A kind of high-strength and high-plasticity medium manganese Q&P steel cold-rolled annealed plate and its preparation process

Abstract

The invention discloses a high-strength and high-plasticity medium-manganese Q and P steel cold-rolling annealing plate and a preparing technology thereof. The annealing plate comprises chemical components including, by weight percent, 0.1%-0.3% of C, 0.8%-2.0% of Si, 4.0%-8.0% of Mn, smaller than or equal to 0.01% of P, smaller than or equal to 0.01% of S, smaller than or equal to 0.01% of N, and the balance iron and inevitable impurities. The preparing technology includes smelting, hot rolling, intermediate annealing, cold rolling and final heat treatment. The Q and P technology is applied to the field of medium-manganese steel field, a two-phase region Q and P technology is developed, and finally complex-phase medium-manganese Q and P steel including martensite, retained austenite and a ferritic structure is obtained, wherein the tensile strength ranges from 900 MPa to 1,300 MPa, plasticity ranges from 24% to 37%, and the product of strength and elongation reaches 30 GPa% to 45 GPa%. The continuous annealing treatment of the medium-manganese steel is achieved, the time of traditional cover annealing is shortened, and meanwhile the high-strength medium-manganese steel plate with strength and plasticity well matched is obtained.

Description

technical field [0001] The invention relates to an automobile plate and a home appliance plate, in particular to a high-strength and high-plasticity medium manganese Q&P steel cold-rolled annealed plate and a preparation process thereof. Background technique [0002] Advanced high-strength steel (AHSS) can maximize the safety of the car while reducing its own weight, so it has become the focus of the major automotive industries. Since the introduction of advanced high-strength steel, it has developed rapidly. The first-generation high-strength steel represented by IF steel, DP steel and TRIP steel, the second-generation high-strength steel represented by TWIP steel and the recently proposed high-strength high-strength steel have been developed. The third-generation high-strength steel represented by Q&P steel. The first generation of high-strength steel improves the strength of steel, but its plasticity is low; although the strength and plasticity of the second-generation h...

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Problems solved by technology

Subsequently, the Q&P process was widely applied in the field of low manganese TRIP steel, and a low manganese TRIP steel using the Q&P process was developed. However, due to the limitation of the composition of the low manganese TRIP steel itself, especially the limitation of Mn content, the final obtained There is not much retained austenite structure, and the strength and performance cannot be significantly improved

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