HIGH STRENGTH STEEL PLATE WITH ULTIMATE TENSILE STRENGTH OF 900 MPA OR MORE EXCELLENT IN HYDROGEN EMBRITTLEMENT RESISTANCE AND METHOD OF PRODUCTION OF SAME

摘要

A high-strength steel sheet having excellent hydrogen embrittlement resistance and a maximum tensile strength of 900 MPa or more, characterized in that (a) 10 to 50 vol% of ferrite, 10 to 60 vol% of bainitic ferrite and/or bainite, and 10 to 50 vol% of tempered martensite exist in the structure of the steel sheet and (b) an iron-containing carbide containing 0.1% or more of Si or both of Si and Al exists in an amount of 4 × 108 (particles/mm3) or more in the structure of the steel sheet.