A Fe-30wt%Ni based alloy, retaining a stable austenitic structure at room temperature, was used for modelling the development of austenite microstructure during hot deformation of conventional carbon-manganese steels. A series of plane-strain compression (PSC) tests were carried out at 950degreesC and a strain rate of 10s(-1) to several strain levels. Evolution of the grain structure, crystallographic texture and dislocation substructure was characterised in detail using light microscopy, electron back-scatter diffraction (EBSD) and transmission electron microscopy (TEM).