CN114875211A - Efficient desiliconization method for smelting stainless steel - Google Patents
Efficient desiliconization method for smelting stainless steel Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 44
- 238000003723 Smelting Methods 0.000 title claims abstract description 25
- 239000010935 stainless steel Substances 0.000 title claims abstract description 25
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 25
- 239000002893 slag Substances 0.000 claims abstract description 59
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 55
- 239000001301 oxygen Substances 0.000 claims abstract description 55
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 55
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 52
- 238000007664 blowing Methods 0.000 claims abstract description 47
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 44
- 239000010959 steel Substances 0.000 claims abstract description 44
- 239000000956 alloy Substances 0.000 claims abstract description 38
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 30
- 230000008569 process Effects 0.000 claims abstract description 27
- 239000010703 silicon Substances 0.000 claims abstract description 24
- 239000007788 liquid Substances 0.000 claims abstract description 22
- 238000005261 decarburization Methods 0.000 claims abstract description 14
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 18
- 229910000604 Ferrochrome Inorganic materials 0.000 claims description 18
- 240000006909 Tilia x europaea Species 0.000 claims description 18
- 229910045601 alloy Inorganic materials 0.000 claims description 17
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 16
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 16
- 239000004571 lime Substances 0.000 claims description 16
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 15
- 229910001356 Nickel pig iron Inorganic materials 0.000 claims description 11
- VNNRSPGTAMTISX-UHFFFAOYSA-N chromium nickel Chemical compound [Cr].[Ni] VNNRSPGTAMTISX-UHFFFAOYSA-N 0.000 claims description 11
- 229910000514 dolomite Inorganic materials 0.000 claims description 11
- 239000010459 dolomite Substances 0.000 claims description 11
- 229910000863 Ferronickel Inorganic materials 0.000 claims description 9
- 230000009467 reduction Effects 0.000 claims description 7
- 230000009286 beneficial effect Effects 0.000 claims description 6
- 238000006243 chemical reaction Methods 0.000 claims description 6
- 238000002360 preparation method Methods 0.000 claims description 6
- 229910001080 W alloy Inorganic materials 0.000 claims description 5
- 230000002349 favourable effect Effects 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 5
- 238000002844 melting Methods 0.000 claims description 5
- 230000008018 melting Effects 0.000 claims description 5
- 238000005262 decarbonization Methods 0.000 claims description 3
- 230000017525 heat dissipation Effects 0.000 claims description 3
- 239000011261 inert gas Substances 0.000 claims description 3
- 230000014759 maintenance of location Effects 0.000 claims description 3
- 230000005855 radiation Effects 0.000 claims description 3
- 238000004904 shortening Methods 0.000 claims description 3
- 229910000805 Pig iron Inorganic materials 0.000 claims description 2
- 239000011819 refractory material Substances 0.000 abstract description 4
- 230000000694 effects Effects 0.000 abstract description 3
- 238000009628 steelmaking Methods 0.000 abstract description 2
- 230000003628 erosive effect Effects 0.000 abstract 1
- 239000011651 chromium Substances 0.000 description 15
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 12
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 11
- 229910052804 chromium Inorganic materials 0.000 description 7
- 229910052759 nickel Inorganic materials 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 229910052742 iron Inorganic materials 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 4
- 241001062472 Stokellia anisodon Species 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
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 238000005070 sampling Methods 0.000 description 3
- VVTSZOCINPYFDP-UHFFFAOYSA-N [O].[Ar] Chemical compound [O].[Ar] VVTSZOCINPYFDP-UHFFFAOYSA-N 0.000 description 2
- 238000010079 rubber tapping Methods 0.000 description 2
- 239000002210 silicon-based material Substances 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 230000008859 change Effects 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
- UGKDIUIOSMUOAW-UHFFFAOYSA-N iron nickel Chemical compound [Fe].[Ni] UGKDIUIOSMUOAW-UHFFFAOYSA-N 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
- 239000002699 waste material Substances 0.000 description 1
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- 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
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- 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
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- 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
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- 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
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- 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
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- 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
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Abstract
The invention relates to the field of steelmaking, in particular to a method for efficiently desiliconizing smelted stainless steel. A method for efficiently desiliconizing smelted stainless steel comprises the following steps: after high-carbon high-silicon premelting liquid produced by a stainless steel primary smelting furnace is added into an AOD furnace, the AOD furnace uses a top gun and a bottom gun with high oxygen supply strength to carry out oxygen blowing desiliconization and decarburization, and meanwhile, normal-temperature alloy materials are added through a high-position stock bin or a crown block trough in the blowing process to control the temperature of molten steel to be continuously in a low-temperature desiliconization state, and slag is added to control the alkalinity of desiliconized slag to achieve the aim of rapid desiliconization until the desiliconization is finished. The method reduces the erosion of the desiliconized slag to the refractory material of the furnace shell, and achieves the effect of completely replacing a desiliconized converter or a desiliconized electric furnace.
