Method for improving metallurgical effect in converter tapping process

Abstract

The invention relates to the technical field of ferrous metallurgy, in particular to a method for improving the metallurgical effect in the converter tapping process, argon blowing in the converter tapping process is completed by adopting a ventilation element, and the ventilation element is arranged below a slag line of a spherical segment position at the bottom of a converter so as to ensure that the ventilation element is located below the liquid level of molten steel in the tapping process. The method has the beneficial effects that argon blowing and stirring in the whole converter tapping process are achieved, the purpose of reducing the carbon and oxygen deposition in the converter tapping process is achieved, the carbon and oxygen deposition in a molten steel tank is reduced by 31%, then the converter blowing time is shortened by 0.25-0.52 s / t, the converter smelting cost is reduced, and the deoxidation alloy adding amount is reduced; endogenous inclusions generated by deoxidation in the molten steel tank are reduced, and the quality of casting blank products is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of iron and steel metallurgy, and in particular to a method for improving the metallurgical effect of a converter steel tapping process. Background Art

[0002] The carbon-oxygen content in the converter smelting process is an important indicator to measure the technical and economic level of the converter. By controlling the carbon-oxygen content of the converter, the oxidizability of the converter end slag can be controlled, thereby reducing the impact of oxide inclusions on the refining and continuous casting processes.

[0003] The carbon and oxygen accumulation in the converter is mainly related to the bottom blowing state of the converter. However, during the converter tapping process, due to the large angle of the converter furnace body, the converter bottom guns are all above the liquid surface during the converter tapping process, and the molten steel cannot be stirred during the tapping process, which affects the metallurgical effect in the converter during the tapping process. Therefore, it is urgent to develop a method to improve the metallurgical effect of the converter tapping process. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides a method for improving the metallurgical effect of the converter tapping process. A permeable element is arranged at the bottom of the converter to spray argon gas. The permeable element is located below the liquid level of the molten steel during the converter tapping process. The molten steel is stirred by blowing argon during the converter tapping process, thereby achieving argon blowing and stirring throughout the converter tapping process, thereby achieving the purpose of reducing carbon and oxygen accumulation during the converter tapping process, reducing the carbon and oxygen accumulation in the molten steel tank by 31%, and further shortening the converter blowing time by 0.25 to 0.52 seconds per ton, reducing the converter smelting cost, reducing the amount of deoxidation alloy added, reducing the endogenous inclusions caused by deoxidation in the molten steel tank, and improving the quality of the cast ingot product.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for improving the metallurgical effect of a converter steel tapping process, wherein argon injection during the converter steel tapping process is performed using a permeable element, and the permeable element is disposed below the slag line at the spherical chip position of the converter bottom. The specific contents include the following:

[0007] S1. During the converter blowing process, the argon gas sprayed from the breathable element located at the spherical part uses a protective flow rate, which is controlled at 0.1 to 0.5 Nm 3 / min;

[0008] S2. After blowing, as the converter angle increases, the flow rate of argon gas injected from the breather element gradually increases. When the converter tapping angle reaches -65°, the argon gas flow rate in the breather element reaches 2.5~4.5Nm 3 / min;

[0009] S3. During the converter tapping process, the molten steel flow rate is controlled at 0.65-0.75 t / s, and the tapping time is controlled at 4-6 min.

[0010] Furthermore, the ventilation element is a slit-type ventilation brick, and the slit width is 0.1 to 0.3 mm.

[0011] Furthermore, the ventilation element is of a clustered tube type, the number of ventilation tubes is 15 to 40, and the diameter is 0.05 to 0.25 mm.

[0012] Furthermore, the slit-type air-permeable bricks are made of high-alumina refractory materials.

[0013] Furthermore, the diameter of the converter tapping port is controlled to be 140-160 mm.

