著者

蓮井 淳 衣川 純一 菅 泰雄

出版者

一般社団法人 溶接学会

雑誌

溶接学会誌 (ISSN:00214787)

巻号頁・発行日

vol.42, no.1, pp.18-28, 1973-01-25 (Released:2011-08-05)

参考文献数

1

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A new underwater plasma welding process has been developed. In this process, viscous liquid is used in place of shielding gas to protect the part being welded from the surrounding water and to stabilize plasma arc.Welding experiments are done by using steel for welded structure of 6 mm in thickness and it is ascertained that this process can be put to practical use.Main results are summarized as follows:(1) Water glass is used as a typical viscous liquid.(2) Water glass shielding for the part being welded has a marked effect on stabilization of underwater plasma arc.(3) Water glass shielding has an effect on heat insulating of the part being welded and lowers the solidification rate of molten metal. Owing to this feature, the weld metal does not include a blowhole and the maximum hardness of the heat-affected zone adjacent to the bond is lowered considerably.(4) The weld resulting from this process has excellent mechanical properties, and especially its ductility and notch toughness can be improved remarkably, compared with those of the weld resulting from nonshielding.(5) Coefficient of viscosity and flow (feeding) rate of shielding water glass should be selected properly. However, the proper range of combinations of viscosity and flow rate may be relatively wide.

著者

蓮井 淳

出版者

公益社団法人 応用物理学会

雑誌

応用物理 (ISSN:03698009)

巻号頁・発行日

vol.25, no.3, pp.108-110, 1956-03-10 (Released:2009-02-09)

参考文献数

5

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Report is made on the propagation of fractures in mild steel plates caused by impact of high speed bullets with observations on twinning of ferrite grains and distortion of twin lines. (1) On the propagation of fracture For as-rolled plates, resistance to fracture is larger in the direction of the rolling than in the direction perpendicular to it. This difference is lost by annealing. In annealed plates, the crack is apt to take its path along pearlite grains. In as-rolled plates, crack with bifurcation is observed. (2) On the deformation after twinning Micro-photographs show that the twinning is completed at the moment of impact followed by intense distortion of twin lines with the flow of ferrite grains. From this fact, it is denied that the twinning would proceed simultaneously with the brittle-type fracture.