Nonequilibrium Grain Boundary Segregation of Sulfur and Its Effect on Intergranular Corrosion for 304 Stainless Steel

The data obtained by bending tests for intergranular embrittlement after 45 h and 450 h exposure to Strauss solution have been reported for 304 stainless steel. The results show that an embrittlement peak appears at 650 degrees C for all samples quenched from 1 260 degrees C and then sensitized for 150 h at 480, 565, 650, 730, 815 and 900 degrees C respectively. The temperature corresponding to the embrittlement peak is decreased to 565 degrees C when the sensitizing time is prolonged to 1 500 h. In this paper, these data are analyzed with an isothermal kinetic model of nonequilibrium grain boundary segregation, indicating that the embrittlement peak is related to the critical time for nonequilibrium grain boundary segregation of sulfur.