INFLUENCE OF CARBON CONTENT ON TRANSFORMATION BEHAVIOR OF AUSTENITE IN 9CR-1MO STEELS

The present work discusses the influence of carbon content on the tran sformation behaviour of austenite in 9Cr-1Mo steels, employing convent ional microscopic techniques. The two main themes of the present work were the role of carbon in altering the choice of decomposition mode o f austenite during various rates of cooling and the influence of carbo n on the variation of a number of microstructural parameters with solu tion treatment temperature. Based on these studies, microstructural ma ps have been proposed depicting the influence of carbon on the decompo sition modes of austenite during cooling. The second section, namely, the variation in microstructural parameters with solutionising tempera ture, highlights the role of carbon in shifting the T-gamma --> T-delt a temperature and the time-temperature-transformation diagram of gamma --> alpha + carbides. (C) 1997 The Institute of Materials.