"Yes, it is certainly possible that the red color you see is rust. Stainless steels are corrosion RESISTANT, not corrosion proof. Chlorides and fluorides and other substances can, and do, attack stainless steels."

"Regarding the effect of the rust: it's going to be mainly aesthetic. Unlike carbon steels, which can rust away, the stainless parts which show rust USUALLY are only surface affected, so a flash rust is all you're going to get. It'll look bad, but should stay structurally sound."

"When stainless is heated, there is a range if temperature within which the anti-corrosiveness of stainless is compromised."

""Passivation" of stainless steel means dipping it in a nitric or citric acid formulation to dissolve any of those stray iron filings and to enhance the formation of the chromium oxide layer- that which makes stainless steel "stainless"."