Method for stably controlling aluminum content in steel by adopting vacuum induction furnace

Abstract

The invention discloses a method for stably controlling the content of aluminum in steel through a vacuum induction furnace. The method comprises the steps that the vacuum induction furnace is adopted for smelting; steel similar to a target steel type is adopted as a raw material to be crushed and processed into long strips of a certain specification to serve as furnace charge, and the hit rate of components is increased; the adding amount of aluminum blocks is calculated by combining target components with different aluminum contents, and the aluminum content in the steel is stably controlled; all the raw materials are added into a crucible to be smelted, and it is guaranteed that smelting is conducted in a vacuum state; after the raw materials are melted for 50-70 seconds, the calculated alloy is added; after the alloy is completely melted, casting under vacuum; and chemical components of the smelted steel grade are inspected to be the same as or similar to target components. According to the method for stably controlling the aluminum content in the steel through the vacuum induction furnace, the aluminum element is added into the steel through the vacuum induction furnace to achieve the light weight of the steel and iron material, and the method is provided for stably controlling the aluminum content in the steel.

Description

Technical Field

[0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a method for stably controlling the aluminum content in steel by using a vacuum induction furnace. Background Art

[0002] With the continuous development of industrial production technology, in order to improve the quality of steel, in the transportation industry, higher requirements have been put forward for lightweight steel materials, emission restrictions, and safety standards. In order to better serve users, the transportation industry has more and more demand for parts with high formability. In order to achieve energy conservation and emission reduction, steel materials are gradually developing in the direction of lightweight and high strength. As a new type of high-strength automotive steel, lightweight high-aluminum dual-phase steel for automobiles is gradually being used in automobile manufacturing. As the main alloying elements of steel, Mn, Si, Al and C can all reduce the density of steel. At room temperature, Al has a high solid solubility in pure Fe (9%). Fe-Al alloy steel (containing trace amounts of other elements) is the simplest low-density steel. Therefore, the study of the steelmaking and aluminum-adding process of low-density steel is of great significance.

[0003] The Chinese patent with application number 201910327231.6 discloses an aluminum-containing low-carbon construction steel and its smelting process. Its composition is calculated by weight percentage as follows: C: 0.03-0.07%, Si: 0.05-0.12%, Mn: 0.20-0.40%, P: ≤0.025%, S: ≤0.025%, Al: 0.012-0.035%, Ti: 0.010-0.030%, B: ≥0.0040%, and the rest is Fe and unavoidable impurities. It includes converter smelting, LF heating, RH refining, LF refining, and billet continuous casting. By adding Al, B, and Ti elements for microalloying, the grain refinement index is achieved, and the purity of the molten steel is improved by taking measures such as reducing the basicity of the refining slag, controlling the amount of calcium wire fed, using all-magnesium refractory materials, and retaining steel and slag.

[0004] The Chinese patent with application number 202010609458.2 discloses a low-cost rapid smelting method for aluminum-containing steel. From molten iron to continuous casting, there are only four links: molten iron → converter → argon station → continuous casting; the method is as follows: the oxygen content of the molten steel at the end of the converter is controlled at ≤600ppm; a certain amount of lime and fluorite are added during the converter tapping process to make slag with suitable alkalinity, and argon is blown at the bottom of the ladle for strong stirring to stir and desulfurize; pure aluminum blocks are directly added during the converter tapping process, and all pure aluminum blocks are added to the ladle before the converter tapping is completed; after the molten steel is tapped and reaches the argon blowing station, in the later stage of argon blowing, after reducing the argon blowing intensity, a certain amount of pure calcium wire is added to calcify and denature the aluminum oxide inclusions in the molten steel, improve the purity of the molten steel, and eliminate aluminum oxide inclusions. The method of producing aluminum-containing steel in a short process replaces the current situation of long-process technology relying on LF refining mode at home and abroad, which greatly reduces costs and has high production efficiency, and has great market promotion value at home and abroad.

