800MPa-grade high-cold-bending cold-rolling dual-phase steel plate and preparation method thereof

Abstract

The invention relates to 800MPa-grade high-cold-bending cold-rolling dual-phase steel. A steel plate comprises the following chemical components in percentage by weight: 0.05-0.09 of C, 0.01-0.05 of Si, 1.7-2.2 of Mn, 0.01-0.04 of Nb, 0.01-0.04 of Ti, 0.1-0.5 of Cr, 0.15-0.3 of Mo, 0.015 of P or less, 0.01 of S or less, 0.3-0.8 of Als, 0.005 of N or less, and the balance of Fe and inevitable impurities. The invention further relates to a preparation method of the 800MPa-grade high-cold-bending cold-rolling dual-phase steel, wherein an annealing process is a continuous annealing process, the strip steel is heated to 800-850 DEG C at a heating rate of 1-3 DEG C / s, and slow cooling is conducted to 700-750 DEG C at the speed of 2-4 DEG C / s after heat preservation is conducted for 120-150 s; air cooling is adopted for rapid cooling, and then rapid cooling is conducted to 250-300 DEG C at the cooling speed of 10-20 DEG C / s; and overaging treatment is conducted for 250-400 s, wherein the smooth elongation is 0.2%-0.5%.

Description

technical field [0001] The invention relates to an 800MPa grade high cold-bend cold-rolled dual-phase steel and a preparation method thereof, belonging to the technical field of automobile plate rolling. Background technique [0002] With the rapid development of the automobile industry, the use of high-strength steel to reduce the weight of automobiles has become an important direction of automobile development. The requirements for the comprehensive performance of automobile materials are becoming increasingly stringent, and its strength level and cold bending performance are also constantly improving. The dual-phase steel with ferrite / martensitic structure has high elongation and high work hardening rate, and has good fatigue resistance. It can be processed into parts with complex shapes, improve the dent resistance of the car, and reduce the weight of the car. , in line with the requirements of automobile safety, weight reduction, energy saving and environmental protecti...

AI Technical Summary

Problems solved by technology

However, the content of C and Mn elements in the composition design is high, which affects the welding performance of the material; the yield strength of the product after annealing is 339-396 MPa, the product yield strength is relatively low, the deformation resistance is poor, and the reliability of the production structural parts is low

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