The material of screw and barrel is alloy steel.The nanometer tungsten carbide was coated evenly on the surface of screws and barrels via laser-coating way.Tungsten carbide content reaches more than 99.5%.The coating hardness is HRC70-75 standard.The coating thickness is 1mm.Our unique laser-coating technique and strict quality control system can guarantee our production of it long-lasting hardness.Also the cracking and agglutination problems will be controlled to the minimum extent. Tungsten carbide coated screws and barrel machined by laser-coating method is suitable to be applied for processing high temperature and high corrosion materials. Its performance is better than those made of HPT3 or the imported alloy. This material’s property will exceeds all that of imported materials.