Stainless steel deck railings (and hardware) in coastal environments (chorine ions present) need periodic maintenance application (i.e., cleaning) of Passification solutions which remove the surface chorine ions. Light rust discoloration can be removed by the passification products. So if you want to extend the life of stainless steel, you should take regular maintenance of it. If there are slight rust spots, you can apply a little rust remover to prevent the damaged rust spots from expanding further and reduce the corrosion spots.
By vevor