Probing influence of welding current on weld quality in two wire tandem submerged arc welding of HSLA steel

Two wire tandem submerged arc welding (SAW-T) involves application of two electrode wires to form a single weld pool with one wire leading the other along the weld interface. Realisation of the influences of the lead and trail wire currents on the weld bead morphology and the weld strength are important in SAW-T. The authors here present an experimental and computational investigation on SAW-T process. The concept of central composite rotatable design is followed for designing the experimental trials. The final weld width and the reinforcement height showed greater sensitivity to trail current while the penetration was influenced primarily by lead current. A three-dimensional heat transfer analysis is carried out using finite element method. The computed weld profiles were validated with the corresponding measured results. The computed cooling rates showed a decline with higher welding current and, the corresponding sample welds showed reduced acicular ferrite percentage and lower weld strength.