Features Specifications: Extrusion Barrels and Screws screws and barrels for blow machine . Instructions for injection single screws and barrels for blow machine : 1.We are a professional company specialized in manufacturing many types of screw, the barrel can be applied on all types of injection moulding machine,rubber hot-feeding extruder, rubber cold-feeding extruder, pin barrel cold feed extruder, plastic extruder with different specifications. 2.The models of screw include: Variable pitch and variable depth, variable pitch and equal depth, variable depth and equal pitch, and equal depth and pitch. Groove multi-die type, composite type, mixing type and separating type. Material: Alloy-steel of high-quality 1)38 CrMoAIA(JIS SACM645) 2)42CrMo(AISI4140) 3)9Cr18MoV 4)CW6Mo5Cr4V2 5)SKD61 Heat-treatment Nitriding treatment Electroplate hard-chrome High-frequency quenching Spraying corrosion wear-resisting dual metal layers Vacuum quenching Technical Parameter Steel Material DIN 41CrA1Mo7 / AST M4140 / GB 38CrMoAlA Deepness of Nitriding Layer 0.7 mm -0.9 mm Hardness of Nitriding HV900 - HV1,000 Nitriding Brittleness ≤Grade 1 Chromate plating Thickness 0.05 mm - 0.10 mm, hardness HV950 Special treatment Carbide coating on screw flight and bimetallic barrel Screw straight tolerance 0.015 mm/m Surface roughness Ra 0.4μm