| Project/Area Number |
58420023
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
機械工作
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| Research Institution | Yokohama National University |
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Principal Investigator |
KUDO Hideaki 横浜国立大学, 工, 教授 (90017848)
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| Project Period (FY) |
1983 – 1985
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| Project Status |
Completed (Fiscal Year 1985)
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| Budget Amount *help |
¥25,000,000 (Direct Cost: ¥25,000,000)
Fiscal Year 1985: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1984: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1983: ¥22,400,000 (Direct Cost: ¥22,400,000)
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| Keywords | aluminium / plasticine / cold pressure welding / upsetting / sideways extrusion / forward extrusion / multi-ram material testing machine / ワイヤブラシ層 |
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| Research Abstract |
1) A material testing machine with four crosswise arranged hydraulic actuators of a <+]-> 16 tonf capacity was designed and installed. By the use of a microcomputer , easy operation and control of the machine, visual watch and precise measurement of current punch loads and strokes were made feasible.
2) To carry out experiments in cold autogenous welding by upsetting of aluminium specimens under superimposed hydrostatic pressure, a special upsetting tooling and a test equipment for pressure transmission medium were deviced. Techniques to attain expansions of joining interface up to 10 and to conduct tensile tests of welded specimens of a minimum length of 6 mm were also elaborated. The best bonding was achieved when a hydrostatic pressure of 30 kgf. <mm^(-2)> was imposed on the side surfaces only at the final stage of upsetting, while superposition of the pressure throughout or in the early period of the process deteriorated bonding. Microscopic examination of longitudinal sections of the specimens indicated that the high pressure increased ductility of the wire-brushed surface layers thus reducing the area of virgin metal surface, while it raised the bond strength at the virgin metal interface. The observed joint strengths were thus attributable to the conflicting effect of pressure.
3) For an experimental investigation of abnormal deformation and material failure in bimetallic welding due to the difference in flow stress, model materials based on plasticine were developed. A two-ram compression tester driven by pulse-motors and transparent toolings for sideways and forward extrusion experiments were also deviced. The experiments revealed that the harder material failed when the flow stress difference was large and the thickness of harder layer was small. A narrower width of the harder billet in the sideways extrusion and a higher reduction in area in the forward extrusion promoted failure.
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