UGIMA 4021 and UGIMA 420A are identical grades that are differently named for the European and North American markets, respectively. The grade is similar to UNS S42000 and is a hardenable martensitic stainless steel with a higher carbon content than type 410. UGIMA 4021/420A contain an addition of calcium by the UGIMA process. This steelmaking technique produces malleable oxide inclusions with a low melting point. The inclusions then lubricate the metal-tool interface in machining and improve productivity. This datasheet provides information on composition. It also includes information on corrosion resistance as well as heat treating and machining. Filing Code: SS-760. Producer or source: Ugine-Savoie.