Method for improving alloy yield in steelmaking process

Abstract

The invention relates to the technical field of steelmaking, and provides a method for improving the alloy yield in the steelmaking process, which comprises the following steps: adding a slagging material in a converter stage for converter smelting, and tapping; and during tapping, starting to add the ferrosilicon alloy when the total outflow amount of the molten steel reaches 1 / 4, starting to add a half mass of the ferromanganese alloy when the total outflow amount of the molten steel reaches 1 / 3, starting to add the residual mass of the ferromanganese alloy when the total outflow amount of the molten steel reaches 2 / 3, and starting to feed an aluminum wire when the total flow amount of the molten steel reaches 3 / 4. According to the technical scheme, the problem that the alloy yield is not high in the steelmaking process in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of steelmaking technology, and more specifically, to a method for improving alloy yield in the steelmaking process. Background Technology

[0002] In the steel smelting industry, adding alloying elements is a key means of controlling the composition of steel and improving its mechanical properties and suitability for special applications. Whether producing ordinary carbon steel, low-alloy steel, or special steel, the precise addition of alloys such as manganese, silicon, chromium, and nickel is required according to product standards. The effect of this addition directly determines the quality grade of the steel. Furthermore, alloy costs account for a significant proportion of the total steelmaking cost, thus having a substantial impact on the company's production efficiency.

[0003] Currently, improper operation of the converter tapping process in steelmaking leads to significant alloy oxidation losses, or poor dissolution and uneven distribution of alloying elements in molten steel. These factors result in unstable alloy yield during production, which not only wastes alloy resources but also causes deviations in the composition of finished products, affecting the stability of the mechanical properties of steel. Summary of the Invention

[0004] This invention proposes a method to improve the alloy yield in the steelmaking process, which solves the problem of low alloy yield in the steelmaking process in related technologies.

[0005] The technical solution of the present invention is as follows: This invention proposes a method for improving alloy yield in steelmaking processes, comprising the following steps: Slag-forming materials are added during the converter stage for converter smelting and steel tapping; During the tapping process, ferrosilicon alloy is added when the total amount of molten steel flowing out reaches 1 / 4; half the mass of ferromanganese alloy is added when the total amount of molten steel flowing out reaches 1 / 3; the remaining mass of ferromanganese alloy is added when the total amount of molten steel flowing out reaches 2 / 3; and aluminum wire is fed when the total amount of molten steel flowing out reaches 3 / 4.

[0006] As a further technical solution, the slag-forming material includes lime.

[0007] As a further technical solution, the amount of slag-forming material added is 28~30 kg / t steel.

[0008] As a further technical solution, the tapping temperature is 1640~1670℃.

[0009] As a further technical solution, the argon flow rate at the bottom of the ladle is controlled to be 3~4 NL / (min·t) during steel tapping.

[0010] As a further technical solution, the amount of silicon-iron alloy added is 5.2~5.4 kg / t steel.

[0011] As a further technical solution, the total amount of manganese-iron alloy added is 19.5~20.5 kg / t steel.

[0012] As a further technical solution, the aluminum wire feeding amount is 0.5~0.6 kg / t steel.

[0013] As a further technical solution, the steel is then tapped and then enters the LF refining stage.

[0014] As a further technical solution, the argon blowing process in the LF refining stage includes a first argon blowing and a second argon blowing.

[0015] As a further technical solution, the argon flow rate for the first argon blowing is 4~4.5 NL / (min·t), and the time is 1~2 min.

[0016] As a further technical solution, the argon flow rate for the second argon blowing is 1.5~2NL / (min·t), and the time is 6~9min.

[0017] In this invention, the argon flow rate for the first argon blowing during the LF refining stage is 4~4.5 NL / (min·t), and the argon flow rate for the second argon blowing is 1.5~2 NL / (min·t), which can further improve the yield of silicon, manganese, and aluminum alloys in the molten steel. Below this range, insufficient stirring will lead to insufficient diffusion of alloying elements in the molten steel, resulting in uneven local component distribution and affecting the yield of alloying elements. Above this range, the oxidation of silicon, manganese, and aluminum alloying elements will be accelerated, leading to elemental alloy burn-off and reducing the alloy yield.

