Martempering
Martempering, also called stepped quenching or interrupted quenching, is a heat-treatment method for steel that reduces stresses during quenching. The steel is heated into the austenite range and then quenched in a bath kept at about 150–300°C (hot oil, molten salt, or molten lead). The piece is held until its entire cross-section reaches the same temperature, staying above the martensite start temperature (Ms). It is then cooled to room temperature, usually in air or oil, and finally tempered.
In martempering, the austenitized part is immersed in a bath just above Ms. The cooling is interrupted so the center has time to catch up with the surface temperature; after removal from the bath, the part is allowed to air-cool to room temperature, completing the transformation of austenite to martensite.
The purpose of martempering is to control stresses and distortions that develop during quenching. A drawback is that it is not suitable for very large cross-sections.
This page was last edited on 3 February 2026, at 10:24 (CET).