Production method of ultrahigh strength steel plate for cold forming and steel plate

Abstract

The invention provides a production method of an ultrahigh strength steel plate for cold forming and the steel plate. The method comprises the steps of smelting, casting, hot rolling, cold rolling, heating the cold-rolled steel plate through a continuous annealing production line with rapid cooling treatment to the austenite temperature, holding the temperature for a certain time, carrying out quenching treatment, obtaining a steel plate with the main structure of M+A and carrying out distribution treatment in a bell type annealing furnace. The steel plate comprises the following components in percentage by mass: 0.02-0.60% of C, 0.05-3.5% of Si, 0.20-3.50% of Mn, P more than or equal to 0.005 but less than or equal to 0.50%, S not more than 0.05%, 0.02-3.00% of Al, Cr not more than 0.50%, Ni not more than 3.00%, Cu not more than 0.50%, Mo not more than 1.50%, V not more than 0.50%, Ti not more than 0.20%, Nb not more than 0.20% and the balance of Fe and unavoidable impurities. The steel plate produced by adopting the method provided by the invention has the advantages of high strength and capability of cold forming and the process route of Q&P steel industrial production is effectively solved.

Description

technical field [0001] The invention belongs to the technical field of metal heat treatment, and in particular relates to a production method of an ultra-high-strength steel plate for cold forming and an ultra-high-strength steel plate produced by the method. Background technique [0002] In recent years, people have paid more and more attention to environmental protection, resources and energy, and the safety standards for automobiles have also been continuously improved. In order to meet the requirements of energy saving and safety, automobiles are required to develop towards lightweight. The development and application of high-strength automotive steel has become one of the mainstream research topics of major steel companies in the world. [0003] For a long time, the traditional quenching and tempering process has been used to produce high-strength steel with martensitic structure. The martensite formed by quenching can increase the strength of steel, and tempering can ...

AI Technical Summary

Problems solved by technology

Some research work has revealed that during the quenching process, the retained austenite between the martensite strips is carburized, and the early literature has also discussed the distribution of carbon between martensite and retained austenite, as well as in silicon-containing steels. During the bainite transformation, carbon will diffuse to the austenite to form carbide-free bainite. However, due to the low quenching temperature, only a small amount of atoms diffuse after quenching and other phase transformations obviously occur during tempering, so the carbon is formed by The distribution of martensite to retained austenite to stabilize austenite has not attracted much attention, and has not developed into a heat treatment process for steel

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