MAIN productS AND SPECIFICATIONSlncongruous parallel double-hde Cylinder doublescrew:50-180 Ratio of hength to diameter:L/D=16-35Cone doubie-hole cylinder and cone double screw:35/80-90/175Technical DATADepth of nitration case:0.6-0.8mmHardness of nitration:900v-1000vFragility of nitration:Lessthan grade 1Roughness of the surface:Ra 0.4umLinearity of the screw:0.015mmThe surface hard chromium plating hardness after nitrogenation:950HvChrome-plating layer thickness:0.01-0.10mm