M C *（1-X Si -n） ③
M C is 1wt% of carbon heating amount, DEG C
n is the oxygen coefficient for decarbonizing and desilicating and takes a constant value of 3-8 percent.
The slag is lime and dolomite, and the addition amount of the slag is as follows: the dolomite is added to increase MgO content in the slag, the effect of protecting the furnace lining is achieved, the addition amount is 1.0-3.0t, the addition amount of lime is calculated according to the alkalinity of desilication slag, the control principle is that the lime is added as early as possible in the early stage of desilication, the alkalinity of the slag in the early-middle stage of desilication is improved, the alkalinity of the slag is gradually reduced along with the progress of desilication reaction, and the slag is controlled to be reduced to 1.3-1.6 until the desilication is finished; the specific lime addition is calculated according to formula (4):
M ash of ash =（M Pre-preparation *10*W Si +M Alloy *10* W Alloy Si ）*2.14*R/Y CaO ④
M Pre-preparation For the amount of pre-melt, t,
W Si the content of Si in the premelt solution,%,
M alloy The addition amount of the alloy, t,
W alloy Si For the Si content,%,
r is the alkalinity target and is a target of the alkalinity,
Y CaO effective content of CaO in lime,%.
The molten steel temperature is favorable for the desilication in a low-temperature state, and the temperature range is 1400-1450 ℃.
Said X Si 、M Si 、M C Definition of M Si The temperature rise of 1wt% of carbon is 340-350 ℃, and M is defined C 1wt% of carbon with a heating rate of 110-120 ℃, X Si For desilication oxygen utilization coefficient, the temperature is 1400-1450 ℃ and is related to the C content in the molten steel, and the C content of the molten steel is more than 4.0 percent and X is higher than X Si 55-60%, X is the content of molten steel C of 3.0-4.0% Si 60 to 64 percent, and X is the content of molten steel C is 2.0 to 3.0 percent Si 64-68%, X is contained in molten steel with C content of 1.0-2.0% Si 68-71%.
The beneficial effects of the invention are as follows: the method carries out oxygen blowing desilication and decarburization by using a top gun and a side (bottom) gun with high oxygen supply strength through AOD (argon oxygen decarburization) combined blowing, simultaneously adds slag in the blowing process to control the alkalinity of desilication slag, and adds a large amount of normal-temperature alloy materials, and controls the temperature of a molten pool to be continuously at the favorable temperature of desilication reaction, thereby realizing the rapid desilication in the blowing desilication period when the AOD uses high-carbon high-silicon melt to smelt stainless steel, providing support for the reduction and pouring out of the follow-up desilication slag, reducing the time of the desilication slag in a furnace, reducing the corrosion of the desilication slag to furnace shell refractory materials, and achieving the effect of completely replacing a desilication converter or a desilication electric furnace.
Drawings
The invention is further described below with reference to the accompanying drawings.
FIG. 1 is a diagram of the production practice of the bath temperature, cold charge at ambient temperature and converting time during converting according to the present invention.
Detailed Description
In order to solve the technical problems, the invention adopts the following technical scheme: after high-carbon high-silicon premelt produced by a stainless steel primary smelting furnace is added into an AOD furnace, oxygen blowing desilication and decarburization are carried out on the AOD by using a top gun and a side (bottom) gun with high oxygen supply strength, and meanwhile, a large amount of high-carbon ferrochrome, ferronickel, scrap steel and other normal-temperature alloy materials are added into a high-level stock bin or a crown block trough in the blowing process to control the temperature of molten steel to be in a low-temperature state favorable for desilication continuously, slag is added to control the alkalinity of desilication slag, and the aim of rapid desilication is fulfilled until desilication is completed.
The high oxygen supply intensity aims to improve smelting efficiency, shorten smelting time and reduce stay time of desilication slag in a furnace, and the preferable air supply parameters in the blowing process of the top gun and the bottom gun are as follows: the top lance adopts a low lance position of 2.0-2.5m and the oxygen supply intensity of the top lance is 1.4-1.8Nm 3 Per min t, oxygen supply intensity of bottom gun of 1.0-1.5Nm 3 Per min t, the inert gas supply intensity of the bottom gun is 0.25-0.40Nm 3 And/min t. (the molten steel amount to be referred to in calculating the strength of the supplied gas is the molten steel amount of the tapped steel)
The adding amount of the normal-temperature alloy material is calculated according to the formula (1) to obtain the effective temperature T of molten steel at the end of desilication 1 . Selection of effective temperature T at the end of the desilication period 1 : according to the steel adding condition, referring to the decarburization desilication heating rate formulas (2) and (3) and the alloy material cooling quantity T Alloy And controlling the temperature of molten steel at 1500-1550 ℃ after desilication is finished. The adding time of the normal temperature alloy material is selected to be preferentially added with the high carbon and high silicon materials, and then the low carbon materials are added; all normal temperature alloy materials are added as early as possible, and the molten steel is kept in a low temperature state which is favorable for desilication by adopting a stripping melting mode, so that the utilization rate of desilication oxygen is improved.
