1, single screw for injection modling machine. 2, 38CrMoAlA base material; 3, ... , 42CrMo, SKD-61, Stainless Steel, etcSurface CoatingNitriding, Bimetallic, Hard Chrome Plated, Quenching, ect.Technical DataNitriding thickness: 0.5~0.8mmNitriding hardness ... ≤ 8000mm Ra0.4μm 0.015mm/m alloy injection machine single screw