An austenitic chromium-nickel stainless steel containing molybdenum which increases general corrosion resistance improves resistance to pitting from chloride ion solutions, and provides increased strength at elevated temperatures. Stainless 316 is similar to 304 except that this alloy is somewhat stronger at elevated temperatures. Applications include exhaust manifolds, furnace parts, heat exchangers, jet engine parts, pharmaceutical and photographic equipment, valve and pump trim, chemical equipment, tanks, evaporators, pulp, paper and textile processing equipment, parts exposed to marine atmospheres and tubing.
303 contains added phosphorus and sulfur for better machining characteristics. Corrosion resistance is slightly less than 302/304.
304 (18-8) is an austenitic steel possessing a minimum of 18% chromium and 8% nickel, combined with a maximum of 0.08% carbon. It is a nonmagnetic steel which cannot be hardened by heat treatment, but instead. must be cold worked to obtain higher tensile strengths. Type 304 is especially suited for all types of dairy equipment – milking machines, containers, homogenizers, sterilizers, and storage and hauling tanks, including piping, valves, milk trucks and railroad cars.
316L is also austenitic, non-magnetic, and thermally nonhardenable stainless steel like Type 304. The carbon content is held to 0.08% maximum, while the nickel content is increased slightly. What distinguishes Type 316 from Type 304 is the addition of molybdenum up to a maximum of 3%. Molybdenum increases the corrosion resistance of this chromium-nickel alloy to withstand attack by many industrial chemicals and solvents, and, in particular, inhibits pitting caused by chlorides. As such, molybdenum is one of the single most useful alloying additives in the fight against corrosion.