Specification:
Screw Diameter: Ø15- Ø300
L/D ratio: 15-46
 
Screw Types:
For different plastic screw can be used: ordinary type, pin type, barrier type,separation type, exhaust type. 
 
Base Material:
1)38CrMoAlA(JIS SACM645)
2)42CrMo(AISI 4140)
3)9Cr18MOV
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Treatment Process:
Tempering Treatment
High-frequency Quenching
Nitriding Treatment
Hard-chrome Electroplating
Bimetallic Alloy Welding
Bimetallic Alloy Centrifugal Casting
 
Nitriding Depth: 0.50mm-0.80mm
Nitriding Hardness: HV900-1000
Nitriding Brittleness: ≤ Grade 1
Surface Roughness: Ra0.4um
Screw Linearity: 0.015mm
Hardness of Chromium Plating after Nitriding: ≥950HV
Thickness of Chromium Plating: 0.05〜0.10mm
Alloy Depth: 0.8-2.0mm
Hardness of Bimetallic Alloy: HRC56-70°（Nicr)