Effect of Strong transient Variations in Operational Parameters on Vacuum Arc Remelting (VAR)

Numerical simulations are employed to investigate the impact of strong transient variations in electrode diameter and melt rate on ingot growth in the vacuum arc remelting process of alloy 718. As the electrode diameter changes, side arcing and arc distribution are also affected, significantly influencing pool depth throughout transient ingot growth. To evaluate these effects, a parametric study is conducted to analyze potential variations in side arcing and arc distribution during the process. The findings reveal that electromagnetic forces play a dominant role in shaping the melt pool. A slight increase in side arcing results in a shallower melt pool, while a higher arc ratio (more diffusive arc) further reduces pool depth, increasing the influence of thermal buoyancy forces. Additionally, smaller electrode diameters and higher melt rates contribute to a deeper pool profile. The simulation results align with the experimental data, confirming the accuracy and reliability of the model.