EXPERIMENTAL CHARACTERIZATION OF MICROSTRUCTURE EVOLUTION IN AUSTENITIC STAINLESS STEEL WITH PHASE TRANSFORMATION

The phase transformation in cold-rolled stainless steel 301 LN sheets is investigated experimentally. A series of uniaxial experiments is performed to investigate the effect of initial anisotropy on the martensitic transformation kinetics. Three methods are employed to measure the martensite content: (1) X-ray diffraction, (2) micrography and (3) magnetic induction. The first two methods require interrupted tests while, the third method allows for the in-situ detection of changes of the martensite volume ratio. All three methods show that the rate of austenite-to-martensite transformation is loading direction dependent. In particular, the magnetic induction technique appears to be sufficiently sensitive to detect these relative differences. However, the results also show that the determination of the absolute martensite volume content can only be quantified with poor accuracy due to the limited accuracy of X-ray diffraction and micrography.