... Barrel material: bimetallic layer PP,PE,PVC,PET,ABS,PPR for Plastic Extruder Machine Conical Twin Screw and Barrel Zhejiang Bohai Conical ... ,EPN/LDPE,HDPE,UHMPE,EVA,PP,PVC,PMMA,POM,PAST,PET,PBTNitride Depth0.5mm-0.8mmTechnology1)Longer time Gas Nitriding treatment ...