Stress Corrosion Cracking of Austenitic Stainless Steel in Concentrated Chloride Solution

Evaluation of SCC Susceptibility of Austenitic Stainless Steel in Salt Water

Abstract

Until now copper tube has been used as heat exchanger tube for saltmaking evaporator, but at present for economical reason austenitic stainless steel tube is used for evaporator. Because SCC of austenitic stainless steel in chloride solution is anxious, SCC tests with some electro seam-weld stainless steel tubes and plates in boiling salt water were investigated. The microstructure of weld joint of seam-weld tube is similar to that of mother metal and corrosion behaviour of seam-weld tube is equal to that of seamless tube in acid corrosion test. At U-bend SCC test of any material SCC not occurred in boiling salt water, but at SCC test by constant load in boiling salt water SCC occurred in Type 304 and 304L at stress above 15kg/mm² and in Type 316L at stress above 25kg/mm². In conclusion, Type 316L is recommended for the material of saltmaking evaporator.