Under what conditions will tinplate rust?

Tinplate can is the common name for electroplated tin sheet steel, the English abbreviation is SPTE, which refers to cold-rolled low-carbon thin steel sheet or steel strip plated with commercial pure tin on both sides. Tin mainly plays a role in preventing corrosion and rust. It combines the strength and formability of steel with the corrosion resistance, solderability and beautiful appearance of tin in a single material. It has the characteristics of corrosion resistance, non-toxicity, high strength and good ductility. Tinplate cans are iron sheets coated with a layer of tin on the surface, which are not easy to rust, and are also called tin-plated iron. This kind of coated steel plate has been called "tinplate can" for a long time in China. Some people think that because the tinplate used to make cans was imported from Macau, Guangdong Province (English name Macau can be read as horse mouth), it is called "tinplate can".

　　 There are also other sayings. For example, China used this kind of tin-plated sheet to make kerosene lamp caps, which were shaped like horse horns, so they were called "tinplate cans." The name "tinplate can" is not exact. Therefore, the name "tinplate can" was no longer used in official documents at the China Tinplate Conference in 1973. Tinplate cans are one of the alloys we often talk about now. The chemical properties of the alloy are very good and can combine the advantages of two or more metals. Tin has stable chemical properties and is not easily corroded. The chemical properties of iron are not very stable and are easily oxidized, but iron has high hardness and good formability.
People often plate tin on the outside of the iron sheet to prevent the iron sheet from rusting. This kind of tin "clothing" is known as the "tinplate". 1 ton of tin can cover more than 7,000 square meters of iron sheet, so tinplate cans are very common and very cheap. The "customer" of tinplate boxes is the canning industry. If you pay attention to protection, tinplate cans can be used for more than ten years and remain stainless.
However, once the tin "clothing" is accidentally broken, the iron sheet is quickly corroded (electrochemical corrosion), and before long, the entire tinplate can is covered with red-brown iron rust spots. Therefore, when using tinplate cans, care should be taken not to damage the tin layer, nor to expose it to moisture or heat. Before liberation, due to imperialist aggression, our country had to rely on foreign imports even for tinplate cans. The name "tinplate" was originally named because it was imported from the horse mouth in Ali, Tibet (the British imported from the horse mouth through India).