... cylinder, plastic extruder screw barrel, plastic screw barrel, screw barrel for plastic extruder, screw and barrel for plastic extrusion machine, screw barrel for plastic extrusion machinery ... layer: ≥950HVHardness of Cr coating layer: HRC55-62Thickness of alloy plating: 0.03-0.08mmDepth of alloy layer:2mmUsed for granulation ...