Thin thermoformed steel with tensile strength being not lower than 1700 MPa directly rolled by sheet billet and production method of thin thermoformed steel

Abstract

The invention provides thin thermoformed steel with tensile strength being not lower than 1700 MPa directly rolled by a sheet billet. The thin thermoformed steel with tensile strength being not lower than 1700 MPa directly rolled by the sheet billet comprises the following components, in percentage by weight, 0.26-0.30% of C, 0.31-0.35% of Si, 1.3-1.5% of Mn, not higher than 0.008% of P, not higher than 0.005% of S, 0.015-0.060% of Als, 0.31-0.35% of Cr, 0.031-0.035% of Ti or 0.031-0.035% of Nb or 0.031-0.035% of V or a mixture mixed by more than two of the three components in any proportion, 0.003-0.004% of B, 0.20-0.25% of Mo, 0.06-0.10% of Ni and not higher than 0.005% of N. The production method of the thin thermoformed steel comprises the steps of desulfurizing molten iron; smelting the molten iron by an electric furnace smelting or a rotating furnace and refining the molten iron; performing continuous casting; performing descaling treatment before putting the molten iron into a soaking pit furnace; performing soaking; performing heating; performing high pressure water descaling before putting the molten iron into a rolling mill; performing rolling; performing cooling; performing coiling; performing austenitizing; performing mould stamping forming; and performing quenching. The steel is high in strength, short in manufacture process and good in quality of product surface, the accuracy of thickness can be controlled within + / -0.03mm and the energy consumption can be greatly reduced; moreover, the steel has great significance to realize automobile lightweight.

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 ≥ 1700 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 2mm. 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, whi...

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Problems solved by technology

[0006] The present invention aims to overcome the low strength level existing in the prior art and cannot meet the needs of users for ultra-high-strength parts, and provides a method that can not only meet the requirements of automobile design for ultra-high-strength mechanical properties, but also successfully complete complex deformations, and No rebound after deformation, high dimensional accuracy of parts, hot-formed steel with tensile strength ≥ 1700MPa and production method

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