A method for manufacturing high-strength thin strip steel for cold forming

Abstract

The invention relates to high-strength thin strip steel for cold forming and a manufacturing method thereof. The manufacturing method comprises the following steps: performing uniform enhanced cooling on a cast strip by adopting a high-pressure dry ice spraying way after the cast strip is discharged from a crystallization roller, thus rapidly cooling the cast strip to below 1280 DEG C, wherein the cooling rate is 200-300 DEG C / s, and by adopting the cooling way of the strip steel after boron treatment, the precipitation of coarse BN (boron nitride) can be promoted, the appearance of low-melting point phase B2O3 and the precipitation of fine AlN can be prevented and the purposes of uniformizing austenite grains and reducing yield ratio are achieved; then performing austenite online recrystallization rolling; cooling the strip steel after hot rolling by atomization cooling, wherein the cooling rate of atomization cooling is 10-70 DEG C / s; coiling at the temperature of 650-750 DEG C. Through the manufacturing method provided by the invention, the high-strength thin strip steel for cold forming of an automobile, which has relatively low yield ratio and excellent stamping performance, can be obtained. The high-strength hot-rolled thin strip steel for cold forming, which is produced by the method, can be directly used for replacing cold-rolled steel with the hot-rolled steel, cancel a cold rolling process step and greatly reduce production cost.

Description

technical field [0001] The invention relates to a continuous casting process, in particular to a high-strength thin steel strip for cold forming and a manufacturing method thereof. Background technique [0002] In the traditional steel production process, tin (Sn) is a typical residual element or harmful element in steel. It is very difficult and expensive to fully remove Sn in the steelmaking process. Once Sn is contained in steel, it is basically impossible to completely eliminate it. , can only reduce the content of Sn by diluting molten steel, all of which lead to the increase of the cost of steel products. [0003] In recent years, due to the continuous recycling of scrap steel, the content of residual elements such as Sn in steel has gradually increased. Sn in steel is an element that is easy to segregate, and it is easy to be enriched at the grain boundary to cause defects such as cracks. Therefore, in the traditional process The content of Sn element in steel is str...

AI Technical Summary

Problems solved by technology

When thin strip continuous casting produces this kind of steel, it can solve the problems of uneven structure, low elongation, high yield strength ratio and poor formability in the thin strip continuous casting process, and meets the needs of bending forming and stamping forming. and other use requirements, so as to meet the use requirements of cold-rolled base materials and "replacing cold with heat" products

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