METHOD FOR PRODUCING HIGH STRENGTH HOT DIP GALVANIZED STEEL SHEET

摘要

PROBLEM TO BE SOLVED: To provide a method where a high strength hot dip galvanized steel sheet in which surface concentration by Si based oxide is effectively suppressed, and having surface appearance free from unplating and excellent plating adhesion can be stably produced at high productivity even in the case of a high strength steel sheet comprising Si at a high concentration (≥1 mass%). SOLUTION: The method for producing a high strength hot dip galvanized steel sheet is provided with: a step where roughness in which the mean spacing S of local summits is≤20μm and the arithmetic mean roughness Ra is≥0.2μm is imparted to the surface of a steel comprising 1 to 3 mass% Si; a step where the steel with the roughness imparted is rolled; a step where the rolled steel is subjected to oxidation heat treatment, and is then subjected to reduction annealing heat treatment; and a step where the heat-treated steel is subjected to hot dip galvanizing. COPYRIGHT: (C)2007,JPO&INPIT