... °~320° Nitrided Hardness HV950°~1000° Nitrided Depth 0.50~0.7mm Nitrided Brittleness above 2 stage Surface Roughness ... Ra0.4 Screw straightness 0.015mm Hardess of surface chromium-plating after Nitriding ... HV≥950HV Chromium-plating Depth 0.05~0.10mm ALLoy Depth 0.8~2.0mm Alloy hardness HRC56°~65 ... /105-110,51/105-120,55/110-125,58/125,60/125-129,65/120-132,68/147,70/ ...