ALEXANDRIA, Va., April 9 -- United States Patent no. 12,270,088, issued on April 8, was assigned to NIPPON STEEL Corp. (Tokyo).
"Steel sheet and method for manufacturing same" was invented by Eriko Tsukamoto (Tokyo) and Kengo Takeda (Tokyo).
According to the abstract* released by the U.S. Patent & Trademark Office: "This steel sheet has a predetermined chemical composition, the metallographic structure includes, by an area ratio, ferrite, bainite and pearlite: 0 to 10% in total, residual austenite: 1 to 15%, and a remainder that is martensite, and a proportion of martensite or residual austenite having a width of 50 nm to 2 micro metre present at a prior austenite grain boundary is 70% or more."
The patent was filed on Oct. 9, 2020, unde...