Preparation method of ultrahigh-strength high-plasticity hot stamping forming steel

Abstract

The invention discloses a preparation method of ultrahigh-strength high-plasticity hot stamping forming steel, and belongs to the technical field of automobile steel. The steel comprises the following chemical components of, in percentage by mass, 0.30%-0.55% of C, 1.0%-2.5% of Si, 1.0%-3.0% of Mn, 0.5%-2.0% of Cr, 0.05%-2.0% of Ni, 0.01%-0.10% of Al, 0.04%-0.15% of Nb, less than or equal to 0.5% of Mo, less than or equal to 0.08% of RE, less than 0.015% of P, less than 0.015% of S, less than or equal to 1.0% of Cu or less than or equal to 0.06% of V, or the combination of the two, and the balance of Fe and inevitable impurity elements, and Si+Mn+Cr is larger than or equal to 3.5% and less than or equal to 5.5%; and automobile parts are obtained through the steps of smelting, pouring solidification, hot rolling, acid pickling, cold rolling, annealing, hot stamping forming and the like. The preparation process of the hot forming steel part is simple, and the structure obtained after hot stamping forming is a martensite matrix and 1.5%-7.0% of retained austenite; and after the components are optimized, it can be guaranteed that the tensile strength of parts is larger than or equal to 2200 MPa, the yield strength is larger than or equal to 1300 MPa, the total elongation is larger than or equal to 9.0%, and the steel is suitable for automobile safety parts and other high-strength-toughness parts and has very important significance on achieving high toughness and light weight of automobiles.

Description

technical field [0001] The invention belongs to the technical field of ultra-high-strength automobile steel, and in particular relates to a preparation method of ultra-high-strength and high-plasticity hot stamping forming steel. Background technique [0002] The rapid development of the automobile industry has brought about safety and environmental pollution problems. In order to protect and create a friendly social environment, the country has continuously increased the requirements for energy conservation and emission reduction in the automobile industry. Lightweight has become the mainstream development trend of the automobile industry. Every 10% reduction in vehicle quality can save fuel consumption by 6-8%. One of the important ways to reduce the weight of automobiles is to use high-strength or ultra-high-strength automobile steel to reduce the thickness of parts on the premise of increasing strength to achieve weight reduction. However, due to the high strength of th...

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Problems solved by technology

[0007] In view of the above technical analysis, improving the low strength

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