Method for controlling Ni content of wire rod for hyperfine steel wire

Abstract

The invention relates to the field of steel production and manufacturing, in particular to a method for controlling the Ni content of a wire rod for a hyperfine steel wire. Comprising the following steps: controlling the proportion of steel scrap smelted by a converter and the nickel content of the steel scrap; adopting a molten steel tank for refining; controlling the oxygen activity of deoxidized molten steel behind the converter; controlling the acid-soluble aluminum content of the molten steel behind the converter; and the NiO content of a tundish covering agent in the molten steel continuous casting process is controlled, and the NiO content of molten steel continuous casting covering slag is controlled. The method has the advantages that the nickel content in the steel is controlled to be at an extremely low level through interface reaction, and the phenomena that the structure dislocation density of a wire rod in the drawing process is excessively increased and work hardening is serious due to the fact that the nickel content is high are prevented; the nickel content of the wire rod is controlled at a low level, the technical problems of large steel wire strength fluctuation and uneven steel wire strength in the heat treatment process after the wire rod is processed into the steel wire are solved, and the quality requirement of the high-quality wire rod for deep processing is met.

Description

Technical Field

[0001] The invention relates to the field of steel production and manufacturing, and in particular to a method for controlling the Ni content of a wire rod for ultra-fine steel wire. Background Art

[0002] High carbon steel wire rod is generally used as the raw material for deep processing products. There are strict requirements for the performance of steel wire processed from wire rod, which requires the nickel content in steel to be extremely low. In order to control the nickel content in steel, a new control method must be developed.

[0003] In the prior art, the application number is CN202010018825.1, and the patent name is "A method for producing SWRH82B steel with low acid-soluble aluminum content", which "includes the following steps: KR hot metal pre-desulfurization treatment, 150-ton top and bottom combined blowing converter, argon blowing after the furnace, LF furnace refining, RH vacuum refining, 165mm×165mm square billet continuous casting, billet heating, high-pressure water descaling, high-speed wire rolling, controlled cooling and coiling; the chemical composition of the SWRH82B steel with low acid-soluble aluminum content is important. The invention introduces a control method for reducing the acid-soluble aluminum content in steel by using low-basicity slag, high-quality alloys, etc., but does not go into the development of a method for controlling the residual nickel content in steel. Summary of the invention

[0004] The purpose of the present invention is to provide a method for controlling the Ni content of wire rod for ultra-fine steel wire, and propose an interface control technical scheme for the nickel content, so as to control the nickel content in the steel to an extremely low level and meet the quality requirements of high-quality steel for deep processing.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions:

[0006] A method for controlling the Ni content of a wire rod for ultra-fine steel wire, specifically comprising:

[0007] S1. Control the proportion of scrap steel in converter smelting and the nickel content of scrap steel;

[0008] S2, control the temperature and oxygen activity of the molten steel after the converter;

[0009] S3, using low nickel, low aluminum and low titanium liquid steel to refine used steel tanks;

[0010] S4, control the oxygen activity of the molten steel after deoxidation in the converter furnace;

[0011] S5, control the acid-soluble aluminum content of the steel liquid after the converter;

[0012] S6, control the S content and oxygen activity of molten steel in the LF furnace refining process;

[0013] S7, controlling the Al2O3 content in the top slag of steel during the LF furnace refining process;

[0014] S8, control the NiO content of the intermediate coating agent during the continuous casting of molten steel;

[0015] S9. Control the NiO content in the continuous casting slag of molten steel.

[0016] In S1, the proportion of scrap steel smelted in the converter is between 5% and 10%, and the nickel content Ni in the scrap steel is ≤ 0.04%.

[0017] In S2, the temperature of the molten steel after the high carbon steel converter is controlled between 1580 and 1610°C, the carbon content after the converter is controlled between 0.3% and 0.5%, the oxygen activity is controlled between 70 and 150 ppm, and the nickel content is controlled between 0.001% and 0.01%.

[0018] In S3, the high carbon steel converter steel ladle uses the steel ladle that has been used in the previous 2-3 times of low nickel, low aluminum and low titanium steel liquid refining, and the Ni, Al and Ti contents of the steel liquid are required to be ≤0.05%, ≤0.005% and ≤0.005%.

[0019] In S4, deoxidation and alloying are carried out in the process of steel tapping after the converter, and the oxygen activity is controlled between 40 and 80 ppm.