Description
Technical Field
The invention relates to the field of steelmaking, in particular to a method for efficiently desiliconizing smelted stainless steel.
Background
With the change of the stainless steel smelting process and the use of cheap high-carbon high-silicon materials, the carbon and silicon contents of AOD smelting stainless steel and steel are gradually increased, and currently, the AOD uses an intermediate frequency furnace or a submerged arc furnace to pre-melt the molten steel and smelt the stainless steel and mix the C content to be more than 3.0 percent and the Si content to be more than 2.0 percent.
The conventional production process of the AOD furnace for smelting stainless steel requires that the Si content of a steel-adding premelting liquid is less than 0.6 percent, and if the AOD uses a high-carbon high-silicon premelting liquid (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 required after desiliconization is finished, but because the silicon oxidation temperature rise speed is high, the high temperature is not beneficial to the desiliconization reaction, the desiliconization time is long, the desiliconization efficiency is low, the temperature at the final desiliconization stage is high, the problems of serious corrosion of materials, splashing at the final desiliconization stage and the like occur in the desiliconization process, and the continuous production is influenced.
In practical production, in order to realize smelting of the high-carbon high-silicon premelting liquid, a desiliconization converter or a desiliconization electric furnace is added in a ring section between a primary smelting furnace and an AOD furnace for desiliconization treatment and then used for AOD, but the desiliconization converter or the desiliconization electric furnace is high in construction cost and production step cost and seriously affects enterprise benefits, so that under the condition that the silicon content of the AOD premelting liquid is very high, the realization of rapid and efficient desiliconization becomes important research content for AOD smelting of the high-carbon high-silicon premelting liquid.
Disclosure of Invention
The invention aims to solve the problems and provides a method for efficiently desiliconizing smelted stainless steel.
The purpose of the invention is realized as follows: a method for efficiently desiliconizing smelted stainless steel comprises the following steps: after high-carbon high-silicon premelting liquid produced by a stainless steel primary smelting furnace is added into an AOD furnace, the AOD furnace uses a top gun and a bottom gun with high oxygen supply strength to carry out oxygen blowing desiliconization and decarburization, and meanwhile, normal-temperature alloy materials are added through a high-position stock bin or a crown block trough in the blowing process to control the temperature of molten steel to be continuously in a low-temperature desiliconization state, and slag is added to control the alkalinity of desiliconized slag to achieve the aim of rapid desiliconization until the desiliconization is finished.
The high oxygen supply intensity aims at improving the smelting efficiency, shortening the smelting time and reducing the retention time of the desiliconized slag in the furnace, and the air supply parameters of the top lance and the bottom lance in the blowing process are as follows: the top lance adopts a low lance position of 2.0-2.5m, the oxygen supply intensity of the top lance is 1.4-1.8Nm3/min t, the oxygen supply intensity of the bottom lance is 1.0-1.5Nm3/min t, and the inert gas supply intensity of the bottom lance is 0.25-0.40 Nm3/min t.
