ABSTRACT
It is a significant effort to pick up perfect welding process variables for improving the quality of weld bead geometry in any welding process. Using process optimization for welding variables is a complicated matter, reason is that, it depends on multi-factors, which is influence by the 282circumstances. In this study, a tungsten solid wire having 2.5 mm diameter has been used as an electrode with direct current electrode negative (DCSP) polarity. An argon gas has been supplied for the shielding purpose. A multi-response optimization technique has been employed to optimize the weld bead geometry and process parameters for Tungsten Inert Gas (TIG) bead-on-plate welding of IS 2062B mild steel. Taguchi’s experimental design method has been used to define the significant sets of experiments of the process variables with the intention of reducing the number of experimental runs. Three important welding process variables viz. current (I), welding speed (S) and gas flows or passes rate (Gf) with a constant voltage were considered in this work. The bead geometry viz. penetration, bead width and HAZ thickness; and hardness of HAZ were computed. The weightage of the responses on overall outcome characteristic of the weld bead has also been assessed numerically by ANOVA (analysis of variance) method. The optimal process variables, which was defined from the Signal to Noise ratios plot, has been validated from the experimental sets. It shows the workability of the gray-based Taguchi method in manufacturing world for on-going development in product quality. It has been noticed that the process variables have a remarkable impact on weld bead geometry as well as hardness of the HAZ.
