From the point of view concerning the equilibrium between molten iron and slag deposited with electrode, we studied the influence of TiO2 or ilumenite, in the FeO-MnO-SiO2 coating saturated with SiO2, on weld metal obtained. Especially, effects on its total silicon content, manganese content and quantity of inclusions were researched. The total silicon content of weld metal increases and the total manganese content decreases with the increase of TiO2 or ilumente content of coating. The increase of silicon content results the decrease of oxygen content and total quantity of inclusions of weld metal. Accordingly, it was observed by a microscope with 400 magnification that the quantity of inclusions decreases with the increase of TiO2 or ilmenite content. But on the case of microscopic examination with 1200 magnification the reverse tendency was observed. That is, the higher dispersion of fine glassy inclusions was recognized on the matrix of weld metal with the increase of TiO2 or ilumenite content of coating.
This method is concerned with the utilization of welding cables without using control cables in order to remotely control a-c arc welding. machine. The current of the welding transformer is adjusted by a small d-c motor whose control is carried out by connecting between wedling cables a control box containing half wave dry rectifiers. When the connection of the senses is turned over, the motor can also rotate reversely. The method has the following advantages: (1) Non-use of control cables ; (2) Non-use of relays ; (3) Control box is small, light and not dangerous electrically ; (4) Simpler operation ; (5) Easier maintenance ; (6) Longer life ; (7) Possibility of common use of a control box for many welding machines;(8) Owing to the employment of welding transformer without moving parts, the control motor is small;(9) Possibility of applications to large welding machines and a-c machines of other types. In the paper, the authors state the structure and the characteristics of the control motor, the control box and the welding transformer of new remote control type, and explain the actual control circuit. This, paper was awarded a Prize amounting to 10, 000 Belgian francs as Honourable Mention in the Arcos International Competition 1953.
Weldability test results made on Cb containing austenitic stainless clad steel, named Remanit 1880SS, have clarified the following points. (1) A mild steel electrode of low hydrogen type proved to be best in welding the mild steel side of the plate. (2) The lower layer of the stainless steel side should first be welded with 25 Cr-20 Ni steel electrodes, and then the upper layer be filled with 19 Cr-12 Ni-Mo-Cb stainless rods having a similar composition to the clad metal. (3) No appreciable difference was found in corrosion resistivity, between the specimens as welded and those after given cold-works such as bending or rolling. (4) Excessive cold working on stainless steel weldment should be avoided, because they are easily hardened due to the formation of martensite in addition to the work-hardening. (5) Martensitic structure disappears by annealing at temperatures above 1000°C.
Conventional formulas were obtained from the fundamental equation in Part I. These are given by equations (2), (3) and (4). Formula (2) is the same type as the formulas of Ogura(2) and Jackson.(3) Constants D and F in formulas (1) and (2) are shown in Table 1. Data of bead-on specimens are given in Figs. 1 and 9. Data of I-butt welded joints and fillet welded joints (see Table 2, Figs. 5 and 6) are shown in Fig. 7. These certify the usefulness of formula (4). Physical meaning of formula (4) was considered from the view point of temperature distribution near the weld. The value of I/h √vh in formula (4) is proportional to the temperature rise at a point near the weld. Constant S3 is proportional to φ-α, where φ is the diameter of electrode and α=0.4-1.0.
Automatic oxy-acethylene welding in steel pipe manufacture is one of the very useful methodes. In this study the manufactured results of steel pipes are made comparison with single or slitted hoops as shown in Table 2. In case of single materials are used, the combination of welding seam is Rim-Rim, but there are Rim-Core or Core-Core in case of slitted materials and the welds has many blow holes or cracks as shown in Photos. 2, 4, 5. The results obtained are as follows; The mostly of blow holes and internal cracks in core side of welds alone based on the segregation in materials. The cracks that growthed along the welded seam mainly based on so called "Spring Back" force when pipe manufacturing in addition to the segregation. There are many factors on spring back force and its measurements on welding are very difficults, but it has intimate relation, for example, to physical, chemical properties and size of hoop, and so types of forming etc.
From the temperature distributions of an infinite cylinder with a distributing heat source, the volterra's integral equation of 2nd kind including an unknown function qm (t) is derived. qm(t) is the heat flow the contact plane between the plate and the elctrode to the material per unit area and time. This integral equation is the Poisson's type and can be calculated by the Whittaker's method. The temperature distributions of the plate and the electrode are fiquired out by using qm(t). qm(t) becomes nearly a constant value after certain time has passed when the adiabatic radius of the plate is small and the diffusibility of the plate is large. In this case, when the current density is constant, it is proved that the radius of the electrode affects the cooling effect of the electrode more than the distance from the thermally neutral point to the contact surface between the electrode and the plate.
Effect of welding on brittle fracture of two high tensile steels was investigated with notched C-Bead Tear Test Specimens which were side-beaded with six electrodes ; four low hydrogen high tensile electrodes, one ilmenite-type mild steel electrode and one hard-facing electrode. The conclusions may be summarized as follows : (a) The effect of welding was very remarkable in crack initiation, and reduced considerably absorbed energy to maximum load, lateral contraction at root-notch, and nominal tensile strength. With a deposit of low ductility, the reduction was very serious. (b) However, the effect of welding was hardly observed in crack propagation through base metal. (c) Some examples were observed in which a ductile heat affected zone of base metal could arrest and change into a ductile fracture the brittle crack which had been propagated through a brittle weld metal. (d) The nominal strength of notched C-Bead Tear Test Specimen was independent of base metal, but depended on the type of electrodes which were used in bead welding. (e) Home made low hydrogen electrodes which were tested, showed the same quality with an imported electrode of low hydrogen type, as far as notch sensitivity of welded plates was concerned.