Cold-rolled hot-galvanized complex phase steel and preparation method thereof

Abstract

The invention relates to a kind of cold-rolled hot-galvanized complex phase steel. Chemical components of the cold-rolled hot-galvanized complex phase steel comprise, by weight, 0.05-0.13% of C, 0.1-0.5% of Si, 1.5-2.5% of Mn, less than or equal to 0.015% of P, less than or equal to 0.015% of S, 0.1-0.6% of Al, 0.2-0.6% of Cr, 0.1-0.5% of Mo, 0.01-0.06% of Nb, 0.01-0.06% of Ti, and the balance Feand inevitable impurities. The invention further relates to a preparation method of the cold-rolled hot-galvanized complex phase steel. The preparation method comprises the following steps of castingmolten steel into a steel billet; conducting hot rolling on the steel billet to obtain a hot-rolled plate and conducting cold rolling on the hot-rolled plate to obtain a cold-hardened steel strip; conducting continuous galvanizing and annealing process treatment on the cold-hardened steel strip to obtain a finished cold-rolled hot-galvanized complex phase steel product. The bending performance ofthe cold-rolled hot-galvanized complex phase steel is improved on the basis of meeting the requirement for strength.

Description

technical field [0001] The invention discloses a cold-rolled hot-dip galvanized multiphase steel and a preparation method thereof, belonging to the technical field of cold-rolled hot-dip galvanized multiphase steel. Background technique [0002] In recent years, with the development of the automobile industry and the needs of energy saving and emission reduction, the steel used in automobiles has gradually developed into high-strength steel, and at the same time, the number of formed parts such as bending and flanging used in high-strength steel is increasing. Traditional high-strength steel is mainly dual-phase steel, and its structure is mainly composed of soft ferrite matrix and high-strength martensite. The performance characteristics of this structure are low yield ratio, high strength, etc. , suitable for the production of stamping and forming parts; but due to the large difference in hardness between ferrite and martensite soft and hard phases, its bending performance...

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Problems solved by technology

Traditional high-strength steel is mainly dual-phase steel, and its structure is mainly composed of soft ferrite matrix and high-strength martensite. The performance characteristics of this structure are low yield ratio, high strength, etc. , suitable for the production of stamping forming parts; but due to the large hardness difference between ferrite and martensite soft and hard phases, its bending performance and hole expansion performance are low, which cannot meet the production of flanging bending forming parts

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