Specifications: 45/90, 45/100,50/105, 51/105, 55/110, 58/124, 60/125, 65/120, 65/132, 68/143, 70/140, 75/150, 80/143, 92/188 The compression ratio of the screw can be designed according to different products and mixtures. Nitrided Hardness: HV 900-1000 Nitrided Case Depth: 0.45mm-0.7mm Alloy hardness: HRC50-65 Alloy depth: 0.8mm-2.0mm Materials: Quality 38CrMoAlA Advanced nitriding process Corrosion&Abrasion resistance bimetal spraying process