[0020] In S5, the acid-soluble aluminum content of the molten steel after the converter is controlled between 0.0005% and 0.0020%.

[0021] In S6, the S content in the steel during the LF furnace refining process is controlled between 0.0050% and 0.012%, and the oxygen activity is controlled between 0.0028% and 0.0050%.

[0022] In S7, the top slag Al2O3 in the steel during the LF furnace refining process is controlled to be ≤3%.

[0023] In S8, the NiO content of the intermediate coating agent during the continuous casting of the molten steel is controlled to be ≤0.5%.

[0024] In S9, the NiO content of the continuous casting protection slag during the continuous casting of the molten steel is controlled to be ≤0.3%.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. Control the nickel content in the steel to an extremely low level through interface reaction, with the nickel content ≤ 0.007%, to prevent the high nickel content from causing the dislocation density of the wire rod to increase too much during the drawing process, resulting in more severe work hardening;

[0027] 2. Controlling the nickel content of wire rod at a low level can also prevent the technical problem of large fluctuations in wire strength and uneven wire strength during the user's heat treatment process after the wire rod is processed into steel wire, and meet the quality requirements of high-quality wire rod for deep processing. DETAILED DESCRIPTION

[0028] The present invention is described in detail below, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0029] A method for controlling the Ni content of a wire rod for ultra-fine steel wire, specifically comprising:

[0030] S1. The higher the proportion of scrap steel in the converter smelting process, the more likely it is that high nickel content scrap steel will be added to the converter, resulting in a high nickel content in the molten steel. Therefore, the proportion of scrap steel in the converter smelting is controlled between 5% and 10%, and the nickel content in the scrap steel is ≤ 0.04%. ;

[0031] S2. Utilize the higher oxygen content after the converter to inhibit the reaction of NiO in the top slag or refractory being reduced into the steel, and prevent the nickel content in the steel from increasing. The temperature of the molten steel after the converter is controlled between 1580 and 1610°C, the carbon content is controlled between 0.3% and 0.5%, the oxygen activity is controlled between 70 and 150ppm, and the nickel content is controlled between 0.001% and 0.01%.

[0032] S3. The molten steel tank for tapping high carbon steel converter shall be the one that has been used for the previous 2-3 times of low nickel, low aluminum and low titanium molten steel refining. The Ni, Al and Ti contents of the molten steel shall be ≤ 0.05%, ≤ 0.005% and ≤ 0.005% to prevent the high carbon steel molten steel from being contaminated.

[0033] S4. Deoxidation and alloying are carried out during the steel tapping process after the converter furnace to control the oxygen activity between 40 and 80 ppm to prevent the oxygen content in the molten steel from being too low, which would prevent the role of inhibiting NiO from being reduced into the molten steel from being effectively exerted.

[0034] S5. The acid-soluble aluminum content of the molten steel after the converter is controlled between 0.0005% and 0.0020% to prevent the acid-soluble aluminum in the molten steel from reducing Ni and entering the molten steel.

[0035] S6. Control the S content in the steel during the LF furnace refining process between 0.0050% and 0.012%, and the oxygen activity between 0.0028% and 0.0050%, and utilize the combined effects of sulfur and oxygen elements to inhibit the reduction reaction of NiO at the interface of molten steel and refined slag.

[0036] S7. Control the Al2O3 content of the top slag in the steel during the LF furnace refining process to be ≤3%, so as to prevent excessive Al2O3 content in the top slag from being reduced into the molten steel, thereby increasing the acid-soluble aluminum content of the molten steel, and further promoting the NiO in the top slag to be reduced into the molten steel, thereby increasing the Ni content of the molten steel.

[0037] S8. Control the NiO content of the intermediate covering agent during the continuous casting of molten steel to ≤0.5%, and the NiO content of the continuous casting protection slag during the continuous casting of molten steel to ≤0.3%, to prevent the nickel element in the covering agent and the protection slag from being reduced to the molten steel and increasing the nickel content of the molten steel.

[0038] The following examples are implemented on the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[0039] Example

[0040] Six embodiments are listed below to further illustrate the specific implementation of the present invention.

