Stainless 321 / AISI 321Stainless 321 is a chromium-nickel steel which was developed with improved intergranular-corrosion resistance. Stainless 321 is resistant to atmospheric corrosion, sterilizing solutions, many organic chemicals, and a wide variety of inorganic chemicals. Type 321 should be used for applications requiring heating between 800 F and 1650 F such as aircraft collector rings, and exhaust manifolds, expansion joints, and high temperature chemical process equipment. Available forms are seamless pipe, welded pipe, seamless tube, welded tube, bar, wire, sheet, plate, forgings, pipe fittings and flanges.