... speed steel W6Mo5Cr4V2 4. quenching treatment screw element for co-rotating twin screw extruder machineMaterial: W6Mo5Cr4V2 high speed tool steel ... auxiliary agents:combustion-supporting machine pelletsPP,PE,PS ect +starch:de-composing machine pelletsPE+fog-preventing dipper ... ,stabilizer:dual-prevention machine pelletsPE,EVA,ABS+carbon black:black machine pelletsColor masterbatch pelletsPE,PP, ...