In this report, we manufactured many steel core rods having various manganese, and silicon contents on trial in industrial scale and using them, prepared the arc-welding electrodes whose coating contains no deoxidizes and a small quantity of reducing-gas-producing material. Then, observing the rule of JES 9001-"Arc welding coated electrodes for general steel constructions", we investigated the properties of the above mentioned electrodse in use and measured the properties of weld steel deposited with them. And the following results were obtained. 1) In use of the steel core rods containing somewhat much quantities of manganese and silicon, the apparent specific gravities, impact values and elongations of the all weld steels are more excellent than those of the all weld steels deposited with the usual steel core rods whose contents of manganese and silicon are lower. However, the composition-point showing contents of manganese and silicon must exist in the field II-The deoxidation product in this field is the FeO-MnO-SiO2 liquid solution which is unsaturated with silica and has good fluidity.- of the diagram of deoxida-tion with manganese and silicon (Fig.1 ). But, if the manganese and silicon contents are too high, there is a tendency for the above mentioned properties of the all weld steels deposited, with them to become lower. 2) The higher the manganese and silicon contents of steel core rods are, the larger the ultimate strengths and hardness of the all weld steels deposited with them become. 3) In use of the steel core and having high silicon contents, there is a tendency for the one layer fillet weld of T-joint to contain portions having the so-called striated structures and minute cracks. However, if silicon contents of the core rods are lower than 0.3%, such a tendency of f the fillet weld is not observed. In such a way, it has been made clear that the steel core rods containing suitable large quantities of manganese and silicon are effective for arc-welding of steel.
It is well known that weldability of cast iron is rather low, and especially, when hardened structure such as white pig iron is formed in weld part, it obstructs usual machining and increases crack sensibility. In this research, the structural change of gray cast iron, which was subjected to short time local heating similar to heating condition by welding, was cleared. And consideration was given to the structure in comparison with the structural distribution of weld part of gray cast iron. Chemical composition of the specimen is shown in Table 1, and the shape of local heating specimen is shown in Fig. 2 and Fig. 3. The following two methods were used for short time local heating. 1. Flash heating. 2. Resistance heating. The characteristic distribution of structure caused by above two methods are shown in Fig. 2 and Fig. 3. 1 The main results obtained from this experiment were as follows; 1. Such structure as white pig iron was not found in the mother metal except in the fuzed zone. 2. Structural distribution of heated part by flash heating is shown in Fig. 2. 3. Structural distribution of heated part by resistance heating is shown in Fig. 3. 4. Structure of welded part was found to be almost similar to that of the specimen which was heated by resistance heating.
The authors have studied fundamental data on oxy-arc cutting, using a cutting rod made of welding rod and an aluminum tube. The results of the investigation are summarized as follows: 1) Oxy-arc cutting is speedier with less oxygen consumption than ordinary oxy-acetylen cutting, provided proper cutting conditions are given 2) In the case of oxy-arc cutting, the nature of cutting is rather different from that of ordinary oxy-acetylene cutting, and it appers more reasonable to call it "Fusion Cutting". However, , ordinary cutting as is obtained from oxy-acetylen cutting can be performed at lower current. 3) As shoun in Fig 7, cutting speed and oxygeq pressure at lower current are converted to opposite characters at higher current.
We studied a newtype of weld groove named "Fusion type", which may be used for elimination of rail joints by arc welding. Using a ordinary mild steel electrode, the D. C. arc welding process was appllied under condition similar to that of field welding. Preheating as a preparatory measure for welding was not allowed. The result of the experiment were as follows. (1) " Fusion type " proved a suitable welded joint, which may be used for field welding of rail. (2) Bevel cut of railend by machining or flame cutting as preparatory step for arc welding, was not necessary. (3) As the color of rail become light red by arc fusion without preheating, the rail could be welded with good weldability. (4) Perfect annealing was found to be a desirable heattreatment for eliminating the residual stress and the hardened structure at the heat affected zpne. (5) Penetration of rail base was found to be more important than that of other portion of the rail as regards statical bending strength. (6) Required bending strength of rail joints was a obtained by a skillfull and careful operation.