Specifications:Ø15mm-Ø300mm
Length/Diameter Ratio:15～55
Screw can be selected from ordinary,gradual,
mutational,pinned,shielding,separating and exhausting types.
Materials:

 Alloy-steel of high quality

1) 38CrMoAlA(JIS SACM645)

2)  9Cr18MoV

Technical data:

Nitrided Hardness: HV 900-1000
Nitrided Case Depth: 0.50mm-0.80mm 

Nitrided Brittleness: Less Than Grade 2
Surface Roughness: Ra 0.4
Screw Straightness: 0.015mm
Surface Chromium-Plating's Hardness After Nitriding:≥900HB
Chromium-Plating Depth: 0.05~0.10mm
Alloy hardness: HRC50-65
Alloy depth: 0.8mm-2.0mm 
Advanced nitriding process
Corrosion&Abrasion resistance bimetal spraying process