A DI material and smelting method thereof

Abstract

The present invention particularly relates to a DI material and a smelting method thereof, and belongs to the technical field of steel smelting. The method comprises: smelting molten iron in a converter to obtain molten steel in a converter; refining the molten steel in the converter to obtain refined molten steel; continuously casting the refined molten steel to obtain a steel billet; during the converter smelting process, controlling the converter bottom blowing flow rate to meet a set flow rate; during the refining process, controlling the pure circulation time to meet a set time, controlling the addition amount of the refined outgoing slag balls to meet a set amount, and not blowing oxygen to raise the temperature during the entire refining process; during the continuous casting process, controlling the drawing speed to meet a set drawing speed to prevent slag curling caused by fluctuations in molten steel; maintaining a steady state by controlling the converter bottom blowing flow rate, controlling the oxygen blowing to raise the temperature, controlling the pure circulation time, optimizing the slag modification method and controlling the drawing speed, performing full process control on the production of DI materials in the steelmaking process, and solving the problem of high scrap rate of DI materials.

Description

Technical Field

[0001] The invention belongs to the technical field of steel smelting, and in particular relates to a DI material and a smelting method thereof. Background Art

[0002] DI material, also known as DWI material (Drawn and Wall Ironed Plate), is the most technically difficult type of high-end plate product. It is known as one of the three fine carbon steel thin plates. It is mainly used for the production of high-level food packaging for food, beverage cans, etc. It has high compressive strength and is easy to recycle.

[0003] DI material is used to make two-piece metal can bodies. The can bodies are subsequently processed by cup punching, drawing, necking and flanging. The thinnest part of the finished can body is only 0.1mm, which is equivalent to the thickness of a piece of paper. In addition, its pressure-bearing requirements are extremely high. Therefore, DI material production is extremely difficult. Strict performance requirements have put forward extremely high requirements on the purity and mechanical properties of steel plates. If the inclusions in the plate exceed the standard by a small amount, sand holes and cracks will appear during the ultra-deep stamping process, resulting in product scrapping. Therefore, the control requirements for inclusions in the steelmaking process are extremely strict, and production is very difficult. Summary of the invention

[0004] The purpose of the present application is to provide a DI material and a smelting method thereof to solve the problem of high scrap rate of DI materials.

[0005] An embodiment of the present invention provides a smelting method of DI material, the method comprising:

[0006] The molten iron is subjected to converter smelting to obtain converter molten steel;

[0007] Refining the converter molten steel to obtain refined molten steel;

[0008] Continuously casting the refined molten steel to obtain a steel billet;

[0009] During the converter smelting process, the converter bottom blowing flow rate is controlled to meet the set flow rate;

[0010] During the refining process, the pure cycle time is controlled to meet the set time, the amount of slag balls added after the refining is controlled to meet the set amount, and oxygen blowing and heating are not performed during the entire refining process;

[0011] During the continuous casting process, the pulling speed is controlled to meet the set pulling speed to prevent slag rolling caused by fluctuation of molten steel.

[0012] Optionally, the set flow rate does not exceed 1000Nm 3 / h.

[0013] Optionally, the set time is greater than 6 minutes.

[0014] Optionally, the set amount is 0.65kg / t-0.70kg / t.

[0015] Optionally, the set pulling speed is ≤1.7m / min.

[0016] Optionally, during the converter smelting process, oxygen blowing and heating are not performed throughout the entire process.

[0017] Optionally, the continuous casting process adopts three-way argon protection casting, and the flow rates of the three-way argon are 3L / min-5L / min, 3L / min-5L / min and 5L / min-8L / min respectively.

[0018] Optionally, the superheat of the molten steel during continuous casting is controlled to be 20°C-35°C.

[0019] Optionally, the water flow rate of the narrow surface of the continuous casting crystallizer is 540L / min-620L / min, and the water flow rate of the wide surface of the continuous casting crystallizer is 4000L / min-4500L / min.

[0020] Based on the same inventive concept, an embodiment of the present invention further provides a DI material, wherein the steel is produced by the smelting method of the DI material as described above.

