High-strength cold-rolled hot-galvanized precipitation reinforced steel and manufacturing method thereof

Abstract

The invention discloses a high-strength cold-rolled hot-galvanized precipitation reinforced steel plate and a manufacturing method thereof. The steel plate comprises the following components: 0.09 to 0.12 weight percent of C, less than or equal to 0.05 weight percent of Si, 0.8 to 1.8 weight percent of Mn, less than or equal to 0.02 weight percent of P, less than or equal to 0.01 weight percent of S, less than or equal to 0.008 weight percent of N, 0.02 to 0.06 weight percent of Al, 0.05 to 0.08 weight percent of Nb and Ti and the balance of Fe and inevitable impurities. The microstructure of the steel plate is ferrite and second phase particles, wherein the diameter of the second phase particles is about less than 6 mu m, the yield strength is 500 to 600MPa, the tensile strength is 570 to 710MPa, and the total coefficient of elongation is over 14 percent (80 gauge length and transverse stretching). The hot-galvanized steel plate has high welding performance and surface quality and can be widely used in automotive structural membranes.

Description

technical field [0001] The invention belongs to the field of metal materials, and relates to a 500MPa grade hot-dip galvanized precipitation strengthening thin steel plate. In particular, it relates to a high-strength cold-rolled hot-dip galvanized precipitation-strengthened steel and a manufacturing method thereof, which can be widely used in automobile structural parts, and has excellent welding performance and good surface quality. Background technique [0002] In recent years, various countries have enacted relevant laws and regulations for the safety, weight reduction and reduction of energy consumption of automobiles, and high-strength hot-dip galvanized steel sheets with excellent corrosion resistance are increasingly used as steel sheets for automobiles. [0003] In the past, low-carbon aluminum-killed steel and phosphorus-containing steel were mainly used, and the strength of the steel plate was mainly improved through solid solution strengthening. However, with th...

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Problems solved by technology

[0013] It can be seen from the above related patents that the Chinese patent CN99801687.X added a certain amount of Cr and Mo, the manufacturing cost increased accordingly, and the yield strength was less than 500MPa

Chinese patent CN02800375.6 also adds Cr, which affects the manufacturing cost, and the addition of Si and Mn is relatively high, which affects the surface quality of hot-dip galvanizing

Chinese patent CN200910046439.7 has low yield strength and tensile strength

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