Abstract
In the first report, the effect of austenitizing temperature on retained austenite in high-carbon high-chromium steel and its decomposition were studied. In this report, the effects of subzero chilling and holding time at isothermal transformation temperatures on retained austenite in the same steel have been investigated by means of hardness and electrical resistance measurement and by magnetic analysis. The results are summarized as follows: (1) The retained austenite is greatly stabilized against transformation by subzero chilling with increase of the holding time at room temperature. (2) The retained austenite transforms into martensite by subzero chilling, but during subsequent heating the martensite begins to decompose at a lower temperature than the decomposition-commencing temperature of martensite in ordinary quenching. (4) The amount of retained austenite increases remarkably with increase of the holding time at the bainite transformation temperature. (4) Complete transformation of the retained austenite is not attained by subzero chilling in liquid oxygen.
