CN113862419A - Method for controlling phosphorus content of molten steel in tapping weak deoxidation mode - Google Patents
Method for controlling phosphorus content of molten steel in tapping weak deoxidation mode Download PDFInfo
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- CN113862419A CN113862419A CN202111092712.7A CN202111092712A CN113862419A CN 113862419 A CN113862419 A CN 113862419A CN 202111092712 A CN202111092712 A CN 202111092712A CN 113862419 A CN113862419 A CN 113862419A
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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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/35—Blowing from above and through the bath
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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
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
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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
- 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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- 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 discloses a method for controlling phosphorus content of molten steel in a tapping weak deoxidation mode. The invention realizes the maximum dephosphorization process and prevents the later dephosphorization by controlling the slag alkalinity, the oxidability and the temperature of the converter blowing process and the blowing terminal point (the slag alkalinity R of the blowing terminal point is 3.2-4.0, the terminal point temperature T is 1620-1650 ℃, the carbon content is 0.04-0.06 wt%, and the oxygen content in the terminal point molten steel is 500-700 ppm), controls the P in the molten steel at a lower level, adopts the 'double-blocking slag' operation during tapping, performs the weak deoxidation alloying (the adding amount of an aluminum block is about 2/3 of the target using amount of a steel type) at the later stage of tapping, utilizes the strong stirring of large argon and the high oxygen partial pressure to flush and dephosphorize, keeps the top slag to have better fluidity, and realizes the dephosphorization of a ladle as much as possible; and slag is removed after tapping, so that the rephosphorization probability and the total mass of phosphorus are further reduced, and the cleanliness of molten steel and the quality of casting blanks are improved.
Description
Technical Field
The invention relates to a method for controlling phosphorus content of molten steel in a tapping weak deoxidation mode, and belongs to the technical field of converter steelmaking.
Background
The cleanliness of steel is an important mark for reflecting the overall quality level of the steel, and is an important index for ensuring the inherent quality of the steel. At present, the cleanliness of steel is generally evaluated by the content of harmful elements in the steel and the characteristics of the type, quantity, size, distribution, form and the like of nonmetallic inclusions, and the harmful elements in the steel mainly comprise O, S, P, H, N five impurity elements and Pb, As, Cu, Zn and the like with lower content, wherein the cleanliness of the steel is restricted by the problems of high proportion, large base number, difficult removal in the smelting process, easy rephosphorization and high control difficulty particularly because of the existence of P.
Phosphorus is harmful in most steel grades, the main hazard being that it segregates at grain boundaries, causing the steel to "cold-chip". With the continuous development of industrial modernization, the requirements of various industries related to national economy on the quality of steel are increasingly improved, the demand of high-quality steel and high-purity steel is continuously increased, the production variety is shifted to the field of high-precision, high-quality and high-added-value steel, and the produced steel for low-temperature containers, marine steel, low-temperature ship plate steel, acid-resistant containers and the like has extremely strict requirements on the content of phosphorus elements in the steel, and the phosphorus content of parts of the produced steel is required to be less than 0.008%. How to remove phosphorus in steel efficiently and control rephosphorization effectively becomes one of the key problems to be solved urgently in converter production.
