Smelting method of molten steel
By optimizing the converter steel discharge and alloying process, combined with the method of refining pre-blown argon forward movement, the problem of long refining and processing time of low carbon steel and permeable steel is solved, and the effect of simplifying operation, shortening time and improving efficiency is achieved.
Patent Information
- Application Number
- CN202411276462.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-12
- Publication Date
- 2025-02-11
AI Technical Summary
The refining and processing time of low-carbon steel and crystal-covered steel in the prior art has long resulted in the waste of molten steel water temperature and temperature measurement originals, increasing production costs.
By optimizing the converter steel discharge process and alloying process, the melting effect of alloys and carbon enhancers is improved, and after the refined pre-blowing argon is moved to the converter, the pre-blowing argon at the station is cancelled, the station sample is taken, and the station sample is waited for the station sample operation is waited for. , the components are adjusted directly according to the furnace sample components.
It greatly simplifies refining operations, shortens refining processing time, improves production efficiency, reduces production costs, and improves the composition uniformity and representativeness of molten steel.
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Figure CN119410864A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of smelting technology, and in particular to a method for smelting molten steel. Background Art
[0002] Low carbon steel is a steel with a low carbon content, and its carbon content is usually between 0.05% and 0.25%. Low carbon steel has good weldability, plasticity and toughness, but its strength and hardness are relatively low. Low carbon steel is often used to manufacture products such as thin plates, pipes, cold-drawn steel wires, and is also used to manufacture automobiles, ships, building structures, etc. Peritectic steel is a special steel that forms a large number of peritectics on the surface of the steel, and its peritectic is mainly composed of iron carbide and other elements. The chemical composition of peritectic steel is complex, and it contains a large amount of alloying elements such as molybdenum, chromium, cobalt, tungsten, etc. to improve its strength, hardness and wear resistance. Peritectic steel has excellent properties such as high strength, high hardness, high wear resistance and high toughness, and is often used to manufacture high-strength and high-wear-resistant parts such as cutting tools, molds, and bearings.
[0003] At present, the difficulty in rapidly smelting low-carbon steel and peritectic steel lies in the generally inaccurate composition after the furnace. Domestic major steel mills need to pre-blow argon before refining, take samples at the station, and wait for samples at the station, which results in a long refining process, resulting in waste of molten steel temperature, temperature measuring components, and refractory materials. Therefore, how to shorten the refining process time of low-carbon steel and peritectic steel, thereby reducing the production cost of low-carbon steel and peritectic steel, increasing output and improving profitability, is a technical problem that needs to be solved urgently. Summary of the invention
[0004] The present application provides a smelting method of molten steel to solve the following technical problem: how to shorten the refining treatment time of low-carbon steel and peritectic steel.
[0005] The present application provides a method for smelting molten steel, the method comprising:
[0006] The molten iron is smelted in a converter to obtain the first molten steel;
[0007] tapping the first molten steel into a converter, washing the converter slag and alloying the converter in the process of tapping the converter, and performing low-level bottom blowing of argon to obtain a second molten steel;
[0008] The second molten steel is subjected to converter slag reforming and high-grade bottom argon blowing to obtain a third molten steel;
[0009] According to the content relationship between the actual composition and the theoretical composition of the third molten steel, the refining process of the third molten steel is determined to obtain molten steel for low-carbon steel and peritectic steel.
[0010] Optionally, determining the refining process of the third molten steel according to the content relationship between the actual composition and the theoretical composition of the third molten steel includes:
[0011] The theoretical composition of the third molten steel is calculated based on the first molten steel and the amount of alloy added;
[0012] Determining whether the content difference between the actual composition and the theoretical composition of the third molten steel meets the set difference range;
[0013] If the conditions are met, the third molten steel is subjected to oxygen and aluminum determination, alloying, refining circulation or argon blowing and stirring;
[0014] If not, the third molten steel is pre-purged with argon, and alloying is performed according to the composition of the third molten steel after the pre-purging with argon, and then a refining cycle or argon blowing and stirring is performed.
