High-strength hot-dip galvanized steel sheet

Abstract

We provide high-strength hot-dip galvanized steel sheets with excellent plating quality, plating appearance, and spot weldability in processed parts. The high-strength hot-dip galvanized steel sheet has: a cold-rolled steel sheet, which is composed of a specific composition, has a structure with a martensite area ratio of 7% or more and less than 25%, and a ferrite area ratio of 50% or more, and the base metal The internal oxidation amount of the surface layer is 0.05g / m per one side 2 The following; intermetallic compounds formed on said cold-rolled steel sheet and containing 0.03 g / m 2 More than 0.12g / m 2 Al below, and Fe with an average particle size of less than 0.7 μm 2 al 5 and a hot-dip galvanized layer, formed on the intermetallic compound, and containing 0.15%≤Al%≤0.30%, wherein in mass %, Al% represents the Al content of the hot-dip galvanized layer, and the hot-dip galvanized layer The surface roughness Ra of the galvanized layer is not less than 0.8 μm and not more than 1.6 μm, the glossiness (G value) is not less than 750 and not more than 850, and the zinc-base plane orientation ratio Zn (002) / (004) is not less than 30% and not more than 60% .

Description

technical field [0001] The present invention relates to a high-strength hot-dip galvanized steel sheet for inner panels of automobiles. Background technique [0002] In recent years, surface-treated steel sheets with antirust properties imparted to raw steel sheets have been used in the fields of automobiles, home appliances, and building materials. Among them, hot-dip galvanized steel sheets that can be produced at low cost and have excellent antirust properties have been used. In particular, European and American automakers believe that by simply increasing the coating thickness of hot-dip galvanized steel sheets, the anti-rust performance can be improved. The situation is that in East Asia, where economic growth is remarkable, large-scale automotive applications can be expected. demand for steel plates. [0003] In the case of a steel sheet for automobiles in which good workability is strictly required, durability cannot be maintained unless the plating quality such as i...

AI Technical Summary

Problems solved by technology

However, in the technology described in Patent Document 1, sufficient consideration has not been given to the plating quality, plating appearance, and spot weldability such as the impact resistance adhesion of the processed part and the corrosion resistance after painting. , need further improvement

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