The normal temperature alloy materials are high carbon ferrochrome, chromium-nickel pig iron, ferronickel and scrap steel, and the total adding amount of the alloy materials is calculated according to a formula (I) 1 Selecting the effective temperature T at the end of the desilication period 1 : according to the steel-adding condition, referring to the formula of temp. -rising rate for decarbonization and desilication and the temp. -lowering quantity of alloy material Alloy (I) Controlling the temperature of molten steel at 1500-; all normal-temperature alloy materials are added as early as possible, a stripping and melting mode is adopted, molten steel is kept in a low-temperature state beneficial to desiliconization continuously, and the desiliconization oxygen utilization rate is improved;
T 1 =T 0 +(t Si +t c )*t-b-T alloy (I) ①
T 0 Is the initial temperature of the pre-molten liquid, DEG C,
t Si the heating rate for desiliconization is DEG C/min,
t c the heating rate of decarburization at DEG C/min,
t is the oxygen blowing time, min,
b is the radiation heat dissipation constant, DEG C,
T alloy (I) The temperature reduction amount of the alloy at normal temperature is measured at the temperature, and the temperature reduction amount of the ton of melt by the ton of alloy is measured as follows: high-carbon ferrochrome 1350 ℃, high-carbon ferrochrome pig iron 1450 ℃, high-carbon ferronickel 1550 ℃, low-carbon ferronickel 1650 ℃, various scrap steels 1650 ℃ and common lime 1850 ℃;
t Si =I*0.8/10*M Si *X Si ②
i is the oxygen supply intensity, Nm 3 /（min*t），
M Si 1wt% silicon temperature rise, DEG C,
X Si the desiliconization oxygen utilization coefficient,%;
t C =I*0.933/10*M C *（1-X Si -n） ③
M C 1wt% carbon rise, DEG C
n is the oxygen coefficient for removing decarburization and desilication, and is a constant value of 3-8%.
The slag charge is lime and dolomite, and the addition amount is as follows: the dolomite is added to increase the MgO content in the slag to play a role in protecting a furnace lining, the addition amount is 1.0-3.0t, the lime addition amount needs to be calculated according to the desiliconization slag alkalinity, the control principle is that the dolomite is added as early as possible at the initial desiliconization stage, the slag alkalinity at the initial desiliconization stage and the middle stage of the desiliconization is improved, the slag alkalinity is gradually reduced along with the progress of the desiliconization reaction, and the slag is controlled to be reduced to 1.3-1.6 after the desiliconization is finished; the specific lime addition is calculated according to a formula (IV):
M ash of =（M Preparation of *10*W Si +M Alloy (I) *10* W Alloy Si ）*2.14*R/Y CaO ④
M Preparation of The amount of pre-melt, t,
W Si the content of Si in the pre-molten liquid is percent,
M alloy (I) The amount of alloy added, t,
W alloy Si The content of Si in each alloy,%,
r is the target of alkalinity,
Y CaO the effective content of CaO in the lime is percent.
The temperature of the molten steel is favorable for the low-temperature state of desiliconization, and the temperature range is 1400-1450 ℃.
Said X Si 、M Si 、M C Definition of M Si The 1wt% carbon temperature rise is 340-350 ℃, and M is clear C 1wt% carbon temperature rise of 110- Si For the desiliconization oxygen utilization coefficient, the temperature is between 1400 ℃ and 1450 ℃, the temperature is related to the C content in the molten steel, and X is more than 4.0 percent Si 55-60 percent of X when the content of the molten steel C is 3.0-4.0 percent Si 60-64 percent of X when the content of the molten steel C is 2.0-3.0 percent Si 64-68 percent of X when the content of the molten steel C is 1.0-2.0 percent Si Is 68-71%.
