• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.101-103
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• 2005

전기강판으로 제작되어진 전기기기의 보다 정확한 수치적인 해석을 위해서는 회전자계(Rotating magnetic flux)에 따른 전기강판의 정화한 자계특성 측정이 필요하다. 이 논문에서는 개발되어진 2방향 자계인가 형 Single sheet tester를 이용하여 회전자계에 따른 전기강판의 자계특성을 측정하였다. 실험을 통하여 등방성 시료와 방향성 시료에 대하여 각각 1.6[T] 와 1.2[T]까지 측정할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.819-821
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• 2001

This paper describes a characteristics of MFL according to the position of Hall sensor Magnetic Flux Leakage(MFL) Method is used to detect surface defect in ferromagnetic plate. A plate has a surface defect and magnetizing equipment are producted to perform Non-Destructive Testing(NDT) using MFL. The SM 45C carbon steel plate is adopted to this experiment. there is a artifical defect with a twice of thickness and a half of depth of plate. Magnetizing equipment is composed of yoke made by layer-built of silicon sheet steel, NdFeB magnetic and iron brushes. Detecting defect is performed by MFL NDT using Hall sensor. It is shown that magnetic flux detected by Hall sensor is affected according to the position of Hall sensor through MFL experiment and numerical analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.852-853
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• 2011

통상적으로 전기기기에 사용되는 전기강판의 자기특성은 B-H 자기특성 곡선을 이용하여 표현되어졌고, 이를 이용하여 전기기기의 자계 분포 해석 및 특성 해석이 이루어져 왔다. 그러나 실제로 전기기기의 전기강판은 인가 자계의 방향에 따라 자기특성이 다르게 나타나고, 자속밀도와 자계세기의 방향이 다르게 나타나는 벡터 자기특성을 가지기 때문에, B-H 곡선과 같은 스칼라 자기 특성으로 전기강판의 자기 특성을 정확히 표현하는 것이 불가능하다. 따라서 전기기기의 정확한 자계 해석 및 특성 해석을 위해서는 전기강판의 벡터 자기특성이 반드시 고려되어야 한다. 본 논문에서는 전기강판의 벡터 자기특성이 전기기기의 자계 분포 해석에 미치는 영향을 알아보고자 하며, 전기강판의 벡터 자기특성의 고려를 위해 ($B_m,\theta_B$)법을 이용하였으며 간단한 형태의 단상 변압기 모델에 유한요소 해석을 적용하였다.

• 한국전자통신학회논문지
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• 제16권3호
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• pp.471-476
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• 2021

분말 야금 기술에 의한 복합 연자성 재료는 전기기기에 일반적으로 사용되는 종래의 전기강판보다 많은 장점을 가지고 있으며, 그 관련 기술은 최근에 상당한 발전을 거듭하고 있다. 복합 연자성 재료는 일반적으로 분말의 형태로 인해 자기적 등방성 가지므로 3차원 자속 및 복잡한 구조의 전기기기 구성에 적합하다. 하지만 SMC와 같이 등방성 자기 특성을 가지는 재료는 복잡한 벡터 히스테리시스를 가지므로 정확한 손실 특성을 예측하는 것이 매우 어렵다. 따라서 본 논문에서는 전기강판 및 SMC의 링 타입 시편을 제작하고 시편 크기에 따라 자기적 특성을 측정한 후, 측정된 자기적 정보를 이용하여 800Hz 이상에서 구동하는 고속 영구자석 전동기의 전자계 해석을 수행하였다. 또한, 해당 모델의 시작품을 제작하고 효율 측정 및 비교를 통해 본 논문의 신뢰성을 입증하였다.

• 소성∙가공
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• 제24권4호
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• pp.256-263
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• 2015

Electric resistance spot welding has been used to join overlapped steel sheets in automotive bodies. Recently to reduce weight in automotive vehicles, non-ferrous metals are being used or considered in car bodies for hoods, trunk lids, doors parts, etc. Various welding processes such as laser welding, self-piercing rivet, friction stir welding are being used. In the current study, a new electric resistance heated friction stir spot welding is suggested for the spot welding of non-ferrous metals. The welding method can be characterized by three uses of heat -- electric resistance heating, friction stir heating and conduction heating of steel electrodes -- for the fusion joining at the interfacial zone between the two sheets. The welding process has variables such as welding current, diameter of the steel electrodes, revolutions per minute (rpm) of the friction stir pin, and the insert depth of the stir pin. In order to obtain the optimal welding variables, which provide the best welding strength, many experiments were conducted. From the experiments, it was found that the welding strength could be reached to the required production value by using an electrode diameter of 10mm, a current of 7.6kA, a stirring speed of 400rpm, and an insert depth of 0.8mm for the electric resistance heated friction stir spot welding of 5052 aluminum 1.5mm sheets.

