... 0.55-0.7mm2) Nitride Hardness: 850-960HV3) Surface Roughness: Ra≤0.8um4) Screw Straightness: 0.015mm5) Bimetallic Hardness: HRC50-626 ... Nitride Hardness: 960-1020HV3) Surface Roughness: Ra≤1.6um4) Bimetallic Hardness: HRC50-655) Bimetallic Depth: 1.5-2.0mmScrew type:Gradual type, mutant ... : PVCwood-plastic., PE wood-plastic,,Super high polymer board,1/2 high Calcium buckle,50-400 high Calcium pipe,50 ...