Finite Element Simulation of Residual Stress in Electrical Discharge Machining (EDM) of AISI H13 Tool Steel Considering Solid-State Phase Transformation

In electrical discharge machining (EDM), the high temperature gradients generated by the electric discharge result in residual stresses on the surface layers of machined materials. These residual stresses can lead to micro-cracks, decrease in strength and fatigue life and possibly catastrophic failure. In this paper, a finite element model (FEM) has been developed to estimate the temperature distribution on the workpiece, the crater size, and the residual stress profile near the surface with considering solid-state phase transformation. The results showed that residual stress profile form is independent from discharge energy, however, with increasing pulse energies the maximum of tensile residual stresses and the depth where the maximum is observed slightly increased, and also the diameter-to-depth ratio of the craters decreased with increasing pulse current that shows deeper craters. The model has been validated using experimental data, wherever possible. The calculated residual stress profiles showed good agreement with the experimental result.

Keywords:

Electrical discharge machining (EDM) , Finite element method (FEM) , Residual stresses , Solid-state phase transformation