extruder,extruding,extrusion,parallel twin screw and barrel 1 38 CrMoA1A 2 42 ... Cr18Mov 4nitriding,spray coating,etc. Specification of this parallel twin screw and barrel:Length-diameter ratio:L/D=18 ... depth:0.5~0.8mm, surface roughness:Ra0.4um, screw straightness: 0.015mm, Chromium plated hardness: >900HV, ... by the machine set which is with this screw and barrel. The pelletizers are alsocan be fitted ...