Parametric investigation and metallurgical analysis on groove formation during magnetic field-assisted electrical discharge turning of Inconel-825 superalloy

The influence of varying magnetic field-assisted conditions (specifically 0.15 and 0.30 T magnetic field) during the electrical discharge turning (EDT) process on the machining performance of cylindrical Inconel-825 superalloy was examined in this study. A detailed evaluation was carried out by varying input parameters such as gap current (Ig), pulse-on time ( T ON ), rotational speed, and magnetic field intensity to determine their effects on material removal rate (MRR), tool wear rate (TWR), overcut (OC), and surface roughness ( R a ). The results indicated that increasing the magnetic field intensity enhanced the material removal rate (MRR) while also increasing the tool wear rate (TWR), potentially due to the influence of the magnetic field on plasma flow and discharge concentration. Additionally, a reduction in OC and R a indicates improved surface quality. The combination of higher magnetic intensity (0.30 T) and current (16 A) yields the most substantial improvement in MRR with acceptable R a . SEM and XRD analyses support these findings, highlighting the advantages of magnetic field-assisted EDT in machining Inconel-825 for aerospace applications. XRD analysis shows grain refinement and increased dislocation density in the EDTed work surfaces, with the highest refinement observed at 0.30 T magnetic intensity.