Comparative Study of Oxidation Resistance in the Presence of Water Vapor of Selected Heat-Resistant Alloys

COMPARATIVE STUDY OF OXIDATION RESISTANCE IN THE PRESENCE OF WATER VAPOR OF SELECTED HEAT-RESISTANT ALLOYS

Vinay P. Deodeshmukh and Nacéra Sabrina Meck

Research and Technology Department, Haynes International, Inc.

1020 West Park Avenue, Kokomo, IN 46904-9013

vdeodeshmukh@haynesintl.com and nsmeck@haynesintl.com

High temperature oxidation kinetics is considerably accelerated in the presence of water vapor which can severely reduce longevity of the components. The purpose of this study was to assess and compare the oxidation resistance of several Ni- and Fe-based alloys in humidified air. The alloys selected in this study are the HASTELLOY^® X, HAYNES^® 230, HR-120^®, 625, 214^®, 347 SS, and MA 253 alloys. The laboratory test program included 1008 hour oxidation exposures at 649^°C (1200^°F), 760^°C (1400^°F), and 871^°C (1600^°F) in air + 5 vol. % H₂O and air + 10 vol. % H₂O. Alloy performances were ranked by assessing weight change and extent of attack which includes metal loss, average internal penetration, and maximum internal penetration. It was found that Ni-based alumina-forming 214 alloy exhibited superior performance compared to the other alloys selected in the study. Among chromia-formers, Fe-based alloys were found to be more susceptible to increased degradation in humidified air.