Material: High quality 38CrMoAl(JIS SACM645) 

Hardness after hardening and tempering: HB280-320

Nitrided Hardness: HV850-1000

Nitrided case depth: 0.50-0.80mm

Nitrided brittleness: less than grade 2

Surface roughness: Ra 0.4

Screw straightness: 0.015mm

Surface chromium-plating's hardness after nitriding: ≥900HV

Chromium-plating depth: 0.025~0.10mm

Alloy Hardness: HRC50-65

Alloy depth: 0.8~2.0mm