Over 29 years experience in screw and barrel , more info pls find kaylee(at)tizatech.com Specification: Diameter: Ã?15-Ã?500 L/D ratio:15-55 Base Materials: 1)38CrMoAlA(SACM 645) 2)42CrMo(AISI 4140) 3)Cr12MoV(SKD11) 4)4Cr5MoSiV1(SKD61) 5)9Cr18MoV 6)40Cr Bimetallic Alloy Materials: 1)Fe-based alloy 2)Ni-based alloy 3)Co-based alloy 4)Tungsten carbide Processing Technology: Heat treatment High-frequency quenching Nitriding treatment Hard-chrome electroplating Bimetallic alloy welding Technical Parameter: Nitrided layer depth:0.50-0.80mm Nitrided hardness: 900-1100HV Nitrided brittleness: Less than 2 level Surface roughness: Ra 0.4 Linearity of screw: 0.015mm Hard-chrome plating hardness: â?¥950HV Chrome-plating layer depth: 0.025~0.10mm Bimetallic layer depth: 2 mm Bimetallic hardness: HRC50-65 Material to be extruded: PP, PE, PVC, ABS, AS, PS etc. We can manufacture all types of screws and barrels according to clientsâ?? requirement