SUS304ステンレス鋼の粒界劣化現象に及ぼす粒界連結性の影響

抄録

Grain boundary degradation phenomena, such as sensitization and intergranular corrosion, result in embrittlement in austenitic stainless steel. The connectivity of random boundaries was evaluated by fractal analysis, because grain boundary degradation phenomena preferentially percolated along the random boundary network. SUS304 austenitic stainless steel specimens with different grain structure and grain boundary character distribution were produced by cold rolling and subsequent annealing. The fractal dimension of random boundary network with maximum connectivity (maximum random boundary connectivity, MRBC) in SU304 specimens were estimated ranging from 1.15 to 1.50. The fractal dimension of MRBC tended to increase with increasing length of MRBC. The SUS304 specimen with the lower fractal dimension of MRBC showed the higher corrosion resistance than the specimen with higher fractal dimension of MRBC, even if the specimens had the similar GBCD. The utility of grain boundary engineering for control of grain boundary degradation phenomena was proposed based on the obtained results.