NACE SP0170 PDF

NACE SP0170 – Protection of Austenitic Stainless Steels and Other Austenitic Alloys from Polythionic Acid Stress Corrosion Cracking During a Shutdown of Refinery Equipment

This standard practice provides mitigation methods to protect austenitic stainless steels and other austenitic alloys from polythionic acid (PTA) stress corrosion cracking (SCC) that can occur during a shutdown of refinery equipment. This standard is directed toward preventing stress corrosion cracking (SCC) caused by polythionic acid (PTA) that can be formed by reaction of oxygen and water with sulfide corrosion products (i.e., metal sulfides) or with other oxidizable sulfur species (e.g., sulfur, hydrogen sulfide [H₂S]). This standard is maintained by Task Group 173.