Dilatometer analysis of one-step quenching and partitioning in two medium carbon steels.Tuesday (27.09.2016) 17:30 - 17:45 Part of:
A one step quenching and partitioning treatment has been applied to two experimental steel compositions 0.3/0.4C-1.5Si-2Mn-0.25Mo-1.0Cr-0.8Al to investigate phase transformation behaviour during isothermal holding below the Ms temperature for these steels (329°C/279°C respectively). Dilatometer measurements indicate significant phase transformation during isothermal holding below the Ms temperature after the formation of initial athermal martensite. Samples quenched after 1 hour of isothermal partitioning exhibited very little, if any, post partitioning phase transformation during cooling, and these treatments yielded microstructures containing athermal martensite, the isothermal phase transformation product, abundant carbides, and around 14% retained austenite in all cases. From these results, we conclude that significant carbon partitioning must have occurred concurrently with the isothermal phase transformation in order to yield such a high retained austenite content at room temperature after quenching.