Production method null of P content high intensity hot dip zincing steel sheet and high intensity alloy hot dip zincing

摘要

PROBLEM TO BE SOLVED: To provide a galvanized steel sheet excellent in uniformity and stickiness of a coated film, and a producing method, with which a galvannealed steel sheet without generating uneven alloying and excellent in powdering resistance can stably be produced. ;SOLUTION: In this producing process of a high strength galvanized steel sheet, with which the high strength steel sheet containing by wt.% ≥0.02% P and/or ≥0.2% Mn, is heated and annealed under non-oxidizing atmosphere and thereafter, dipped into a galvanizing bath containing Al to execute the galvanizing, or the producing process of the high strength galvannealed steel sheet further executing the alloying heat treatment of the galvanized coating, a coating composed of one or more kinds selected among metallic compounds of Ni, Co, Sn and Cu base in the range of 1-200 mg/m2 as an amount converted into the metallic quantity, is stuck on the surface of the steel sheet prior to annealing.;COPYRIGHT: (C)2000,JPO