The Studies of Bead Formation in Submerged Arc Tandem Method

In the case of Two Electrodes Tandem Method

Abstract

Studies on the bead formation have been carried out in the case of two electrodes submerged arc tandem method.
It has been made clear that two arcs have their own functions in bead formation; that is, the lead-arc has the function of "Digging the base-metal" and the trial one that of "Regulating the bead appearance."
Taking these functions into consideration, the possibility of high speed welding has been examined with five kinds of tandem methods.
As the result of it, it is found out that the deflection of the trail arc chiefly influences the bead appearance, and that the bead appearance is beautiful even in the high speed range if only the trail arc is deflected in the welding direction.
When an alternating current is used, the phase angle between two arc-currents is very important, and when a direct current is used, attention must be paid to the earth position; that is, start side or end side.
It means that the bead appearance is governed by the interaction between the magnetic fields of the arcs and the current through the base metal.