2021 Volume 62 Issue 3 Pages 412-419
A system was developed based on which the pit growth automatically stops any time after the pit initiation under a chloride solution droplet. The atmospheric pitting corrosion of austenitic stainless steels with various sulfur (S) concentrations was investigated using this system. The results confirm that the initiation sites of pitting corrosion are manganese sulfide inclusions under the droplets regardless of the S concentration. In addition, the growth behavior of the active dissolution area is independent of the S concentration. When these specimens are subjected to wet–dry cycle tests, the probability of pitting corrosion increases with increasing S concentration due to the increase in initiation sites. The onset of pitting corrosion is independent of the chloride concentration. On the other hand, repassivation strongly depends on the S concentration.
This Paper was Originally Published in Japanese in Zairyo-to-Kankyo 68 (2019) 347–354.