[0018] The working principle and beneficial effects of this invention are as follows: In this invention, by controlling the timing and order of alloy addition during steel tapping, the recovery rates of silicon, manganese, and aluminum are improved. Ferrosilicon alloy is added when 1 / 4 of the total molten steel has flowed out. At this point, silicon forms oxides, allowing sufficient time for diffusion and distribution. This creates a favorable low-oxygen environment for the subsequent addition of ferromanganese alloy and aluminum wire, reducing burn-off of manganese and aluminum due to oxygen reactions. While diffusing in the molten steel, silicon interacts with other components, adjusting the physicochemical properties of the steel and improving its solubility for the subsequently added ferromanganese alloy and aluminum wire. This allows manganese and aluminum to better integrate into the molten steel and distribute evenly. When one-third of the molten steel has flowed out, half the mass of ferromanganese alloy is added. Manganese promptly participates in the deoxidation reaction and begins alloying the molten steel, with the manganese evenly dispersed throughout. When two-thirds of the molten steel has flowed out, the remaining mass of ferromanganese alloy is added. The manganese integrates better with the molten steel. The added manganese interacts with the previously added silicon and manganese, enhancing the alloying reaction within the molten steel, optimizing the composition distribution, further improving the manganese yield, and avoiding localized unevenness caused by excessive addition, which would affect the yield. When three-quarters of the molten steel has flowed out, aluminum wire is fed. The aluminum reacts with the remaining oxygen to form alumina inclusions, which float to the surface of the molten steel and are removed, ensuring a reduction in oxygen content. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] In the following examples and comparative examples, the silicon-iron alloy contains 72% silicon; the manganese-iron alloy contains FeMn. 80 C 0.2 .

[0021] Example 1 Taking refined Q355 steel as an example, a method for improving alloy yield in the steelmaking process includes the following steps: In the converter stage, lime at a rate of 28 kg / t of steel is added for converter smelting, followed by tapping at a temperature of 1640℃. During tapping, the bottom-blowing argon flow rate in the ladle is controlled at 3 NL / (min·t). When the total amount of molten steel flowing out reaches 1 / 4, 5.2 kg / t of ferrosilicon alloy is added. When the total amount of molten steel flowing out reaches 1 / 3, half the mass of ferromanganese alloy is added. When the total amount of molten steel flowing out reaches 2 / 3, the remaining mass of ferromanganese alloy is added (the total amount of ferromanganese alloy added is 19.5 kg / t of steel). When the total amount of molten steel flowing out reaches 3 / 4, aluminum wire is fed at a rate of 0.5 kg / t of steel. After tapping, the process enters the LF refining stage, where the first and second argon blowing are performed. The argon flow rate for the first argon blowing is 3 NL / (min·t) for 1 min, and the argon flow rate for the second argon blowing is 1 NL / (min·t) for 6 min. After the LF refining is completed, samples are taken, and the elemental yield is calculated.

[0022] Example 2 Taking refined Q355 steel as an example, a method for improving alloy yield in the steelmaking process includes the following steps: In the converter stage, lime of 30 kg / t steel is added for converter smelting, followed by tapping at a temperature of 1670℃. During tapping, the bottom blowing argon flow rate of the ladle is controlled at 4 NL / (min·t). When the total amount of molten steel flowing out reaches 1 / 4, 5.4 kg / t steel ferrosilicon alloy is added. When the total amount of molten steel flowing out reaches 1 / 3, half the mass of ferromanganese alloy is added. When the total amount of molten steel flowing out reaches 2 / 3, the remaining mass of ferromanganese alloy is added (the total amount of ferromanganese alloy added is 20.5 kg / t steel). When the total amount of molten steel flowing out reaches 3 / 4, aluminum wire is fed at a rate of 0.6 kg / t steel. After tapping, the process enters the LF refining stage, where the first and second argon blowing are performed. The argon flow rate for the first argon blowing is 3 NL / (min·t) for 2 minutes, and the argon flow rate for the second argon blowing is 1 NL / (min·t) for 9 minutes. After the LF refining is completed, samples are taken, and the elemental yield is calculated.

