1. Material: 38CrMoAl A Nitriding treatment, Surface hardness: HV≥900 Nitriding depth: 0.5-0.8mm 
2. Material: Special stainless steel Quenching treatment, hardness: HRC55-58, Suitable for the screw which used for transparent plastic products and high corrosion plastic processing, prolong life of screw. 
3. Material: Tungsten alloy. Surface spraying, improve abrasion performance of screw

1. Material: 38CrMoAl A Nitriding treatment, Surface hardness: HV≥900 Nitriding depth: 0.5-0.8mm 
2. Material of barrel inside layer: Tungsten carbide alloy, Centrifugal casting, prolong life of barrel