The invention has the beneficial effects that: according to the method, oxygen blowing desilicication and decarburization are carried out by AOD (argon oxygen decarburization) combined blowing by using a top gun and a side (bottom) gun with high oxygen supply strength, slag is added in the blowing process to control the alkalinity of desilicication slag, a large amount of normal-temperature alloy materials are added, and the temperature of a molten pool is controlled to be continuously at the favorable temperature of desilicication reaction, so that when AOD uses high-carbon high-silicon melt to smelt stainless steel, the quick desilicication in the blowing desilicication period is realized, support is provided for the reduction and pouring of subsequent desilicication slag, the time of desilicication slag in the furnace is reduced, the corrosion of desilicication slag to a furnace shell refractory material is reduced, and the effect of completely replacing a desilicication converter or a desilicication electric furnace is achieved.
Drawings
The invention is further described below with reference to the accompanying drawings.
FIG. 1 is a production practice chart of bath temperature, cold charge at normal temperature and converting time in the converting process of the present invention.
Detailed Description
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: after high-carbon high-silicon premelting liquid produced by a stainless steel primary smelting furnace is added into an AOD furnace, the AOD furnace uses a top gun and a side (bottom) gun with high oxygen supply strength to carry out oxygen blowing desiliconization and decarburization, meanwhile, a large amount of high-carbon ferrochrome, chromium-nickel pig iron, nickel iron, waste steel and other normal-temperature alloy materials are added through a high-position stock bin or a crown block trough in the blowing process to control the temperature of molten steel to be continuously in a low-temperature state beneficial to desiliconization, and slag is added to control the alkalinity of desiliconization slag, so that the aim of rapid desiliconization is fulfilled until desiliconization is completed.
The high oxygen supply intensity aims at improving the smelting efficiency, shortening the smelting time and reducing the retention time of the desiliconized slag in the furnace, and the preferred air supply parameters of the top gun and the bottom gun in the blowing process are as follows: the top lance is 2.0-2.5m at low lance position, and the oxygen supply intensity of the top lance is 1.4-1.8Nm 3 Min t, bottom lance oxygen supply intensity 1.0-1.5Nm 3 Min t, bottom gun inert gas supply intensity 0.25-0.40 Nm 3 Min t. (the molten steel amount to be referred to for calculating the air feed intensity is the molten steel amount to be tapped)
SaidThe total amount of the alloy material at normal temperature is calculated according to a formula (I) 1 . Selecting the effective temperature T at the end of the desilication period 1 : according to the steel-adding condition, referring to the formula of temp. -rising rate for decarbonization and desilication and the temp. -lowering quantity of alloy material Alloy (I) And controlling the temperature of the molten steel at the end of desiliconization at 1500 ℃ and 1550 ℃. The high-carbon high-silicon material is preferentially added when the alloy material at normal temperature is added, and then the low-carbon material is added; all normal temperature alloy materials are added as early as possible, a stripping and melting mode is adopted, molten steel is kept in a low-temperature state beneficial to desiliconization continuously, and the desiliconization oxygen utilization rate is improved.