[0021] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0022] The DI material smelting method provided in the embodiment of the present invention maintains a steady state by controlling the bottom blowing flow rate of the converter, controlling the oxygen blowing temperature rise, controlling the pure cycle time, optimizing the slag modification method and controlling the pulling speed, and performs full process control of the production of DI materials in the steelmaking process to solve the problem of high scrap rate of DI materials.

[0023] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 It is a flow chart of the method provided by the embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below in conjunction with specific implementations and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific implementations and examples are used to illustrate the present invention, rather than to limit the present invention.

[0027] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. In the event of a conflict, the present specification takes precedence.

[0028] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0029] The technical solution of the embodiment of the present application is to solve the above technical problems, and the overall idea is as follows:

[0030] According to a typical embodiment of the present invention, a DI material smelting method is provided, which adopts a BOF-RH-CCM process route to organize smelting, and the specific method includes:

[0031] S1. The molten iron is subjected to converter smelting to obtain converter molten steel; during the converter smelting process, the converter bottom blowing flow rate is controlled to meet the set flow rate;

[0032] In some embodiments, the set flow rate does not exceed 1000Nm 3 / h, and no oxygen blowing is performed to increase the temperature during the entire converter smelting process.

[0033] Control the converter bottom blowing flow rate not exceeding 1000Nm 3 / h. Properly increasing the bottom blowing gas supply intensity is beneficial to improving the bottom blowing stirring effect of the converter. If the bottom blowing gas supply intensity is too high, the life of the bottom blowing gas supply components will be shortened.

[0034] Specifically, in this embodiment, the converter scrap steel in the converter process is controlled according to the fine scrap steel mode to reduce the sulfur increase, and the bottom blowing argon is used throughout the process, and the bottom blowing flow rate target in the later stage does not exceed 1000Nm 3 / h, swing the alloy chute to avoid accumulation when adding, stir vigorously for 1 to 3 minutes to ensure that there is no unmelted slag or alloy material on the slag surface. The tapping temperature of the converter is controlled at 1665-1685℃, the target oxygen of the converter end point is 350-550ppm, it is strictly forbidden to blow oxygen to raise the temperature, maintain the end point temperature, the target is not post-blowing, aluminum deoxidation and alloying operation, the target aluminum content entering the station is> 0.030%, the converter adopts front and rear slag blocking, and the tapping slag is modified by adding calcium aluminum slag balls 0.4-0.5kg / ton of steel on the slag surface

[0035] S2. Refining the molten steel in the converter; obtaining refined molten steel; during the refining process, controlling the pure cycle time to meet the set time, controlling the amount of slag balls added to the refined outlet to meet the set amount, and the entire refining process is not carried out by blowing oxygen to raise the temperature;

[0036] In some embodiments, the setting time is greater than 6 min, and the setting amount is 0.65 kg / t-0.70 kg / t.

[0037] The pure circulation time is controlled to be greater than 6 minutes in order to ensure that the inclusions are fully floated and removed. If the time is too short, it will be unfavorable for the inclusions to grow and collide and be removed.

[0038] The amount of slag balls added after refining is controlled to be 0.65kg / t-0.70kg / t, which can reduce the TFe content in the slag and the oxidation of the slag on the molten steel. If the amount added is too small, the adverse effect is that the slag contains oxidizing properties, which can easily continue to oxidize the molten steel to form Al2O3 type inclusions. If the amount added is too large, it will cause waste of raw materials and increase steelmaking costs.

[0039] Specifically, in this embodiment, RH refining is adopted for refining, scrap steel is added in the early stage of the RH refining process, the last batch of scrap steel is added 10 minutes before vacuum treatment, the carbon content at the refining station is controlled according to the target carbon content, the oxygen target before deoxidation is <320ppm, the pure cycle time is controlled according to >6min, oxygen blowing and heating are prohibited during the process, and the aluminum slag balls at the station are controlled according to (0.65-0.70kg / t).

[0040] S3. Continuously casting the refined molten steel to obtain a steel billet; during the continuous casting process, controlling the casting speed to meet the set casting speed to prevent slag curling caused by fluctuations in the molten steel.

