Effect of Alloying Elements on Intergranular Corrosion Susceptibility of Mo Contained Austenitic Stainless Steel in Nitric Acid Solution

Abstract

In this study, effects of alloying elements such as Mo, Cr and Ni on intergranular corrosion (IGC) resistance of Mo contained austenitic stainless steels in boiling 65% nitric acid solution (Huey Test) were studied.
Obtained results are as follows; (1) Mo deteriorates IGC resistance of austenitic stainless steel in Huey test due to enhance precipitation of Laves ((Fe, Cr)₂Mo) phase at grainboundary. (2) Cr improves IGC resistance of Mo contained austenitic stainless steel in Huey test, which is considered to reduce dissolution rate of Laves phase into nitric acid solution by increasing Cr content in Laves phase as increasing Cr content of stainless steel. (3) Ni suppresses occurrence of IGC of Mo contained austenitic stainless steel in Huey test.