T 1 =T 0 +(t Si +t c )*t-b-T Alloy ①
T 0 Is the initial temperature of the premelt solution, DEG C
t Si For desilication heating rate, DEG C/min
t c For decarburization heating rate, DEG C/min
t is oxygen blowing time, min
b is radiation heat dissipation constant, DEG C
T Alloy The temperature reduction value of the normal temperature alloy to ton molten liquid is as follows: high-carbon ferrochrome 1350 ℃, high-carbon ferrochrome 1450 ℃, high-carbon ferronickel 1550 ℃, low-carbon ferronickel 1650 ℃, various waste steels 1650 ℃ and ordinary lime 1850 DEG C
t Si =I*0.8/10*M Si *X Si ②
I is oxygen supply intensity, nm 3 /（min*t）
M Si Is 1wt% silicon heating amount, DEG C
X Si For desilication oxygen utilization coefficient%
t C =I*0.933/10*M C *（1-X Si -n） ③
M C Is 1wt% of carbon heating amount, DEG C
n is the oxygen coefficient for decarbonizing and desilicating, and is constant and is generally 3-8%
The slag is mainly Dan Huibai marble; the addition amount is as follows: the dolomite is mainly added to increase the MgO content in the slag, so as to protect the furnace lining, and the addition amount is generally 1.0-3.0t. The lime addition amount is calculated according to the desilication slag alkalinity, the control principle is that the lime is added as early as possible in the desilication initial stage, the slag alkalinity in the desilication initial-middle stage is improved, the slag alkalinity is gradually reduced along with the desilication reaction, the desilication is finished, and the slag is controlled to be reduced to 1.2-1.5. The specific lime addition is calculated according to formula (4):
M ash of ash =（M Pre-preparation *10*W Si +M Alloy *10* W Alloy Si ）*2.14*R/Y CaO ④
M Pre-preparation T is the amount of premelted solution
W Si Si content in the premelt solution%
M Alloy Alloy addition amount, t
W Alloy Si Si content in each alloy,%
R is an alkalinity target
Y CaO Effective content of CaO in lime%
After desilication is finished, reducing and recycling chromium oxide in the slag, and pouring out desilication slag; the desilication slag is left in the furnace, so that on one hand, the slag alkalinity is low in the converting process, and splashing is easily caused when the converting is continued; on the other hand, if the alkalinity in the converting process is increased, the slag quantity in the furnace is overlarge, the service life of the refractory is reduced, and the loss of chromium and nickel in the slag in the reduction period is increased.
The molten steel temperature is favorable for the desilication in a low-temperature state, and the temperature range is 1400-1450 ℃.
Said X Si 、M Si 、M C Definition of M Si The temperature rise of 1wt% of carbon is 340-350 ℃, and M is defined C 1wt% of carbon with a heating rate of 110-120 ℃, X Si For desilication oxygen utilization factor, at a temperature between 1400-1450 ℃, related to the C content in the molten steel, the reference factors are as follows:
| c content of molten steel | ＞4.0% | 3.0-4.0% | 2.0-3.0% | 1.0-2.0% |
| X Si | 55-60% | 60-64% | 64-68% | 68-71% |
The invention provides a high-efficiency desilication method for AOD smelting stainless steel, which comprises the steps of carrying out oxygen blowing desilication and decarburization by using a top gun and a side (bottom) gun with high oxygen supply strength for combined blowing, simultaneously adding slag in the blowing process to control the alkalinity of desilication slag, adding a large amount of normal-temperature alloy materials, controlling the temperature of a molten pool to be continuously at the favorable temperature of desilication reaction, realizing rapid desilication in the blowing desilication period when the AOD is used for smelting stainless steel, providing support for reduction and pouring of subsequent desilication slag, reducing the time of the desilication slag in a furnace, reducing the corrosion of the desilication slag to furnace shell refractory materials, and achieving the effect of completely replacing a desilication converter or a desilication electric furnace.
