Computer simulation of the heat treatment process applied to a forged shaft

  • G.M. La Vecchia
  • A. Pola
  • F. Zola


Process modelling using finite elements analysis is very effective to design an optimized process in order
to obtain high quality forging parts. For instance, the application of computational analysis on heavy forgings
allows the definition of an adequate forging process in terms of temperature, pressure and ramp speed
as well as the heat treatment procedure. Quenching and tempering represent a critical phase in the production
of heavy forged steel parts. In fact, improper cooling can cause the obtainment of undesired microstructure
(i.e. bainite instead of martensite at the component surface as a consequence of a soft cooling) or unexpected
residual stress distribution, related to severe heat treatment steps causing cracks. The aim of the present study
was to evaluate the adequacy of an industrial heat treatment procedure applied to a heavy 4140 steel forged
shaft by means of finite elements simulation, a technique able to predict the temperature/time distribution
along the thickness of the forged part in various heating or cooling conditions. A comparative study
of experimental and numerical superficial temperature distribution was also proposed, allowing the validation
of the numerical model used and, subsequently, of the internal temperatures and stresses distribution.