CN 201910270142.2 discloses an efficient smelting process for producing low-phosphorus clean steel by a converter, which produces the low-phosphorus clean steel by the operation method of 'double slag + full slag' through the timely adjustment of slag charge, the control of oxygen lance position and oxygen supply amount when the converter is added for smelting the low-phosphorus clean steel. CN201910090722.3 discloses a method for smelting low-phosphorus steel, which can stably produce qualified casting blanks with finished product P less than or equal to 0.005% under the condition of given molten iron and steel scraps by optimizing parameters and procedures, and also adopts a double-slag operation method. The double-slag method is characterized in that the dephosphorization effect of the early stage blowing is improved, the dephosphorization slag is poured out of the converter after the early stage blowing, the phosphorus content of the whole converter system is reduced, and the dephosphorization is further carried out in the later stage decarburization blowing to achieve the aim of producing low-phosphorus steel. The above-mentioned "double slag operation" mode can cause certain influence on production rhythm, metal yield, etc. CN201910568664.0 discloses a method for producing ultra-low phosphorus steel by a converter, which adopts a nitrogen stirring process to produce the ultra-low phosphorus steel at the final stage of blowing, and the process flow design is as follows: the oxygen converting process of the converter adopts a single slag method for dephosphorization, a gas medium is switched into nitrogen after a gun is lifted at the end point, the nitrogen is inserted into molten steel for stirring, slagging is carried out during the stirring process, slag is poured out for tapping, and the phosphorus content at the end point of the converter tapping is less than or equal to 0.005 percent. The nitrogen stirring process reduces the oxidability of molten steel, but is not suitable for low-nitrogen steel, and can also have certain influence on production rhythm.
Disclosure of Invention
Aiming at the problems, the invention provides a method for controlling the phosphorus content of molten steel in a tapping weak deoxidation mode. The invention effectively reduces the phosphorus content of the molten steel at the converting end point and the rephosphorization degree in the tapping process, reduces the phosphorus content in the molten steel, improves the cleanliness of the molten steel and the quality of casting blanks and basically does not influence the production rhythm by controlling the alkalinity, the oxidability and the temperature of the slag at the converting end point and adopting the 'double-slag-blocking' operation during tapping and taking the measures of weak deoxidation alloying at the later stage of tapping, slag flushing and mixing at the top of a steel ladle, slag skimming after tapping and the like.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a method for controlling the phosphorus content of molten steel in a tapping weak deoxidation mode is characterized by sequentially comprising the following steps of:
1) converter blowing
Oxygen top-bottom combined blowing converter steelmaking, wherein the blowing process is stably controlled, the TSC temperature of the sublance is controlled to be 1570-1590 ℃, and the carbon content is controlled to be 0.20-0.40 wt%; the low temperature and certain oxidizability are beneficial to dephosphorization, too high TSC temperature can cause the molten steel w (P) to be higher, so that the dephosphorization difficulty in the later stage of blowing is high, w (C) is too high, so that the blowing time in the later stage of blowing is long, and the rephosphorization of the molten steel is increased due to high temperature rise;
2) drawing carbon
The carbon drawing gun position at the blowing end point is kept for more than 15s, the one-time hit rate of the end point is ensured, the temperature and the components of the molten steel meet the target requirements, and the phenomenon of secondary blowing or high-temperature peroxidation caused by low temperature is avoided; the blowing end point target requirement is as follows: the slag alkalinity R is 3.2-4.0, the end point temperature T is 1620-1650 ℃, the carbon content is 0.04-0.06 wt%, and the oxygen content in the end point molten steel is 500-700 ppm;
3) preparatory work before tapping
By adopting the tapping 'double slag stopping' technology, the sliding plate blocks slag at the early stage during tapping; opening bottom blowing argon of a steel ladle before tapping, and controlling the flow of the argon to be 50 NL/min-100 NL/min;
4) alloying by weak deoxidation during tapping
Preparing a steel ladle in place, pouring the converter to a steel tapping angle, and opening the sliding plate to start tapping; increasing the flow of bottom-blown argon to 300 NL/min-600 NL/min after tapping for 28-32 s, adding small-particle lime and small-particle fluorite to ensure better fluidity and higher alkalinity of slag, and carrying out flushing dephosphorization by strong stirring of large argon and high oxygen partial pressure; sequentially adding ferromanganese, ferrosilicon (or ferro-silico-manganese), and an aluminum block with the target use amount of 60-70% of steel grade, ensuring the weak deoxidation effect, and controlling the content of FeO in the slag to be 16-17 wt%; the tapping time is controlled to be 3-4 min;
5) blowing argon to weakly stir after tapping
After tapping is finished, argon blowing and weak stirring are continuously carried out for 3-8 min (on the principle of not exposing molten steel), so that the aim of preventing slag crusting from influencing the slag-raking effect is fulfilled, floating of impurities in the molten steel is promoted, and then the bottom blowing of argon gas is stopped;
6) slag removal for steel ladle
And (3) slagging off the steel ladle, namely, when slagging off is finished until 75-85% of the molten steel surface is exposed, adding a covering agent of the steel ladle, and waiting for entering the next procedure.
