This process is now used extensively for the heat treatment of this high-carbon steel parts or low-alloy Steels of thicker section and gives a much tougher product than by oil hardening and then tempering to the same hardness. Alternatively, by Austempering it is possible to attain a high hardness coupled with excellent toughness.

In Austempering, the steel is heated to the normal hardening temperature in a neutral salt bath or an atmosphere furnace and then the pieces are quenched in an agitated bath of FRANK 150 ( FANK 220 ) at 250-450°C, more usually 280-300°C. The lower the temperature of the austempering bath, the longer will it be necessary to soak the parts in it to complete transformation and vice versa, but for carbon steel treated at 280-300°C, the soaking time is normally 20-30 minutes.

Afterwards, the parts are cooled either in air or in water and washed in hot water. A few of a large number of parts which are now austempered are small springs, and clips, leaf springs, chain links, spanners, forks, spades, shears, cutter blades, harrow discs shoe shanks and toe caps etc.