HIGH STRENGTH STEEL SHEET EXCELLENT IN DELAYED FRACTURE RESISTANCE AND CORROSION RESISTANCE

摘要

PROBLEM TO BE SOLVED: To provide a high strength steel sheet which is suitable for a strength member for an automobile and a building material and is excellent in delayed fracture resistance and corrosion resistance.SOLUTION: There is provided a high strength steel sheet in which the surface of the steel sheet is covered with an Fe-Zn alloy layer, the Fe-Zn alloy layer has a coating amount of 0.1 g/mor more and less than 90 g/mand an Fe concentration of 40 mass% or more and 80 mass% or less. A stable rust containing a corrosion product having high protective performance is formed by the formation of an Fe-Zn layer having a high Fe concentration and the stable rust suppresses intrusion of hydrogen.SELECTED DRAWING: None