Application of Taguchi Methods and ANOVA in GTAW Process Parameters Optimization for Aluminium Alloy 7039

Abstract

Aluminium alloy 7039 is an Al-Mg-Zn alloy employed in aircraft, automobiles, infantry combat vehicles and high speed trains due to their low density, high specific strength and excellent corrosion resistance. Pulsed Gas Tungsten Arc Welding is used in this study for welding AA7039. The influence of the various GTAW process parameters, i.e. Pulse Current, Base current and Pulse Frequency on welds were studied for properties of weld like microhardness, ASTM grain size number and heat affected zone (HAZ) width. The settings of the process parameters were determined by using Taguchi's experimental design method. Orthogonal arrays of Taguchi, the signal-to-noise (S/N) ratio, the analysis of variance (ANOVA), and regression analyses are employed to find the optimal process parameter levels and to analyze the effect of these parameters on the weld properties. Confirmation test with the optimal levels of welding parameters was carried out in order to illustrate the effectiveness of the Taguchi optimization method.