What is the need of stainless steel?
Stainless steel is an alloy based on iron mixed with chromium and nickel. Chromium and other substances form a strong oxide film on the surface, making it a metal that is resistant to corrosion. It is a "rust-resistant" metal. The alloy component chromium forms the passivation film. This film has the property of repairing immediately, even if it is destroyed by scratches, etc., but corrosion occurs in an environment where the film is deteriorated and destroyed. It does not look like red rust on iron, but it causes various corrosion depending on the conditions and environment.