45/90, 45/100, 50/105, 51/105, 55/110, 55/120, 58/124, 60/125, 65/120, 65/132, 68/143, 70/135, 70/140, 75/150, 80/143, 80/156, 92/188
The above are standard specifications, we can customize according to customers’ requirements.
The compression ratio of screws can be designed according to different products and mixtures.
Technical Parameter:
Hardness After Hardening & Tempering:HB280-320
Nitrided hardness: 950-1100HV 
Nitrided layer depth:0.50-0.80mm
Nitrided brittleness: Less than 2 level
Surface roughness: Ra 0.4μm
Linearity of screw: 0.015mm/m
Bimetallic layer depth: ≥3mm
Bimetallic hardness: HRC60-72
Hard-chrome plating hardness after nitriding: ≥950HV
Chrome-plating layer depth: 0.025~0.10mm