Vertical section of Fe–C–2Si–2Mn–1 Cr system for carbon contents up to 0·8 wt-% and associated phase compositions

Abstract

Abstract Phase coexistence in the Fe–C–Si–Mn–Cr system, as the base system of a large number of low alloy steels, has been studied experimentally and theoretically. The vertical section of the phase diagram of the Fe–C–2Si–2Mn–1 Cr system near the eutectoid point (700–900°C; 0·14–0·80 wt-%C) and the chemical composition of the phases present were determined by means of scanning electron microscopy and energy dispersive X-ray analysis. Thermodynamic calculations of the Fe–C–Si–Mn–Cr system equilibria, based on the Hillert–Staffansson model, for low contents of silicon, manganese, and chromium were performed. These calculations gave results very close to both the experimentally determined phase boundaries and the composition of phases. A wide eutectoid zone (about 50 K) was found to exist in the system, for all carbon contents studied.MST/1940