The purpose of this experiment is to obtain the fundamental data concerning the welding speed. To get good arc welding of good quality and higher efficicncy it, is necessary to determine the relation between the welding current and the welding speed distinctiy. Contineous beads have been laid on mild steel plates with a welding bed of which moving speed can finelly regulate by the combination of gears. Following articles are noted in this reports (1) Most suitable and allowable maximum welding speed for each amperage. Speed limitation for the formation of "under-cut" to each welding current. (2) Effect of preheating temperatures of mother plate on the welding speed and formation of "under-cut." (3) Effect of plate thickness on the welding speed. (4) Effect of surface scales of mother plate on the welding speed and the formation of blow holes.
In Part I the theoretical solution for the temperature distribution of welded plates under unstationary states is exhibited. Now we observed the actual temperature distribution of welded plates using thermo-couples, compared it with the calculated one, and obtained the conclusion that this theoretical solution approximately coinsides with the actual temperature distribution. The experimental and the theoretical temperature distributions of welded plates are shown in Figs. 4, 5, 6 and 7.