T 1 =T 0 +(t Si +t c )*t-b-T Alloy (I) ①
T 0 The initial temperature of the pre-melt, DEG C
t Si The heating rate for desiliconization is DEG C/min
t c For decarburization, the temperature rise rate is set at DEG C/min
t is the oxygen blowing time min
b is the radiation heat dissipation constant, DEG C
T Alloy (I) The temperature reduction amount of the normal temperature alloy is as follows, the temperature reduction amount of the common ton of alloy at the temperature to the ton of molten liquid is as follows: high-carbon ferrochrome 1350 ℃, high-carbon ferrochrome pig iron 1450 ℃, high-carbon ferronickel 1550 ℃, low-carbon ferronickel 1650 ℃, various scrap steels 1650 ℃ and common lime 1850 DEG C
t Si =I*0.8/10*M Si *X Si ②
I is the oxygen supply intensity, Nm 3 /（min*t）
M Si 1wt% silicon heat-up, DEG C
X Si For desiliconizing the oxygen utilization coefficient%
t C =I*0.933/10*M C *（1-X Si -n） ③
M C 1wt% carbon rise, DEG C
n is the oxygen coefficient for removing decarburization and desilication, is a constant and generally takes 3 to 8 percent
The slag charge is mainly lime dolomite; the addition amount is as follows: the dolomite is added mainly to increase the MgO content in the slag and play a role in protecting the furnace lining, and the addition amount is generally 1.0-3.0 t. The lime addition amount needs to be calculated according to the desilication slag alkalinity, the control principle is that the lime is added as early as possible at the initial desilication stage, the slag alkalinity at the initial desilication stage to the middle stage is improved, the slag alkalinity is gradually reduced along with the progress of the desilication reaction, and the slag is controlled to be reduced to 1.2-1.5 after the desilication is finished. The specific lime addition is calculated according to a formula (IV):
M ash of =（M Preparation of *10*W Si +M Alloy (I) *10* W Alloy Si ）*2.14*R/Y CaO ④
M Preparation of For the amount of premelt liquid, t
W Si For the Si content in the pre-melt, according to
M Alloy (I) Amount of alloy added, t
W Alloy Si For the Si content in each alloy%
R is an alkalinity target
Y CaO Effective content of CaO in lime%
After desiliconization is finished, pouring desiliconized slag after chromium oxide in the slag is reduced and recovered; the desiliconized slag is left in the furnace, on one hand, the slag is easy to splash when the converting process is continued due to low alkalinity; on the other hand, if the alkalinity in the converting process is increased, the slag amount in the furnace is too large, the service life of refractory materials is influenced, and the loss of chromium and nickel in the slag in the reduction period is increased.
The temperature of the molten steel is favorable for the low-temperature state of desiliconization, and the temperature range is 1400-1450 ℃.
Said X Si 、M Si 、M C Definition of M Si The 1wt% carbon temperature rise is 340-350 ℃, and M is clear C 1wt% carbon temperature rise of 110- Si For the desiliconization oxygen utilization coefficient, the reference coefficient is related to the content of C in the molten steel at the temperature of 1400 ℃ and 1450 ℃, and the reference coefficient is 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 method for efficiently desiliconizing AOD (argon oxygen decarburization) smelting stainless steel, which is characterized in that a top gun with high oxygen supply strength and a side (bottom) gun are used for blowing oxygen for desiliconization and decarburization, slag is added in the blowing process to control the alkalinity of desiliconized slag, a large amount of normal-temperature alloy materials are added, and the temperature of a molten pool is controlled to be continuously at the favorable temperature of desiliconization reaction, so that the rapid desiliconization in the blowing desiliconization period is realized when the AOD uses high-carbon high-silicon melt to smelt the stainless steel, the support is provided for the reduction and pouring of the follow-up desiliconized slag, the time of the desiliconized slag in the converter is reduced, the corrosion of the desiliconized slag to the furnace shell refractory material is reduced, and the effect of completely replacing a desiliconization converter or a desiliconization electric furnace is achieved.
Examples
The present invention will be described in further detail with reference to the following specific examples:
example 1
The pre-melt smelting 304 produced in a 180t top side double blown AOD furnace using an intermediate frequency furnace, the present example is the following sequential steps:
1) adding high-carbon ferrochrome and chromium-nickel pig iron into the intermediate frequency furnace for melting, tapping to a premelt ladle after melting into premelt liquid, wherein the tapping amount is 110t, and the weight percentage of each element C: 4.2%, Si: 3.3%, Cr: 23%, Ni: 6.5 percent, and the balance of iron and inevitable impurities.
