Method for removing transverse crack defects of continuous casting billet corner of boron steel

Abstract

The invention discloses a method for removing transverse crack defects of a continuous casting billet corner of boron steel. The method comprises the steps of: adopting a whole argon blowing mode for smelting of a converter; in refining, finally, adjusting boron alloying after finishing adjustment of other alloy ingredients and temperature; controlling N content of molten steel in a casting process to be less than or equal to 50ppm and B content to be less than or equal to 80ppm; and controlling the strength of secondarily cooling of the continuous casting billet to be a water ratio being less than or equal to 0.90 / kg, wherein the ratio of cooling water quantity of the secondary cooling at continuous casting stages in the total water ratio is 15-20% in a foot roller area, 15-22% in a vertical section area, 15-40% in an arc section area and 3-5% in a straightening area; and the narrow-surface temperature of a continuous casting billet in a bent area is more than 1000 DEG C, and the narrow-surface temperature of the continuous casting billet in the straightening area is more than 870 DEG C. According to the method for removing the transverse crack defects of the continuous casting billet corner of the boron steel, the nitrogen content in the molten steel is effectively reduced; the transverse cracks of the corner are removed; and the corner cut loss and the heat loss are avoided.

Description

technical field [0001] The invention relates to the technical fields of steelmaking, refining and continuous casting, in particular to a method for eliminating transverse crack defects at corners of boron-containing steel continuous casting slabs. Background technique [0002] Boron-containing steel is an alloy steel based on Mn and B instead of Cr and Ni steel. Adding trace element boron to the steel can significantly improve the hardenability of the steel and save a lot of precious and rare metal elements. However, due to the addition of trace element B in the steel, the crack sensitivity of the steel is greatly increased. In the continuous casting slab, it is manifested as a transverse crack at the corner, and on the hot-rolled coil, it is manifested as an edge crack and warped skin defect, resulting in a downgrade or outright dismissal. Hot charging and hot delivery cannot be carried out during production, and all the continuous casting slabs are off-line to check the c...

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is to provide a method for eliminating the defects of transverse cracks at the corners of the boron-containing steel continuous casting slab, and to solve the problem that the crack sensitivity of the steel is greatly increased due to the addition of trace element B in the boron-containing steel

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