Screw diameter：Ø20mm-Ø300mm
Aspect ratio：L/D=15～55
Tempering hardness：HB240°～280°
Nitridation hardness：HV850°～1000°
Nitration case depth：0.45～0.7mm
Nitridation brittleness：≤二级
Surface roughness：Ra0.4
Screw straightness：0.015mm
Chromium coating hardness after nitridation：HV≥900HV
Chromium coating thickness：0.05～0.10mm
Dual alloy depth：0.8～2.0mm
Dual alloy hardness：HRC56°～65°
Material:
High-quality steel
①38CrMoALA (JIS SACM645)
②316 stainless steel
③SKD61
Heat treatment:
Nitriding treatment
Hard chrome plating layer
High-frequency quenching
Spray corrosion resistance, wear-resistant bimetallic layer
Vacuum hardening
