CORROSION FATIGUE LIFE PREDICTION FOR SUS 403 STAINLESS STEEL IN 3% NaCl AQUEOUS SOLUTION.

In order to estimate the corrosion fatigue property of SUS 403 stainless steel, a corrosion fatigue test was performed under rotating bending in 3% NaCl aqueous solution at frequencies from 0. 03 to 30 Hz up to ten thousand hours. Fatigue strength was monotonously decreased with increasing numbers of cycles and decreasing test frequency, except for the case of 30 Hz where fatigue limit was observed. The depth of corrosion pits at the origin of fatigue cracks was linearly correlated to the failure time on log-log coordinates. Microscopic observations revealed that the initiation of fatigue crack from a pit became possible when the growth rate of a hypothetical crack having the same depth as the pit exceeds the growth rate of the pit. Thus the corrosion fatigue life could be predicted from the crack initiation period and propagation period.