| 摘要 |
PURPOSE:To improve welding speed in the stage of high speed submerged arc welding with multiple electrodes in tandem, by using a flux having specific ratios among the contents of MgO, Al2O3, TiO2 and CaF2. CONSTITUTION:A baked flux which contains 6-15% MgO, 5-15%, Al2O3, 5- 20% TiO2, 6-15% CaF2, 25-35% SiO2, 4-15% MnO and 5-15% CaO, consists of the compsn. in the range wherein the equations[I],[II]are satisfied simultaneously among the contents of MgO, Al2O3, TiO2 and CaF2, and of which the median diameter occupying 50% in a cumulative grain size distribution is 500-800mum and <=295mum grain sizes are <=15% the entire part is used as a flux. AC current is conducted to four pieces of electrodes disposed in order of L, M1, M2, T in the advancing direction of welding, and the 3-phase AC current at which a 120 deg. current phase difference is provided among the three electrodes except the electrode L or T and the electrode L or T has a 0+ or -30 deg. current phase difference with respect to the furthest electrode is conducted. |
