SJZS PVC 45 plastic extrusion Conical Twin Screw Barrel 1.Materials:38CrMoAIA,42CrMo,SKD61 2.Application:PVC,PE, ... .Roughness of the surface:Ra 0.4um7.Linearity of the screw:0.015mm8.Chromium-plating layer thickness:0.03-0.08mm9 ... : Common Nitrided: approx 2 years Bimetallic : much longer lifetime Conical Twin Screw Barrel Diameter 45/90-92/188mm Min. Order 1 set ...