A method of austempering of steel parts is described. The steel parts are
initially austenitized and subsequently quenched to a start temperature
which is higher than the martensite start temperature. Then the steel
parts are subjected to a first isothermal holding at the start temperature
for a first time period. Subsequently the steel parts are held for a
second isothermal time period at a finish temperature which is higher than
the start temperature. The method described is particularly well suited
for rapid austempering of steel parts, a pure bainitic structure being
achievable, and the core hardness of the steel parts obtained being
settable via the start temperature, the finish temperature, the duration
of the first time period, and the duration of the second time period.
