Hot forming steel directly rolled through medium and thin slab and having tensile strength larger than or equal to 1900 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 1900 MPa comprises components including, by weight percent, 0.31% to 0.40% of C, 0.36% to 0.44% of Si, 1.6% to 2.0% of Mn, not larger than 0.006% of P, not larger than 0.004% of S, 0.015% to 0.060% of Als, 0.36% to 0.49% of Cr, 0.036% to 0.045% of Ti or 0.036% to 0.045% of Nb or 0.036% to 0.045% of V or mixing of two or more of Ti, Nb and V with the any proportion, 0.004% to 0.005% of B, 0.26% to 0.35% of Mo, 0.11% to 0.20% of Ni 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, complex deformation can be smoothly completed, not springback exists after deformation, the size precision of parts is high, and the steel and the method have the important significance in automobile light weight.

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 ≥ 1900 MPa directly rolled with a medium-thin slab and a production method thereof, and is suitable for producing products with a thickness 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 ult...

AI Technical Summary

Problems solved by technology

[0006] The present invention overcomes the disadvantages of the prior art that the strength level is low and cannot meet the user's requirements for stiffness, and provides a method that can meet the requirements of automobile design for ultra-high-strength mechanical properties, and can successfully complete complex deformation, and after deformation No springback, high dimensional accuracy of parts, hot-formed steel with tensile strength ≥ 1900MPa and production method

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