ALEXANDRIA, Va., Dec. 16 -- United States Patent no. 12,497,677, issued on Dec. 16, was assigned to NIPPON STEEL Corp. (Tokyo).
"High strength steel sheet" was invented by Kyohei Ishikawa (Tokyo).
According to the abstract* released by the U.S. Patent & Trademark Office: "A high strength steel sheet including a sheet thickness center part and a surface layer soft part formed at one side or both sides of the sheet thickness center part, wherein the sheet thickness center part has a predetermined chemical composition and has a microstructure comprising tempered martensite: 85% or more, the surface layer soft part has a thickness of more than 10 micro metre to 5.0% or less of the sheet thickness, a microstructure comprising ferrite: 80% or m...