Optimization of Welding Parameters for Carbon Steel Fabrication: A Trade-off between Tensile Strength and Heat-Affected Zone

This study focused on optimizing gas metal arc welding (GMAW) parameters for AISI 1045 carbon steel to balance the ultimate tensile strength (UTS) and heat affected zone (HAZ) size of the weldment. Using a full factorial design of experiments (27 trials), the influence of welding current, arc voltage, and travel speed on UTS and HAZ size of AISI 1045 carbon steel weldments were investigated. From the analysis of results, using Analysis of variance (ANOVA) technique, the results revealed that current, travel speed and arc voltage contributed 74.41%, 19.05% and 0.04%, respectively, to the total percentage of variations on UTS data. All the other parameters showed great contribution on UTS except the arc voltage which had a p-value > 0.05. For the HAZ, current, travel speed and arc voltage contributed 5.08%, 62.9% and 20.12%, respectively. All the three parameters significantly affected the HAZ with p-value < 0.05. To find the trade-off between these two objectives, the multi-objective particle swarm optimization (MOPSO) technique along with Pareto frontier methods was employed to evaluate them. The MOPSO technique showed the best trade-off results of UTS 571.55 MPa and HAZ size of 19.97 mm. For engineering applications requiring higher strength, the UTS of 610 MPa was achieved with its corresponding HAZ size of 26.52 mm. Conversely, for minimal HAZ size with better strength, the HAZ of 15.16 mm was determined, along with the UTS of 525.72 MPa.