Taguchi’s design’s Optimization of Commercial Steel Welding made by Semi-Automated GTAW

GTAW is a widely used welding process in industry. It has advantageous mechanical and metallurgical properties over other welding processes such as GMAW. In order to obtain optimal welding conditions, it’s vital to optimize the welding parameters. Commercial steel also referred as mild steel is often used for construction that needs to yield tensile strength. The later was reported to be sensitive to the hardness of welding. The work is to investigate the influence or effect of the transverse tensile strength and hardness of mild steel welding made by semi-controlled GTAW at a variation of groove shape, welding current, and welding speed. The analysis made with Taguchi’s design orthogonal array technique to demonstrate the effect of the welding parameters and optimize these parameters on the tensile strength of the welding. The results showed that higher transverse tensile strength showed higher welding hardness (i.e., 232 MPa and 2555 VHN shown at V-shaped welding). The tensile strength and hardness increased at lower welding current (170 A), V-shaped welding, and higher welding speed (150 mm/min). This combination has shown optimal conditions for stronger and highly effective GTAW welding. The increased internal stresses in welding caused lower transverse tensile strength and hardness of welding. Possibly the lower interpass heat input to increase and thus, lower transverse tensile strength of welding.