Examples
The invention is described in further detail below in connection with specific examples:
example 1
The 180t top side combined blowing AOD furnace uses a premelt solution produced by an intermediate frequency furnace for smelting 304, and the embodiment comprises the following steps in sequence:
1) Adding high-carbon ferrochrome and ferrochrome-nickel pig iron into an intermediate frequency furnace for melting, tapping to a premelting ladle after smelting into premelting liquid, wherein the tapping amount is 110t, and the weight percentage of each element is C:4.2%, si:3.3%, cr:23%, ni:6.5% of iron and the balance of unavoidable impurities.
2) Adding the premelt into an AOD furnace, shaking the furnace to measure the temperature, regulating the temperature to 1415 ℃, blowing after shaking the furnace, and blowing a top lance with the lance position of 2.6m and the oxygen flow of 290Nm of the top lance 3 Per minute, bottom lance oxygen flow 160Nm 3 Per min, bottom gun nitrogen flow 35Nm 3 /min。
3) After blowing is started, adding high-carbon ferrochrome 25t, lime 15t and dolomite 1.5t from a high-level bin, and blowing oxygen to 1500Nm 3 When the chromium-nickel pig iron is added through a trough for 55t, all materials are added as soon as possible in the desilication period, and the oxygen blowing amount of the furnace is 3325Nm 3 When all the materials are added. The weight percentage of C in the high-carbon ferrochrome is 7.8%, the weight percentage of Si is 3.5%, and the weight percentage of Cr is 50.5%; the weight percentage of C in the chromium-nickel pig iron is 2.7 percent, and the weight percentage of Si is 1.5The weight percentage of Cr is 2.3 percent, and the weight percentage of Ni is 9.8 percent.
4) When the oxygen blowing amount reaches 5609Nm 3 When the blowing is stopped. And (5) temperature measurement and sampling are carried out in the deslagging process of the desilication slag. Measuring the temperature to 1521 ℃, and taking a steel sample and a slag sample to confirm components, wherein the steel sample comprises the following elements in percentage by weight: c:3.4%, si:0.21%, cr:18.9%, ni:6.4 percent of iron and unavoidable elements, and Cr in slag 2 O 3 The content is 1.05%, and the slag alkalinity is 1.31.
In the example, the content of carbon and silicon in the AOD steel-added alloy material is higher than that in the conventional process, the content of carbon and silicon in the high-carbon ferrochrome and chromium-nickel pig iron in the alloy material added in the blowing process is also higher, the total silicon amount removed in the blowing process is 4.7t, and the oxygen blowing time in the desilication period is 12.4min.
Example 2
The pre-melt smelting 304 produced by the submerged arc furnace is performed in the 120t top side combined blowing AOD furnace, and the embodiment comprises the following steps in sequence:
1) Adding the premelt produced by the submerged arc furnace into an AOD furnace, adding 66t of steel, and adding the weight percentage C of each element of the steel components: 3.1%, si:2.2%, cr:2.3%, ni:10.3% of iron and the balance of unavoidable impurities.
2) Adding the premelt into an AOD furnace, shaking the furnace to measure the temperature, shaking the furnace to correct the temperature to 1378 ℃, blowing, and blowing a top lance with the lance position of 2.6m and the oxygen flow of 160Nm 3 Per min, bottom lance oxygen flow 120Nm 3 Per min, bottom gun nitrogen flow 20Nm 3 /min。
3) After blowing is started, adding high-carbon ferrochrome 30t, lime 8.5t and dolomite 1.0t from a high-level bin, and blowing oxygen to 1000Nm 3 When the chromium-nickel pig iron is added through a trough for 16t, all materials are added as soon as possible in the desilication period, and the oxygen blowing amount of the furnace is 2131Nm 3 When all the materials are added. The weight percentage of C in the high-carbon ferrochrome is 8.0%, the weight percentage of Si is 3.0%, and the weight percentage of Cr is 52.1%; the weight percentage of C, si, cr and Ni in the chromium-nickel pig iron is 2.6%, 1.4%, 2.0% and 9.5%, respectively.
4) When the oxygen blowing amount reaches 3456Nm 3 When the blowing is stopped. Feeding silicon-removed slag in the slag pouring processAnd (5) performing line temperature measurement and sampling. Measuring the temperature to 1546 ℃, and taking a steel sample and a slag sample to confirm components, wherein the steel sample comprises the following elements in percentage by weight: c:2.6 % of Si:0.29%, cr:15.7%, ni:7.8 percent of iron and unavoidable elements, and Cr in slag 2 O 3 The content is 0.77%, and the slag alkalinity is 1.34.
The content of carbon and silicon in the premelted liquid produced by the submerged arc furnace is higher than that in the conventional process, the content of carbon and silicon in the high-carbon ferrochrome and chromium-nickel pig iron in the alloy materials added in the blowing process is also higher, the total silicon amount removed in the blowing process is 2.2t, and the oxygen blowing time in the desilication period is 10.9min.
