Base material:
1)38CrMoAlA(JIS SACM645)
2)42CrMo(AISI 4140)
3)9Cr18MOV​​​​​​​

Process:
Heat treatment
High-frequency quenching
Nitriding treatment
Hard-chrome electroplating
Bimetallic alloy welding
Bimetallic alloy centrifugal casting

Technical Parameters:
Nitriding depth: 0.50mm-0.80mm
Nitriding Hardness: 900-1000HV
Nitride brittleness: <= 1
Surface roughness: Ra 0.4
Linearity of the screw: 0.015mm
Chrome after nitriding surface layer hardness: ≥950HV
Chrome plating thickness: 0.025 ~ 0.085mm
Depth of double alloys: 3mm
Warranty and service: 1 year