Influence of Magnets on Arc Shape and Bead Geometry in Gas Tungsten Arc Welding

A unique methodology has been developed with the compilation of two magnets to produce the double axial magnetic field, and the effect on the arc shape and the bead characteristics in the gas tungsten arc welding (GTAW) process have been investigated. The load-carrying capacity of the joint depends upon the bead geometry. The developed methodology is capable of altering the arc shape and consequently the bead geometry of weld as per the requirement. Experimental results show that the double axial magnetic field changes the arc shape from a conical to constricted conical. It is further observed that magnetic configurations North-South-South-North (N-S-S-N) and Zero-Zero-South-North (0-0-S-N) provided better results than other configurations. The North-South-South-North (N-S-S-N) configuration produced a minimum penetration (0.98 mm) and a maximum shape factor (7.81), along with good appearance of weld beads. This configuration is suitable for cladding and hardfacing applications. The increased penetration (3.03 mm) was achieved with the Zero-Zero-South-North (0-0-S-N) configuration compared with conventional welding (2.20 mm). Similarly, this configuration yielded a higher bead width (8.13 mm) than conventional welding (5.90 mm). This configuration is suggested for the single-pass welding operation.