人工海水中における耐海水2相ステンレス鋼の腐食疲労き裂進展挙動

抄録

The corrosion fatigue crack growth rate of dual-phase stainless steel SUS329J1 has been measured in synthetic sea water at various stress ratios and stress cycle frequencies under free corrosion and a cathodic potential. In air the roughness-induced wedge effect enlarges the region II in the load-strain hysteresis loop. In synthetic sea water, the corrosion products-induced wedge effect under free corrosion and the Ca and Mg deposites-induced wedge effect under a cathodic potential are conspicuous, thereby enlarging the region II and raising K_op. Under free corrosion the stress assisted dissolution accerelates the crack growth rate at a low ΔK_eff. In addition, at a high ΔK_eff at R=0.1 and f=0.17Hz the crack growth rate is much more accerelated due to hydrogen embrittlement. Under a cathodic potential, ΔK_th is remarkably high. But the crack growth rate is much accerelated due to hydrogen embrittlement in terms of ΔK_eff.