... experience for pvc screw barrel for plastic extruder 2.38CrMoAlA,nitrided 3.different designs Material of pvc screw barrel for plastic extruder Alloy-Steel ... different design of screw barrel to meet customer's demand. Gradual type,mutant type,wave type,barrier type,double screen type, ... ,separation type,exhaust type, pin type, mixed type, double-head type,three-head type,multi head type etc.Production ...