US Patent Issued to NIPPON STEEL on Sept. 22 for "Duplex stainless steel pipe" (Japanese Inventors)

ALEXANDRIA, Va., Sept. 24 -- United States Patent no. 12,742,233, issued on Sept. 22, was assigned to NIPPON STEEL Corp. (Tokyo).

"Duplex stainless steel pipe" was invented by Seiya Okada (Tokyo), Yuji Arai (Tokyo) and Daisuke Matsuo (Tokyo).

According to the abstract* released by the U.S. Patent & Trademark Office: "The duplex stainless steel pipe according to the present disclosure consists of, by mass %, C: 0.030% or less, Si: 1.00% or less, Mn: 0.10 to 7.00%, P: 0.040% or less, S: 0.0050% or less, Cr: 20.0 to 30.0%, Ni: 4.2 to 10.0%, Mo: 0.5 to 5.0%, Cu: 0.5 to 6.0%, N: less than 0.350%, O: 0.0005 to 0.0100%, and Ca: 0.0005 to 0.0100%, with the balance being Fe and impurities. A microstructure consists of, in volume ratio, ferrite in ...