Image Number 2 for United States Patent #5232520.
A high strength martensitic stainless steel having superior anti-fatigue characteristics when used in a corrosive or erosive environment. The steel has a proof strength of 80 to 110 kg/mm.sup.2 and a composition containing specified amounts of carbon, silicon, manganese, chromium, nickel, molybdenum, vanadium, and nitrogen, the balance being substantially iron and incidental inclusions. The contents of the additives are such that a nickel equivalent Nieq given by the following Formula (1) ranges between 10.5 and 12.9 wt. %:where, [Ni], [Mn], [Cr], [Si], and [Mo], respectively represent the contents of Ni, Mn, Cr, Si, and Mo, respectively. The steel may also contain niobium or copper. The steel is produced by a process which includes a hot work and a subsequent cooling at a specific cooling rate to a specific temperature range.