... anti-wear ally. Screw barrel details:1.screw barrel Material of screw:38CrMoAIA. 2.screw barrel through Nitriding treatment,Surface hardness ... layer:Tungsten alloy ,Surface spraying,prolong life of screw.7.Barrel Heating zone: Cast aluminum ring heater + Stainless steel shell ... as the media to provide accurate temperature control. 9.Barrel cooling method:Cylinder surface groove, set with brass, aluminum ...