Electrothermomechanical Processing of High Carbon Steels

Abstract

Passing high density electric current through some metals has been shown to induce microstructural changes, such as grain refinement. Known as electropulsing, the process has previously been successfully applied to cold-drawn pearlitic steel wire over a very short treatment period (current density >103 A·mm-2 and pulse width <10-4s) and with low energy expenditure. Once optimised, electropulsing treatment may offer potential time-and energy-saving advantages over traditional grain refinement techniques. However, to date, very little research on the effects of electropulsing on pearlitic steel exists in the literature and is limited to steel wire. The current work was conducted to determine whether electropulsing treatment is capable of producing similar grain refinement and spheroidisation behaviour in the microstructure of cold-deformed high carbon pearlitic steel sheet (0.92wt%C). High current density electropulsing treatment was applied to pearlitic steel samples of 40 to 70% rolling reduction for 50 or 100 pulses. The electropulsing treatment did produce microstructural changes in pearlitic steel plate that was similar to that observed in pearlitic steel wire over a relatively short treatment time. These changes involved grain refinement and spheroidisation and were enhanced with increasing cold rolling reduction.