Analyses of Hybrid Taguchi Methods for Optimization of Submerged Arc Weld

Abstract

In the present work, an attempt has been made to search an optimal process environment, capable of producing desired high quality submerged arc weldment. The optimal process environment consists of several process control parameters called factors. In this paper, four process variables viz.voltage (OCV), wire feed rate, traverse speed and electrode stick-out have been considered. Taguchi’s L25 Orthogonal Array (OA) has been adopted for conducting experiments to produce bead-on-plate weld on mild steel plates. Four bead geometry parameters: depth of penetration, reinforcement, bead width and percentage dilution have been chosen as objective functions. These individual objective functions have been accumulated to calculate an overall quality indicator; which has been optimized finally. The aim was to convert a multi-objective optimization problem towards a single objective function, with the goal to optimize it. Two hybrid techniques, firstly, Taguchi method coupled with grey relational analysis; and secondly, Taguchi method in combination with Desirability Function (DF) approach has been applied. Comparison has been made on aforesaid two hybrid optimization techniques. Relative advantages as well as disadvantages of these techniques have been highlighted too. Optimal results have been verified through additional experiments; showed satisfactory results. Sensitivity analysis has been carried out to visualize the sensitiveness of the individual response weightages as well as the index of desirability function, influencing the optimal setting with the aim to satisfy varying requirements of different quality characteristics of the weld bead geometry.