a. Advanced Nitriding Technology .
b. Anti-corrosion and Wear-resisting Duplex Metal Spraying Technology .
c. we uses special alloy powders being sprayed and welded on the screw's ridge,and uses different alloy and welding methods for the screw of different functions .
Maximum screw length
Barrel inner bore diameter
A. 38crmoala in high quality
B. alloy steel in high quality
A. nitriding treatment
B. alloy coating spraying
C. heating treatment
D. screw fully hardening
E. vacuum quenching
F: electroplate hard chrome
A: depth of nitrition layer: 0.6-0.8mm
B: nitriding treatment for 7 day and night, surface hardness HV>900
C: fragility of nitriding: less than grade 1
D: surface roughness: ra0.4um
E: streightness of screw: 0.015mm
F: depth of bimetallic layer>2mm
G: hardness of alloy platig: HRC 62-72
H: surface of hardness of chrome coating layer: HRC 62-72
I: thickness of chrome coating layer: 0.03-0.06mm