[0015] Optionally, judging whether the content difference between the actual composition and the theoretical composition of the third molten steel satisfies a set difference range includes:
[0016] Determine whether the content difference between the actual composition and the theoretical composition of the third molten steel meets the set difference range; wherein,
[0017] When the component is C, the content difference between the actual component and the theoretical component is ≤0.005%;
[0018] When the component is Si or Mn, the content difference between the actual component and the theoretical component is ≤0.03%.
[0019] Optionally, the step of subjecting the third molten steel to oxygen and aluminum determination, alloying, and refining circulation or argon blowing and stirring includes:
[0020] The third molten steel is subjected to oxygen and aluminum determination using an oxygen determination instrument, and the aluminum element of the molten steel is adjusted according to the oxygen and aluminum determination values, and then alloying and refining circulation or argon blowing and stirring are performed.
[0021] Optionally, the refining cycle or argon blowing and stirring time is ≥ 6 min.
[0022] Optionally, the argon gas flow rate of the pre-purging argon is 600NL / min to 1200NL / min, and the time of the pre-purging argon is 2min to 6min.
[0023] Optionally, the argon flow rate of the low-speed bottom blowing argon is 200NL / min to 600NL / min, and the time of the low-speed bottom blowing argon is from the start of alloying in the converter to the end of steel tapping from the converter.
[0024] Optionally, the argon flow rate of the high-end bottom blowing argon is 800NL / min to 1200NL / min, and the time of the high-end bottom blowing argon is 2min to 6min.
[0025] Optionally, the step of washing converter slag and alloying converter during the process of tapping steel from the converter includes:
[0026] When the steel is tapped from the converter to 1 / 4 to 1 / 3, small particles of lime and fluorite are added to the molten steel, followed by steel grit, aluminum, recarburizer and alloy.
[0027] Optionally, in the first molten steel, the C content is 0.015% to 0.08%, the O content is 0.025% to 0.065%, and the tapping temperature of the first molten steel is 1635°C to 1665°C, calculated by mass fraction.
[0028] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:
[0029] The present application provides a method for smelting molten steel, including: smelting molten iron in a converter to obtain a first molten steel; tapping the first molten steel in a converter, washing the converter slag and alloying the converter during the converter tapping, and blowing argon at a low level to obtain a second molten steel; modifying the second molten steel in a converter slag and blowing argon at a high level to obtain a third molten steel; determining the refining process of the third molten steel according to the content relationship between the actual composition and the theoretical composition of the third molten steel, and obtaining molten steel for low-carbon steel and peritectic steel. By optimizing the converter tapping process and alloying process, the melting effect of alloys and carburizers is improved; by moving the refining pre-argon blowing to the back of the converter, the pre-argon blowing at the station, taking samples at the station, and waiting for the samples at the station can be directly cancelled during the refining process, and the alloying and adjusting the composition can be performed directly according to the composition of the samples after the furnace. This greatly simplifies the refining operation, shortens the refining process time, and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.
[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0032] Figure 1 A schematic flow chart of a method for smelting molten steel provided in an embodiment of the present application. DETAILED DESCRIPTION
[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.
[0034] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.
[0035] In addition, in the description of the specification of the present application, the terms "including", "comprising", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second", etc. are only used to distinguish one entity from another entity, and do not necessarily require or imply any such actual relationship or order between these entities. In this article, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A and B can be singular or plural. In this article, "at least one" means one or more, and "plurality" means two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc or abc, where a, b, c can be single or plural, respectively.
[0036] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.
[0037] Figure 1 A schematic flow chart of a method for smelting molten steel provided in an embodiment of the present application.
[0038] See also Figure 1 The present application provides a method for smelting molten steel, the method comprising:
[0039] S1, smelting the molten iron in a converter to obtain the first molten steel;
[0040] In some embodiments, in the first molten steel, the content of C is 0.015% to 0.08%, and the content of O is 0.025% to 0.065%, calculated by mass fraction.
