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Material:38CrMoAIA

Tempering hardness: HV260-280

Diameter:Φ15mm-Φ300mm

L/D:4-35

Nitrided Hardness: HV900-1000

Depth of nitriding: 0.5mm-0.7mm

Nitriding brittleness: ≦ 2 grade

Surface roughness:Ra 0.4um

Straightness of the screw/barrel:0.015mm/m

Inside&outside diameter tolerance:≦0.02mm

Circular run-out:≦0.04mm

Screw length tolerance:≦0.03mm

Key&spine tolerance grade:Grade 7