2) Adding the pre-molten liquid into an AOD furnace, shaking the furnace to measure the temperature, wherein the temperature is 1415 ℃, shaking the furnace and then converting, the position of a top lance of the converting is 2.6m, and the oxygen flow of the top lance is 290Nm 3 Min, bottom lance oxygen flow 160Nm 3 Min, bottom gun nitrogen flow 35Nm 3 /min。
3) After the blowing is started, 25t of high-carbon ferrochrome, 15t of lime and 1.5t of dolomite are added from a high-level stock bin, and the oxygen blowing amount reaches 1500Nm 3 55t of chromium-nickel pig iron is added through a material groove, all materials are added as soon as possible in the desilication period, and the oxygen blowing amount in the furnace is 3325Nm 3 The addition is completed completely. The weight percentage of C in the high-carbon ferrochrome is 7.8 percent, the weight percentage of Si is 3.5 percent, and the weight percentage of Cr is 50.5 percent; the chromium-nickel pig iron contains 2.7 wt% of C, 1.5 wt% of Si, 2.3 wt% of Cr and 9.8 wt% of Ni.
4) When the oxygen blowing amount reaches 5609Nm 3 When the blowing is stopped. And measuring the temperature and sampling in the deslagging process of the desiliconized slag. Measuring the temperature at 1521 ℃, taking a steel sample and a slag sample to confirm the 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 inevitable elements as the rest, and Cr in the slag 2 O 3 The content is 1.05 percent, and the slag alkalinity is 1.31.
In the example, the content of carbon and silicon in AOD steel added 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 4.7t, and the oxygen blowing time in the desiliconization period is 12.4 min.
Example 2
The 120t top side combined blown AOD furnace uses premelt smelting 304 produced by a submerged arc furnace, the present example being the following sequential steps:
1) adding premelting liquid produced by the submerged arc furnace into the AOD furnace, wherein the steel adding amount is 66t, and the weight percentage of each element of the steel adding components is as follows: 3.1%, Si: 2.2%, Cr: 2.3%, Ni: 10.3% and the balance of iron and inevitable impurities.
2) Adding the pre-molten liquid into an AOD furnace, shaking the furnace to measure the temperature, keeping the temperature at 1378 ℃, shaking the furnace, blowing,the lance position of the converting top lance is 2.6m, and the oxygen flow of the top lance is 160Nm 3 Min, bottom gun oxygen flow 120Nm 3 Min, bottom gun nitrogen flow 20Nm 3 /min。
3) After the start of blowing, 30t of high-carbon ferrochrome, 8.5t of lime and 1.0t of dolomite are added from a high-level bunker, and the oxygen blowing amount reaches 1000Nm 3 During the process, 16t of chromium-nickel pig iron is added through a material groove, all materials are added as soon as possible in the desilication period, and the oxygen blowing amount of the furnace is 2131Nm 3 The addition is completed completely. The weight percentage of C in the high-carbon ferrochrome is 8.0 percent, the weight percentage of Si is 3.0 percent, and the weight percentage of Cr is 52.1 percent; the chromium-nickel pig iron contains 2.6 wt% of C, 1.4 wt% of Si, 2.0 wt% of Cr and 9.5 wt% of Ni.
4) When the oxygen blowing amount reaches 3456Nm 3 When the blowing is stopped. And measuring the temperature and sampling in the deslagging process of the desiliconized slag. Measuring the temperature to 1546 ℃, taking a steel sample and a slag sample to confirm the components, wherein the steel sample comprises the following elements in percentage by weight: c: 2.6%, Si: 0.29%, Cr: 15.7%, Ni: 7.8 percent of iron and inevitable elements as the rest, and Cr in the slag 2 O 3 The content is 0.77 percent, and the slag alkalinity is 1.34.
The premelting liquid produced by the submerged arc furnace of the embodiment has higher carbon and silicon contents than those of the AOD furnace in the conventional process, the carbon and silicon contents of the high-carbon ferrochrome and chromium-nickel pig iron in the alloy materials added in the blowing process are also higher, the total silicon amount removed in the blowing process is 2.2t, and the oxygen blowing time in the desiliconization period is 10.9 min.
