Abstract: The failure of stress corrosion cracking of light-component removal column was analyzed by means of metallographic, SEM, and chemical composition analysis. It was concluded that the failure was caused by stress corrosion cracking of austenitic stainless steel in polythionic acid environment. The electrochemical and SCC test of selected stainless steel of 321, 316L and 2205 were carried out. The results showed that 316L and 2205 steels have good SCC resistance to polythionic acid. The above conclusions can provide a basis for the selection of materials for the system.

Key words: light component removal column, polythionic acid, stress corrosion cracking/SCC