Thin hot forming steel rolled directly through sheet billet and with tensile strength being larger than or equal to 1500MPa and production method

Abstract

The invention discloses thin hot forming steel rolled directly through a sheet billet and with the tensile strength being larger than or equal to 1500MPa. The thin hot forming steel comprises, by weight, 0.21%-0.25% of C, 0.26%-0.30% of Si, 1.0%-1.3% of Mn, 0-0.01% of P, 0-0.005% of S, 0.015%-0.060% of Als, 0.25%-0.30% of Cr, 0.026%-0.030% of Ti or 0.026%-0.030% of Nb or 0.026%-0.030% of V or a mixture of any two of the above components, 0.003%-0.004% of B and 0-0.005% of N. The production method includes the production steps of molten iron desulphurization, smelting and refining through an electric furnace or converter, continuous casting, dephosphorization treatment before entering a soaking pit, soaking, heating, high pressure water dephosphorization before entering a rolling mill, rolling, cooling, coiling, austenitizing, mold stamping forming and quenching. The thin hot forming steel is short in process, good in surface quality and high in thickness precision; the quality requirement of cold-rolled products can be met, and complex deformation can be achieved smoothly; and moreover, no resilience exists after deformation, and dimensional accuracy of parts is high.

Description

technical field [0001] The invention relates to a steel for auto parts and a production method thereof, in particular to a hot-formed steel with a tensile strength ≥ 1500 MPa directly rolled by a thin slab and a production method thereof, and is suitable for producing products with a thickness of 0.8 to 2 mm. Background technique [0002] With the development of the automobile industry and the gradual development of automobile design and manufacturing in the direction of energy saving, environmental protection and safety, automobile lightweight has become the mainstream direction of automobile design at present and for a long time to come. [0003] The study found that the vehicle's vehicle weight and energy consumption have a linear relationship. According to statistics, every 10% reduction in vehicle weight can increase fuel efficiency by 6% to 8%. One of the most important ways to reduce the weight of automobiles is to use high-strength and ultra-high-strength steels, wh...

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Problems solved by technology

[0006] The present invention overcomes the shortcomings of the prior art, such as the long process flow and the low strength level of the direct rolling of medium and thin slabs, resulting in high manufacturing costs and the inability to meet the needs of users for ultra-high-strength parts, and provides a short process, product surface Good quality, high thickness precision, can meet the quality requirements of cold-rolled products, can successfully complete complex deformation, and there is no rebound after deformation, high dimensional precision of parts, hot-formed steel with tensile strength ≥ 1500MPa and production method

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