1700 MPa-grade hot forming steel and production method thereof

Abstract

The invention belongs to the technical field of steel production, and discloses 1700 MPa-grade hot forming steel and a production method thereof. The molten steel comprises the following chemical components in percentage by mass: 0.20-0.25% of C; 0.8-1.0% of Si; 5.5-6.0% of Mn; 2.5-3% of Cr; 0.03-0.06% of Nb; less than or equal to 0.003% of Al; less than or equal to 0.020% of P; less than or equal to 0.004% of S; less than or equal to 0.005% of N; less than or equal to 0.003-0.006% of O, and the balance being Fe and unavoidable impurity elements. On the basis of a thin strip casting and rolling process, through reasonable process and component design, the 1700 MPa-grade hot forming steel which is free of a decarburized layer and a banded structure and resistant to high temperature and oxidation is provided, the defect that existing hot forming steel has the banded structure is overcome, and the defect that existing bare board hot forming steel has the decarburized layer is overcome.

Description

technical field [0001] The invention belongs to the technical field of iron and steel production, and in particular relates to a thin specification, no decarburization layer, no band structure, high-temperature oxidation-resistant 1700MPa grade hot-formed steel and a production method thereof. Background technique [0002] For every 10% reduction in vehicle weight, fuel efficiency can be increased by 6-8%. One of the most important ways to reduce vehicle weight is to use high-strength or ultra-high-strength steels, which can significantly reduce vehicle weight without compromising crash safety. However, during the cold forming process of high-strength or ultra-high-strength steel, there are problems such as cracking, springback, and parts that cannot meet the precision requirements. The problem of ultra-high-strength steel with a pressure of 1500 MPa and above is particularly serious. [0003] The hot forming technology combines high-temperature forming with quenching stren...

AI Technical Summary

Problems solved by technology

[0013](1) The problem of band structure that seriously affects the properties of hot-formed steel is not solved;

[0014](2) The problem of surface decarburization of bare hot-formed steel was not solved;

[0015](3) The problem of needing shot peening to remove iron oxide scale after thermoforming of bare board is not solved;

[0016](4) Most of them belong to the Mn-B alloy system, and the elongation after fracture is low;

[0017](5) High energy consumption and high process cost in the production process

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