... experience for single screw 2.38CrMoAlA,high quality 3.different design to make costomer's requirement Material Alloy-Steel of High-quality1)38CrMoAlA( ... different design of screw barrel to meet customer's demand. Gradual type,mutant type,wave type,barrier type,double screen type, ... type,separation type,exhaust type, pin type, mixed type, double-head type,three-head type,multi head type etc.Production ...