We are a professional manufacturer of screw and barrel for 17years,we can supply and design all kinds of screw&barrel according to your requirments base material 1.38 CrMoAIA(JIS SACM645) 2.42CrMo(AISI4140) 3.9Cr18MoV 4.CW6Mo5Cr4V2 5.SKD61 bimetallic alloy maerials: 1.Fe-based alloy 2,Ni-based alloy 3,Co-based alloy 4.NiCo-based alloy 5.Tungsten carbide Heat-treatment Nitriding treatment Electroplate hard-chrome High-frequency quenching Spraying corrosion wear-resisting dual metal layers Depth of Nitrated Layer 0.5-0.8mm Hardness of nitration 900-1020Hv Fragility of nitration Less than grade 1 Surface roughness Ra 0.4um Hardness of Cr-coating Layer ≥950Hv Thickness of Cr-coated Layer 0.03-0.08m Appliance PVC, PP, PE, PA, PC, ABS, AS etc guarantee period a year if there is any need ,please contact us.