BASE METAL FOR HOT DIP ZINC ALLOY COATING BATH, HOT DIP COATING BATH, HOT DIP ZINC ALLOY COATED STEEL AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain a high temp. corrosion resistant hot dip zinc alloy coated steel by applying hot dip galvanizing on a steel surface as a substrate plating and forming a hot dip zinc alloy coated layer thereon. ;SOLUTION: After hot dip galvanizing is applied on a steel surface as a substrate plating, hot dip zinc alloy coating is applied on a surface of a substrate plating layer with using a hot dip zinc alloy coating bath, which has a composition consisting of, by weight, 3-30% Al, 0.7-3.5% in total at least one kind among Cu, Ag, Au and the balance Zn with inevitable impurities. This two step coating has corrosion resistance by a salt spray test equivalent to hot dip aluminizing, crack is not generated at a high temp. corrosion resistance test and is produced at a cost lower than a hot dip aluminized product, a hot dip galvanized-hot dip zinc alloy coated steel having excellent corrosion resistance in a high temp. atmosphere is obtained.;COPYRIGHT: (C)1999,JPO