Optimization of process variables for shielded metal arc welding dissimilar mild steel and medium carbon steel joints

Shielded metal arc welding (SMAW) is one of the most important processes of joining two metals or materials because of its high efficiency and low time requirement. This work studied the tensile strength of SMAW dissimilar mild steel (MS) and medium carbon steel (CS) with various process variables such as Welding Current (WC), Electrode Angle (EA), and Root Face (RF). The chosen variable ranges are WC of 140,180 and 200Amp, EA of 30,45 and 60 degrees and RF of 1,2 and 3 mm respectively to identify the important variables on Tensile strength (TS). Design of experiments (DOE) is executed as per Taguchi L9 OA for recognizing the optimal level of variables to accomplish maximum tensile strength. The experimental result is witnessed that the highest TS (201.38 MPa) is attained at sample-8 when WC -140 Amp, EA-45 degree and RF-1mm are maintained whereas the lowest TS (41.61 MPa) is obtained at sample-9 due to increment of the electrode angle (60 degree) and root face (2 mm), Analysis of variance result is revealed that Electrode Angle is the most important variable (73.97%) which improves TS of the SMAW joints, followed by Root face (6.24%) and Welding current (5.12%).