Hot-dip galvanized dual-phase steel with good bake hardening performance and preparation method thereof

Abstract

The invention discloses a hot-dip galvanized dual-phase steel with good baking hardening performance and a preparation method thereof. The chemical composition of the steel is calculated by mass fraction: C: 0.08%-0.12%, Si: 0.1%-0.4% , Mn: 1.8%~2.6%, Cr: 0.2%~0.7%, Mo: 0.1%~0.4%, P: ≤0.010%, S: ≤0.006%, Ti: 0.01%~0.04%, Al: 0.1%~ 0.4%, the balance is iron and other unavoidable impurities; the metallographic structure of the steel is: ferrite, martensite and bainite, and the carbon content in the ferrite reaches above 20ppm. The invention ensures that the carbon content dissolved in the ferrite reaches more than 20ppm, suppresses the surface decarburization of the steel plate during the heating process, and has no obvious decarburization layer between the finished plate substrate and the coating layer, thereby obtaining good bake hardening performance BH2 ≥80MPa.

Description

technical field [0001] The invention relates to the technical field of steel preparation, in particular to a hot-dip galvanized dual-phase steel with good bake hardening performance and a preparation method thereof. Background technique [0002] As the automotive industry has increasingly stringent requirements for lightweight, safety, and low emissions, the proportion of high-strength steel used in new automotive models continues to increase. A typical representative, in the body structure designed by the project of "ultra-light steel car body-advanced car concept", high-strength steel with a tensile strength of 1000MPa accounts for the largest proportion, accounting for 29% to 30% of the weight of the car body about. [0003] Now the car body needs to be painted during the production process, including drying and bonding paint during the body baking. The baking process not only helps the painting work, but also has a certain impact on the mechanical properties of the mate...

AI Technical Summary

Problems solved by technology

However, the domestic automobile industry has not required the BH value of high-strength steel for a long time. There has been a lack of detailed research and reports on how to stably control the increase in the bake-hardening value of ultra-high-strength steel and other materials used in automotive structural parts.

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