Mechanical Characterization of Pipe Joint of Mild Steel IS: 1079, Gr.O in Submerged Arc Welding (SAW) Process Using Taguchi Method

Submerged arc welding (SAW) process is automated and semi-automated down hand traditional fusion welding process. High metal deposition ability begets excellent weld-quality and productivity. SAW process has dominated its supremacy in large structural application in manufacturing and production industries. Due to its high deposition rates, SAW is used for butt and fillet joints mostly in large structural applications. Joining of pipes is always a challenging task due to the 360° positional requirement. In this investigation, a novel approach has been taken to join two pipe-segments of mild steel with the help of in-house-built pipe welding setup. Full penetration weld is achieved by optimizing the heat input through optimizing process parameters. Welding input parameters were varied to get the mechanical properties of the welded joint as the response. Taguchi-based optimization process was employed to understand the effect of the inputs on the responses. Welding parameters largely influence the quality performance characteristics of the welded joint. Taguchi’s orthogonal array design is utilized to dictate the impact of control factors. ANOVA was performed for predicting parametric significance onto the performance characteristics through mean S/N (signal-to-noise) ratio plot and % contribution. Since, all the fabricated joint specimens fail in between the HAZ and base metal, it is preferable to achieve lowest possible width of the HAZ from design point of view. Moreover, load vs displacement graph after tensile test and cooling curve at different distances to the welding central plane have been depicted. Ultimately, a few inferences are settled down depending upon the experiment-strategic-values.