... straightness and cylindricity 2.High accuracy and hardness, 3.Wear resistance and corrosion-resistance Instruction1.HardnessHRC60±2Remark2.Depth ... of hardening layer0.8—3mm 3.Material45#Steel(GCr15) 4.Surface RoughnessRa0.1—Ra0 ... , the roller of printing machinery, textile machinery, the axis of transmission mechanical, all kinds of cylinder, oil cylinder ...