Weld Bead Geometry and Shape Relationship in Submerged ARC Welding using Recycled Slag

Submerged Arc Welding (SAW) is the most versatile method in the Automation industry which is diligently working on the concept of waste utilization and energy saving. During SAW, the flux melts and converts into non-biodegradable product known as slag. This slag is then recycled and thus proves to be an important measure in reducing waste. Slag consumption will not only prevent environmental pollution but also proves economical. When additives/ deoxidisers and binders were added to slag, it rejuvenates the workability, mechanical properties, metal integrity and bead quality of the welded specimen. In this paper, an attempt has been made to formulate slag equivalent to fresh flux and then pertained to study its effects on bead geometry shape relationship of mild steel bead on plate. For this, Response Surface Methodology (RSM) technique was adopted and mathematical models were developed to relate the input parameters (wire feed rate, arc voltage, travel speed and nozzle to tip distance) with response parameters (such as bead width, bead height, bead penetration, weld penetration shape factor {WRSF} and weld reinforcement form factor {WRFF}). These models are then checked for adequacy using ‘F' test and ‘t' test, respectively. Adequacy test revealed that newly designed slag proves beneficial in presaging the weld bead quality. Also, the RSM approach helps in selecting optimum process controllable variables.