The multi-metal cleaning agent and rust inhibitor were introduced.The multi-metal cleaning agent does not contain strong alkali and is mainly used to remove the oil of the assembly parts in the assembly process of the hydraulic system.The multi-metal cleaning agent has strong cleaning power and is non-corrosive to metals such as cast aluminum and copper.The multi-metal rust inhibitor is a water-based weak alkaline product and used with the cleaning agent.After the anti-rust treatment,a uniform and dense protective film can be formed on the surface of the cast iron workpiece.The film can not only prevent the cast iron and carbon steel from rusting to improve the corrosion resistance,but also has no adverse effect on the adhesion of the subsequent paint film and metal.Therefore it is suitable for rust prevention between multi-metal processes such as cast iron,carbon steel,cast aluminum and copper.