ALEXANDRIA, Va., Nov. 25 -- United States Patent no. 12,480,191, issued on Nov. 25, was assigned to NIPPON STEEL Corp. (Tokyo).
"Steel sheet" was invented by Yuya Suzuki (Tokyo).
According to the abstract* released by the U.S. Patent & Trademark Office: "A steel sheet has a predetermined chemical composition, when a sheet thickness is denoted by t, a metallographic structure at a t/4-position, which is a position t/4 away from a surface, in a cross section in a sheet thickness direction includes, by volume percentage, martensite: 70% or greater and residual austenite: 10% or greater, the maximum grain diameter of the residual austenite is less than 5.0 micro metre when a Mn concentration is measured at a plurality of measurement points at...