In the step 1), reasonable lance position and feeding mode are controlled in the converter blowing process, slag making materials and cooling agents are reasonably added, the temperature of a molten pool is controlled to be uniformly and slowly increased, the slag is ensured to have good fluidity and foaming, and splashing and drying return are avoided.
Further, in the step 4), the reference addition amount of the small-particle lime and the small-particle fluorite per ton steel is 2.0 kg-3.0 kg and 0.5 kg-1.0 kg respectively, and the addition amount of the aluminum blocks is 2/3 of the target use amount of the steel.
Further, ferromanganese is added when the steel is tapped in the step 4) for 1.3-1.7 min, and ferrosilicon or ferrosilicomanganese is added after the steel is tapped for 2-2.2 min, and then aluminum blocks are added.
The invention ensures and improves the thermodynamic and kinetic conditions of dephosphorization by controlling the slag alkalinity, the oxidability and the temperature of the converter blowing process and the blowing terminal point, realizes the maximum process dephosphorization and prevents the later period rephosphorization, and controls the molten steel w (P) at a lower level; the double-slag-stopping operation is adopted during tapping, so that the slag discharging amount during tapping is effectively reduced, and the phosphorus return probability and the phosphorus return amount are reduced; carrying out weak deoxidation alloying (the adding amount of an aluminum block is about 2/3 of the target using amount of the steel grade) at the later stage of tapping, strongly stirring by utilizing large argon and carrying out flushing-mixing dephosphorization by utilizing high oxygen partial pressure, keeping good fluidity of top slag while ensuring the amount and alkalinity of the top slag, and realizing ladle dephosphorization as much as possible; and slag removal is carried out after tapping, so that the rephosphorization probability and the total quality of phosphorus are further reduced, and worries about refining high-efficiency treatment and stable pouring of a casting machine are relieved.
The invention has the beneficial effects that:
1. by the method, the phosphorus content of the converter tapping endpoint is less than or equal to 0.005 wt%, the phosphorus content of the finished product after the weak deoxidation tapping is less than or equal to 0.006 wt%, and the stable control of the lower phosphorus content is realized.
2. The mode controls the production process, does not increase the production link, and basically has no influence on the production rhythm and the metal yield.
Detailed Description
The effects of the present invention will be described below with reference to specific examples.
Example 1
1) Converter blowing
According to the components of molten iron, the adding amount of each ton of steel of slag-making materials light burnt lime, light burnt dolomite and a coolant (iron ore) in the blowing process is respectively 30kg, 6kg and 10 kg.
