In pursuit of enhanced mechanical properties, this study departs from the conventional low‐temperature bainitic transformation approach, which typically relies on elevated carbon content. A medium‐carbon steel with a nominal composition of Fe–0.447C–1.09Si–3.02Mn–0.926Cr–0.216Mo–1.68Co (in mass%) was produced using a vacuum induction melting furnace. The as‐cast material was homogenised and hot‐rolled, followed by austenitisation at 950°C for 30 min and subsequent isothermal transformation to bainite at 260°C. X‐ray diffraction (XRD) and electron microscopy analyses confirmed the presence of retained austenite, bainite, and cementite precipitates. The application of electropulsing led to a more uniform distribution and increased volume fraction of retained austenite, the formation of martensite, and partial dissolution of cementite. The refined microstructure and enhanced fraction of high‐angle grain boundaries were attributed to partial recrystallisation induced by the athermal effects of the electron wind force. Consequently, the electropulsed sample exhibited superior tensile properties, with a yield strength (YS) of 1532 MPa, an ultimate tensile strength (UTS) of 1768 MPa, and a total elongation (TE) of 9.56%, outperforming the conventional bainitic structure (YS: 1385 MPa, UTS: 1721 MPa, TE: 9.43%). These results demonstrate the effectiveness of electropulsing treatment as a novel and efficient processing route for tailoring microstructure and enhancing the mechanical performance of bainitic steels.
Kumar et al. (Fri,) studied this question.