ALEXANDRIA, Va., June 25 -- United States Patent no. 12,338,518, issued on June 24, was assigned to NIPPON STEEL Corp. (Tokyo) and NIPPON STEEL SG WIRE Co. LTD. (Tokyo).
"Valve spring" was invented by Shinya Teramoto (Tokyo), Yutaka Neishi (Tokyo), Michimasa Aono (Tokyo), Satoru Mineta (Tokyo), Shoichi Suzuki (Tokyo) and Tatsuro Ochi (Tokyo).
According to the abstract* released by the U.S. Patent & Trademark Office: "A valve spring which has an excellent fatigue limit is provided. A chemical composition of the valve spring according to the present embodiment contains, in mass %, C: 0.50 to 0.80%, Si: 1.20 to less than 2.50%, Mn: 0.25 to 1.00%, P: 0.020% or less. S: 0.020% or less: Cr: 0.40 to 1.90%, V: 0.05 to 0.60%, Ca: 0.0001 to 0.0050%...