Effect of Cr on the Hot Ductility of Austenitic Fe-Mn-Al-C Lightweight Steel

Abstract

In this study, a hot ductility test was performed for Fe-30Mn-10.5Al-0.9C-Cr austenitic lightweight steels. The test was carried out through a commercial Gleeble simulator at a heating rate of 350 °C/sec and cooling rate of 50 °C/sec, with a stroke rate of 50 mm/sec. Microstructural analysis for understanding the hot ductility behavior was conducted through optical and scanning electron microscopy. The lightweight steels exhibited similar hot ductility behavior in accordance with temperature despite the addition of Cr. The experimental results indicated that the κ-carbide precipitation had an insignificant influence on the hot ductility test. However, ductility at low temperature was induced by slip mechanism, while dynamic recrystallization had significant influence at high temperatures during the on-heating thermal cycle. In the on-cooling thermal cycle, the melted and re-solidified grain boundaries decreased the overall ductility, exhibiting the same tendency as that observed in the on-heating test.