A method for controlling cracks at corners of low-carbon boron-containing steel continuous casting slabs

Abstract

The invention relates to a method for controlling corner cracks in low-carbon boron-containing steel continuous casting slabs. The method of the present invention includes: (1) component control; (2) controlling the molten iron ratio in the converter smelting process at 85.0% to 87.0%, using the bottom blowing mode throughout the process, and blowing nitrogen first and then blowing one shot of argon during the blowing process. For bottom blowing, the ratio of nitrogen to argon is 1:9; (3) The C content at the smelting end point is controlled at 0.035±0.02, and the tapping temperature is 1660±5°C; (4) The converter smelting tapping process adopts a semi-deoxidation process. steel; (5) Deoxidizer and alloying are performed simultaneously during the tapping process; (6) After tapping the steel, the ladle is directly transferred to the argon station for argon blowing refining; (7) During the continuous casting process, the width of the continuous casting billet is , the narrow surface foot roller area, the second to fourth areas of the vertical bend section, and the arc section 1 adopt strong cooling control, while the arc sections 2 to 8 adopt conventional cooling control. The invention realizes the stable control of the incidence rate of cracks at the corners of the cast slab to <0.1% in the low-carbon boron-containing steel.

Description

Technical field:

[0001] The invention relates to a method for controlling cracks at corners of low-carbon boron-containing steel continuous casting slabs, and belongs to the technical field of continuous casting of iron and steel. Background technique:

[0002] Boron-containing steel is an important part of microalloyed steel. Adding boron to steel can significantly improve the hardenability of steel, and can improve the high-temperature strength and creep strength of heat-resistant steel, improve the red hardness of high-speed steel and the cutting ability of tools, and is widely used in modern steel production. However, in the actual continuous casting production process of boron-containing steel, transverse crack defects frequently occur at the corners of the slab, resulting in serious cracks and warped skin quality defects at the edge of the rolled product. For this reason, most of the continuous casting slabs produced need to be off-line for corner flame cleaning, whic...

Examples

Embodiment Construction

[0023] A method for controlling cracks at corners of low-carbon boron-containing steel continuous casting slabs, the method comprising:

[0024] (1) Composition control: In the low-carbon boron-containing steel, C: 0.025-0.050, Si: ≤0.035, Mn: 0.13-0.22, P: ≤0.02, S: ≤0.015, Alt: 0.025-0.050, B: 0.001~0.002, the balance is iron;

[0025] (2) The ratio of molten iron in the converter smelting process is controlled at 85.0% to 87.0%. The bottom blowing mode is adopted throughout the whole process, and nitrogen is blown first and then argon is blown to the bottom of the blowing process to prevent supplementary blowing. Nitrogen and argon The use ratio is 1:9;

[0026] (3) The C content at the end of smelting is controlled at 0.035±0.02, and the tapping temperature is 1660±5°C;

[0027] (4) The steel tapping process of converter smelting adopts the semi-deoxidation process to tap steel;

[0028] (5) Deoxidizer and alloying are carried out at the same time during the tapping pro...

Technical field:

[0001] The invention relates to a method for controlling cracks at corners of low-carbon boron-containing steel continuous casting slabs, and belongs to the technical field of continuous casting of iron and steel. Background technique:

[0002] Boron-containing steel is an important part of microalloyed steel. Adding boron to steel can significantly improve the hardenability of steel, and can improve the high-temperature strength and creep strength of heat-resistant steel, improve the red hardness of high-speed steel and the cutting ability of tools, and is widely used in modern steel production. However, in the actual continuous casting production process of boron-containing steel, transverse crack defects frequently occur at the corners of the slab, resulting in serious cracks and warped skin quality defects at the edge of the rolled product. For this reason, most of the continuous casting slabs produced need to be off-line for corner flame cleaning, whic...

Examples

Embodiment Construction

[0023] A method for controlling cracks at corners of low-carbon boron-containing steel continuous casting slabs, the method comprising:

[0024] (1) Composition control: In the low-carbon boron-containing steel, C: 0.025-0.050, Si: ≤0.035, Mn: 0.13-0.22, P: ≤0.02, S: ≤0.015, Alt: 0.025-0.050, B: 0.001~0.002, the balance is iron;

[0025] (2) The ratio of molten iron in the converter smelting process is controlled at 85.0% to 87.0%. The bottom blowing mode is adopted throughout the whole process, and nitrogen is blown first and then argon is blown to the bottom of the blowing process to prevent supplementary blowing. Nitrogen and argon The use ratio is 1:9;

[0026] (3) The C content at the end of smelting is controlled at 0.035±0.02, and the tapping temperature is 1660±5°C;

[0027] (4) The steel tapping process of converter smelting adopts the semi-deoxidation process to tap steel;

[0028] (5) Deoxidizer and alloying are carried out at the same time during the tapping pro...