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Fujisawa, Japan

Suzuki R.,Kobe Steel | Kasai R.,Shinko Welding Service Co. | Suga T.,Osaka University | Nakagomi T.,Shinshu University
Journal of Structural and Construction Engineering | Year: 2014

It is suggested asymmetry detail which has the non-scallop (access hole) method for upper side and the reinforcement welding around toe of the scallops for lower side of the beam. The purpose is to develop the detail and joint method has easiness to product and high capacity of plastic deformation suitable for on-site. In addition, new developed backing-less method which is overhead welding and overlay using the special consumable was combined instead of the backing plate which is jointed to groove bottom of the end of beam flange. Full-size beam-to-column assemblies applied these methods had high capacity of plastic deformation. This improvement mechanism is regard as reduction stress concentrations and controls of these balances by shape of overlay metal formed by arc welding. As the leg length of reinforced weld become increase, strain ratio of outer against center become decrease in the groove weld width of the beam end. Source


Reiichi S.,Kobe Steel | Tetsuo S.,Osaka University | Ryu K.,Shinko Welding Service Co. | Tadao N.,Shinshu University
Yosetsu Gakkai Ronbunshu/Quarterly Journal of the Japan Welding Society | Year: 2014

Improvement of the deformation capacity of the column-to-beam joint is an important theme for improving earthquake-resistant performance of building structures. One of the reasons decreasing the deformation capacity is the stress concentration against the beam flange by the scallop (access hole) existence. The non-scallop method is generally recommended to improve this problem, but it has large problem that is not able to apply to on-site joint process. The reinforce welding method around the scallop bottom has developed to be able to apply to on-site joint, and get performance more than the non-scallop method. Improving mechanism is combination with 1) decreasing the stress concentration, 2) increasing effective thickness, and 3) increasing total length of breaking line. The deformation capacity by reinforce welding method around the scallop bottom is maximum 3.2 times as for the conventional scallop method in the reverse repeating bend test using actual structure that beam flange has 19mm thickness and 490N/2 class steel. This improving effect is better than the non-scallop method. Source


Suga T.,Osaka University | Kasai R.,Shinko Welding Service Co. | Suzuki R.,Kobe Steel | Sasaki T.,Kobe Steel | Nakagomi T.,Shinshu University
Journal of Structural and Construction Engineering | Year: 2013

In recent years, many bracket-less structures are applied at beam-column for convenience of transport and it is welded at field. However, this structure style has backing metal on the outside of lower flange beams, that becomes origin of brittle failure. In this paper, the new backing-less welding method is examined, which can be welded in overhead position with high-efficiency. Then, its workability and performance is investigated, compare with usual backing-process. At the result, the new backing-less process achieves both workability and improvement of fatigue strength by applying exclusive flux-cored wire. Source


Suzuki R.,Kobe Steel | Suga T.,Osaka University | Kasai R.,Shinko Welding Service Co. | Nakagomi T.,Shinshu University
Welding International | Year: 2016

Improvement of deformation capacity for a column-to-beam joint is an important theme for improving the earthquake-resistance performance of building structures. One of the causes of decreasing deformation capacity is the existence of stress concentration against the beam flange by the scallop (access hole). The non-scallop method is generally recommended to improve this problem, but it has a large disadvantage in that it is not able to apply to the on-site joint process. The reinforce welding method around the scallop bottom has been developed to be able to apply to an on-site joint and obtain better performance than the non-scallop method. The improved mechanism is a combination of: (1) decreasing the stress concentration; (2) increasing effective thickness; and (3) increasing total length of the breaking line. The deformation capacity by the reinforce welding method around the scallop bottom is a maximum 3.2 times that for the conventional scallop method in the reverse repeating bend test using an actual structure with a beam flange of 19 mm thickness and 490 N mm−2 class steel. This improving effect is better than the non-scallop method. © 2016 Informa UK Limited, trading as Taylor & Francis Group Source


Suga T.,Osaka University | Murai Y.,Shinko Welding Service Co. | Kobashi T.,Shinko Welding Service Co. | Ueno K.,Tosei Electrobeam Co. | And 3 more authors.
Welding International | Year: 2016

In many industries, there are applications that require the joining of stainless steel and copper components; therefore, the welding of dissimilar stainless steel/copper joints is a common process. For this investigation, the optimal brazing conditions and suitable filler metals for laser brazing of stainless steel/copper lap joints were studied. Tensile shear force increases with increases in the laser spot diameter or in the laser irradiation angle, which is associated with increased bonding width; however, as bonding width approaches 2 mm, tensile shear force reaches a saturated value due to fracturing at the HAZ of the Cu base plate. In order to obtain joints with high tensile shear strength, laser brazing was optimized by using Cu–Si-based filler metal under the following conditions: laser power, 4 kW; spot diameter, 3 mm; laser irradiation angle, 80°; irradiation position shift, 0.6 mm; brazing speed, 0.30 m/min; and filler metal feed speed, 0.30 min. Concerning filler metals, it was found that the Ni–Cu type showed relatively large tensile shear force even at high welding speeds in comparison with those of the Cu–Si, Cu, Cu–Ni, Ni–Cu and Ni types, respectively. © 2016, © 2015 Taylor & Francis. Source

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