Optimization of Process Parameters of Manual Arc Welding of Mild Steel Using Taguchi Method

Abstract

This study was based on design of experiment (DOE) using Taguchi method with four welding parameters namely; welding current, (ii) welding speed, (iii) root gap and (iv) electrode angle considered for experimentation. An orthogonal array of L9 experimental design was adopted and ultimate tensile strength was investigated for each experimental run. The tensile test was carried out on extracted welded and unwelded specimens using universal testing machine (UTM). Microstructures of the welded specimens were carried out and analyzed. Statistical analysis (ANOVA) and signal to noise ratio were used to study the significant effect of input parameters on ultimate tensile strength and optimized conditions for the process performance respectively. The results showed that experiment number 7 has the highest ultimate tensile strength (UTS) of 487MPa and S/N ratio of 53.74 dB. The S/N ratio of higher value indicates better characteristic of optimum MMAW process performance. The study shows that the optimum condition is A3B1C3D2 at welding current 100A, electrode angle of 700, root gap of 3.3 mm and a welding speed of 3.6 mm/s .