The grey-based Taguchi method was used to enhance the TIG-MIG hybrid welding process parameters for mild steel

Abstract

Metal Industry and Machine Technology Development Enterprise is Ethiopia's leading manufacturing industry, producing a diverse range of industrial machinery and products. The main welding process used to join the products is MIG welding, which has several flaws, including low weld-metal toughness, spatter formation, undercut formation, and finally poor tensile strength and toughness. The company also uses TIG welding, which uses an inert gas to produce less smoke and fumes. While this technology produces precise welds, it is a time-consuming operation with a lower production rate. As a result, a special type of welding process is required that incorporates the properties of both types of welding processes. As a result, the hybrid TIG-MIG welding configuration was proposed. The optimization of process parameters of EN24 mild steel material for TIGMIG hybrid welding is presented in this paper. The test was carried out on a 6 mm EN24 mild steel plate. The butt joint configuration was used. MIG welding current, TIG welding current, MIG welding voltage, TIG welding voltage, and welding gun travel speed were used as process parameters. A single-level L27 orthogonal array is used to optimize process parameters. Tensile and hardness tests are used to evaluate the mechanical properties of the weld joint. The optimum level setting of the test, according to the mean effect plot of GRG, is MIG welding current of 200 A, MIG welding voltage of 15 V, TIG welding current of 200 A, TIG welding voltage of 18 V, and welding gun travel speed of 5 mm/s. The significant process parameters were investigated using ANOVA. MIG welding current and MIG welding voltage were significant factors in the ANOVA, with percentage contributions of 44.19 % and 49.20 %, respectively. Five confirmation tests were performed, and the results show that the mean grey relational grade of the conformation test was 0.7594, which falls within the 90 % confidence interval, indicating that the experiment is reliable. Finally, MIG welding, TIG welding, and TIG-MIG hybrid welding processes were compared, with the results indicating that TIG-MIG hybrid welding has the highest hardness and tensile strength of all. Based on the findings, it is possible to conclude that the company should use the hybrid welding method to improve the weld joint's hardness and tensile strength.