Life Extension of High Temperature Structural Alloys RA602CA in Gas Carburizing Atmosphere

RA602CA is an oxidation resistant high strength nickel based alloy that has been widely used for furnace fixtures in heat treatment processes. Aluminizing can be used to increase the high temperature oxidation and carburization resistance of nickel-based alloys. In this paper RA602CA and Aluminized RA602CA were selected to study their performance in an industrial carburization furnace for times up to two years. The test samples were exposed in an 0.7wt%C carburizing atmosphere at approximately 900C for 3 months, 6 months, 12months, 18months, 24 months. In this report the microstructural development of both aluminized and unaluminized alloys during the prolonged exposure in the carburizing environment will be presented and discussed. It was found that the weight gain for the aluminized alloys was uniformly less than the as-fabricated alloys.