Parallel twin screw and barrel(twin parallel screw) Diameter 65mm-120mm Min.Order 1 set Materials 38CrMoAIA 9Cr18Mo,SKD61 Discount Available Application PE,HDPE pipe,sheet,profile Payment Term T/T, L/C Technical Process 1.Rough Machining 2.Quenching and Tempering 3.Finish Machining 4.Nitriding 5.Spraying and welding with alloy power 6.Screw polishing Technological Parameter Roughness Ra 0.4um Hardness of Quenching and Tempering HB 240-280 ...