... , single screw and barrel 1for various extruding machines 2 38CrMoA1A 3PTA, ion nitride,and more Specifications of this single screw and barrel ... Nitriding depth:0.5~0.8mm, surface roughness:Ra0.4um, screw straightness:0.015mm, Chromium plated hardness:>900HV, Chromium layer thickness ... hardness: 60~70 Product types:almost all kinds of single-screw types can be made. Scope of application:PP, PE, ...