Example 3
The 180t top side combined blowing AOD furnace is used for smelting 304 premelt produced by an intermediate frequency furnace and an electric furnace, and the embodiment comprises the following steps in sequence:
1) Smelting high-carbon ferrochrome in a medium-frequency furnace, smelting ferrochrome and nickel pig iron in an electric furnace, mixing the produced premelt solution, adding the mixture into an AOD furnace, adding 175t of steel, and adding the weight percentage C of each element of steel components: 2.8%, si:1.4%, cr:16.5%, ni:5.6% of iron and the balance of unavoidable impurities.
2) Adding the premelt into an AOD furnace, shaking the furnace to measure the temperature, shaking the furnace to be normal at 1423 ℃, blowing, and blowing a top lance with the lance position of 2.7m and the oxygen flow of 280Nm 3 Per min, bottom lance oxygen flow 130Nm 3 Per min, bottom gun nitrogen flow 40Nm 3 /min。
3) After blowing is started, adding high-carbon ferrochrome 18t, lime 9.5t and dolomite 1.5t from a high-level bin, then adding high-carbon ferronickel 15t, adding all materials in the desilication period as soon as possible, and blowing oxygen 1931Nm in the heat of the furnace 3 When all the materials are added. The weight percentage of C in the high-carbon ferrochrome is 7.8%, the weight percentage of Si is 2.7%, and the weight percentage of Cr is 51.9%; the weight percentage of C in the high-carbon ferronickel is 2.1%, the weight percentage of Si is 1.8%, and the weight percentage of Ni is 18.5%.
4) When the oxygen blowing amount reaches 3446Nm 3 When the blowing is stopped. And (5) temperature measurement and sampling are carried out in the deslagging process of the desilication slag. Measuring the temperature to 1546 ℃, and taking a steel sample and a slag sample to confirm components, wherein the steel sample comprises the following elements in percentage by weight: c:2.5 % of Si:0.24%, cr:18.5% Ni:6.2 percent of iron and unavoidable elements, and Cr in slag 2 O 3 The content is 0.83%, and the slag alkalinity is 1.39.
The content of carbon and silicon in the premelted solution produced by the intermediate frequency furnace and the electric furnace is higher than that in the conventional process, the content of carbon and silicon in the high-carbon ferrochrome and the high-carbon ferronickel in the alloy materials added in the blowing process is also higher, the total silicon amount removed in the blowing process is 2.7t, and the oxygen blowing time in the desilication period is 8.5min.
The above embodiments are merely examples of the present invention, but the present invention is not limited to the above embodiments, and any changes or modifications within the scope of the present invention are intended to be included in the scope of the present invention.
Claims (2)
1. A method for smelting stainless steel and efficiently desilicating is characterized in that: the method comprises the following steps: after high-carbon high-silicon premelt produced by a stainless steel primary smelting furnace is added into an AOD furnace, oxygen blowing desilication and decarburization are carried out by the AOD through a top gun and a bottom gun with high oxygen supply strength, and meanwhile, in the blowing process, normal-temperature alloy materials are added through a high-level stock bin or a crown block material tank to control the temperature of molten steel to be in a desilication low-temperature state continuously, slag is added to control the alkalinity of desilication slag, so that the aim of rapid desilication is fulfilled, and desilication is completed;
the high oxygen supply intensity aims to improve smelting efficiency, shorten smelting time and reduce stay time of desilication slag in a furnace, and the air supply parameters in the blowing process of the top gun and the bottom gun are as follows: the top gun adopts a low gun position of 2.0-2.5m, the oxygen supply intensity of the top gun is 1.4-1.8Nm3/min t, the oxygen supply intensity of the bottom gun is 1.0-1.5Nm3/min t, and the inert gas supply intensity of the bottom gun is 0.25-0.40Nm3/min t; the normal temperature alloy material is high carbon ferrochrome, ferronickel and scrap steel, the addition amount of which is calculated according to the formula (1) to calculate the effective temperature T of molten steel at the end of desilication 1 Selection of effective temperature T at the end of the desilication period 1 : according to the steel adding condition, referring to the decarburization desilication heating rate formulas (2) and (3) and the alloy material cooling quantity T Alloy Controlling the temperature of molten steel at 1500-1550 ℃ after desilication, and selecting the adding time of normal-temperature alloy materials to preferentially add high-carbon high-silicon materials and then add low-carbon materials; all usualThe temperature alloy material is added as early as possible, and the molten steel is kept in a low-temperature state which is favorable for desilication by adopting a stripping melting mode, so that the utilization rate of desilication oxygen is improved;