[0041] In some embodiments, the tapping temperature of the first molten steel is 1635°C to 1665°C.
[0042] In the above embodiment, the quality parameters of the output molten steel can be controlled by the dynamic decarburization model and the temperature model, which can provide the best reaction conditions for the subsequent refining process and achieve the best control effect. Exemplarily, the tapping temperature of the first molten steel can be 1635°C, 1640°C, 1645°C, 1750°C, 1755°C, 1765°C, etc.; in terms of mass fraction, the C content can be 0.015%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.08%, etc., and the O content can be 0.025%, 0.03%, 0.035%, 0.040%, 0.050%, 0.055%, 0.060%, 0.065%, etc.
[0043] S2, tapping the first molten steel into a converter, washing the converter slag and alloying the converter in the process of tapping the converter, and performing low-level bottom blowing of argon to obtain a second molten steel;
[0044] In some embodiments, the converter slag washing and converter alloying are performed during the converter steelmaking process, including: adding small particles of lime and fluorite to the molten steel when the converter steelmaking is 1 / 4 to 1 / 3, and then adding steel sand aluminum, recarburizer and alloy.
[0045] In the above embodiment, in the metallurgical converter steelmaking industry, lime and fluorite are mainly used as raw materials for smelting slag and furnace washing. In the presence of a certain amount of calcium fluoride, it can make the thicker slag thinner to increase the fluidity of the slag and make it easier to desulfurize. Steel sand aluminum is used as a raw material for deoxidation of molten steel.
[0046] In some embodiments, the argon flow rate of the low-speed bottom blowing argon is 200NL / min to 600NL / min, and the time of the low-speed bottom blowing argon is from the start of alloying in the converter to the end of steel tapping from the converter.
[0047] In the above embodiment, the efficiency of alloy melting is improved by controlling the flow rate and time of bottom blowing argon, thereby ensuring complete melting of the carburizer or alloy. For example, the argon flow rate of low-speed bottom blowing argon can be 200NL / min, 300NL / min, 350NL / min, 400NL / min, 500NL / min, 600NL / min, etc.
[0048] S3, subjecting the second molten steel to converter slag reforming and high-grade bottom argon blowing to obtain a third molten steel;
[0049] It should be noted that after the steel is tapped from the converter, a feed chute can be used to add a modifier in batches to the surface of the ladle top slag, thereby performing converter slag modification operations.
[0050] After the converter slag is modified, the present application reduces the time for refining to wait for the arrival sample by moving the refining pre-puffing argon to the back of the converter. At the same time, the present application measures the temperature and composition of the third molten steel after the high-grade bottom argon blowing, thereby directly eliminating the operations of pre-puffing argon at the arrival station, taking the arrival sample, and waiting for the arrival sample.
[0051] In some embodiments, the argon flow rate of the high-end bottom blowing argon is 800NL / min to 1200NL / min, and the time of the high-end bottom blowing argon is 2min to 6min.
[0052] In some embodiments, the efficiency of alloy melting is improved by controlling the flow rate and time of bottom blowing argon, thereby ensuring that the carburizer or alloy is completely melted and absorbed by the molten steel. For example, the argon flow rate of high-grade bottom blowing argon can be 800NL / min, 900NL / min, 1000NL / min, 1100NL / min, 1200NL / min, etc., and the time of high-grade bottom blowing argon can be 2min, 3min, 4min, 5min, 6min, etc.
[0053] S4. Determine the refining process of the third molten steel according to the content relationship between the actual composition and the theoretical composition of the third molten steel to obtain molten steel for low-carbon steel and peritectic steel.
[0054] In some embodiments, the refining process of the third molten steel is determined according to the content relationship between the actual composition and the theoretical composition of the third molten steel, including: calculating the theoretical composition of the third molten steel according to the first molten steel and the amount of alloy added; judging whether the content difference between the actual composition and the theoretical composition of the third molten steel satisfies the set difference range; if so, subjecting the third molten steel to oxygen and aluminum determination, alloying, and refining cycle or argon blowing and stirring; if not, subjecting the third molten steel to argon pre-blowing, and alloying according to the composition of the third molten steel after pre-blowing, and then subjecting it to refining cycle or argon blowing and stirring.
