Corrosion tests of 10 kinds of stainless steels have been conducted for 5 years under three conditions of marine environments, which are atmospheric corrosion, intermittent seawater spray and intermittent seawater immersion.
Rating number increased with PRE(Cr+3.3Mo+16N;mass%) value in all test conditions and the stainless steels of which the value were over 37 showed excellent corrosion resistance under marine environments.
Maximum pit depth decreased with increasing PRE value in all test conditions.
Rating number settled after a couple of months from the start and then the number almost unchanged. On the contrary maximum pit depth grew with increasing test duration. It is suggested that the progress of corrosion mainly depened on the pit growth.
