317L stainless steel pipe

Alloy 317L (UNS S31703) is a molybdenum-containing austenitic stainless steel that offers higher chemical resistance than traditional chromium-nickel austenitic stainless steels such as Alloy 304. In addition, Alloy 317L has higher creep, stress-break and tensile strengths at elevated temperatures compared to conventional stainless steels. It is a low carbon or "L" grade that resists sensitization during welding and other thermal processing.

317L has excellent corrosion resistance in a wide range of chemicals, especially in acidic chloride environments such as those encountered in pulp and paper mills. Increased chromium, nickel and molybdenum content compared to 316L stainless steel improves resistance to chloride pitting and general corrosion. The resistance increases with increasing molybdenum alloy content. 317L can withstand sulfuric acid concentrations up to 5% and temperatures up to 120°F (49°C). The alloy has excellent resistance to higher concentration solutions at temperatures below 100°F (38°C). However, it is recommended that in-service tests be conducted to consider the effects of specific operating conditions that may influence corrosion behavior. During condensation of sulfur gases, 317L is more resistant to corrosion at the condensation point than conventional alloy 316. Acid concentration has a significant effect on corrosion rates in such environments and should be carefully determined and tested by maintenance personnel.