SIMPLIFIED X-RAY ANALYSIS OF RETAINED AUSTENITE,

An investigation was made to develop a series of charts to simplify the determination of volume percentage of retained austenite by X-ray techniques. The relative intensities of selected martensite and austensite diffraction lines were computed as functions of weight and percentage carbon. Charts were prepared from these data displaying volume percentage of retained austenite as functions of weight percentage of carbon and the integrated intensity ratios between selected pairs of austenite and martensite diffraction lines. These charts apply only when the diffraction lines are obtained with the use of filtered chromium or cobalt X-radiations and an X-ray diffractometer. The X-ray determinations made with the use of these charts were substantiated by quantitative metallographic examination of specimens containing approximately 7, 20, and 50 austenite, respectively. The amounts of austenite read from the charts agreed within or - 2 percent by volume. The charts were found to facilitate and to accelerate X-ray determination of retained austenite. Author