Due to the ensuing shift toward adoption of increased levels of scrap during steel production to reduce the carbon footprint, it is essential that the effects of tramp elements entering the produced steel from the scrap are understood. In this context, effects of four major tramp elements (Ni, Cu, Cr, and Mo) on the phase transformation and the microstructure evolution of medium‐manganese steels are studied by theoretical predictions. The results indicate that Cu and Ni are beneficial, whereas Cr and Mo have mixed effects due to the formation of different equilibrium metal carbides. The Cu and Ni concentrations of 0.1–0.5 wt% marginally increase the maximum retained austenite content by 2 vol%. Cr reduces the achievable maximum amount of retained austenite more strongly (decrease by 8 vol% for 0.5 wt% Cr) than Mo (decrease by 4 vol% with 0.5 wt% Mo), and Cr gives a wider processing window for achieving a microstructure with a lower variation than Mo. Combined effects of the elements are to decrease the maximum retained austenite by 8 vol% with lowering of processing temperature by 20 °C. This work provides a guideline for the selection of the optimum processing window of medium‐manganese steels in a circular economy.</jats:p>

Medium-Mn steels have attracted immense attention for automotive applications owing to their outstanding combination of high strength and superior ductility. This steel class is generally characterized by an ultrafine-grained duplex microstructure consisting of ferrite and a large amount of austenite. Such a unique microstructure is processed by intercritical annealing, where austenite reversion occurs in a fine martensitic matrix. In the present study, austenite reversion in a medium-Mn alloy was simulated by the multiphase-field approach using the commercial software MICRESS® coupled with the thermodynamic database TCFE8 and the kinetic database MOBFE2. In particular, a faceted anisotropy model was incorporated to replicate the lamellar morphology of reversed austenite. The simulated microstructural morphology and phase transformation kinetics (indicated by the amount of phase) concurred well with experimental observations by scanning electron microscopy and in situ synchrotron high-energy X-ray diffraction, respectively.