Austempering is a heat treatment that produces a ductile, stable bainitic structure in steel applications. The treatment is done in two steps: first heat into the austenite phase and then quench to a temperature level so that the austenite is transformed into bainite instead of martensite. Bainite is tougher than martensite.



  • Lower distortion compared to a traditional quench and temper process
  • Tougher parts
  • Shock resistance




The HVF and VVF systems from Nitrex deliver superior performance for austempering applications requiring high strength and toughness.

Horizontal Vacuum Series

Vertical Furnace Series


Austempering is used in a wide variety of applications in the automotive, rail, and heavy-engineering industries: applications include gears, shafts, crankshafts, camshafts, clutch plates, seat belt components, drive shafts, rollers, rocker arms, and many others.

Austempering benefits ferrous metals, particularly ductile irons and medium- to high-carbon steels including:

  • AISI 4140
  • AISI 4340
  • AISI 5160
  • AISI 6150
  • AISI 1045-1095