Example 3
At 180t top side re-blown AOD furnace using premelt smelting 304 produced in an intermediate frequency furnace + electric furnace, the present example is the following sequential steps:
1) smelting high-carbon ferrochrome in an intermediate frequency furnace, smelting chromium-nickel pig iron in an electric furnace, mixing the produced premelted solution, adding into an AOD furnace, adding steel, wherein the steel adding amount is 175t, and the weight percentage of each element of the steel adding components is C: 2.8%, Si: 1.4%, Cr: 16.5%, Ni: 5.6 percent, and the balance of iron and inevitable impurities.
2) Adding the pre-molten liquid into an AOD furnace, shaking the furnace to measure the temperature of 1423 ℃, shaking the furnace, blowing, wherein the top lance position of the blowing is 2.7m, and the oxygen flow of the top lance is 280Nm 3 Min, bottom gun oxygen flow 130Nm 3 Min, bottom gun nitrogen flow 40Nm 3 /min。
3) After the blowing is started, 18t of high-carbon ferrochrome, 9.5t of lime and 1.5t of dolomite are added from a high-level bunker, 15t of high-carbon ferronickel is added, all materials are added as soon as possible in a desilication period, and the oxygen blowing amount of the furnace is 1931Nm 3 The addition is completed completely. The weight percentage of C in the high-carbon ferrochrome is 7.8 percent, the weight percentage of Si is 2.7 percent, and the weight percentage of Cr is 51.9 percent; 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 measuring the temperature and sampling in the deslagging process of the desiliconized slag. Measuring the temperature to 1546 ℃, taking a steel sample and a slag sample to confirm the components, wherein the steel sample comprises the following elements in percentage by weight: c: 2.5%, Si: 0.24%, Cr: 18.5%, Ni: 6.2 percent of iron and inevitable elements as the rest, and Cr in the slag 2 O 3 The content is 0.83 percent, and the slag alkalinity is 1.39.
The content of carbon and silicon in the premelted liquid produced by the intermediate frequency furnace and the electric furnace is higher than that of the AOD furnace in the conventional process, the content of carbon and silicon in high-carbon ferrochrome and 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 desiliconization period is 8.5 min.
The above description is only an embodiment of the present invention, but the structural features of the present invention are not limited thereto, and any changes or modifications within the scope of the present invention by those skilled in the art are covered by the present invention.
Claims (6)
1. A method for efficiently desiliconizing smelted stainless steel is characterized by comprising the following steps: the method comprises the following steps: after high-carbon high-silicon premelting liquid produced by a stainless steel primary smelting furnace is added into an AOD furnace, the AOD furnace uses a top gun and a bottom gun with high oxygen supply strength to carry out oxygen blowing desiliconization and decarburization, and meanwhile, normal-temperature alloy materials are added through a high-position stock bin or a crown block trough in the blowing process to control the temperature of molten steel to be continuously in a low-temperature desiliconization state, and slag is added to control the alkalinity of desiliconized slag to achieve the aim of rapid desiliconization until the desiliconization is finished.
2. The method for efficiently desiliconizing smelted stainless steel according to claim 1, characterized in that: the high oxygen supply strength aims at improving the smelting efficiency, shortening the smelting time and reducing the retention time of the desiliconized slag in the furnace, and the air supply parameters in the top gun and bottom gun blowing process are as follows: the top lance adopts a low lance position of 2.0-2.5m, the oxygen supply intensity of the top lance is 1.4-1.8Nm3/min t, the oxygen supply intensity of the bottom lance is 1.0-1.5Nm3/min t, and the inert gas supply intensity of the bottom lance is 0.25-0.40 Nm3/min t.
