A Method for Preventing Corner Cracks of Billet Bulb Flat Steel Continuous Casting Billet

A corner crack and bulb flat steel technology, which is applied in the field of billet bulb flat steel production, can solve the problems of serious corner cracks, inability to deal with defects, and rejection of cast slabs, and achieve the effect of reducing sensitive rigidity

Active Publication Date: 2022-06-14
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to reduce the defect rate of transverse cracks at the corners of the billet, the ultra-weak cooling process in the secondary cooling zone is adopted. Although this method can reduce the defect rate of transverse cracks at the corners, the corner cracks still occasionally appear on the billet, and the corners On the contrary, the cracks are more serious, and even the secondary finishing treatment of the casting slab cannot completely remove the defects, resulting in the casting slab being rejected

Method used

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  • A Method for Preventing Corner Cracks of Billet Bulb Flat Steel Continuous Casting Billet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] The casting section is AH32 flat bulb steel with a cross section of 180mm×180mm. The specific process is as follows:

[0041] S1: The temperature of molten steel AH32 of bulb flat steel is adjusted before pouring in the LF furnace, so that the superheat of molten steel in the tundish before pouring is kept at 35 °C; during the temperature adjustment process in the LF furnace, the temperature in the LF furnace is adjusted to In the state of slight positive pressure, the pressure difference inside and outside the furnace is maintained at 0.03MPa; during the LF heating process, 35kg of calcium carbide slag is added per 100 tons of molten steel.

[0042] S2: After adjusting the molten steel temperature to be 6°C higher than the target temperature set by the upper machine, the molten steel is subjected to bottom blowing argon and weak stirring for 3.5 minutes.

[0043] S3: The mold copper tube with an inverted taper of 0.75% / m is used, the vibration frequency of the mold is ...

Embodiment 2

[0052] The casting section is AH32 flat bulb steel with a cross section of 150mm×150mm. The specific process is as follows:

[0053] S1: The temperature of molten steel AH32 for bulb flat steel is adjusted before pouring in the LF furnace, so that the superheat of molten steel in the tundish before pouring is kept at 40 °C; during the temperature adjustment process in the LF furnace, the temperature in the LF furnace is adjusted to In a slightly positive pressure state, the pressure difference inside and outside the furnace is maintained at 0.02MPa; during the LF heating process, 40kg of calcium carbide slag is added to every 100 tons of molten steel.

[0054] S2: After adjusting the molten steel temperature to be 8°C higher than the target temperature set by the upper machine, the molten steel is subjected to bottom blowing argon and weak stirring for 4 minutes.

[0055] S3: The mold copper tube with an inverted taper of 0.65% / m is used, the vibration frequency of the mold is...

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Abstract

The invention relates to a method for preventing cracks at the corners of billet bulbous flat steel continuous casting slabs. The corner adopts a rapid and strong cooling process to reduce the corner temperature of the slab to 100°C to 300°C, ensuring that the corner temperature of the continuous casting slab is lower than 350°C during the straightening process, so as to improve the strength of the corner, and at the same time Able to avoid brittle zones. The advantages are: the inclusions in the molten steel are significantly reduced, which not only improves the cleanliness of the slab, but also reduces the crack sensitivity at the corner; The quality of the continuous casting slab is improved. After the slab with corner defects is peeled and cleaned, it can fully meet the rolling requirements of the bulbous flat steel and improve the qualified rate of rolled products.

Description

technical field [0001] The invention belongs to the production field of billet flat bulb steel, and particularly relates to a method for preventing corner cracks of continuous casting billet of billet bulb flat steel. Background technique [0002] Flat bulb steel is a medium profile for shipbuilding aids. With the rapid development of my country's shipbuilding industry, the domestic demand for flat bulb steel is growing. However, in the production process, it is often found that there are cracking defects in the ball head of the bulb flat steel, which leads to a significant reduction in the product qualification rate and brings huge losses to the enterprise. Through sampling analysis, the cracking of the head of the bulbous flat steel is caused by the existence of transverse cracks at the corners of the billet continuous casting billet. [0003] In order to improve the rolling qualification rate of the slab, it is necessary to carry out peeling and finishing treatment on th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22D11/124B22D11/22B22D11/115B22D11/117C21C7/076
CPCB22D11/124B22D11/225B22D11/115B22D11/117C21C7/076Y02P10/20
Inventor 李德军许孟春黄玉平吕春风康伟
Owner ANGANG STEEL CO LTD
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