Application of metal cored filler wire for environmental-friendly welding of low alloy steel: experimental investigation and parametric optimization

Motivated by the crescente demand for eco-friendly and worker-safe welding techniques, this study optimizes current (A), voltage (V), and gas flow rate (GFR) for regulated metal deposition (RMD) welding of ASME SA387 Gr.11 Cl.2 steel. Employing MEGAFIL 237 M metal cored filler wire and a Taguchi L₉ orthogonal array, bead-on-plate trials were conducted to evaluate heat-affected zone (HAZ), depth of penetration (DOP), and bead width (BW). A unique dual-pronged optimization approach was implemented. The utility function method, combined with Taguchi’s signal-to-noise (S/N) ratio, maximized desirable and minimized undesirable responses. Additionally, TOPSIS with Taguchi S/N ratio identified the optimal process parameters. Both optimization strategies converged on identical. A = 135 A, V = 14 V, and GFR = 13 L/min. Notably, voltage emerged as the most influential factor in the mean S/N response table, highlighting its critical role in controlling weld quality. The proposed procedures offer a robust framework for determining optimal RMD welding conditions in pipeline applications. This not only enhances weld integrity and worker safety but also paves the way for sustainable manufacturing and continuous quality improvement in the field.