ALEXANDRIA, Va., June 19 -- United States Patent no. 12,331,408, issued on June 17, was assigned to NIPPON STEEL Corp. (Tokyo).
"Surface-treated steel sheet" was invented by Atsuo Shimizu (Tokyo), Yoshikatsu Nishida (Tokyo), Shin Ueno (Tokyo) and Hiromasa Shoji (Tokyo).
According to the abstract* released by the U.S. Patent & Trademark Office: "A surface-treated steel sheet includes: a base steel sheet; a plated layer formed on the base steel sheet and containing 50 mass % or more of Zn and 0.3 mass % or more of Mg; and a chemical conversion coating formed on the plated layer. The chemical conversion coating contains a silicon compound, P and F, and Mg, an average Si concentration of the chemical conversion coating is 10 mass % or more, t...