[0055] In some embodiments, the determining whether the content difference between the actual composition and the theoretical composition of the third molten steel satisfies a set difference range includes: determining whether the content difference between the actual composition and the theoretical composition of the third molten steel satisfies a set difference range; wherein, when the component is C, the content difference between the actual composition and the theoretical composition is ≤0.005%; when the component is Si or Mn, the content difference between the actual composition and the theoretical composition is ≤0.03%.
[0056] In some embodiments, the subjecting the third molten steel to oxygen and aluminum determination, alloying, and refining cycle or argon blowing and stirring includes: using an oxygen determiner to determine the oxygen and aluminum of the third molten steel, and adjusting the aluminum element of the molten steel according to the oxygen and aluminum values, and then alloying and refining cycle or argon blowing and stirring.
[0057] The present application adopts the fixed oxygen and aluminum values to guide the aluminum adjustment operation during refining, thereby improving the level of rapid and accurate aluminum control.
[0058] Specifically, a converter post-furnace composition prediction system is added to the secondary steelmaking system. According to the converter endpoint sample (the composition of the first molten steel) and the amount of alloy added, the post-furnace theoretical composition is calculated and displayed on the secondary steelmaking system, and sent to the secondary refining station as the theoretical arrival station composition, thereby obtaining the theoretical composition content of the third molten steel. At the same time, the temperature and composition of the third molten steel are measured after the high-grade bottom blowing of argon as the actual composition content of the third molten steel.
[0059] During the process of hoisting the ladle to the refining, the actual composition of the third molten steel is reported back. The actual composition of the third molten steel is compared with the theoretical composition. If the deviation between the two is small (C deviation is within ±0.005%, Si or Mn deviation is within ±0.03%), the post-furnace sample is considered accurate. Refining calculates the required amount of alloy to be added according to the actual composition of the third molten steel (except aluminum, which needs to be refined to determine oxygen and aluminum at the station), and adds the alloy to the weighing bucket for standby. After refining to the station, the oxygen and aluminum are determined, and the amount of aluminum added is calculated based on the oxygen and aluminum values. Then, aluminum and the alloy in the weighing bucket are added to the molten steel for composition adjustment. Finally, the refining cycle or argon blowing and stirring is ≥6 minutes, and the refining can be ended, and the ladle is hoisted to the continuous casting for pouring. If the deviations between the two are large (C deviation is greater than ±0.005%, Si or Mn deviation is greater than ±0.03%), argon is pre-blown for 3 minutes before entering the refining station, and temperature is measured and sampled. After the sample is reported back, alloying is carried out. Finally, the refining cycle or argon blowing and stirring is ≥6 minutes, and then the refining can be ended and the ladle is hoisted to the continuous casting station for pouring.
[0060] In some embodiments, the refining cycle or argon blowing and stirring time is ≥ 6 min.
[0061] In the above embodiment, by controlling the flow rate and time of the refining cycle or argon blowing and stirring, on the one hand, the efficiency of alloy melting can be improved, thereby ensuring that the alloy is completely melted and absorbed by the molten steel, and on the other hand, the composition and temperature of the molten steel can be uniform, and inclusions can be promoted to float. For example, the time of the refining cycle or argon blowing and stirring can be 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 12 minutes, etc.
[0062] In some embodiments, the argon pre-purge has an argon gas flow rate of 600 NL / min to 1200 NL / min, and a pre-purge time of argon is 2 min to 6 min.
