Deep-cold-rolled steel plate with high product of strength and elongation and preparation method

Abstract

The invention relates to a deep-cold-rolled steel plate with high product of strength and elongation and a preparation method thereof. The steel comprises the following chemical components in percentage, by mass, 0.18%-0.25% of C, 0.3%-1.5% of Si, 2.8%-3.5% of Mn, 0.5%-1.5% of Al, less than or equal to 0.05% of P, less than or equal to 0.05% of S, 0.10%-0.15% of V and the balance of Fe and inevitable impurities, wherein the sum of Si and Al is less than or equal to 2.0%. Compared with traditional medium manganese steel, the alloy proportion of the low-manganese Mn-TRIP steel plate manufactured through deep cold rolling is greatly reduced, and the plasticity is remarkably improved; compared with a traditional cold-rolled structure, equiaxed ferrite obtained through deep cold rolling is obviously refined and is reduced to be smaller than 1 micron, and the yield strength of the steel plate is improved; meanwhile, VC precipitation is promoted, and the precipitation strengthening effect is achieved; and the austenite content is remarkably increased, the stability of room-temperature austenite is optimized, and the work hardening capacity of the steel plate is enhanced.

Description

technical field [0001] The invention relates to the field of advanced high-strength steel manufacturing, in particular to a high-strength plasticity cryogenically rolled steel plate and a preparation method thereof. Background technique [0002] In order to cope with the huge pressure of energy saving, emission reduction, environmental protection and safety improvement, the development of high-strength, high-toughness plasticity, light-weight and low-density automotive steel has become an urgent task for the steel and automotive industries. The research and development of advanced high-strength steel has roughly gone through three stages. The first generation mainly consists of interstitial-free high-strength low-alloy steel, C-Mn steel, bake-hardening, dual-phase steel, strain-induced plasticity steel, and multi-phase steel. , martensitic steel, which is also the current mainstream commercial automotive steel variety, but the lower alloy content leads to different balance b...

AI Technical Summary

Problems solved by technology

However, the addition of high Al content promotes the stabilization of austenite and the formation of coarse δ ferrite, and it is difficult for δ ferrite to recrystallize effectively in the critical zone annealing process after cold rolling and fibrosis , the banded structure will be distributed in the structure, seriously affecting the transverse and longitudinal properties of the steel plate

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