[0041] In some embodiments, the pulling speed is set to ≤1.7m / min, and the continuous casting process adopts three-way argon protection casting, and the flow rates of the three-way argon are 3L / min-5L / min, 3L / min-5L / min and 5L / min-8L / min respectively; the superheat of the cast steel liquid is controlled to 20℃-35℃; the water flow rate of the narrow surface of the continuous casting crystallizer is 540L / min-620L / min, and the water flow rate of the wide surface of the continuous casting crystallizer is 4000L / min-4500L / min.

[0042] Controlling the pulling speed to ≤1.7m / min can effectively prevent excessive liquid level fluctuations from causing slag roll-up; the three-way argon gas is reasonably controlled according to the target to reduce nozzle blockage.

[0043] Specifically, in this embodiment, the casting speed of the continuous casting process is controlled at ≤1.7m / min, the three-way argon is controlled at the target (3-5)-(3-5)-(5-8)L / min, the steel retention rate is (0.02-0.04) tons per ton of steel in the smelting furnace, and the slag under the ladle is prevented from causing molten steel pollution. The continuous casting speed is ≤1.7m / min, the superheat is controlled at 20-35°C, the water flow rate of the narrow and wide surface of the crystallizer is 540-620L / min, 4000-4500L / min, and the water inlet immersion depth is 160-180mm. After the slab is off the line, the flame cleaning of the four sides of the slab is carried out by 3-5mm to improve the quality of the slab.

[0044] By optimizing the quality of converter scrap steel, adjusting the converter bottom blowing flow rate, etc., in the RH refining process, by controlling the oxygen blowing temperature rise, extending the pure cycle time, optimizing the slag modification method, the steady-state casting of the casting machine ensures the liquid level fluctuation to improve the slab quality, and the key technologies for producing DI materials in the steelmaking process are sorted out throughout the whole process. The present invention has high process application value, is easy to operate, and can meet customer product needs.

[0045] According to another typical embodiment of the present invention, a DI material is provided, wherein the steel material is produced by the smelting method of the DI material as described above.

[0046] The DI material and smelting method of the present application will be described in detail below in combination with embodiments, comparative examples and experimental data.

[0047] Example 1

[0048] Each steelmaking process produces one furnace of DI material, and the process route is converter → RH refining → casting machine.

[0049] The converter scrap is controlled according to the fine scrap mode, using argon blowing throughout the process, and the bottom blowing flow rate in the later stage is 980Nm 3 / h, swing the alloy chute to avoid accumulation when adding, stir vigorously for 3 minutes, and there is no unmelted slag and alloy material on the slag surface. The tapping temperature of the converter is 1671℃, the target oxygen of the converter end point is 421ppm, the end point temperature is appropriate, no oxygen blowing to raise the temperature, aluminum deoxidation and alloying operation, the aluminum content entering the station is >0.031%, the converter adopts front and rear slag blocking, and the tapping slag is modified by adding 139kg of calcium aluminum slag balls on the slag surface.

[0050] Scrap steel is added in the early stage of the RH refining process, and the last batch of scrap steel is added 8 minutes before vacuum treatment. The carbon content of the refined outlet is controlled according to the target carbon content, the oxygen target before deoxidation is 297ppm, the pure cycle time is 6.5min, all aluminum is adjusted at one time, no oxygen is blown to increase the temperature during the process, and 198kg of high-calcium aluminum slag balls are added at the outlet. The oxygen before deoxidation and the final target composition are all as expected, and the RH final composition is all qualified. The TFe of the RH incoming slag is 2.88%, the CaO / Al2O3 of the incoming slag is 1.67, the TFe of the outgoing slag is 3.94%, and the CaO / Al2O3 of the outgoing slag is 1.24. The actual amount of steel retained is >10.6 tons to prevent the slag from the ladle from causing steel liquid pollution.

[0051] The cross-section of this furnace is 1200mm×237mm, the pulling speed is 1.6m / min, the three-way argon is controlled according to the target 4.5-4.5-7L / min, the superheat is controlled at 25℃, the water flow rate on the narrow and wide sides of the crystallizer is 580L / min and 4200L / min, the water inlet immersion depth is 170mm, and the flame cleaning of 3.5mm on all four sides of the slab is carried out after it comes off the line to improve the quality of the slab, and the casting process is normal.

