Although stainless steel
is much more resistant to corrosion than ordinary carbon or alloy steels, in some circumstances it can corrode. It is 'stain-less' not 'stain-impossible'. In normal atmospheric or water based environments, stainless steel will not corrode as demonstrated by domestic sink units, cutlery, saucepans and work-surfaces.
In more aggressive conditions, the basic types of stainless steel may corrode and a more highly alloyed stainless steel can be used.