RELATIONSHIP BETWEEN MAGNETIC PROPERTIES, SENSITIZATION, AND CORROSION OF INCOLOY ALLOY 800 AND INCONEL ALLOY 600

Sensitization processes in two high Ni-Cr-Fe alloys are studied by Huey and accelerated Strauss tests, magnetic permeability measurements, and scanning electron microscopy. There is good agreement between the two corrosion tests for Incoloy Alloy 800 but not for Inconel Alloy 600. High Huey corrosion rates are associated with large magnetic permeabilities which result from chromium depletion near the grain boundaries. The relative contribution of the chromium depleted region and of electrochemical effects to the Huey corrosion rate could not be determined because the formation and disappearance of the chromium depleted zone and of the continuous grain boundary carbides occur concurrently.