LAUSR

Abstract This paper deals with the assessment of the stability of retained austenite in δ-TRIP steels at two different isothermal holding time durations. Longer holding time leads to an improvement in austenite stability by greater carbon enrichment. This caused a significant increase in the hole expansion ratio at a tensile strength of 800 MPa. The microstructure mediated approach was employed to characterize the difference arising from different holding durations. The deformation-induced transformation of austenite into martensite mapped on the specimens after hole expansion proved that the austenite stability plays a significant role in the hole expandability of δ-TRIP steels.