• 조명전기설비학회논문지
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• 제25권2호
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• pp.126-130
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• 2011

Transparent conductive oxide (TCO) is an important part in the construction of dye-sensitized solar cells (DSCs) because of its low sheet resistance, sufficient light transparent ability and high photoelectrical response as a porous photo-electrode material of DSCs. However, the use of TCO for the two DSC electrodes can result in significant cost increase for the less effective DSCs compared to Si based solar cell. Therefore, the replacement of TCO is required for the commercial production of DSCs. In this study, TCO electrodes are replaced by stainless steel mesh. The 3.44[%] efficiency of the prepared TCO-less DSCs sample was obtained.

• Journal of Magnetics
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• 제16권4호
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• pp.453-456
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• 2011

Demagnetization for a tube sample which was made of a galvanized steel sheet was performed by applying a magnetic field with a decrement to remove the remanent magnetization of the material. An orthogonal fluxgate magnetic field sensor was used to measure a magnetic field created from a ferromagnetic material. To evaluate the remanent magnetization, the measured magnetic fields were separated into two magnetic field components by the remnant magnetization and the induced one. The horizontal and the vertical bias fields should be controlled separately during demagnetization to remove the horizontal and the vertical components of the remanent magnetization of the tube sample.

• 한국표면공학회지
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• 제36권3호
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• pp.251-255
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• 2003

With increasing environmental demands in surface treatment of steel sheets, the passivation layers containing hexavalent chromium $(Cr^{+6})$ are being replaced by non-chromium or trivalent chromium compounds. After review on the various types of inorganic compounds, the zirconates was chosen as the candidate for alternative to sodium dichromate in the aspect of its barrier properties with excellent adhesion to organics. The ammonium zirconium carbonate (AZC) and sodium hexafluorozirconate (SFZ) could be reach $70-80\%$ level of CDC (cathodic dichromate) treatment by their single applications. But high porosity in the AZC layer and poor electrical conductivity of SFZ solution limit the single application of zirconate. Mixed composition of zirconates to compensate their inferiorities or incorporation of organic compounds to seal the porosity seems to be inevitable to match up the target level of Cr-free passivation of tinplate.

• Design & Manufacturing
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• 제12권3호
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• pp.25-30
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• 2018

Recently The automotive industry is trying to increase the energy efficiency by reducing the weight of the car body and engine components as a way to achieve high energy efficiency. In particular, the reduction of the weight of the vehicle through the weight reduction of the vehicle body has the advantage that the fuel consumption and the output can be improved. But at the same time, there is the disadvantage that the strength becomes weak due to the reduction of the material thickness. Therefore, in order to overcome these disadvantages, materials with high strength according to the unit thickness have been actively developed, and researches for applying them have also been increasing. In this study, we will investigate the application of cold rolled steel sheet, which is a lightweight material, to a horn bracket that secures a installed in an automobile engine room. The horn bracket secures the horn on the car engine and is bolted to the outer wall of the engine. The momentum is acted on the bracket due to the distance between the bolt fastening part and the car horn installed on the bracket end side. Therefore, the body part of the bracket is more likely to be destroyed by the influence of the continuous stress. In this paper, design optimization for weight reduction and strength enhancement was performed to solve this problem, and possibility of applying the rolled steel sheet material as lightweight material by tensile test and fabrication was confirmed.

• 마이크로전자및패키징학회지
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• 제24권1호
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• pp.1-8
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• 2017

Fe-9.8Si-6.0Al mother alloy was manufactured using by Fe-3.5Si recycled scrap and Si powder. And then, soft magnetic alloy powder of $D_{50}$ size and sphere type were prepared by gas atomization process. To obtain the soft magnetic powder of a high aspect ratio, in the first, we conducted the ball milling process for 8 hours. And heat treatment was performed under $650^{\circ}C$, 2 hours and $N_2$ atmosphere condition for reducing the residual stress of the powder. Based on these process, we made around $50{\mu}m$ diameter Fe-9.8Si-6.0Al powder, which morphology and shape was a similar to the commercial Fe-Si-Al powder. Finally, the soft magnetic sheets were prepared by tape casting process using by those powders. The permeability of the tape casting sheet was measured, and we confirmed the possibility of reusing to the soft magnetic materials of Fe-Si electric sheet scrap.