Effects of process parameters in gas tungsten arc welding of thin titanium plates

This work systematically investigated the effects of process parameters on the technological responses, including the tensile force TF and average micro hardness AMH in the gas tungsten arc welding (GTAW) of titanium. Controlled parameters are the welding current I, gas flow rate F, and arc gap G. The objective of this work is to improve the tensile strength with respect to micro hardness constraints. A GTAW welding machine was adopted in conjunction with the Box-Behnken matrix to conduct experimental trails. The nonlinear relationships between welding parameters and responses were developed using response surface method (RSM). Subsequently, an optimization technique entitled desirability approach (DA) was used to solve the trade-off analysis between responses considered and find the optimal parameters. The conformity test was performed in order to evaluate the accuracy of optimizing values. The results showed that the welding current had the greatest influence on the outputs considered, compared to other factors. The measured improvements using optimal parameters of tensile force and average micro hardness are approximately 4.10% and 6.12% in comparison with initial settings. A hybrid approach comprising RSM and desirability approach can be considered as an effective method for parameter optimization and observation of reliable values in GTAW processes.