Galvanized bake hardening steel and production method thereof

Abstract

The invention discloses galvanized bake hardening steel and a production method thereof. The production method comprises procedures of hot rolling, cold rolling and galvanizing; a substrate comprises the following chemical components in percentage by weight: 0.002-0.003% of C, Si not higher than 0.006%, 0.3-0.5% of Mn, 0.025-0.040% of P, S not higher than 0.009%, 0.007-0.014% of Nb, 0.030-0.060% of Als, N not higher than 0.0030%, and the balance of Fe. The chemical components are designed, and the technological parameters of the hot rolling, cold rolling and galvanizing procedures are adjusted and optimized, so that the Nb-contained bake hardening steel for deep drawing with excellent comprehensive performance can be successfully produced without adding other alloy elements; the substrate produced by the method is easily galvanized; and the galvanized bake hardening steel with excellent surface quality can be produced. A galvanized plate produced by the method has such characteristics as proper yield strength, high n value (strain hardening index) and r value (plastic strain ratio) and good bake hardenability; and meanwhile, the alloy content is reasonably matched, the production cost is reduced, and the considerable economic benefit is brought to enterprises.

Description

Technical field [0001] The invention belongs to the technical field of galvanized sheet production, in particular to a galvanized bake hardened steel and a production method thereof. Background technique [0002] With the development of the automobile industry, the demand for stamping steel is increasing rapidly, especially galvanized sheets with excellent corrosion resistance are rapidly replacing cold-rolled sheets. However, the yield strength of the bake hardened steel before forming is low, and the strength of the steel plate is improved after the product is stamped, formed and painted and baked, and it has excellent deep drawing performance and high strength performance. The characteristics of galvanized bake-hardened steel products are consistent with the weight reduction, energy saving, and anti-corrosion trends of automobile steel plates, so they are mostly used in high-end automobile manufacturers. [0003] Domestic and foreign scientific research institutes and steel com...

AI Technical Summary

Problems solved by technology

The patent document with the publication number CN101994056A discloses an ultra-low-carbon bake-hardened steel plate with excellent stamping performance and its manufacturing process. Hardened steel high strength requirements

Patent Publication No. CN102400046A discloses a high-strength bake-hardening steel and its preparation method, which also uses more alloying elements, in addition to Nb and Ti, there are also Cu, Ni, etc., and the production cost is correspondingly greatly increased

Images