Tinplate (also known as tinplate) refers to a cold-rolled thin steel plate coated with an extremely thin layer of metallic tin on both sides, which combines the hardness and strength of steel with the easy weldability, corrosion resistance and bright appearance of tin. The tin plate has the advantages of tasteless, non-toxic, light weight, easy processing and forming. Printing different patterns can also beautify products, so it has been widely used in the food canning industry, electronic devices, chemical paint and other industries. In the process of tin plate production, after tinning, the tin plate should be passivated in order to prevent the tin layer from oxidizing and yellowing when the tin plate is stored or the coating is baked, and to improve the performance of the tin plate such as sulfur resistance.