... the screw's ridge,and uses different alloy and welding methods for the screw of different functions.Materials38CrMoAlA (JIS SACM645)SKD61 ... feed screw barrelu Blocks screwu Gear boxu screw barrel for blowing molding machineu All other plastic machineryScrew and Barrel ... any specification of extruder screw barrel and injection screw barrel for Haitian, Demag, Engle, Nigro bossi, arburg, NPM, BOY, ...