Development of submerged arc welding method using hot wire

In the fabrication of steel bridge, submerged arc welding (SAW) is widely utilized. In order to increase the efficiency for the production of welds, the increase in electrode such as SAW with multiple wire electrodes is effective. However, heat input also increases with increasing the number of electrode. The new welding method based on SAW method with one electrode, F-SAW, was developed in the present investigation. An electrically heated filler wire, hereafter referred to as hot wire, was inserted into the rear part of weld pool made with leading SAW electrode. By using the hot wire without arc, increase in heat input could be suppressed but the amount of weld deposit could be greatly increased. Welding speed of F-SAW for deck plate 16-mm thick became two times compared with that with ordinary SAW. In the present study, mechanical properties of the weld metal formed with F-SAW were clarified. Mechanical properties of the weld metal formed with F-SAW could be improved, compared with those with SAW. Moreover, those with F-SAW was greatly improved by selecting the hot wire and cut wire. The microstructure formed with F-SAW was so fine. The refined microstructure in F-SAW might improve the mechanical properties of the weld metal.