[0052] Example 2

[0053] Each steelmaking process produces one furnace of DI material, and the process route is converter → RH refining → casting machine.

[0054] The converter scrap is controlled according to the fine scrap mode, using argon blowing throughout the process, and the bottom blowing flow rate in the later stage is 1000Nm 3 / h, swing the alloy chute to avoid accumulation when adding, stir vigorously for 3 minutes, and there is no unmelted slag and alloy material on the slag surface. The tapping temperature of the converter is 1671℃, the target oxygen of the converter end point is 421ppm, the end point temperature is appropriate, no oxygen blowing to raise the temperature, aluminum deoxidation and alloying operation, the aluminum content entering the station is >0.031%, the converter adopts front and rear slag blocking, and the tapping slag is modified by adding 139kg of calcium aluminum slag balls on the slag surface.

[0055] Scrap steel is added in the early stage of RH refining process, and the last batch of scrap steel is added 8 minutes before vacuum treatment. The carbon content of refined outgoing station is controlled according to the target carbon content, the oxygen target before deoxidation is 297ppm, the pure cycle time is 6min, all aluminum is adjusted at one time, no oxygen is blown to increase the temperature during the process, and 198kg of high-calcium aluminum slag balls are added outgoing station. The oxygen before deoxidation and the final target composition are all as expected, and the final composition of RH is all qualified. The TFe of RH incoming slag is 2.88%, the CaO / Al2O3 of incoming slag is 1.67, the TFe of outgoing slag is 3.94%, the CaO / Al2O3 of outgoing slag is 1.24, and the actual amount of steel retained is >10.6 tons to prevent the slag under the ladle from causing steel liquid pollution.

[0056] The cross-section of this furnace is 1200mm×237mm, the pulling speed is 1.7m / min, the three-way argon is controlled according to the target 3-3-5L / min, the superheat is controlled at 20℃, the water flow rate on the narrow and wide surfaces of the crystallizer is 540L / min and 4000L / min, the water nozzle immersion depth is 170mm, and the slab is flame-cleaned 3.5mm on all four sides after it comes off the line to improve the quality of the slab, and the casting process is normal.

[0057] Example 3

[0058] Each steelmaking process produces one furnace of DI material, and the process route is converter → RH refining → casting machine.

[0059] The converter scrap is controlled according to the fine scrap mode, using argon blowing throughout the process, and the bottom blowing flow rate in the later stage is 900Nm 3 / h, swing the alloy chute to avoid accumulation when adding, stir vigorously for 3 minutes, and there is no unmelted slag and alloy material on the slag surface. The tapping temperature of the converter is 1671℃, the target oxygen of the converter end point is 421ppm, the end point temperature is appropriate, no oxygen blowing to raise the temperature, aluminum deoxidation and alloying operation, the aluminum content entering the station is >0.031%, the converter adopts front and rear slag blocking, and the tapping slag is modified by adding 139kg of calcium aluminum slag balls on the slag surface.

[0060] Scrap steel is added in the early stage of RH refining process, and the last batch of scrap steel is added 8 minutes before vacuum treatment. The carbon content of refined outgoing station is controlled according to the target carbon content, the oxygen target before deoxidation is 297ppm, the pure cycle time is 8min, all aluminum is adjusted at one time, no oxygen is blown to increase the temperature during the process, and 198kg of high-calcium aluminum slag balls are added outgoing station. The oxygen before deoxidation and the final target composition are all as expected, and the RH final composition is all qualified. The TFe of RH incoming slag is 2.88%, the CaO / Al2O3 of the incoming slag is 1.67, the TFe of the outgoing slag is 3.94%, the CaO / Al2O3 of the outgoing slag is 1.24, and the actual amount of steel retained is >10.6 tons to prevent the slag from the ladle from causing steel liquid pollution.

