All thermo-mechanical manufacturing processes create residual stresses in the component.  Compressive residual stresses in the surface of a part can improve the mechanical properties such as fatigue life and corrosion resistance.  However, the presence of residual stresses may be detrimental to the integrity of the part under service conditions.  For these reasons, understanding the source of such stresses, their control, and relief are critical to the application of the manufacturing process.

The residual stress distribution in the unitized EBF³ structure depends upon parameters such as heat input, travel speed, wirefeed speed, baseplate and deposit thickness, part geometry, and process schedule.  Additional parameters used to control distortion and residual stress include external constraint (clamping), preheat, post-heat, active cooling, machined lands, and insulation.  To identify the relative significance of each process parameter on residual stress distribution and to arrive at some optimal combination of parameters, a finite element analysis model was developed and used to guide the design of experiments.  Experimental studies coupled with surface profile and residual stress measurements were used to validate the finite element model.  To date, one set of deposition parameters (beam power, translation speed, and wire feed rate) was selected and used for all cases evaluated.  Salient features of the model are presented for various process parameter cases and selected experimental trials are presented to verify the model.