... material: bimetallic layer PP,PE,PVC,PET,ABS,PPR for Plastic Extruder Machine Conical Twin Screw and Barrel Zhejiang ... screw barrelDiameterΦ25/53,35/77,45/90,51/10,55/110,65/120,65/132,70/140,75 ... screw's ridge,and uses different alloy and welding methods for the screw of different functions.Materials38CrMoAlA (JIS SACM645)SKD61 ... materials)Bimetallic: much longer lifetime.Nitriding timeOver 180 hours