The converter adopts an oxygen top-bottom combined blown converter, controls reasonable lance position and feeding mode in the blowing process, reasonably adds slag making materials and cooling agents, controls the uniform and slow temperature rise of a molten pool, ensures that slag has good fluidity and foaming, avoids splashing and drying, and controls the molten steel w (P) at a lower level. The converter converting process is controlled stably, and the TSC result of the sublance is as follows: the temperature is 1575 ℃, the carbon content is 0.32 wt%, and the phosphorus content test result is 0.036 wt%;
2) drawing carbon
The carbon drawing gun position at the blowing end point is kept for 23s, and the end point is hit once: slag alkalinity R is 3.8, end point temperature T is 1642 ℃, carbon content is 0.042 wt%, oxygen content is 520 ppm;
3) preparation before tapping
The alloy and the ladle additive which are clean and have low phosphorus content are used, so that the phosphorus increase of molten steel is reduced; the steel ladle is a red ladle for normal turnover, the interior of the ladle is clean and has no residue, the bottom-blown brick has good ventilation, and no obvious residue is left on the periphery of the ladle edge; the steel tapping hole is smooth and regular, the shape is good, and the steel flow is prevented from diffusing, absorbing oxygen and increasing nitrogen; the steel tapping ladle, the steel tapping hole condition, the alloy and the ladle additive are qualified, and the steel tapping 'double slag stopping' technology is adopted, so that the sliding plate slag stopping blocks earlier-stage slag during steel tapping; opening a ladle bottom blowing 5s before tapping, wherein the argon flow is 60 NL/min;
4) alloying by weak deoxidation during tapping
The steel ladle is prepared in place, the converter is poured to a steel tapping angle, and the sliding plate is opened to start steel tapping. Increasing the bottom blowing argon flow to 380NL/min after tapping for 30s, and adding 2.2kg/t of steel with small-particle lime and 0.6kg/t of steel with small-particle fluorite; adding ferromanganese (the manganese content in the ferromanganese is 65 percent and the adding amount is 23kg/t steel) when tapping for 1.5min, adding ferrosilicon (the silicon content in the ferrosilicon is 75 percent and the adding amount is 10kg/t steel) and aluminum blocks (the adding amount is 1.6kg/t steel and 2/3 of the target using amount of steel) after tapping for 2min, and controlling the content of FeO in slag to be 16-17 wt%; before tapping and slag discharging, the sliding plate is opened to block slag and close the sliding plate, tapping and slag discharging are controlled, and the tapping time is 3.5 min;
5) blowing argon to weakly stir after tapping
After tapping, continuously blowing argon for weak stirring for 5min (on the principle of not exposing molten steel), and then closing the bottom of the steel ladle to blow argon;
6) slag removal for steel ladle
Hoisting the steel ladle to a slag skimming position, and skimming slag according to the operation requirement; and (3) slagging off the steel ladle, tilting the steel ladle opening to be flush with the molten steel surface, starting slagging off operation, and when slagging off is completed until the molten steel surface is exposed by 80%, ensuring a stable and slow principle in the operation of the slagging off process, and completely avoiding slagging off and bringing out molten steel. Whether the slag skimming is clean or not affects the rephosphorization amount of the subsequent refining process, so the slag skimming is clean as much as possible on the premise of not affecting the loss of molten steel; after slagging off, adding 30kg of ladle covering agent, and waiting for entering the next procedure;
by the method of example 1, the phosphorus content was 0.0045 wt% and the finished product was 0.0052 wt% after tapping.
Example 2
1) Converter blowing
According to the components of molten iron, the adding amount of each ton of steel of slag-making materials light burnt lime, light burnt dolomite and a coolant (iron ore) in the converting process is respectively 28kg, 10kg and 12 kg;
the converter is a combined blown converter with oxygen top and bottom, the blowing process of the converter controls reasonable gun position and feeding mode, the splashing and drying returning phenomena are avoided, the process control is stable, and the TSC result of the sublance is as follows: the temperature is 1582 ℃, the carbon content is 0.26 wt%, and the phosphorus content assay result is 0.028 wt%;
2) drawing carbon
The carbon drawing gun position at the blowing end point is kept for 20s, and the end point is hit once: slag alkalinity R is 3.6, end point temperature T is 1628 ℃, carbon content is 0.046 wt%, and oxygen content is 500 ppm;
3) preparation before tapping
The steel tapping ladle, the steel tapping hole condition, the alloy and the ladle additive are qualified, and the steel tapping 'double slag stopping' technology is adopted, so that the sliding plate slag stopping blocks earlier-stage slag during steel tapping; opening a ladle bottom blowing 5s before tapping, wherein the argon flow is 80 NL/min;
4) alloying by weak deoxidation during tapping
The steel ladle is prepared in place, the converter is poured to a steel tapping angle, and the sliding plate is opened to start steel tapping. Increasing the bottom blowing argon flow to 400NL/min after tapping for 30s, and adding 2.1kg/t of steel with small-particle lime and 0.5kg/t of steel with small-particle fluorite; when tapping is carried out for 1.5min, firstly adding ferromanganese (the manganese content in the ferromanganese is 65 percent, and the adding amount is 22kg/t steel), and after tapping is carried out for 2min, adding ferrosilicon (the silicon content in the ferrosilicon is 75 percent, and the adding amount is 11kg/t steel) and aluminum blocks (the adding amount is 1.6kg/t steel, and 2/3 of the target using amount of steel types); controlling the content of FeO in the slag to be 16-17 wt%; before tapping and slag discharging, the sliding plate is opened to block slag and close the sliding plate, tapping and slag discharging are controlled, and the tapping time is 3.8 min;
5) blowing argon to weakly stir after tapping
After tapping, continuously blowing argon for weak stirring for 5min (on the principle of not exposing molten steel), and then closing the bottom of the steel ladle to blow argon;
6) slag removal for steel ladle
Lifting the steel ladle to a slag removing position, removing slag according to the operation requirement, and finishing slag removing when the slag is removed until the molten steel surface is exposed by 80%; and after slagging off is finished, adding 40kg of ladle covering agent, and waiting for entering the next working procedure.