[0023] Example 3 Taking refined Q355 steel as an example, a method for improving alloy yield in the steelmaking process includes the following steps: In the converter stage, lime of 29 kg / t steel is added for converter smelting, followed by tapping at a temperature of 1655℃. During tapping, the bottom blowing argon flow rate of the ladle is controlled at 3.5 NL / (min·t). When the total amount of molten steel flowing out reaches 1 / 4, 5.3 kg / t steel ferrosilicon alloy is added. When the total amount of molten steel flowing out reaches 1 / 3, half the mass of ferromanganese alloy is added. When the total amount of molten steel flowing out reaches 2 / 3, the remaining mass of ferromanganese alloy is added (the total amount of ferromanganese alloy added is 20 kg / t steel). When the total amount of molten steel flowing out reaches 3 / 4, aluminum wire is fed at a rate of 0.55 kg / t steel. After tapping, the process enters the LF refining stage, where the first and second argon blowing are performed. During the first argon blowing, the argon flow rate is 3 NL / (min·t) and the time is 1.5 min. During the second argon blowing, the argon flow rate is 1 NL / (min·t) and the time is 8 min. After the LF refining is completed, samples are taken, and the elemental yield is calculated.

[0024] Example 4 Taking refined Q355 steel as an example, a method for improving alloy yield in the steelmaking process includes the following steps: In the converter stage, lime of 29 kg / t steel is added for converter smelting, followed by tapping at a temperature of 1655℃. During tapping, the bottom argon flow rate of the ladle is controlled at 3.5 NL / (min·t). When the total amount of molten steel flowing out reaches 1 / 4, 5.3 kg / t steel ferrosilicon alloy is added. When the total amount of molten steel flowing out reaches 1 / 3, half the mass of ferromanganese alloy is added. When the total amount of molten steel flowing out reaches 2 / 3, the remaining mass of ferromanganese alloy is added (the total amount of ferromanganese alloy added is 20 kg / t steel). When the total amount of molten steel flowing out reaches 3 / 4, aluminum wire is fed at a rate of 0.55 kg / t steel. After tapping, the process enters the LF refining stage, where the first and second argon purgings are performed. The argon flow rate for the first purging is 4 NL / (min·t) for 1.5 min, and the argon flow rate for the second purging is 1.5 NL / (min·t) for 8 min. After the LF refining is completed, samples are taken, and the elemental yield is calculated.

[0025] Example 5 Taking refined Q355 steel as an example, a method for improving alloy yield in the steelmaking process includes the following steps: In the converter stage, lime of 29 kg / t steel is added for converter smelting, followed by tapping at a temperature of 1655℃. During tapping, the bottom argon flow rate of the ladle is controlled at 3.5 NL / (min·t). When the total amount of molten steel flowing out reaches 1 / 4, 5.3 kg / t steel ferrosilicon alloy is added. When the total amount of molten steel flowing out reaches 1 / 3, half the mass of ferromanganese alloy is added. When the total amount of molten steel flowing out reaches 2 / 3, the remaining mass of ferromanganese alloy is added (the total amount of ferromanganese alloy added is 20 kg / t steel). When the total amount of molten steel flowing out reaches 3 / 4, aluminum wire is fed at a rate of 0.55 kg / t steel. After tapping, the process enters the LF refining stage, where the first and second argon purgings are performed. During the first argon purging, the argon flow rate is 4.5 NL / (min·t) and the time is 1.5 min. During the second argon purging, the argon flow rate is 2 NL / (min·t) and the time is 8 min. After the LF refining is completed, samples are taken, and the elemental yield is calculated.

[0026] Example 6 Taking refined Q355 steel as an example, a method for improving alloy yield in the steelmaking process includes the following steps: In the converter stage, lime of 29 kg / t steel is added for converter smelting, followed by tapping at a temperature of 1655℃. During tapping, the bottom blowing argon flow rate of the ladle is controlled at 3.5 NL / (min·t). When the total amount of molten steel flowing out reaches 1 / 4, 5.3 kg / t steel ferrosilicon alloy is added. When the total amount of molten steel flowing out reaches 1 / 3, half the mass of ferromanganese alloy is added. When the total amount of molten steel flowing out reaches 2 / 3, the remaining mass of ferromanganese alloy is added (the total amount of ferromanganese alloy added is 20 kg / t steel). When the total amount of molten steel flowing out reaches 3 / 4, aluminum wire is fed at a rate of 0.55 kg / t steel. After tapping, the process enters the LF refining stage, where the first and second argon blowing are performed. During the first argon blowing, the argon flow rate is 5 NL / (min·t) for 1.5 min, and during the second argon blowing, the argon flow rate is 2.5 NL / (min·t) for 8 min. After the LF refining is completed, samples are taken, and the elemental yield is calculated.

