Conical twin screw &barrel 1,Surface Roughness :Ra 0.4 2,Screw Straightness :0.015mm Technical Specification1,Hardness ... Grade 15,Surface Roughness :Ra 0.46,Screw Straightness :0.015mm7,Surface Chromium-Plating’s ... Resistance Bimetal Spraying Process7,Horniness screw (HTP1:abrasion HTP2:corrosion resistance,HTP3:abrasion and corrosion resistance) Conical twin screw &barrel for plastic extruder