By adopting the method of the embodiment 2, the phosphorus content is 0.0041 wt% after tapping, and the phosphorus content of the finished product is 0.0050 wt%.
Example 3
1) Converter blowing
According to the components of molten iron, the adding amount of each ton of steel of slag-making materials light burnt lime, light burnt dolomite and a coolant (iron ore) in the converting process is respectively 27kg, 7kg and 11 kg;
the converter is a combined blown converter with oxygen top and bottom, the reasonable lance position and feeding mode are controlled in the blowing process of the converter, the process slag has good fluidity and foaming, the phenomena of splashing and drying return are avoided, and the TSC result of the sublance is as follows: the temperature is 1572 ℃, the carbon content is 0.36wt percent, and the phosphorus content test result is 0.038wt percent;
2) drawing carbon
The carbon drawing gun position at the blowing end point is kept for 22s, and the end point is hit once: slag alkalinity R is 3.5, end point temperature T is 1642 ℃, carbon content is 0.040 wt%, oxygen content is 560 ppm;
3) preparation before tapping
The steel tapping ladle, the steel tapping hole condition, the alloy and the ladle additive are qualified, and the steel tapping 'double slag stopping' technology is adopted, so that the sliding plate slag stopping blocks earlier-stage slag during steel tapping; opening a ladle bottom blowing 5s before tapping, wherein the argon flow is 72 NL/min;
4) alloying by weak deoxidation during tapping
The steel ladle is prepared in place, the converter is poured to a steel tapping angle, and the sliding plate is opened to start steel tapping. Increasing the bottom blowing argon flow to 460NL/min after tapping for 30s, and adding 2.0kg/t steel of small-particle lime and 0.5kg/t steel of small-particle fluorite; when tapping is carried out for 1.5min, firstly adding ferromanganese (the manganese content in the ferromanganese is 65 percent, and the adding amount is 21kg/t of steel), and after tapping is carried out for 2min, adding ferrosilicon (the silicon content in the ferrosilicon is 75 percent, and the adding amount is 9kg/t of steel) and aluminum blocks (the adding amount is 1.5kg/t of steel, and 2/3 of the target using amount of steel types); controlling the content of FeO in the slag to be 16-17 wt%; before tapping and slag discharging, the sliding plate is opened to block slag and close the sliding plate, tapping and slag discharging are controlled, and the tapping time is 4.0 min;
5) blowing argon to weakly stir after tapping
After tapping, continuously blowing argon for weak stirring for 5min (on the principle of not exposing molten steel), and then closing the bottom of the steel ladle to blow argon;
6) slag skimming
Lifting the steel ladle to a slag removing position, removing slag according to the operation requirement, and finishing slag removing when the slag is removed until the molten steel surface is exposed by 80%; after slagging off is finished, adding 50kg of ladle covering agent, and waiting for entering the next procedure;
by the method of example 3, the phosphorus content was 0.0046 wt% and the finished product was 0.0054 wt% after tapping.
