Cold rolled quenched ductile steel and preparation method

Abstract

The application provides cold rolled quenched ductile steel and a preparation method. The cold rolled quenched ductile steel comprises the following chemical components in mass percent: 0.18 to 0.23 percent of C, 1.5 to 2.2 percent of Mn, 1.3 to 1.8 percent of Si, not greater than 0.02 percent of P, not greater than 0.008 percent of S, 0 to 0.05 percent of Nb, 0 to 0.1 percent of Ti and the balance Fe and inevitable impurities. According to the application, the cold rolled quenched ductile steel prepared by adopting processes of slab preparation, heating, hot rolling, cooling, coiling, cold rolling, continuous annealing and the like reaches 980 to 1200 MPa in tensile strength and reaches more than 25 GPa.% in product of strength and elongation.

Description

technical field [0001] The present application relates to the technical field of ultra-high-strength steel, in particular to a cold-rolled quenched ductile steel and a preparation method thereof. Background technique [0002] The descriptions in this section merely provide background information related to the disclosure in this application and may not constitute prior art. [0003] In recent years, the automobile industry has developed rapidly, and the number of automobiles has increased sharply, which puts forward new requirements for the safety of vehicles. At the same time, problems such as resource scarcity and energy shortage have become increasingly prominent, and environmental problems have become increasingly severe. More and more countries and groups have begun to pay attention to ecological and environmental protection. Therefore, while ensuring vehicle safety, reducing fuel consumption and saving energy has become an inevitable direction for the development of a...

AI Technical Summary

Problems solved by technology

[0006] It is generally difficult for traditional low-carbon and low-alloy TRIP steels to reach the high-strength level of 980MPa, while medium-carbon or high-alloy TRIP steels will bring difficulties in smelting and welding while increasing their strength;

[0007] The one-step partitioning Q&P steel has higher tensile strength and lower elongation due to the low partitioning temperature; the two-step partitioning Q&P steel requires a continuous heat treatment line to have high-speed cooling in order to obtain a sufficient amount of retained austenite without sacrificing strength. And the special function of rapid temperature rise after quenching, but most of the current industrial production lines do not have such conditions

Even if the production line has such capabilities, it will increase the difficulty of control, leading to problems such as unstable performance, poor roll uniformity, and poor connection with other products, thereby affecting production efficiency and product quality.

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