• 자원리싸이클링
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• 제20권6호
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• pp.37-42
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• 2011

구리관의 절단 공정에서 구리 칩 스크랩이 발생해왔다. 분쇄에 의하여 구리칩 스크랩을 분말화하는 가능성이 연구되었다. 본 연구에서는 로드 밀링, 수평식 볼밀링과 같은 두 가지 타입의 분쇄 방식이 적용되었다. 구리 칩은 로드 밀링에 의하여 분말 형태로 분쇄될 수 없었다. 반면에 36시간 이상 수평식 볼밀링에 의하여 구리칩은 분말로 변화하였다. 수평식 볼밀링에 의한 구리 칩의 분말로 재활용이 가능하였고 48시간 동안 밀링된 원료중 $75{\sim}150{\mu}m$ 범위의 분말은 25.3%이였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.191-196
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• 2007

This paper presents the measuring technique for local heat transfer coefficients using a copper sensor in a rod bundle with mixing vanes. A copper sensor consists of a cartridge heater and four pieces of thermocouple. The Heater is located at the center of the copper sensor and thermocouples measure the surface temperature of the copper sensor. Unheated copper sensor and heated copper sensor are able to measure the local heat transfer coefficient at the position where the heated copper sensor is installed. However the entire region of a rod bundle is actually not heated, the decay of local heat transfer coefficients measured represents overestimated value rather than an actual value. The calibration curve for local heat transfer coefficients is presented using the correction factor calculated by CFD.

• 소성∙가공
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• 제4권2호
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• pp.123-130
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• 1995

The present study is concerned with the hydrostatic extrusion process for the copper-clad aluminum rod through metallurgical joining. The rigid viscoplastic finite element analyses are performed for the steady state extrusion process of the bimetal rod. An algorithm for finding the interface profile of the bimetal rod by tracking a particle path in Eulerian domain is presented. The distributions of the effective strain rate, equivalent stress and hardness are examined for the several extrusion ratios. Experiments are also carried out for the copper-clad aluminum rod at room temperature. It is found out that the finite element predictions are generally in good agreement with the experimental observations. The detail comparisons of the extrusion loads predicted by the element method with those by experiments are given.

• 한국주조공학회지
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• 제29권5호
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• pp.198-203
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• 2009

In order to manufacture copper ultra fine wire used for bonding wire in integrated circuit package, continuous casting process, which can produce high purity copper rod with small cross section, and wiredrawing process have to be optimized to prevent wire brakeage during entire manufacturing process of fine wire. The optimum condition for producing copper rod with mirror surface has to established by investigation of the effects of several parameters such as withdrawal speed, superheat and rod diameter on grain morphology of the cast rod and on its drawing characteristics to fine wire. The purpose of this study is to propose the optimized process parameters in continuous casting process in order to produce cast rod without internal defects, and to predict microstructure orientation suitable for wire drawing process.

• 해양환경안전학회지
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• 제5권2호
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• pp.27-33
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• 1999

The present study is concerned with the hydrostatic extrusion process of copper-clad aluminum rod through metallurgical joining. In this study, the rigid plastic finite element program, HICKORY, is used to analyze the steady state extrusion process of the bimetal rod. Simulations are performed for copper-clad aluminum rod with several extrusion ratio to give the distributions of effective strain rate, equivalent stress and hardness. Experiments are also carried out for aluminum-inserted copper rod at room temperature. It is found out that finite element predictions are generally in good agreement with the experimental observations. The detail comparison of the extrusion loads by the finite element method with those by experiments are given.

• 한국전기전자재료학회논문지
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• 제26권6호
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• pp.472-477
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• 2013

This paper carried out the comparative analysis on ground impedance of a carbon block and a copper rod. Two types of grounding electrode were compared ; a carbon block (L : 1 m, ${\Phi}$ : 245 mm) buried at a depth of 0.8 m and a three-linked copper rod (L : 1 m, ${\Phi}$ : 10 mm) of equilateral triangles with 1 m spacing. Ground impedance depending on applied current source was evaluated by the application of a sine wave current with 60 Hz ~ 3.5 MHz, a fast-rise pulse with rising time of 200 ns, a standard lightning impulse of $8/20{\mu}s$ and a 600 Hz square wave. Ground impedance for both electrodes were almost the same value below 100 kHz, and increased rapidly afterwards. The maximum ground impedance appeared $400{\Omega}$ at around 1.5 MHz. Ground impedance of the carbon block was lower at the square wave and was higher at fast-rise pulse than that of the copper rod. Also, ground impedance as ages showed no difference for the last 8 months. From the results, it is likely that ground performance for both electrodes shows no difference against commercial frequency and lightning impulse current, while the copper rod shows better performance against a fast-rise pulse with rise-time of a few hundred ns.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.167-168
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• 2006

A hyrdrothermal synthesis has been developd to prepare rod-like crystals of copper oxide using copper nitrate trihydrate as a function of synthesis temperature, stirring speed and solution pH value. The properties of the fabricated crystals were studied using scanning electron microscopy, X-ray diffraction and particle size analysis. The morphology of the synthesized CuO was dependent on both the pH value of the solution and the morphology of the seed materials. Synthesized particles have regular morphologies and a uniform size distribution.

• 대한기계학회논문집
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• 제19권4호
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• pp.1041-1050
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• 1995

The deformed shape of rod specimen of copper alloys was measured after the high-velocity impact against a rigid anvil and analyzed with one-dimensional theory to determine dynamic yield stress and strain-rate sensitivity which is defined as the ratio of dynamic yield stress to static flow stress. The evvect of two-dimensional deformation on the determination of dynamic yield stress by the one-dimensional theory, was investigated through comparison with the analysis by hydrocode. It showed that the one-dimensional theory is relatively consistent with two-dimensional hydrocode in spite of its simplicity in analysis.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 압출 및 인발 심포지엄
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• pp.9-19
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• 1999

A clad material is a different type of the typical composites which is composed of two or more materials joined at their interface surface. The advantage of clad material is that the combination of different materials can satisfy both the need of good mechanical properties and the other demand of user such as electrical properties instantaneouly. This paper is concerned with the direct and indirect extrusion process of copper-clad aluminum rod. Extrusion of copper-clad aluminum rod was simulated using a commercially available finite element package of DEFORM. The simulations were performed for copper-clad aluminum rod to predict the distributions of temperature, effective stress, effective strain rate and moan stress for some sheath thicknesses, die exit diameters and die temperatures.

• 조명전기설비학회논문지
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• 제14권1호
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• pp.118-123
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• 2000

본 논문에서는 상용주파 고장전류 및 뇌격전류를 모두 효과적으로 대지로 방류할 수 있는 새로운 형태의 접지 봉인 아크유도형 침부 접지봉을 고안하여 특성올 연구, 분석하였다. 아크유도형 침부 접지봉의 구조는 일반 접지 용의 표면에 침을 부착한 후 동파이프에 넣었다. 이 고안된 접지봉이 배전선로의 피뢰기 접지봉에 사용될 경우의 특성올 검토한 결과, 침과 동파이프 사이에서 아크가 발생하여 전기에너지를 효과적으로 소모함으로써 피뢰기 1차측 전압이 감소됨을 확인하였다.