[0061] The cross-section of this furnace is 1200mm×237mm, the pulling speed is 1.5m / min, the three-way argon is controlled according to the target 5-5-8L / min, the superheat is controlled at 35℃, the water flow rate on the narrow and wide surfaces of the crystallizer is 620L / min and 4500L / min, the water inlet immersion depth is 170mm, and the flame cleaning of 3.5mm on all four sides of the slab is carried out after it comes off the line to improve the quality of the slab, and the casting process is normal.

[0062] Comparative Example 1

[0063] Each steelmaking process produces one furnace of DI material, and the process route is converter → RH refining → casting machine.

[0064] The converter scrap is controlled according to the fine scrap mode, using argon blowing throughout the process, and the bottom blowing flow rate in the later stage is 1100Nm 3 / h, swing the alloy chute to avoid accumulation when adding, stir vigorously for 3 minutes, and there is no unmelted slag and alloy material on the slag surface. The tapping temperature of the converter is 1671℃, the target oxygen of the converter end point is 421ppm, the end point temperature is appropriate, no oxygen blowing to raise the temperature, aluminum deoxidation and alloying operation, the aluminum content entering the station is >0.031%, the converter adopts front and rear slag blocking, and the tapping slag is modified by adding 139kg of calcium aluminum slag balls on the slag surface.

[0065] Scrap steel is added in the early stage of the RH refining process, and the last batch of scrap steel is added 8 minutes before vacuum treatment. The carbon content of the refined outlet is controlled according to the target carbon content, the oxygen target before deoxidation is 297ppm, the pure cycle time is 6.5min, all aluminum is adjusted at one time, no oxygen is blown to increase the temperature during the process, and 198kg of high-calcium aluminum slag balls are added at the outlet. The oxygen before deoxidation and the final target composition are all as expected, and the RH final composition is all qualified. The TFe of the RH incoming slag is 2.88%, the CaO / Al2O3 of the incoming slag is 1.67, the TFe of the outgoing slag is 3.94%, and the CaO / Al2O3 of the outgoing slag is 1.24. The actual amount of steel retained is >10.6 tons to prevent the slag from the ladle from causing steel liquid pollution.

[0066] The cross-section of this furnace is 1200mm×237mm, the pulling speed is 1.6m / min, the three-way argon is controlled according to the target 4.5-4.5-7L / min, the superheat is controlled at 25℃, the water flow rate on the narrow and wide sides of the crystallizer is 580L / min and 4200L / min, the water inlet immersion depth is 170mm, and the flame cleaning of 3.5mm on all four sides of the slab is carried out after it comes off the line to improve the quality of the slab, and the casting process is normal.

[0067] Comparative Example 2

[0068] Each steelmaking process produces one furnace of DI material, and the process route is converter → RH refining → casting machine.

[0069] The converter scrap is controlled according to the fine scrap mode, using argon blowing throughout the process, and the bottom blowing flow rate in the later stage is 980Nm 3 / h, swing the alloy chute to avoid accumulation when adding, stir vigorously for 3 minutes, and there is no unmelted slag and alloy material on the slag surface. The tapping temperature of the converter is 1671℃, the target oxygen of the converter end point is 421ppm, the end point temperature is appropriate, no oxygen blowing to raise the temperature, aluminum deoxidation and alloying operation, the aluminum content entering the station is >0.031%, the converter adopts front and rear slag blocking, and the tapping slag is modified by adding 139kg of calcium aluminum slag balls on the slag surface.

[0070] Scrap steel is added in the early stage of RH refining process, and the last batch of scrap steel is added 8 minutes before vacuum treatment. The carbon content of refined outgoing station is controlled according to the target carbon content, the oxygen target before deoxidation is 297ppm, the pure cycle time is 5min, all aluminum is adjusted at one time, no oxygen is blown to increase the temperature during the process, and 198kg of high-calcium aluminum slag balls are added outgoing station. The oxygen before deoxidation and the final target composition are all as expected, and the RH final composition is all qualified. The TFe of RH incoming slag is 2.88%, the CaO / Al2O3 of incoming slag is 1.67, the TFe of outgoing slag is 3.94%, the CaO / Al2O3 of outgoing slag is 1.24, and the actual amount of steel retained is >10.6 tons to prevent the slag under the ladle from causing steel liquid pollution.

