Official Answer
Answer
Passivation is a chemical process that removes 'tramp' iron from the surface of stainless steel rings, enhancing the protective chromium-oxide layer. According to AMS 2700 (Method 1 - Nitric Acid or Method 2 - Citric Acid), the process ensures that no iron particles from the coiling tools remain embedded in the ring. This is critical for preventing 'bleeding' or localized rust spots on a component that is otherwise corrosion-resistant. In the pharmaceutical industry, passivated 316 SS rings are mandatory to prevent contamination of the product stream.
