High aluminium low manganese steels were elaborated in order to study the phase equilibrium in the range of 900–1100°C. Two different quaternary alloys have been studied (Fe–9 to 10wt%Al–1.7wt%Mn–0.2wt%C and Fe–9 to 10wt%Al–8wt%Mn–0.2wt%C). Equilibrium phase's nature was identified at four temperatures for two alloys. Equilibrium phase fraction and chemical compositions were determined at 900°C. Thanks to these equilibrium results, we tried to understand the non-equilibrium microstructure observed after different thermal histories (DTA cycles, isothermal treatment followed by quench, reception state) and identify DTA events in a coherent way.
2007 by The Iron and Steel Institute of Japan