Nitriding process,Bimetallic layer of this parallel twin screw and barrel. Specification of this parallel twin screw and barrel: PX-62~200 Length-diameter ratio:L/D=18~25 The screw compression ratio should be decided based on different ingredients and different products. Technical indexes: 38CrMoALA, Nitriding process, Nitriding hardness: HV950~1000, ,Nitriding layer depth:0.45~0.7mm, surface roughness:Ra0.4, screw straightness: 0.015mm, Chromium plated hardness: >900HV, Chromium layer thickness: 0.05~0.10mm, twin-alloy depth:0.8~2.0mm; twin-alloy hardness: 60~70 The product introduction in brief: PVC pipe,special shaped,plate,sheet can be processed by the machine set which is with this screw and barrel. The pelletizers are alsocan be fitted with this unit.