| Project/Area Number |
60550521
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
溶接工学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
ISHIDA Tsuneo The Research Institute for Iron,Steel and Other Metals, TOHOKU UNIVERSITY., 金属材料研究所, 助手 (70005916)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1986: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1985: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Dissimilar metal welding / Plasma arc / Butt fusion welding / Pulsed arc welding / Convection swirl / <delta> -ferrite / Ripple shape / 組成的過冷 |
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| Research Abstract |
Interfacial phenomena of butt fusion welding and filler metal deposit by plasma arc and morphology of bead formation by pulsed TIG arc have been investigated for dissimilar metal system. The intermetallic layers formed at the interface by plasma arc fusion welding of mild steel and aluminium are <eta> -phase and <theta> -phase, and the use of copper filler metal in order to retard the intermetallic layer formation produces unmixed region due to occurrence of the convection at the under bead. The weldment of mild steel and copper has a segregation and becomes an unmixed zone on account of the occurrence of convection in the fusion zone and convection swirls at the fusion boundary region. The weld of mild steel to stainless steel becomes complete mixed zone in fusion region, however, the formations of <alpha> -ferrite band and fine <delta> -ferrite occur at the mild steel and the stainless steel sides,respectively. In plasma arc deposit fusion boundary, Ni infiltration and diffusion into base metal due to grain boundary wetting occur with C and Si addition in iron base metal when Ni,Ni-Fe,Fe is deposited on Fe,Fe-C and Fe-C-Si base metals. Tongue-like structure in the neighbourhood of the fusion line is observed when Ni is deposited on Co, while fine columnar substructure in fusion boundary region can be detected in Ni-Fe deposit on Co. Bead surface of mild steel under pulsed TIG arc indicates ripple shape. The ripple population increases parabolically with increasing pulse frequency and decreases with increasing transfer speed of torch. Bead width of mild steel is decreased with increased frequency and transfer speed. Bead penetration decreases with increasing frequency and the magnitude of the decrease is great in the middle frequency region(47.5-500Hz). Intermetallic compounds at the interface produced by the pulsed TIG arc welding of mild steel and aluminium are predominantly <zeta> -phase and <eta> -phase.
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