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An algorithm and program for determination of welding parameters under given leg length, welding speed and length between tip and base metal by CO2 arc welding are proposed. The welding parameters were set to obtain the globular transfer.Calculated parameters were confirmed to given effective leg length and reinforcement by welding experiment.

Diffusion welding method using alloyed layer with sputtering after Ar ion bombarding on bonding surface of IN738LC has been studied.In this report, effect of Ar ion bombardment on oxide film of bonding surface, effect of sputtering condition on formation of alloyed layer and measurement of melting temperature were investigated.The results indicated that: oxide film on bonding surface can be removed by Ar ion bombardment, formation rate of alloyed layer is very fast in 3×10-3 Torr Ar and melting temperature of alloyed layer was 1080-1100°C.

Resistance pressure welding of SUS304 stainless steel using insert material of Ni-base BNi-2 brazing alloy powder was studied. The effect of the welding conditions upon mechanical and metallurgical properties of the joint was investigated.The results are summarized as followed:(1) The tensile strength of the joint is higher than 600 MPa (equal to that of the base metal), and the shrinkage of weldment for 10 mm is less than 0.1 mm. These properties are obtained by using the following conditions: weld current 157 A/mm2, weld time 0.2 sec and pressure 49 MPa.(2) Temperatures at the joint surface and at a distance of 1 mm from the joint interface are different by more than 300°C on the welding conditions of weld current 254 A/mm2, weld time 0.04 sec and pressure 49 MPa.(3) In the case of the same deformation, metallurgically better welding results are obtained by using the welding conditions of higher weld current and shorter weld time. For example, on the welding conditions of 254 A/mm2 and 0.08 sec, Si content in the joint layer equals to that in the base metal, but on 58 A/mm2 and 5.0 sec, Si element gathers like a film at the center of the joint layer.

A resistance pressure welding method using insert material was investigated. In this method, a layer of insert material (BNi-2, SUS304, BAg-1) was placed between two base metals to raise electrical contact resistance, and electric current was passed through the layer causing concentrated heating at the interface. The molten layer of low melting point was pressed out of the joint interface. Various types of insert materials were tried for joining SUS304 stainless steel. Metallography of the joint sections was investigated. It was found that BNi-2 with high hardness with high hardness and reaction for base metal gave better joint characteristics of high tensile strength, small deformation and homogeneity of the joint layer.

Surface temperature near the rear end part of molten pool in girth TIG welding for 2 mm thick, 25.4 mm diameter stainless steel tube was measured with a PbS infrared radiation pyrometer. Effects of welding position and distance from arc center to a measuring point on the relation between the surface temperature and the reverse side bead width were investigated at down-hand, vertical down, over head, vertical up welding position of orbital TIG welding.Temperature near the rear end, part of molten pool becomes high in order down-hand, vertical up, vertical down, over head welding position under the same reverse side bead width condition. Mutual correlation exists at each welding position between surface temperature at the position 5-10 mm away from the center of the arc and the reverse side bead width. It indicates the possibility of adaptive control of the reverse side bead width by monitoring the temperature near the rear end part of molten pool during the TIG welding.

Superconducting magnets in fusion reactor system produce enormous electromagnetic force which generates very high stress working on the containers of these magnets at cryogenic temperature. The candidate alloys for the structural material of containers are non magnetic stainless steels with improved yield strength and toughness at cryogenic temperature. Containers are produced as welded structures, so that these properties on the structural material are also indispensable for the weld metal.The chemical compositions of stainless steel weld metal are usually controlled to include a small quantity of δ-ferrite for the prevention of hot cracking in welds. The δ-ferrite is, however, ferromagnetic and causes the reduction in cryogenic toughness of weld metal. On the other hand, the weld metal of 19Cr-13Ni-5Mn type is known as fully austenitic one with very low susceptability on hot cracking in welds. The improvement of weld metal of this type resulted in the development of the fully austenitic weld metal of l7.5Cr-l6.5Ni-6.5Mn type with improvde cryogenic strengths. The effects of carbon and molybdenum contents on the tensile properties and Charpy impact properties were examined on this type of weld metal.Conclusions are as follows. It is possible to assure the yield strength of the weld metal of 2.3% molybdenum content higher than 1000 MPa when carbon content is higher than 0.07% and carbon plus nitrogen content is higher than 0.13%. While the weld metal decreases in the elongation and reduction in area as the addition of carbon, the weld metal which contains 0.13% of carbon and 2.3% of molybdenum indicates about 40% of elongation and about 300% of reduction in area at 4.2 K. The Charpy absorved energy and lateral expansion of the weld metal at 4.2 K are equal to those at 77 K. The weld metal decreases in the absorved energy and lateral expansion as the addition of carbon content, but the weld metal which contains 0.13% of carbon and 2.3% of molybdenum indicates about 60J of absorved energy and 0.8 mm of lateral expansion at 4.2 K. The relation between yield strength and absorbed energy at 4.2 K on the weld metal coincides with the lower limit line of absorbed energy of the stainless steels SUS304LN and SUS316LN of high yield strength.