[0005] The Chinese patent with application number 202110192639.4 discloses a method for producing sulfur-containing aluminum-containing steel. The molten steel after converter smelting is refined in the LF furnace, and slag-making materials are added during the converter steel-tapping process to form high-basicity refined slag with a binary basicity of 8 to 14. Slag-making materials are added during the converter steel-tapping process to form high-basicity refined slag with a binary basicity of 8 to 14. After the LF enters the station and is heated for 11-18 minutes, ferrosilicon powder is added to the ladle to form low-basicity refined slag with a binary basicity of 3 to 5. The present invention does not use calcium treatment, avoids the problem of large particle inclusions produced by calcium treatment, and realizes continuous casting of more than 8 furnaces of sulfur-containing aluminum-containing steel. Summary of the invention

[0006] The purpose of the present invention is to provide a method for stably controlling the aluminum content in steel by using a vacuum induction furnace, adding aluminum elements to steel by using a vacuum induction furnace to achieve lightweight steel materials, and providing a method for stably controlling the addition of aluminum content in steel.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] The present invention discloses a method for stably controlling the aluminum content in steel by using a vacuum induction furnace, comprising:

[0009] Use vacuum induction furnace for smelting;

[0010] Use steel similar to the target steel grade as raw material for breaking and processing into long strips of certain specifications as furnace charge to improve the hit rate of components;

[0011] The amount of aluminum block added is calculated based on the target composition with different aluminum contents to stably control the aluminum content in the steel;

[0012] Add all raw materials into the crucible for smelting, and ensure that it is carried out under vacuum;

[0013] 50-70s after the raw materials are melted, add the calculated alloy;

[0014] After ensuring that all the alloy is melted, cast it under vacuum;

[0015] Check the chemical composition of the steel after smelting to ensure it is the same or close to the target composition.

[0016] Further, a 25kg vacuum induction furnace is used for smelting.

[0017] Further, it is processed into strips of 30 cm in length and 3 cm in width as furnace charge.

[0018] Furthermore, the vacuum degree is 90 Pa.

[0019] Furthermore, the calculated alloy was added 60 s after the raw materials were melted.

[0020] Furthermore, after heating for 2 minutes, the alloy is ensured to be completely melted and then cast under vacuum.

[0021] Furthermore, raw materials with similar composition to the target steel grade are used for smelting, and the specific composition is shown in the following table:

[0022]

[0023] Based on the different alloy contents and yields, the addition amounts of different alloys were calculated, including 5.1 g of carbon, 151.7 g of ferrosilicon alloy, 224.6 g of ferromanganese alloy, 510 g of aluminum block, 164.3 g of ferrochromium alloy, 13 g of ferroniobium alloy, and 6.2 g of ferrotitanium alloy.

[0024] Furthermore, raw materials with similar composition to the target steel grade are used for smelting, and the specific composition is shown in the following table:

[0025]

[0026] Based on the different alloy contents and yields, the addition amounts of different alloys were calculated, including 5.1 g of carbon, 151.7 g of ferrosilicon alloy, 224.6 g of ferromanganese alloy, 1020.9 g of aluminum block, 164.3 g of ferrochromium alloy, 13 g of ferroniobium alloy, and 6.2 g of ferrotitanium alloy.

[0027] Compared with the prior art, the beneficial technical effects of the present invention are:

[0028] This paper adopts a vacuum induction furnace to conduct experiments. According to the requirements of different steel grades for aluminum content, combined with the characteristics of vacuum smelting and the aluminum yield, the addition amount is calculated. Since aluminum is more active in chemical properties, from the atomic structure, the number of outermost electrons is 3, and it is easy to lose electrons to form a stable structure. Aluminum can react with oxygen at room temperature, and can also react with acid and strong alkali solutions. Therefore, in the actual steelmaking process, it is more difficult to control the aluminum element in steel. In the field experiment, the aluminum content in the steel was set to 0.50%. By adding aluminum elements multiple times during the refining process, the aluminum content of the steel finally obtained was 0.64%, indicating that the precise control of aluminum elements in steel is complicated. The present invention achieves the purpose of stably controlling the aluminum content in steel by a vacuum induction furnace through small furnace smelting, and provides technical support for industrial production to stably control the aluminum content in steel. The analysis method is simple and effective, low cost, and has broad application prospects. DETAILED DESCRIPTION

[0029] Case 1:

[0030] 1. A 25kg vacuum induction furnace is used for smelting of the test steel, and the aluminum content of the test steel is required to be 2.0%.

