Residual Stress Prediction for Dual Frequency Induction Hardening Considering Creep and Transformation Plasticity During Heating

Dual frequency induction hardening can be a low distortion alternative to case hardening for gearings. In order to get a better understanding regarding the residual stress evolution, a 2-D numerical model has been developed, considering short time austenitization kinetics of quenched and tempered AISI 4140 as well as creep and transformation plasticity during heating. Creep and austenitization experiments under uniaxial compressive stress were conducted using a deformation dilatometer. The mechanical properties of AISI 4140 were determined with a specifically developed short time austenitization device. Dual frequency hardening of cylindrical specimens and subsequent determination of residual stress depth profiles serve as evaluation data. The induction heating model considering nonlinear magnetic material behaviour is realized with MSC.Marc®, whereas the mechanical response is implemented in Abaqus/Standard®. The austenitization experiments under uniaxial compressive stress cause a shift of the transformation temperatures to higher temperatures, caused by the uniaxial loading. Austenitization experiments show that transformation plasticity plays a considerable role during heating. Comparison of residual stress measurements with those predicted by the current model show better agreement when transformation plasticity and creep are considered during heating.