TP317L is a type of austenitic stainless steel that is commonly used in high-temperature and corrosive environments, particularly in the chemical, petrochemical, and oil and gas industries. It is a low-carbon version of TP317 stainless steel and is designed to have improved resistance to sensitization, which is the formation of chromium carbides at high temperatures that can cause the steel to become susceptible to corrosion.

TP317L has a composition of 18% chromium, 11% nickel, and 3% molybdenum, which gives it excellent corrosion resistance in a variety of corrosive environments, including acidic, alkaline, and chloride-containing environments. It also has good mechanical properties, including high strength, toughness, and ductility.

TP317L is typically used in applications such as heat exchangers, boilers, superheaters, and condensers, where high temperatures and corrosive environments are present. It is also used in the pharmaceutical, food processing, and pulp and paper industries, among others.