Retained Austenite and Its Measurement by X-Ray Diffraction

This paper shows that retained austenite (R.A.) exists in many hardenable steels and that its presence can induce both positive and negative changes in various mechanical and engineering properties. The economic considerations of these changes are particularly important in such finished products as bearings, gears and tool steels. Discussed in the paper are the following aspects of the R.A. problem; (1) origin of R.A., (2) methods for its control, (3) quantity levels in various steels, and (4) various methods for its measurement. The x-ray diffraction technique of R.A. measurement is shown to be a very accurate and fast tool for the quantification of R.A. in the microstructure of such products whether subjected to measurement after heat treatment, or after deformation processing and return from service.