screw barrel for injection molding machine Material:38CrMoALA, SKD61,9cr18MoV etc. Bimetallic Material: Ni-based alloy steel,Co-based Alloy steel,Tungsten carbide alloy Treatment: PTA spraying,HVOF spraying ,Harden,thermo refining etc. Surface hardness:55 -72HRC Nitriding Layer: 0.5mm-0.8mm Bimetallic thickness: 2.5mm-4mm