Determination of retained austenite content in Fe-Cr-Ni weld metal.

Several techniques, including dilatometry, X-ray diffraction, electron backscattering diffraction and magnetisation measurement, were applied and compared in order to reliably determine the retained austenite content of Fe-Cr-Ni steel weld metal. In this work, based on a proposed novel numeric solution for martensite transformation kinetics, it was found that the dilatometric method presented consistent results along with the magnetisation method in the quantification of mechanically unstable or stable retained austenite. By contrast, the X-ray diffraction method was inaccurate and time-consuming for the measurement of mechanically unstable retained austenite. However, the X-ray diffraction method was relatively successful when the retained austenite was mechanically stable. In addition, the magnetisation method seemed to be the only reliable way to detect small amounts (less than 5 vol.-%) of retained austenite in Fe-Cr-Ni weld metal. [ABSTRACT FROM AUTHOR]