[0014] Furthermore, after the steel tapping is completed, the oxygen content of the molten steel in the molten steel tank is reduced by 30 to 80 ppm compared to the oxygen content at the end of converter blowing.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1) The present invention reduces carbon-oxygen accumulation in the molten steel ladle by 31%, thereby shortening the converter blowing time by 0.25 to 0.52 seconds per ton, reducing converter smelting costs, reducing the amount of deoxidizing alloy added, reducing endogenous inclusions generated by deoxidation in the molten steel ladle, and improving the quality of cast products.

[0017] 2) The breather element is located at the spherical notch of the converter bottom to ensure that the argon blowing port of the breather element is below the molten steel surface during the tapping process, so as to achieve argon blowing and stirring throughout the converter tapping process, thereby reducing carbon and oxygen accumulation during the converter tapping process, improving blowing efficiency, shortening blowing time, and improving the metallurgical effect of converter tapping. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the position of the ventilation element described in the present invention.

[0019] In the figure: 1. Breathing element; 2. Molten steel level. DETAILED DESCRIPTION

[0020] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0021] A method for improving the metallurgical effect of a converter tapping process, wherein argon is injected during the converter tapping process using a permeable element 1. The permeable element 1 is disposed below the slag line at the bottom of the converter at a spherical part position to ensure that the permeable element 1 is below the molten steel level 2 during the tapping process. The molten steel is stirred by argon during the converter tapping process, achieving argon blowing and stirring throughout the converter tapping process, thereby reducing carbon and oxygen accumulation during the converter tapping process. The method includes the following:

[0022] S1. During the converter blowing process, the argon gas is sprayed from the breathable element 1 located at the spherical part using a protective flow rate, which is controlled at 0.1 to 0.5 Nm 3 / min;

[0023] S2. After blowing, as the converter angle increases, the flow rate of argon gas injected from the breather element 1 gradually increases. When the converter tapping angle reaches -65°, the argon gas flow rate in the breather element 1 reaches 2.5~4.5Nm 3 / min;

[0024] S3. During the converter tapping process, the molten steel flow rate is controlled at 0.65-0.75 t / s, and the tapping time is controlled at 4-6 min.

[0025] Furthermore, the ventilation element 1 is a slit-type ventilation brick, and the slit width is 0.1 to 0.3 mm.

[0026] Furthermore, the ventilation element 1 is of a clustered tube type, with 15 to 40 ventilation tubes and a diameter of 0.05 to 0.25 mm.

[0027] Furthermore, the slit-type air-permeable bricks are made of high-alumina refractory materials.

[0028] Furthermore, the diameter of the converter tapping port is controlled to be 140-160 mm.

[0029] Furthermore, after the steel tapping is completed, the oxygen content of the molten steel in the molten steel tank is reduced by 30 to 80 ppm compared to the oxygen content at the end of converter blowing.

[0030] Example 1

[0031] Adopt slit-type air-permeable bricks, which are made of high-aluminum refractory materials. The slit width is 0.1mm. During the blowing process, the air-permeable brick protection flow is controlled at 0.2Nm 3 / min. After blowing, as the converter angle increases, the gas flow rate inside the permeable element 1 at the spherical part gradually increases. When the converter tapping angle reaches -65°, the argon flow rate inside the permeable element 1 at the spherical part can reach 2.5Nm 3 / min, the steel liquid flow rate during the tapping process is 0.65t / s, the tapping port diameter is controlled at 140mm, and the tapping time is controlled at 4.5min. After the tapping is completed, the oxygen content of the molten steel in the molten steel tank is reduced by 35ppm compared with the oxygen content at the end of the converter blowing.

[0032] Example 2

[0033] Adopt slit-type air-permeable bricks, which are made of high-alumina refractory materials. The slit width is 0.15mm. During the blowing process, the air-permeable brick protection flow is controlled at 0.3Nm 3 / min. After blowing, as the converter angle increases, the gas flow inside the permeable element 1 at the spherical part gradually increases. When the converter tapping angle reaches -65°, the argon flow inside the permeable element 1 at the spherical part can reach 3Nm 3 / min, the steel liquid flow rate during the tapping process is 0.7t / s, the tapping port diameter is controlled at 145mm, and the tapping time is controlled at 5min. After the tapping is completed, the oxygen content of the molten steel in the molten steel tank is reduced by 45ppm compared with the oxygen content at the end of the converter blowing.

