METHOD FOR MAKING A ZN-FE GALVANNEALED STEEL SHEET WITH AN EXCELLANT ANTI-POWDERING

摘要

The method increases the powdering resistance of galvanized steel by using heat treatment for alloying after galvanizing. The method comprises (A) galvanizing in the molten zinc bath; (B) heat treatment for alloying iron and zinc for 10 to 15 seconds at 400 to 470 C; (C) cooling the steel strip at the cooling rate of 15 to 20 C per second; (D) pickling in the bath containing 5 to 10 wt.% hydrochloric acid for 5 to 20 seconds.