Joining of metals to plastics and to glasses can be performed by the methods of plating and vapor depositing and by use of a proper organic adhesive agent. Diffusion bonding of metals to ceramics and to cermets can also be performed with some proper brazing materials. However, it seems that making of a smaller point joint for the precision components by such joining methods is very difficult. In addition, these joining methods will be attended with many difficulties in operation.
Ultrasonic welding, as known well, possesses many characteristics superior to other conventional welding methods. Consequently, there is good prospect that make a smaller point joint of metals to the above non-metallic materials can be made by this. Since there was little research on such welding, some experiments were carried out in order to make clear the possibility and bonding mechanism of the ultrasonic welding of metals to non-metallic materials.
This report describes the relation between the welding conditions and the weld properties, the output energy loss at the weld interface with the non-metallic materials diformed and softened during the welding and some results of photomicro examination on the weld interface in the ultrasonic welding of low carbon steel to some plastics and to glass.
To obtain good welds of such combinations, it is probably necessary that the non-metallic materials be not greatly deformed and softened during the welding and materials possess some elements such as O, N, Al, Si and others which make an atomic bond to the metals a foil interleaf and are more diffusible into the foil interleaf.
In this work, welding of low carbon steel to glass and to acrylic or polypropylene was performed without any difficulty by use of Al foil interleaf. Welding of steel to polyethylene or fluorinated ethylene was attended with some difficulties, especially, fluorinated ethylene could not be welded to steel. This is probably due to some energy loss at the weld interface on account of softening and deforming of the latter materials during the welding, and also due to the materials possessing no elements which are diffusible into Al foil interleaf.

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In welded structures it is necessary to prevent initiation of brittle fracture from weld defects or crack in the joint at their service temperature and stress level specially in case of high strength steels. It is estimated that the bond of joint is more brittle than the base metal and that the degree of embrittlement depends on the welding heat input.
In this paper, the effect of heat input on the brittle fracture initiation characteristics of the base metal, the bond and the weld metal of welded joints for 60, 70 and 80 kg/mm² high strength steels was investigated.
In addition, the path of brittle crack propagation, the effects of welding procedure such as the shielded and submerged arc weldings, the stress relieving, and the inhomogenity on the brittle fracture initiation characteristics were investigated.

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Regarding to the momentum of cutting oxygen stream, in the report 1, author described some results of considerations to the phenomena of oxygen stream in the case of without preheating flame. In this paper, cutting oxygen has been considered in the case of with preheating flame.
To study the effect of preheating flame on the momentum of cutting oxygen stream, total head of oxygen stream is measured at various conditions of cutting oxygen pressure and preheating flame, and it has been confirmed that preheating flame is very useful to keep the momentum of cutting oxygen stream. The momentum of cutting oxygen stream is kept most effectively under the conditions as follows.
(1) At about 4 kg/cm² of cutting oxygen pressure.
(2) Preheating flame applied is neutral mixture.
(3) At suitable preheating gas flow rate.
(4) Increasing of numbers of preheating orifice. And the best keeping effect is obtained by annular preheating flame.
Relation between momentum of oxygen and cut plate thickness will be described in another paper.

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The stress corrosion cracking of austenitic stainless steels occurs not only due to the welding stress, but also due to the working process such as pressing and bending. Especially there are many problems, when the cold-worked material is welded, that is to say, the sensitivity of the material for stress corrosion cracking will be changed by plastic deformation, while at the same time, the value of welding stress in the cold worked material is assumed to become higher.
In this reportt authors discussed the cold work dependence of the sensitivity for stress corrosion cracking in two kinds of austenitic stainless steels such as SUS 27 and SUS 32 in the boiling solution of 42% MgCl₂.
In the material like SUS 27 which transforms to quasi-martensite under cold working, the resistance to stress corrosion cracking grows through cold working. It is estimated that the quasi-martensite acts as an anode spot in the corrodent, consequently the type of corrosion changes into general corrosion.
Next, it is confirmed by experiment that the resistance to stress corrosion cracking of cold worked SUS 27 drops through reheating to over 500°C. This is due to the fact that the martensitic structure is resolved.
On the other hand, the material like SUS 32 shows no change in the time-to-fracture of stress corrosion, even though it has been cold worked. In this material, no martensitic transformation has been observed after the cold working process.
Next, authors measured. the welding stress of the pre-tensioned plates. The tensile residual stress along the weld line reachers a maximum at about 10 mm distance from weld line, and it is almost the same value as the increased yield stress of the cold worked material.
The initiation of cracks in such material is earlier than that in the material without the cold working process. This fact can be observed in both SUS 27 and SUS 32.
From this experiment, it may be said that even though the cold work is confirmed, in laboratory, to be good for stress corrosion cracking, this fact cannot be applied to welded structures for prevention of stress corrosion cracking.

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From the foregoing reports, it is known that the creep rupture strength of welded specimens is influenced by initial conditions of structure in the heat-affected zone. In this report, the influence of heat treatment after welding on the creep rupture strength of large size welded specimens is investigated. The specimens are made under the following three conditions of heat treatment after welding: (a) 550°C×2.5 hrs., furnace cooling, (b) 650°C×2.5 hrs., furnace cooling and (c) 900°C×2.5 hrs., furnace cooling.
The results are as follows;
(1) The creep rupture strengths of welded specimens, treated under 650°C×2.5 hrs., furnace cooling and 900°C×2.5 hrs., furnace cooling after welding, are superior to that of the as-welded one. The heat treatment under 550°C×2.5 hrs., furnace cooling seems to decrease the creep rupture strength.
(2) The welded specimens, treated under above conditions, arc ruptured at the heat-affected zone of base metal near the bond.

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