Phosphorus acid chloride treatment Characteristic and after the painting the melting Zn plated steel sheet for heat treatment processing which is superior corrosion-resistant and after being heated

摘要

PROBLEM TO BE SOLVED: To provide a hot dip galvanized steel sheet for hot pressing by which a high strength and high tension steel working member having excellent phosphate treatability and post-painting corrosion resistance can be obtained and a method useful for manufacturing such steel sheet.;SOLUTION: In the hot dip galvanized steel sheet for hot pressing to be subjected to working after being heated to the Ac₁ point or above of a steel base material, the maximum value of an Al concentration is 25 atm% and multiple oxides of Mg and Zn exist at a ratio to attain ≤0.9 in the atomic concentration ratio A regulated by the following formula (1) as the oxide film formed on the surface of the galvanized layer after the heating. The formula (1) is A=[Mg]/[Zn], where [Mg] and [Zn] each signify the concentration (atomic%) of Mg and Zn in the oxides.;COPYRIGHT: (C)2007,JPO&INPIT