The process of quenching an austenitized ferrous alloy in a medium at a temperature in the upper portion of the tempera?ture range of martensite formation, or slightly above that range, and holding in the medium until the temperature throughout the alloy is substantially uniform. The alloy is then allowed to cook in air through the temperature range of martensite formation
A heat treatment involving austenitization followed by step quenching, at a rate fast enough to avoid the formation of ferrite, pearlite or bainite to a temperature slightly above the Ms point. Soaking must be long enough to avoid the formation of bainite. The advantage of martempering is the reduction of thermal stresses compared to normal quenching. This prevents cracking and minimizes distortion.
A hardening treatment of a steel involving a slow cool through the martensitic transformation range to reduce stresses associated with the quenching of austenite. An important aspect of martempering is that no transformation product other than martensite should form. See Austenite, Martensite, Quenching.