Screws and barrels for extruder machine Depth of nitrated layer: 0.5-0.8mm Hardness of nitration: 900-1020hv Fragility of nitration: less than grade 1 Surface roughness: ra 0.4um Surface hardness of nitrated cr coating layer:í²950hv Hardness of bimetallic layer: hrc55íp-72íp Thickness of cr-coating layer: 0.03-0.08mm Depth of bimetallic layer:ú+2mm Specifications of screw: ª)20-ª)250 l/d 15-50 we offer various types of extruder screws and adjust to different compression ratio, which can fulfill customer's requirement perfectly.