Sand blasting is one of the best surface pretreatment methods. It can not only completely remove the oxide scale, rust, old paint film, oil stain and other impurities on the metal surface, so that the metal surface shows a uniform metal color, but also make the metal surface obtain a certain roughness. Dalian sanding and derusting to obtain a surface with uniform roughness And change the machining stress into compressive stress Improve the adhesion between the anti-corrosion coating and the base metal and the corrosion resistance of the metal itself. Commonly used in coating, thermal spraying and plastic roughening treatment In addition to sand blasting, surface roughening treatment methods include threading method, knurling method, electric spark roughening method, etc.