Tandem Submerged Arc Welding
A high-performance welding process employing two independently controlled wire electrodes within a single molten pool beneath a flux layer. It achieves extremely high deposition rates and travel speeds for thick-walled structures.
Tandem submerged arc welding means: two wires run simultaneously into the same weld pool, both under flux. You can control the two arcs separately, which gives you a decent deposition rate and you can make good progress on thick plates. The trick is to coordinate the two wires cleanly. If one draws more current than the other, the pool becomes unstable and you get an unclean weld. Also watch for even wire feed, otherwise you get lack of fusion or cracks. In practice, this means: first set the parameters for the first wire properly, then add the second. The flux feed must always follow nicely so that the pool stays covered. And inspect the weld after the first test piece carefully, then you'll see if the two arcs harmonize.