[0063] In the above embodiment, the present application moves the refining pre-blowing of argon to the back of the furnace. In actual production, the actual composition of 80% or more of the third molten steel has a small deviation from the theoretical composition. In the refining process, the pre-blowing of argon at the station, the sampling at the station, and the waiting for the sampling at the station can be directly cancelled, and the alloying and adjusting composition can be performed directly according to the composition of the sample at the back of the furnace, which greatly simplifies the refining operation, shortens the refining processing time, and improves production efficiency. In a few cases, the actual composition of the third molten steel has a large deviation from the theoretical composition, and it is necessary to blow argon again before alloying and adjusting the composition, so as to ensure that the deviation between the composition of the molten steel and the theoretical composition meets the deviation range. Exemplarily, the argon gas flow rate of the pre-blowing of argon can be 600NL / min, 700NL / min, 800NL / min, 900NL / min, 1000NL / min, 1100NL / min, 1200NL / min, etc., and the pre-blowing time can be 2min, 3min, 4min, 5min, 6min, etc.
[0064] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to industry standards. If there is no corresponding industry standard, then the conditions recommended by the manufacturer are followed.
[0065] Example
[0066] The present application provides a method for smelting molten steel for low-carbon steel and peritectic steel, comprising the following steps:
[0067] S11, smelting the molten iron in a converter to obtain a first molten steel; wherein, in the first molten steel, the content of C is 0.04%, the content of O is 0.035%, and the tapping temperature of the first molten steel is 1640° C.;
[0068] S21, tap the first molten steel from the converter, add small-grained lime and fluorite to the molten steel when the converter taps 1 / 4 to 1 / 3, then add steel sand aluminum, carburizer and alloy, and perform low-grade bottom blowing of argon from the start of converter alloying to the end of converter tapping to obtain the second molten steel; add a converter post-furnace composition prediction system to the secondary steelmaking system, calculate the post-furnace theoretical composition based on the converter endpoint sample (the composition of the first molten steel) and the amount of alloy added, and display it on the secondary steelmaking system, and send it to the secondary refining station as the theoretical arrival station composition, so as to obtain the theoretical composition content of the third molten steel. Among them, the argon flow rate of the low-grade bottom blowing of argon is 600NL / min;
[0069] S31, subjecting the second molten steel to converter slag reforming and high-end bottom blowing of argon to obtain a third molten steel; after the high-end bottom blowing of argon, the temperature and composition of the third molten steel are measured as the actual composition content of the third molten steel. The argon gas flow rate of the high-end bottom blowing of argon is 1200NL / min, and the high-end bottom blowing of argon lasts for 3 minutes;
[0070] S41. According to the actual and theoretical composition of the third molten steel, the C deviation is within the range of 0.003%, and the Si or Mn deviation is 0.02%, which meets the set difference range; according to the actual composition of the third molten steel, the required alloy addition amount is calculated (except aluminum, aluminum adjustment requires refining and entering the station to determine oxygen and aluminum), and the alloy is added to the weighing bucket for standby. After refining to the station, the oxygen and aluminum are determined, and the amount of aluminum added is calculated according to the oxygen and aluminum values, and then the aluminum and the alloy in the weighing bucket are added to the molten steel for composition adjustment. Finally, argon is blown and stirred for 8 minutes to end the refining, and molten steel that meets the composition requirements of low-carbon steel and peritectic steel is obtained. The ladle is hoisted to the continuous casting for pouring. At the same time, the refining station sample is cancelled for low-carbon and peritectic steel, and the processing cycle is significantly reduced. The production organization model has been adjusted, and the refining processing cycle is shortened by 3 minutes without causing adverse effects on production.
[0071] In addition, one or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:
[0072] In the embodiment of the present invention, the melting effect of the alloy and the carburizer is improved by optimizing the converter steel-making process and the alloying process; by optimizing the bottom blowing process after steel-making, it is ensured that the alloy and the carburizer are completely melted and the post-furnace sample is uniform and representative. By optimizing the refining oxygen determination and oxygen determination and aluminum determination systems, the accuracy of the detection of the aluminum content in the molten steel is improved, providing a basis for the precise control of the aluminum content in the molten steel during refining. By adopting the above measures to improve the uniformity and representativeness of the composition of the post-furnace sample, the refining eliminates the need for pre-argon blowing at the station, taking samples at the station, and waiting for samples at the station, and directly adjusts the composition according to the composition of the post-furnace sample, which greatly simplifies the refining operation, shortens the refining process time, and improves production efficiency.