3. The method for efficiently desiliconizing smelted stainless steel according to claim 1, which is characterized by comprising the following steps of: the normal temperature alloy materials are high carbon ferrochrome, chromium-nickel pig iron, ferronickel and scrap steel, and the total adding amount of the alloy materials is calculated according to a formula (I) 1 Selecting the effective temperature T at the end of the desilication period 1 : according to the steel-adding condition, referring to the formula of temp. -rising rate for decarbonization and desilication and the temp. -lowering quantity of alloy material Alloy (I) Controlling the temperature of molten steel at 1500-; all normal-temperature alloy materials are added as early as possible, a stripping and melting mode is adopted, molten steel is kept in a low-temperature state beneficial to desiliconization continuously, and the desiliconization oxygen utilization rate is improved;
T 1 =T 0 +(t Si +t c )*t-b-T alloy (I) ①
T 0 The initial temperature of the pre-molten liquid, DEG C,
t Si the heating rate for desiliconization is DEG C/min,
t c the heating rate of decarburization at DEG C/min,
t is the oxygen blowing time, min,
b is the radiation heat dissipation constant, DEG C,
T alloy (II) The temperature reduction amount of the alloy at normal temperature is lower than DEG C, and the measured value of the temperature reduction amount of the ton of molten liquid by the ton of alloy is as follows: high-carbon ferrochrome 1350 ℃, high-carbon ferrochrome pig iron 1450 ℃, high-carbon ferronickel 1550 ℃, low-carbon ferronickel 1650 ℃, various scrap steels 1650 ℃ and common lime 1850 ℃;
t Si =I*0.8/10*M Si *X Si ②
i is the oxygen supply intensity, Nm 3 /（min*t），
M Si 1wt% silicon temperature rise, DEG C,
X Si the desiliconization oxygen utilization coefficient,%;
t C =I*0.933/10*M C *（1-X Si -n） ③
M C 1wt% carbon rise, DEG C
n is the oxygen coefficient for removing decarburization and desiliconization, and is a constant value of 3-8%.
4. The method for efficiently desiliconizing smelted stainless steel according to claim 1, characterized in that: the slag charge is lime and dolomite, and the addition amount is as follows: the dolomite is added to increase the MgO content in the slag to play a role in protecting a furnace lining, the addition amount is 1.0-3.0t, the lime addition amount needs to be calculated according to the desiliconization slag alkalinity, the control principle is that the dolomite is added as early as possible at the initial desiliconization stage, the slag alkalinity at the initial desiliconization stage and the middle stage of the desiliconization is improved, the slag alkalinity is gradually reduced along with the progress of the desiliconization reaction, and the slag is controlled to be reduced to 1.3-1.6 after the desiliconization is finished; the specific lime addition is calculated according to a formula (IV):
M ash of =（M Preparation of *10*W Si +M Alloy (I) *10* W Alloy Si ）*2.14*R/Y CaO ④
M Preparation of The amount of pre-melt, t,
W Si the content of Si in the pre-molten liquid is percent,
M alloy (I) The amount of alloy added, t,
W alloy Si The content of Si in each alloy,%,
r is the target of alkalinity,
Y CaO the effective content of CaO in the lime is percent.
5. The method for efficiently desiliconizing smelted stainless steel according to claim 1, characterized in that: the temperature of the molten steel is favorable for the low-temperature state of desiliconization, and the temperature range is 1400-1450 ℃.
6. The method for efficiently desiliconizing smelted stainless steel according to claim 3, characterized in that: said X Si 、M Si 、M C Definition of M Si The 1wt% carbon temperature rise is 340-350 ℃, and M is clear C 1wt% carbon temperature rise of 110- Si For the desiliconization oxygen utilization coefficient, the temperature is between 1400 ℃ and 1450 ℃, the temperature is related to the C content in the molten steel, and X is more than 4.0 percent Si 55-60 percent of X when the content of the molten steel C is 3.0-4.0 percent Si 60-64 percent of X when the content of the molten steel C is 2.0-3.0 percent Si 64-68 percent of X when the content of the molten steel C is 1.0-2.0 percent Si Is 68-71%.
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| CN115710614A (en) * | 2022-11-17 | 2023-02-24 | 山西太钢不锈钢股份有限公司 | Method for preventing AOD smelting from splashing in early stage |
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| 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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| 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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| CN115710614A (en) * | 2022-11-17 | 2023-02-24 | 山西太钢不锈钢股份有限公司 | Method for preventing AOD smelting from splashing in early stage |
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