Post-processing of large castings, large foundry processing manufacturers can use liquid sandblasting to clean the oxide scale and residue on the surface of the casting, which can not only remove impurities, but also play a role in polishing and improving the surface finish of the casting; Use grinding wheels, abrasive cloths, sandpaper and other abrasives to remove impurities such as burrs, protrusions and oxide scales on the surface of steel castings, so that the surface is smooth. In addition, methods such as mechanical, electrochemical and chemical polishing can further improve the gloss and corrosion resistance of castings.