Profile: Zhoushan Dinghai Shenglong Machinery Manufacturing Co., Ltd. is a manufacturer of screws and barrels. We design & manufacture a full series of screws and barrels, applied for various extruding machines & plastic injection molding machines. We also design and manufacture screws with special alloys & special flight geometry to meet specific customer applications. Screws are made from nitro alloy steel like 38CrMoAla, and 41CrAlMo7. Toughening, tempering, stress relieving, gas nitriding & additional bimetallic coatings can be incorporated on flights depending on the process application. We also do special surface treatment like hard nickel plating, chrome plating, & titanium coating depending on the material to be processed.