[0073] In the embodiment of the present invention, 80% or more of the low-carbon and peritectic steels eliminate the need for refining samples at the station, thereby reducing the consumption of one sample per furnace and saving production costs.
[0074] In the embodiment of the present invention, a post-furnace composition prediction model is developed to achieve the ability to efficiently evaluate the accuracy of the post-furnace sample composition. At the same time, the refining uses the fixed oxygen and aluminum values to guide the aluminum adjustment operation, which improves the level of rapid and accurate aluminum control.
[0075] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.
Claims
1. A method for smelting molten steel, characterized in that: The method comprises: The molten iron is smelted in a converter to obtain the first molten steel; tapping the first molten steel into a converter, washing the converter slag and alloying the converter in the process of tapping the converter, and performing low-level bottom blowing of argon to obtain a second molten steel; The second molten steel is subjected to converter slag reforming and high-grade bottom argon blowing to obtain a third molten steel; According to the content relationship between the actual composition and the theoretical composition of the third molten steel, the refining process of the third molten steel is determined to obtain molten steel for low-carbon steel and peritectic steel.
2. The method according to claim 1, characterized in that The refining process of the third molten steel is determined according to the content relationship between the actual composition and the theoretical composition of the third molten steel, comprising: The theoretical composition of the third molten steel is calculated based on the first molten steel and the amount of alloy added; Determining whether the content difference between the actual composition and the theoretical composition of the third molten steel meets the set difference range; If the conditions are met, the third molten steel is subjected to oxygen and aluminum determination, alloying, refining circulation or argon blowing and stirring; If not, the third molten steel is pre-purged with argon, and alloying is performed according to the composition of the third molten steel after the pre-purging with argon, and then a refining cycle or argon blowing and stirring is performed.
3. The method according to claim 2, characterized in that The determining whether the content difference between the actual composition and the theoretical composition of the third molten steel meets the set difference range includes: Determine whether the content difference between the actual composition and the theoretical composition of the third molten steel meets the set difference range; wherein, When the component is C, the content difference between the actual component and the theoretical component is ≤0.005%; When the component is Si or Mn, the content difference between the actual component and the theoretical component is ≤0.03%.
4. The method according to claim 2, characterized in that: The step of subjecting the third molten steel to oxygen and aluminum determination, alloying, refining circulation or argon blowing and stirring comprises: The oxygen and aluminum content of the third molten steel is determined by using an oxygen meter, and the aluminum element of the molten steel is adjusted according to the oxygen and aluminum values, and then alloying, refining circulation or argon blowing and stirring are carried out.
5. The method according to claim 2, characterized in that: The refining cycle or argon blowing and stirring time is ≥6 minutes.
6. The method according to claim 2, characterized in that The argon gas flow rate of the pre-purging argon is 600NL / min to 1200NL / min, and the time of the pre-purging argon is 2min to 6min.
7. The method according to claim 1, characterized in that The argon flow rate of the low-speed bottom blowing argon is 200NL / min to 600NL / min, and the time of the low-speed bottom blowing argon is from the start of alloying in the converter to the end of steel tapping in the converter.
8. The method according to claim 1, characterized in that The argon flow rate of the high-grade bottom blowing argon is 800NL / min to 1200NL / min, and the time of the high-grade bottom blowing argon is 2min to 6min.
9. The method according to claim 1, characterized in that: The process of washing converter slag and alloying converter during the converter steel tapping process includes: When the steel is tapped from the converter to 1 / 4 to 1 / 3, small particles of lime and fluorite are added to the molten steel, followed by steel grit, aluminum, recarburizer and alloy.
10. The method according to claim 1, characterized in that In terms of mass fraction, in the first molten steel, the content of C is 0.015% to 0.08%, the content of O is 0.025% to 0.065%, and the tapping temperature of the first molten steel is 1635° C. to 1665° C.