T 1 ＝T 0 +(t Si +t c )*t-b-T alloy ①
T 0 For the initial temperature of the premelt, DEG C,
t Si for the desilication heating rate, DEG C/min,
t c for decarburization heating rate, the temperature is increased at the temperature of/min,
t is the oxygen blowing time, min,
b is the radiation heat dissipation constant, DEG C,
T alloy The temperature reduction value of the ton alloy for the ton melt is as follows: high-carbon ferrochrome 1350 ℃, high-carbon ferrochrome 1450 ℃, high-carbon ferronickel 1550 ℃, low-carbon ferronickel 1650 ℃, various waste steels 1650 ℃ and ordinary lime 1850 ℃;
t Si ＝I*0.8/10*M Si *X Si ②
i is oxygen supply intensity, nm 3 /(min*t)，
M Si Is 1wt% of silicon heating amount, DEG C,
X Si for desilication oxygen utilization coefficient,%,
t C ＝I*0.933/10*M C *(1-X Si -n) ③
M C is 1wt% of carbon heating amount, DEG C
n is the oxygen coefficient for removing decarburization and desilication, and the constant value is 3-8%;
the slag is lime and dolomite, and the addition amount of the slag is as follows: the dolomite is added to increase MgO content in the slag, the effect of protecting the furnace lining is achieved, the addition amount is 1.0-3.0t, the addition amount of lime is calculated according to the alkalinity of desilication slag, the control principle is that the lime is added as early as possible in the early stage of desilication, the alkalinity of the slag in the early-middle stage of desilication is improved, the alkalinity of the slag is gradually reduced along with the progress of desilication reaction, and the slag is controlled to be reduced to 1.3-1.6 until the desilication is finished; the specific lime addition is calculated according to formula (4):
M ash of ash ＝(M Pre-preparation *10*W Si +M Alloy *10*W Alloy Si )*2.14*R/Y CaO ④
M Pre-preparation For the amount of pre-melt, t,
W Si the content of Si in the premelt solution,%,
M alloy The addition amount of the alloy, t,
W alloy Si For the Si content,%,
r is the alkalinity target and is a target of the alkalinity,
Y CaO effective content of CaO in lime,%;
the molten steel temperature is favorable for the desilication in a low-temperature state, and the temperature range is 1400-1450 ℃.
2. The method for efficiently desilicating the smelted stainless steel according to claim 1, wherein the method comprises the following steps: said X Si 、M Si 、M C Definition of M Si The temperature rise of 1wt% of carbon is 340-350 ℃, and M is defined C 1wt% of carbon with a heating rate of 110-120 ℃, X Si For desilication oxygen utilization coefficient, the temperature is 1400-1450 ℃ and is related to the C content in the molten steel, and the C content of the molten steel is more than 4.0 percent and X is higher than X Si 55-60%, X is the content of molten steel C of 3.0-4.0% Si 60 to 64 percent, and X is the content of molten steel C is 2.0 to 3.0 percent Si 64-68%, X is contained in molten steel with C content of 1.0-2.0% Si 68-71%.
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| GB2141739A (en) * | 1983-05-18 | 1985-01-03 | Nisshin Steel Co Ltd | Process for producing low P chromium-containing steel |
| CN101928804A (en) * | 2010-08-31 | 2010-12-29 | 振石集团东方特钢股份有限公司 | Production method of austenitic stainless steel |
| CN105970112A (en) * | 2016-06-24 | 2016-09-28 | 邢台钢铁有限责任公司 | Large-specification and low-strength 2Cr13 annealing wire and production method thereof |
| CN113737082A (en) * | 2021-08-27 | 2021-12-03 | 中冶赛迪工程技术股份有限公司 | Method for smelting nickel-chromium stainless steel by using high-nickel molten iron for AOD furnace |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| GB2141739A (en) * | 1983-05-18 | 1985-01-03 | Nisshin Steel Co Ltd | Process for producing low P chromium-containing steel |
| CN101928804A (en) * | 2010-08-31 | 2010-12-29 | 振石集团东方特钢股份有限公司 | Production method of austenitic stainless steel |
| CN105970112A (en) * | 2016-06-24 | 2016-09-28 | 邢台钢铁有限责任公司 | Large-specification and low-strength 2Cr13 annealing wire and production method thereof |
| CN113737082A (en) * | 2021-08-27 | 2021-12-03 | 中冶赛迪工程技术股份有限公司 | Method for smelting nickel-chromium stainless steel by using high-nickel molten iron for AOD furnace |
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