August 12, 2016
Type 316L (UNS S31603) is the second most commonly produced alloy in the 300 series after Type 304 (S30400) and its variants.
In environments where 304 or its low carbon version, 304L (S30403), are found to be inadequate, 316L is the first grade that should be considered. Typically, this grade is used extensively in environments where chlorides are present (e.g. road salts, coastal areas) and similarly in process industries requiring acidic or higher temperature solutions. Some older names for 316L include the “marine grade” or “acid-resistant grade.” Like all nickel-containing austenitic stainless steels, 316L has excellent welding and forming characteristics.
Corrosion resistance and fabricability
While the chromium content is slightly lower than in 304, it is the 2.0% minimum molybdenum (Mo) that greatly improves the corrosion resistance of 316L, with increased pitting and crevice corrosion resistance in chloride-containing solutions. The exact composition varies slightly between the various international standards, but the 10.0% minimum nickel content ensures that the steel remains fully austenitic, with optimum corrosion resistance and ease of fabrication.
Some of the many thousands of applications of 316L are found in pharmaceutical, chemical and biochemical processing, pulp and paper, offshore and onshore oil and gas, architectural applications in urban and coastal locations, food processing, hospitals, potable water and sewage treatment, and transport containers.
Type 316L is not only easy to fabricate, offering versatility with good corrosion resistance in a broad range of environments with a long track record of use, but it is also widely available in all product forms in large and small quantities, direct from the mill or from stockholders.