[0034] Example 3

[0035] Adopt slit-type air-permeable bricks, which are made of high-alumina refractory materials. The slit width is 0.2mm. During the blowing process, the air-permeable brick protection flow is controlled at 0.4Nm 3 / min. After blowing, as the converter angle increases, the gas flow rate inside the permeable element 1 at the spherical part gradually increases. When the converter tapping angle reaches -65°, the argon flow rate inside the permeable element 1 at the spherical part can reach 3.5Nm 3 / min, the steel liquid flow rate during the tapping process is 0.75t / s, the tapping port diameter is controlled at 150mm, and the tapping time is controlled at 5.5min. After the tapping is completed, the oxygen content of the molten steel in the molten steel tank is reduced by 40ppm compared with the oxygen content at the end of the converter blowing.

[0036] Example 4

[0037] The clustered tube type ventilation element 1 is used, with 20 ventilation tubes and a diameter of 0.2mm. During the blowing process, the ventilation brick protection flow rate is controlled at 0.25Nm 3 / min. After blowing, as the converter angle increases, the gas flow rate inside the permeable element 1 at the spherical part gradually increases. When the converter tapping angle reaches -65°, the argon flow rate inside the permeable element 1 at the spherical part can reach 3.5Nm 3 / min, the steel liquid flow rate during tapping is 0.7t / s, the tapping port diameter is controlled at 155mm, and the tapping time is controlled at 5.5min. After tapping, the oxygen content of the molten steel in the molten steel tank is reduced by 65ppm compared with the oxygen content at the end of converter blowing.

[0038] From the above examples, it can be concluded that after tapping, the oxygen content of the molten steel in the molten steel ladle is reduced by 30 to 80 ppm compared to the oxygen content at the end of converter blowing, and the carbon-oxygen accumulation in the molten steel ladle is reduced by 31%. This further shortens the converter blowing time by 0.25 to 0.52 s / t, reduces converter smelting costs, reduces the amount of deoxidizing alloy added, reduces endogenous inclusions caused by deoxidation in the molten steel ladle, and improves the quality of cast ingot products.

[0039] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and concepts of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for improving the metallurgical effect of a converter steel tapping process, characterized in that: The argon injection during the converter tapping process is completed by a permeable element, which is arranged below the slag line at the spherical part position of the converter bottom. The specific contents include the following: S1. During the converter blowing process, the argon gas sprayed from the breathable element located at the spherical part uses a protective flow rate, which is controlled at 0.1 to 0.5 Nm 3 / min; S2. After blowing, as the converter angle increases, the flow rate of argon gas injected from the breather element gradually increases. When the converter tapping angle reaches -65°, the argon gas flow rate in the breather element reaches 2.5~4.5Nm 3 / min; S3. During the converter tapping process, the molten steel flow rate is controlled at 0.65-0.75 t / s, and the tapping time is controlled at 4-6 min.

2. A method for improving the metallurgical effect of a converter steel tapping process according to claim 1, characterized in that: The ventilation element is a slit-type ventilation brick with a slit width of 0.1 to 0.3 mm.

3. A method for improving the metallurgical effect of the converter steel-tapping process according to claim 2, characterized in that: The slit-type air-permeable bricks are made of high-alumina refractory material.

4. The method for improving the metallurgical effect of the converter steel-tapping process according to claim 1, characterized in that: The ventilation element is of cluster tube type, the number of ventilation tubes is 15 to 40, and the diameter is 0.05 to 0.25 mm.

5. The method for improving the metallurgical effect of the converter steel tapping process according to claim 1, characterized in that: The diameter of the converter tapping port is controlled to be 140-160 mm.

6. The method for improving the metallurgical effect of the converter steel tapping process according to claim 1, characterized in that: After the steel tapping is completed, the oxygen content of the molten steel in the molten steel tank is reduced by 30 to 80 ppm compared with the oxygen content at the end of the converter blowing.

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