Claims (7)
1. A method for controlling the phosphorus content of molten steel in a tapping weak deoxidation mode is characterized by sequentially comprising the following steps of:
1) converter blowing
Oxygen top-bottom combined blowing converter steelmaking, wherein the blowing process is stably controlled, the TSC temperature of the sublance is controlled to be 1570-1590 ℃, and the carbon content is controlled to be 0.20-0.40 wt%; (ii) a
2) Drawing carbon
The carbon drawing gun position at the converting end point is kept for more than 15s, the one-time hit rate of the end point is ensured, and the target requirement of the converting end point is as follows: the slag alkalinity R is 3.2-4.0, the end point temperature T is 1620-1650 ℃, the carbon content is 0.04-0.06 wt%, and the oxygen content in the end point molten steel is 500-700 ppm;
3) preparatory work before tapping
By adopting the tapping 'double slag stopping' technology, the sliding plate blocks slag at the early stage during tapping; opening bottom blowing argon of a steel ladle before tapping, and controlling the flow of the argon to be 50 NL/min-100 NL/min;
4) alloying by weak deoxidation during tapping
Preparing a steel ladle in place, pouring the converter to a steel tapping angle, and opening the sliding plate to start tapping; increasing the bottom-blowing argon flow to be 300 NL/min-600 NL/min after tapping for 28-32 s, and adding lime and fluorite; then adding ferromanganese, ferrosilicon or ferrosilicon-manganese and aluminum blocks with the target use amount of 60-70% of steel grade in sequence to ensure the weak deoxidation effect;
5) blowing argon to weakly stir after tapping
After tapping, continuously blowing argon and stirring for 3-8 min, and taking the principle that molten steel is not exposed;
6) slag removal for steel ladle
And (3) slagging off the steel ladle, namely, when slagging off is finished until 75-85% of the molten steel surface is exposed, adding a covering agent of the steel ladle, and waiting for entering the next procedure.
2. The method for controlling phosphorus content of molten steel in the tapping weak deoxidation mode as claimed in claim 1, wherein during the tapping in said step 4), FeO content in slag is controlled to be 16 wt% to 17 wt%.
3. The method for controlling the phosphorus content of molten steel in the tapping weak deoxidation mode as claimed in claim 1, wherein the tapping time in the step 4) is controlled to be 3 min-4 min.
4. The method for controlling phosphorus content of molten steel in a tapping weak deoxidation mode as claimed in claim 1, wherein said step 4) of adding small particle lime and small particle fluorite in an amount of 2.0kg to 3.0kg and 0.5kg to 1.0kg per ton of steel, respectively.
5. The method for controlling phosphorus content of molten steel in the tapping weak deoxidation mode as claimed in claim 1, wherein in said step 4), the amount of aluminum blocks added is 2/3 corresponding to the target amount of steel.
6. The method for controlling the phosphorus content of molten steel in the weak deoxidation mode of tapping as claimed in any one of claims 1 to 5, wherein ferromanganese is added during 1.3-1.7 min of tapping in step 4), ferrosilicon or ferrosilicomanganese is added after 2-2.2 min of tapping, and aluminum blocks are added.
7. The method for controlling the phosphorus content of molten steel in the tapping weak deoxidation mode as claimed in any one of claims 1-5, characterized in that, in the step 1), reasonable lance position and feeding mode are controlled in the converter blowing process, slag making material and cooling agent are reasonably added, the temperature of the molten pool is controlled to be uniformly and slowly increased, good fluidity and foaming of slag are ensured, and splashing and re-drying are avoided.
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| CN114908215A (en) * | 2022-03-24 | 2022-08-16 | 南京钢铁股份有限公司 | Method for controlling content of B in gear steel |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114292985A (en) * | 2022-01-07 | 2022-04-08 | 鞍钢股份有限公司 | Treatment method for high phosphorus content after converter tapping |
| CN114908215A (en) * | 2022-03-24 | 2022-08-16 | 南京钢铁股份有限公司 | Method for controlling content of B in gear steel |
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