Hot-dip galvanized ultra-low carbon bake-hardening steel and production method thereof

Abstract

The invention discloses hot-dip galvanized ultra-low carbon bake-hardening steel. The hot-dip galvanized ultra-low carbon bake-hardening steel comprises the following chemical components in percentage by mass: 0.001-0.005% of C, 0-0.12% of Si, 0-1.0% of Mn, 0-0.50% of P, 0.01-0.30% of Al, 0.004-0.01% of Ti, 0.0003-0.0040% of B, less than or equal to 0.010% of S and less than or equal to 0.01% of S as limiting elements and the balance of Fe and unavoidable impurities. The invention also discloses a production method of the hot-dip galvanized ultra-low carbon bake-hardening steel. According to the hot-dip galvanized ultra-low carbon bake-hardening steel and the production method thereof which are disclosed by the invention, by adding the B element and reasonably controlling key alloying elements such as C, Mn, P and Ti and hot-rolling, cold-rolling and hot-dip galvanizing processes, the hot-dip galvanized ultra-low carbon bake-hardening steel which has the advantages of secondary processing embrittlement resistance and excellent comprehensive mechanical properties is produced, the requirements of high-end car users are met and considerable economic benefits are brought.

Description

technical field [0001] The invention relates to the technical field of steel production, in particular to a hot-dip galvanized ultra-low-carbon bake-hardening steel and a production method thereof. Background technique [0002] In the 1970s, bake hardening steel began to be used in the automobile industry, and it has received extensive attention for its high strength, good dent resistance and formability, and it has solved the problem of high strength and good formability. contradiction. The basic principle of bake-hardening steel plate is strain aging. The annealed steel plate after hot rolling and cold rolling maintains an appropriate amount of solid solution carbon or / and nitrogen atoms. After the steel plate is deformed, it is painted and baked, and its strength is significantly increased. . At present, bake-hardened steel sheets have been widely used in the production of automotive interior and exterior panels, mainly including continuous annealing and galvanized prod...

AI Technical Summary

Problems solved by technology

In the prior art, in order to improve the strength of the steel plate, the solid solution strengthening element P is added, and P segregates to the grain boundary. The P content at the grain boundary can be 10 times higher than that in the matrix, which is easy to cause secondary processing embrittlement of the steel plate, so that The high-speed collision of stamped automotive sheet parts in a severe cold environment causes grain boundary fractures, leading to dangerous accidents of cracking of automotive parts

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