[0071] The cross section of this furnace is 1200mm×237mm, the casting speed is 1.6m / min, the three-way argon is controlled according to the target 4.5-4.5-7L / min, the superheat is controlled at 25℃, the water flow rate of the narrow and wide sides of the crystallizer is 580L / min, 4200L / min, the water inlet immersion depth is 170mm, and the flame cleaning of the four sides of the slab is 3.5mm after the slab is off the line to improve the quality of the slab, and the casting process is normal. Related experiments:

[0072] The steels prepared in Examples 1-3 and Comparative Examples 1-2 were inspected, and the results are shown in the following table.

[0073] Cold rolled sheet defect rate Example 1 0.30％ Example 2 0.32％ Example 3 0.31％ Comparative Example 1 0.74％ Comparative Example 2 0.76％

[0074] It can be seen from the above table that the method provided in the embodiment of the present application can effectively reduce the scrap rate of DI materials when preparing DI materials; by comparing the comparative example with the embodiment, it can be seen that the bottom blowing flow rate in the middle and late stages of comparative example 1 is 1100 Nm 3 / h, resulting in a significantly accelerated erosion rate of the bottom blowing components and the furnace bottom; in Comparative Example 2, the RH refining pure cycle time was 5min, and the inclusions were not fully removed by floating, resulting in an increased incidence of defects in the final cold-rolled products.

[0075] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0076] The method provided in the embodiment of the present invention optimizes the quality of converter scrap steel, adjusts the converter bottom blowing flow rate, etc., in the RH refining process, controls the oxygen blowing temperature rise, extends the pure cycle time, optimizes the slag modification method, and ensures the liquid level fluctuation through steady-state casting of the casting machine to improve the quality of the slab. The key technologies for producing DI materials in the steelmaking process are sorted out throughout the entire process. The method has high process application value, is easy to operate, and can meet customer product needs.

[0077] Finally, it should be noted that the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article, or apparatus.

[0078] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0079] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A smelting method of DI material, characterized in that: The method comprises: The molten iron is subjected to converter smelting to obtain converter molten steel; Refining the converter molten steel to obtain refined molten steel; Continuously casting the refined molten steel to obtain a steel billet; During the converter smelting process, argon is blown throughout the process, and the target flow rate of the bottom blowing in the later stage does not exceed 1000Nm 3 / h, the tapping temperature of the converter is controlled at 1665-1685℃, the target oxygen of the converter endpoint is 350-550ppm, oxygen blowing is strictly prohibited to increase the temperature, the endpoint temperature is maintained, the target is not post-blowing, aluminum deoxidation and alloying operation, the target aluminum content entering the station is> 0.030%, the converter adopts front and rear slag blocking, and the tapping slag is modified by adding calcium aluminum slag balls 0.4-0.5kg / ton of steel on the slag surface; RH refining is adopted for refining. Scrap steel is added in the early stage of RH refining process. The last batch of scrap steel is added 10 minutes before vacuum treatment. The carbon content of refining outlet is controlled according to the target carbon content. The oxygen target before deoxidation is <320ppm. The pure cycle time is controlled according to >6min. Oxygen blowing and temperature increase are prohibited during the process. The aluminum slag balls at the outlet are controlled according to 0.65kg / t-0.70kg / t. The casting machine pulling speed of the continuous casting process is controlled to be ≤1.7m / min. The continuous casting process adopts three-way argon protection casting. The flow rates of the three-way argon are 3L / min-5L / min, 3L / min-5L / min and 5L / min-8L / min respectively. The steel retention rate per ton of steel in the smelting furnace is 0.02 tons to 0.04 tons. The superheat of the continuous casting molten steel is controlled to be 20-35°C. The water flow rate on the narrow side of the continuous casting crystallizer is 540L / min-620L / min, the water flow rate on the wide side of the continuous casting crystallizer is 4000L / min-4500L / min, and the water inlet immersion depth is 160-180mm.

2. A DI material, characterized in that: The DI material is prepared by the smelting method described in claim 1.

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