... ,PE,PVC,PET,ABS,PPR for Plastic Extruder Machine Conical Twin Screw and Barrel material ... PP,PE,PVC,PET,ABS,PPR for Plastic Extruder Machine Conical Twin Screw and Barrel Zhejiang Bohai ... 's ridge,and uses different alloy and welding methods for the screw of different functions.Materials38CrMoAlA ... .5mmWarranty period:2-4years(Depends on the plastic raw materials)Bimetallic: much longer lifetime.Nitriding ...