[0041] Table 1 lists the process parameters of converter temperature, carbon content, oxygen activity, Ni content, number of steel tank rinses, post-furnace deoxidation oxygen activity, post-converter acid-soluble aluminum content, LF refining sulfur content, LF refining oxygen content, Al2O3 content in top slag during LF furnace refining, NiO content in covering agent, NiO content in protective slag, and NiO content in wire rod in Examples 1 to 6. The nickel content in the steel is controlled to an extremely low level by interfacial reaction, and the nickel content is ≤0.007%, so as to prevent the excessive increase in the structural dislocation density of the wire rod during the drawing process due to the high nickel content, and the occurrence of more serious work hardening. The nickel content of the wire rod is controlled at a relatively low level, which can also prevent the technical problems of large fluctuations in the strength of the steel wire and uneven strength of the steel wire during the heat treatment process of the user after the wire rod is processed into steel wire, and meet the quality requirements of high-quality wire rod for deep processing.

[0042] Table 1 is a table of process parameters for Examples 1 to 6

[0043]

[0044] The present invention controls the nickel content in the steel to an extremely low level through interface reaction, with the nickel content being ≤0.007%, so as to prevent the phenomenon that the structural dislocation density of the wire rod increases too much during the drawing process and the work hardening is more serious due to the high nickel content; by controlling the nickel content of the wire rod at a relatively low level, the technical problems of large fluctuations in the strength of the steel wire and uneven strength of the steel wire that occur during the user's heat treatment process after the wire rod is processed into a steel wire can be prevented, thereby meeting the quality requirements of high-quality wire rods for deep processing.

Claims

1. A method for controlling the Ni content of a wire rod for ultra-fine steel wire, characterized in that: Specifically include: S1. Control the proportion of scrap steel in converter smelting and the nickel content of scrap steel; S2, control the temperature and oxygen activity of the molten steel after the converter; S3, using low nickel, low aluminum and low titanium liquid steel to refine used steel tanks; S4, control the oxygen activity of the molten steel after deoxidation in the converter furnace; S5, control the acid-soluble aluminum content of the steel liquid after the converter; S6, control the S content and oxygen activity of molten steel in the LF furnace refining process; S7, controlling the Al2O3 content in the top slag of steel during the LF furnace refining process; S8, control the NiO content of the intermediate coating agent during the continuous casting of molten steel; S9. Control the NiO content in the continuous casting slag of molten steel.

2. The method for controlling Ni content in wire rod for ultra-fine steel wire according to claim 1, characterized in that: In S1, the proportion of scrap steel smelted in the converter is between 5% and 10%, and the nickel content Ni in the scrap steel is ≤ 0.04%.

3. The method for controlling Ni content in wire rod for ultra-fine steel wire according to claim 1, characterized in that: In S2, the temperature of the molten steel after the high carbon steel converter is controlled between 1580 and 1610°C, the carbon content after the converter is controlled between 0.3% and 0.5%, the oxygen activity is controlled between 70 and 150 ppm, and the nickel content is controlled between 0.001% and 0.01%.

4. The method for controlling Ni content in wire rod for ultra-fine steel wire according to claim 1, characterized in that: In S3, the high carbon steel converter steel ladle uses the steel ladle that has been used in the previous 2-3 times of low nickel, low aluminum and low titanium steel liquid refining, and the Ni, Al and Ti contents of the steel liquid are required to be ≤0.05%, ≤0.005% and ≤0.005%.

5. The method for controlling Ni content in wire rod for ultra-fine steel wire according to claim 1, characterized in that: In S4, deoxidation and alloying are carried out in the steel-making process after the converter furnace, and the oxygen activity is controlled between 40 and 80 ppm.

6. The method for controlling Ni content in wire rod for ultra-fine steel wire according to claim 1, characterized in that: In S5, the acid-soluble aluminum content of the molten steel after the converter is controlled between 0.0005% and 0.0020%.

7. The method for controlling Ni content in wire rod for ultra-fine steel wire according to claim 1, characterized in that: In S6, the S content in the steel during the LF furnace refining process is controlled between 0.0050% and 0.012%, and the oxygen activity is controlled between 0.0028% and 0.0050%.

8. The method for controlling Ni content in wire rod for ultra-fine steel wire according to claim 1, characterized in that: In S7, the top slag Al2O3 in the steel during the LF furnace refining process is controlled to be ≤3%.

9. The method for controlling Ni content in wire rod for ultra-fine steel wire according to claim 1, characterized in that: In S8, the NiO content of the intermediate coating agent during the continuous casting of the molten steel is controlled to be ≤0.5%.

10. The method for controlling Ni content in wire rod for ultra-fine steel wire according to claim 1, characterized in that: In S9, the NiO content of the continuous casting protection slag during the continuous casting of the molten steel is controlled to be ≤0.3%.

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