... on 38CrMoAlA. conical twin screw and barrel for plastic extruder, granulator or pelletizer Ruian Yumin machine screw co.,ltd is a ... factory specialized in making screw barrel, filter, mould, gearbox ... : nitriding treatment, alloy coating spraying, heating treatment, screw fully hardeningDiameter: Φ45-Φ200(according to the demands ...