[0031] 2. Use raw materials with similar composition to the target steel grade for smelting. The specific composition is shown in the following table:

[0032]

[0033] 3. Based on the different alloy contents and yields, calculate the amount of different alloys added: 5.1g carbon, 151.7g ferrosilicon alloy, 224.6g ferromanganese alloy, 510g aluminum block, 164.3g ferrochromium alloy, 13g ferroniobium alloy, and 6.2g ferrotitanium alloy.

[0034] 4. Ensure that smelting is carried out under vacuum with a vacuum degree of 90pa.

[0035] 5. Add various alloys 1 minute after the raw materials are melted.

[0036] 6. After heating for 2 minutes, ensure that the alloy is completely melted and then cast under vacuum.

[0037] 7. The chemical composition of the steel after smelting was tested and the aluminum content was 2.01%, which is basically the same as the designed target composition.

[0038] Case 2:

[0039] 1. A 25kg vacuum induction furnace is used for smelting of the test steel, and the aluminum content of the test steel is required to be 4.0%.

[0040] 2. Use raw materials with similar composition to the target steel grade for smelting. The specific composition is shown in the following table:

[0041]

[0042] 3. Based on the different alloy contents and yields, calculate the amount of different alloys added: 5.1g carbon, 151.7g ferrosilicon alloy, 224.6g ferromanganese alloy, 1020.9g aluminum block, 164.3g ferrochromium alloy, 13g ferroniobium alloy, and 6.2g ferrotitanium alloy.

[0043] 4. Ensure that smelting is carried out under vacuum with a vacuum degree of 90pa.

[0044] 5. Add various alloys 1 minute after the raw materials are melted.

[0045] 6. After heating for 2 minutes, ensure that the alloy is completely melted and then cast under vacuum.

[0046] 7. The chemical composition of the steel after smelting was tested and the aluminum content was 4.05%, which is basically the same as the designed target composition.

[0047] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for stably controlling the aluminum content in steel using a vacuum induction furnace, characterized in that: include: The smelting is carried out using a vacuum induction furnace; Use steel similar to the target steel grade as raw material for breaking and processing into long strips of certain specifications as furnace charge to improve the hit rate of components; The amount of aluminum block added is calculated based on the target composition with different aluminum contents to stably control the aluminum content in the steel; Add all raw materials into the crucible for smelting, and ensure that it is carried out under vacuum; 50-70s after the raw materials are melted, add the calculated alloy; After ensuring that all the alloy is melted, cast it under vacuum; Check the chemical composition of the steel after smelting to ensure it is the same or close to the target composition.

2. The method for stably controlling the aluminum content in steel using a vacuum induction furnace according to claim 1, characterized in that: A 25kg vacuum induction furnace is used for smelting.

3. The method for stably controlling the aluminum content in steel using a vacuum induction furnace according to claim 1, characterized in that: Processed into strips of 30cm in length and 3cm in width as furnace charge.

4. The method for stably controlling the aluminum content in steel using a vacuum induction furnace according to claim 1, characterized in that: The vacuum degree is 90pa.

5. The method for stably controlling the aluminum content in steel using a vacuum induction furnace according to claim 1, characterized in that: 60s after the raw materials are melted, add the calculated alloy.

6. The method for stably controlling the aluminum content in steel using a vacuum induction furnace according to claim 1, characterized in that: After heating for 2 minutes, ensure that the alloy is completely melted and then cast under vacuum.

7. The method for stably controlling the aluminum content in steel using a vacuum induction furnace according to claim 1, characterized in that: The raw materials with similar composition to the target steel grade are used for smelting. The specific composition is shown in the following table: Based on the different alloy contents and yields, the addition amounts of different alloys were calculated, including 5.1 g of carbon, 151.7 g of ferrosilicon alloy, 224.6 g of ferromanganese alloy, 510 g of aluminum block, 164.3 g of ferrochromium alloy, 13 g of ferroniobium alloy, and 6.2 g of ferrotitanium alloy.

8. The method for stably controlling the aluminum content in steel using a vacuum induction furnace according to claim 1, characterized in that: The raw materials with similar composition to the target steel grade are used for smelting, and the specific composition is shown in the following table: Based on the different alloy contents and yields, the addition amounts of different alloys were calculated, including 5.1 g of carbon, 151.7 g of ferrosilicon alloy, 224.6 g of ferromanganese alloy, 1020.9 g of aluminum block, 164.3 g of ferrochromium alloy, 13 g of ferroniobium alloy, and 6.2 g of ferrotitanium alloy.

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