Martempering and marquenching are terms often associated with hot oil quenching. Formally, martempering (full martempering, true martempering) is a term applied when an austenitized work piece is quenched into a medium whose temperature is essentially maintained in a bath just above the martensite start (Ms) temperature of the steel and held in that medium until its temperature is uniform throughout - but not long enough to permit bainite (or pearlite) formation - and then allowed to cool in air.