[0027] Comparative Example 1 Taking refined Q355 steel as an example, a method for improving alloy yield in the steelmaking process includes the following steps: In the converter stage, lime of 29 kg / t steel is added for converter smelting, and then the steel is tapped at a temperature of 1655℃. During tapping, the bottom blowing argon flow rate of the ladle is controlled at 3.5 NL / (min·t). When the total amount of molten steel flowing out reaches 1 / 2, 5.3 kg / t steel ferrosilicon alloy and 20 kg / t steel ferromanganese alloy are added sequentially, and aluminum wire with a feed rate of 0.55 kg / t steel is fed in. After tapping, the steel enters the LF refining stage for the first and second argon blowing. During the first argon blowing, the argon flow rate is 3 NL / (min·t) and the time is 1.5 min. During the second argon blowing, the argon flow rate is 1 NL / (min·t) and the time is 8 min. After the LF refining is completed, samples are taken and the elemental recovery rate is calculated.

[0028] Comparative Example 2 Taking refined Q355 steel as an example, a method for improving alloy yield in the steelmaking process includes the following steps: In the converter stage, lime of 29 kg / t steel is added for converter smelting, and then the steel is tapped at a temperature of 1655℃. During tapping, the bottom blowing argon flow rate of the ladle is controlled at 3.5 NL / (min·t). When the total amount of molten steel flowing out reaches 1 / 3, 5.3 kg / t steel ferrosilicon alloy and 20 kg / t steel ferromanganese alloy are added sequentially, and aluminum wire with a feed rate of 0.55 kg / t steel is fed in. After tapping, the steel enters the LF refining stage for the first and second argon blowing. During the first argon blowing, the argon flow rate is 3 NL / (min·t) and the time is 1.5 min. During the second argon blowing, the argon flow rate is 1 NL / (min·t) and the time is 8 min. After the LF refining is completed, samples are taken and the elemental yield is calculated.

[0029] Comparative Example 3 Taking refined Q355 steel as an example, a method for improving alloy yield in the steelmaking process includes the following steps: In the converter stage, lime of 29 kg / t steel is added for converter smelting, followed by tapping at a temperature of 1655℃. During tapping, the bottom blowing argon flow rate of the ladle is controlled at 3.5 NL / (min·t). When the total amount of molten steel flowing out reaches 2 / 3, 5.3 kg / t steel ferrosilicon alloy and 20 kg / t steel ferromanganese alloy are added sequentially, along with aluminum wire fed at a rate of 0.55 kg / t steel. After tapping, the process enters the LF refining stage for the first and second argon blowing. During the first argon blowing, the argon flow rate is 3 NL / (min·t) for 1.5 min, and during the second argon blowing, the argon flow rate is 0.5 NL / (min·t) for 8 min. After the LF refining is completed, samples are taken, and the elemental yield is calculated.

[0030] Comparative Example 4 Taking refined Q355 steel as an example, a method for improving alloy yield in the steelmaking process includes the following steps: In the converter stage, 29 kg / t of lime was added to the steel for converter smelting, followed by tapping at a temperature of 1655℃. During tapping, the bottom blowing argon flow rate of the ladle was controlled at 3.5 NL / (min·t). When the total amount of molten steel flowing out reached 1 / 4, 5.3 kg / t of ferrosilicon alloy was added. When the total amount of molten steel flowing out reached 1 / 3, 20 kg / t of ferromanganese alloy was added. When the total amount of molten steel flowing out reached 3 / 4, aluminum wire was fed at a rate of 0.55 kg / t of steel. After tapping, the steel entered the LF refining stage, where the first and second argon blowing were performed. During the first argon blowing, the argon flow rate was 3 NL / (min·t) and the time was 1.5 min. During the second argon blowing, the argon flow rate was 1 NL / (min·t) and the time was 8 min. After the LF refining was completed, samples were taken, and the elemental yield was calculated.

