900 MPa-stage high-cold-bending-property low-alloy high-strength steel plate and preparation method thereof

Abstract

A 900 MPa-stage high-cold-bending-property low-alloy high-strength steel plate comprises the chemical components of, by weight, 0.05-0.1% of C, 0.2-0.6% of Si, 0.5-1.0% of Mn, 0.03-0.1% of Nb, 0.05-0.1% of Ti, 0.015% or the less of P, 0.008% or the less of S, 0.03-0.06% of Als and 0.005% or the less of N. The hot-rolling finish-rolling temperature is 880-910 DEG C, after rolling, cooling is conducted through a laminar flow cooling system till the temperature is 620-650 DEG C, and then reeling is conducted; the cold-rolling reduction rate is controlled to be 50-60%; and an annealing technologyis a continuous half-annealing method. According to the 900 MPa-stage high-cold-bending-property low-alloy high-strength steel plate, by matching low-carbon and Nb and Ti microalloying component design with reasonable rolling and half-annealing technological design, the steel plate precipitation strengthening effect is strengthened, and the high-cold-bending-property low-alloy high-strength steelplate with the welding and good cold-bending property is obtained.

Description

technical field [0001] The invention relates to a 900MPa grade high-cold-bending low-alloy high-strength steel plate 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 realize the lightweight of automobiles has become an important direction of automobile development. High-strength steel has a high yield ratio, sufficient plasticity and toughness, and low-alloy high-strength steel has good formability, weldability, wear resistance and corrosion resistance. [0003] Low-alloy high-strength steel with high cold-bending performance is to add a certain amount of alloying elements such as niobium or titanium to low-carbon steel, so that it can form carbides and nitrides with carbon, nitrogen and other elements and precipitate on the ferrite matrix to improve the steel. The strength of low alloy high-strength steel with...

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Problems solved by technology

Low-alloy high-strength steel with high cold-bending performance is obtained through semi-annealing heat treatment and controlled rolling process. At present, low-alloy high-strength steel with a grade of 600 MPa and below has been widely used, but research and development of low-alloy high-strength steel with high cold-bending performance and above 900 MPa still remains Less, can no longer meet the lightweight needs of the automotive industry

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