Stainless steel tubes have the ability to resist air oxidation - rust, and also have the ability to resist corrosion in acids, alkalis, and salts - that is, corrosion resistance. However, the magnitude of its corrosion resistance varies with the chemical composition of the stainless steel itself, the state of addition, the conditions of use, and the type of environmental media. For example, 304 stainless steel pipe has excellent rust resistance in dry and clean air, but it is moved to the seaside area, and it will soon rust in the sea fog containing a lot of salt. Therefore, stainless steel pipes are rarely used as guardrails in coastal areas near the sea, but stainless steel materials that are more resistant to corrosion than 304 stainless steel pipes, such as 430, are used.

Therefore, it is not a kind of stainless steel that can resist corrosion or rust under any environment. Any stainless steel may rust. When the surface of the stainless steel appeared brown rust, people were amazed: "Stainless steel is not rusted, rust is not stainless steel, is there a problem with steel?". This is a one-sided misconception about the lack of understanding of stainless steel. Stainless steel will also rust under some conditions.