[0031] Comparative Example 5 Taking refined Q355 steel as an example, a method for improving alloy yield in the steelmaking process includes the following steps: In the converter stage, 29 kg / t of lime was added to the steel for converter smelting, followed by tapping at a temperature of 1655℃. During tapping, the bottom blowing argon flow rate of the ladle was controlled at 3.5 NL / (min·t). When the total amount of molten steel flowing out reached 1 / 4, 20 kg / t of ferromanganese alloy was added. When the total amount of molten steel flowing out reached 1 / 3, 5.3 kg / t of ferrosilicon alloy was added. When the total amount of molten steel flowing out reached 3 / 4, aluminum wire was fed at a rate of 0.55 kg / t of steel. After tapping, the steel entered the LF refining stage for the first and second argon blowing. During the first argon blowing, the argon flow rate was 3 NL / (min·t) for 1.5 min, and during the second argon blowing, the argon flow rate was 1 NL / (min·t) for 8 min. After the LF refining was completed, samples were taken, and the elemental yield was calculated.

[0032] Experimental Example The yields of silicon, manganese, and aluminum in the molten steel prepared in Examples 1-6 and Comparative Examples 1-5 are shown in Table 1. Table 1. Yields of silicon, manganese, and aluminum in molten steel obtained in Examples 1-6 and Comparative Examples 1-5

[0033] 1. Compared with Comparative Examples 1-5, Examples 1-6 showed that the recovery rates of silicon, manganese, and aluminum elements in the molten steel obtained by Examples 1-6 were significantly higher than those of Comparative Examples 1-5. This indicates that controlling the timing and order of alloy addition during tapping—starting with the addition of ferrosilicon alloy when the total molten steel flow reaches 1 / 4, adding half the mass of ferromanganese alloy when the total molten steel flow reaches 1 / 3, adding the remaining mass of ferromanganese alloy when the total molten steel flow reaches 2 / 3, and feeding aluminum wire when the total molten steel flow reaches 3 / 4—can improve the recovery rate of alloy elements.

[0034] 2. Compared with Examples 3 to 6, the recovery rates of silicon, manganese, and aluminum elements in the molten steel obtained in Examples 4 to 5 were further improved compared with Examples 3 and 6. This indicates that controlling the argon flow rate of the two argon blowing processes in the LF refining stage: the argon flow rate of the first argon blowing is 4 to 4.5 NL / (min·t) and the argon flow rate of the second argon blowing is 1.5 to 2 NL / (min·t), which can further improve the recovery rate of alloying elements.

[0035] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for improving alloy yield in steelmaking processes, characterized in that, Includes the following steps: Slag-forming materials are added during the converter stage for converter smelting and steel tapping; During the tapping process, ferrosilicon alloy is added when the total amount of molten steel flowing out reaches 1 / 4; half the mass of ferromanganese alloy is added when the total amount of molten steel flowing out reaches 1 / 3; the remaining mass of ferromanganese alloy is added when the total amount of molten steel flowing out reaches 2 / 3; and aluminum wire is fed when the total amount of molten steel flowing out reaches 3 / 4.

2. The method for improving alloy yield in steelmaking process according to claim 1, characterized in that, The slag-forming material includes lime; The amount of slag-forming material added is 28~30 kg / t steel.

3. The method for improving alloy yield in steelmaking process according to claim 1, characterized in that, The tapping temperature is 1640~1670℃; The argon flow rate at the bottom of the ladle during tapping is controlled to be 3~4 NL / (min·t).

4. The method for improving alloy yield in steelmaking process according to claim 1, characterized in that, The amount of silicon-iron alloy added is 5.2~5.4 kg / t steel.

5. The method for improving alloy yield in steelmaking process according to claim 1, characterized in that, The total amount of manganese-iron alloy added is 19.5~20.5 kg / t steel.

6. The method for improving alloy yield in steelmaking process according to claim 1, characterized in that, The aluminum wire feed rate is 0.5~0.6 kg / t steel.

7. The method for improving alloy yield in steelmaking process according to claim 1, characterized in that, After the steel tapping is completed, the steel enters the LF refining stage.

8. The method for improving alloy yield in steelmaking process according to claim 7, characterized in that, The argon blowing process in the LF refining stage includes a first argon blowing and a second argon blowing.

9. A method for improving alloy yield in steelmaking process according to claim 8, characterized in that, The argon flow rate for the first argon purge is 4~4.5 NL / (min·t), and the time is 1~2 min.

10. A method for improving alloy yield in steelmaking process according to claim 8, characterized in that, The argon flow rate for the second argon blowing is 1.5~2 NL / (min·t), and the time is 6~9 min.

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