Hot forming steel directly rolled through medium and thin slab and having tensile strength larger than or equal to 1500 MPa and production method

Abstract

Hot forming steel directly rolled through a medium and thin slab and having tensile strength larger than or equal to 1500 MPa comprises components including, by weight percent, 0.21% to 0.25% of C, 0.26% to 0.30% of Si, 1.0% to 1.3% of Mn, not larger than 0.01% of P, not larger than 0.005% of S, 0.015% to 0.060% of Als, 0.25% to 0.30% of Cr, 0.026% to 0.030% of Ti or 0.026% to 0.030% of Nb or 0.026% to 0.030% of V or mixing of two or more of Ti, Nb and V with the any proportion, 0.003% to 0.004% of B, 0.17% to 0.19% of Mo and not larger than 0.005% of N. Production steps comprise molten iron desulfuration, electric furnace or converter smelting and refining, continuous casting, descaling treatment before the steel enters a soaking pit furnace, uniform heating, heating, high-pressure water descaling before the steel enters a rolling mill, rolling, cooling, reeling, austenitizing, mold punching molding and quenching. The flow is short, the product surface quality is good, the thickness precision is high, the quality requirement of a cold rolled product can be met, the complex deformation can be smoothly completed, no springback exists after deformation, and the size precision 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 with a medium-thin slab and a production method thereof, and is suitable for producing products whose thickness is greater than 2 to 100 MPa. 10mm. 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 u...

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Problems solved by technology

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

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