Diffusion welding method using alloyed layer of low melting temperature on bonding surface of IN 738LC with CO2 laser has been studied.In this report, effect of laser beam irradiating condition on formation of alloyed layer, measurement of melting temperature and boride precipitates of the alloyed layer were investigated.The results indicated that homogeneous alloyed layer was obtained by irradiating linearly focused laser beam (Output: 1.8 kW, Scanning Speed: 0.3 m/min) on bonding surface coated with BNi-2 powder (grain size: 74-105μm). The alloyed layer was about 300μm in thickness, melting temperature of the alloyed layer was about 1170°C.

Press-Soldering is a method to make a joint at a relatively lower temperature and obtain a higher joint strength. Press-Soldering experiments at I kgf/mm2 and 3 kgf/mm2 pressure were done using Bi-Pb type solder with Ag and Zn additions to obtain a sound alloyed layer at a temperature below 350°C. Tensile strength, heat-resistivity and composition of the alloyed layers of press-soldered Cu to Cu joints were investigated. A joint which was press-soldered at 350°C with 3 kgf/mm2 pressure using a Bi-42%Pb-3%Ag-2%Zn solder showed the best result. The joint had 8 kgf/mm2 of tensile strength and the remelting temperature above 820°C. In this case, two alloyed layers were found in the joint interface. The composition of the alloyed layers were Cu-18.5%Zn-2.5%Ag and Ag-29%Zn-3.5%Cu respectively.

In a nuclear power plant, large numbers of pipe are set in very complex and narrow space. Because welding in such places is difficult, remote control pipe welding equipment, in such all welding sequence are controlled.by mini-computer, has been developed. In this report authors investigated the monitoring equipment for TIG welding.1) For optical system reduction contrast ratio in welding part, small monitoring equipment produced with combination of pinhole, screened filter, selective filter and lens has been developed.2) Informations can be obtained the following phenomena from monitoring equipment. (1) arc states (2) states of molten pool, (3) bead appearance, (4) groove shape, (5) weaving width, (6) molten states of filler wire.3) The monitoring equipment developed has been applied to welding procedure in a nuclear power plant.

Lipid peroxidation mediated by oxygen free radicals plays an important role in the pathogenesis of inflammatory bowel disease (IBD). Vitamin E is a lipid-soluble antioxidant and is generally considered to protect against lipid peroxidation of the cell membrane and to scavenge singlet oxygen and superoxide anion radical. Therefore, vitamin E or its derivatives are expected to have particular application for patients suffering from IBD. The aim of this study was to investigate the antioxidative effects of the water-soluble vitamin E derivative, 2-(alpha-D-glucopyranosyl)methyl-2,5,7,8-tetra-methylchroman-6-ol(TMG), on the therapy of experimental colitis in rats. Colitis was induced in male Wistar rats weighing 200 g using an enema of trinitrobenzene sulfonic acid (TNBS) dissolved in 50% ethanol; TMG dissolved in physiological saline was injected intra-peritoneally every day from 24 h after the enema of TNBS. The damage score, wet weight of the colon, and increase in body weight were estimated 1 week after the enema of TNBS. Thiobarbituric acid-reactive substances (TBA-RS), an index of lipid peroxidation, and tissue-associated myeloperoxidase (MPO) activity in the colonic mucosa were measured 1 week after the induction of colitis. As a result, increase in body weight was inhibited by the induction of colitis, although the inhibition was reduced in the group treated with TMG. The damage score, wet weight, TBA-RS and MPO activity were increased significantly in the colitis group; however, they were inhibited by the administration of TMG. These results suggest that TMG is effective for the treatment of colitis in rats induced by TNBS. In the future, TMG could be a new therapeutic agent for IBD.