Preparation method of ultrahigh-strength high-plasticity high-temperature-oxidation-resistant steel through hot stamping forming

Abstract

The invention discloses a preparation method of ultrahigh-strength high-plasticity high-temperature-oxidation-resistant steel through hot stamping forming. The steel comprises the following components of, in percentage by mass, 0.25%-0.45% of C, 1.0%-3.0% of Si, 3.0%-5.5% of Mn, less than or equal to 2.5% of Ni, 0.8%-2.0% of Al, 0.04%-0.10% of Nb, less than or equal to 0.5% of Mo, less than or equal to 0.005% of B, less than or equal to 0.04% of Ti, less than or equal to 0.1% of RE, less than or equal to 0.015% of P, less than or equal to 0.015% of S, less than or equal to 1.5% of Cu or less than or equal to 0.08% of V or less than or equal to 0.5% of W, or a combination of a plurality of components, and the balance Fe, wherein Si / Al satisfies 1.2-2.2, Si + Al is greater than 2.5, and Mn is greater than Al + Si. The hot-formed steel is obtained through smelting, pouring, forging, hot rolling, air cooling or simulated curling, acid pickling, cold rolling, annealing and hot forming. The preparation process of the hot-formed steel is simple, after component optimization and hot stamping forming, the structure comprises a martensite matrix and 2.0%-10.0% residual austenite, it can be guaranteed that the tensile strength is larger than or equal to 1900 MPa, the yield strength is larger than or equal to 1200 MPa, the total ductility is larger than or equal to 9.5%, meanwhile, the high-temperature oxidation resistance is remarkably improved, it can be guaranteed that after a steel plate is heated to a temperature smaller than or equal to 950 DEG C in air, and subjected to heat preservation for shorter than or equal to 5 min, and after hot stamping forming, the thickness of an oxide layer is smaller than or equal to 4.2 micrometer, and an expensive AlSi coating can be omitted, so that the cost is reduced, and the production efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of high-strength plastic automobile steel, and in particular relates to a hot stamping forming steel for automobile and a related process. Background technique [0002] The emergence of automobiles has brought great convenience to human beings, changed the way of travel, and promoted social progress, but at the same time it has also brought about serious consumption of resources and environmental pollution from exhaust emissions. In order to improve these problems, the automobile industry and scientific researchers are actively developing new steel types or new processes to obtain ultra-high-strength automobile steel, so as to reduce the thickness of automobile steel plates to reduce the weight of automobiles, thereby reducing automobile fuel consumption and exhaust emissions. The emergence of hot forming technology and its application in the automotive field can produce ultra-high-strength automotive steel....

AI Technical Summary

Problems solved by technology

[0007] In view of the above technical problems, the purpose of the present invention is to improve the oxidation problem and the low plasticity problem in the heating and heat preservation process of the current hot-formed steel, and provide a method for preparing an ultra-high-strength, high-plasticity, high-temperature oxidation-resistant hot stamping forming steel. The present invention adopts a new Composition design to produce ultra-high strength and high plasticity hot stamping steel with good high temperature oxidation resistance, which can be used for automotive safety structural parts and reinforced components, etc.

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