Influence of Stress on Low Temperature Sensitization of SUS304 Stainless Steel

By using carbide nucleation-heat-treated SUS304 stainless steel specimens, the effect of various type of stresses applied during 500°C isothermal heat treatment on Low Temperature Sensitization (LTS) was examined. The Degree of Sensitization (DOS) was detected by means of the Electrochemical Potentionkinetic Reactivation (EPR) test and Strauss test. The main results of the study are as follows :1) When constant tensile stress is applied to the specimens during isothermal heat treatment, the LTS was accelerated more than unstressed specimens. The degree of acceleration was larger when the applied stress was larger. The acceleration of the LTS was also seen even when the stress less than proof stress at the test temperature.2) The electrochemical potentiokinetic reactivation ratio of the specimens after 100 h of the LTS test corresponded to strain rather than stress.3) When alternating stress was applied to the specimens during the isothermal heat treatment, the LTS was accelerated even more than when constant tensile strees was applied.