• 한국기계가공학회지
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• 제21권2호
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• pp.109-115
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• 2022

The demand for metal 3D printing technology is increasing in various industries. The materials commonly used for metal 3D printing include aluminum alloys, titanium alloys, and stainless steel. In particular, for applications in the aviation and defense industry, aluminum alloy 3D printing parts are being produced. To improve the corrosion resistance in the 3D printed aluminum alloy outputs, a post-treatment process, such as chromate coating, should be applied. However, powdered materials, such as AlSi7Mg and AlSi10Mg, used for 3D printing, have a high silicon content; therefore, a suitable pretreatment is required for chromate coating. In the desmut step of the pretreatment process, the chromate coating can be formed only when a smut composed of silicon compounds or oxides is effectively removed. In this study, suitable desmut solutions for 3D printed AlSi7Mg and AlSi10Mg materials with high silicon contents were presented, and the chromate coating properties were studied accordingly. The smut removal effect was confirmed using an aqueous desmut solution composed of sulfuric, nitric, and hydrofluoric acids. Thus, a chromate coating was successfully formed. The surfaces of the aluminum alloys after desmut and chromate coating were analyzed using SEM and EDS.

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.211-215
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• 2006

This paper presents a new structure for the universal motor using soft magnetic composite (SMC). The stator for this new type of motor is made by combination of the SMC pole and the silicon steel yoke. The shape of the 3D SMC pole is designed to minimize ohmic loss and amount of stator coil. To design the pole shape, the 3D analysis in the design procedure is replaced with an equivalent 2D analysis. Finally, the optimal shape is analyzed by 3D FEM and the performance is discussed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2006년도 제30회 학술논문발표회 초록집
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• pp.125-125
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• 2006

• 한국세라믹학회지
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• 제51권5호
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• pp.516-521
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• 2014

This paper describes the development of a new piezoelectric unimorph cantilever structure intended to improve electrical output power, compared to a conventional cantilever. The proposed structure employs a cylindrical bar attached to one side of a steel plate, which is a significant factor in forced vibration mode. The feasibility of the proposed methodology was assessed experimentally and theoretically. The influence of three different types of bar material (i.e., stainless steel, silicon rubber, and urethane), and bar position, on the output voltage were examined and compared with those without the bar. The optimal position and material for the bar were identified through experimental and theoretical analyses. It appears that the electrical output power of the proposed cantilever is about 40% higher than that of a conventional unimorph cantilever.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 춘계학술대회 논문집
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• pp.208-211
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• 1995

This proper focuses on results of relative permeability(${\mu}$$\sub$r/), core loss(W) and magnetic induction [B] measurements on some of the most commonly used core materials(PN-18, 20, 30, 60, Pohang Iron '||'&'||' Steel Co., Ltd.) In case of Stress Relief Annealing(SRA). Results of magnetic induction[B] showed weak variations but core lass reduced strongly after SRA Core loss reduced from 3.071 ∼7.819(W/kg) and 11.377~3.988[W/kg] to 2.88~5.492[W/kg] and 1.213~2.134[W/kg] at 1.5[T] 50 Hz and 1.0 [T] 50Hz respectively after SRA. This SRA process leads to significant changes In magnetic properties and core loss of non-oriented silicon steel sheet.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.18-21
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• 2000

A nonconstact technique for reducing the core loss of a grain oriented silicon steel has been developed by the use of mechanical scribing Q-switched laser plasma jet or electron beam irradiation. Among these methods electron beam irradiation has advantages of domain refining without any deformation or damage of insulating film on the surface of a grain criented Si-Fe. Over the past years this processing was performed in vaccum of 10-4 Torr or below causing the problem of high cost and difficulty of continuous works. In this paper a miniature electron permeable window through which electron beam energy 4-80keV and average current 0.1-2mA. were obtained for electron beam irradiating on air was designed and manufactured.

• 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.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.171-174
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• 2008

We present results demonstrating that low power consumption phosphorescent AMOLED displays can be fabricated on ultra-thin ($25{\mu}m$) stainless steel substrates, combining an amorphous silicon backplane with a top emission phosphorescent OLED frontplane. We will present preliminary results of flexibility testing on these displays.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2006년도 춘계 학술대회 개요집
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• pp.121-123
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• 2006

The aim of present study is to investigate the effect of welding parameters and heat treatment conditions on the formability of the laser welded silicon steel sheet. It was found that there is optimum range of the heat input ($0.6{\sim}0.7kJ/cm$) and gap distance ($0.125{\sim}0.150mm$) for the high tensile strength and the avoidance of the fracture in weld metal, Also, it was essential for the improvement of formability to perform pre- and post-welding heat treatment which cause the uniform mixture of base metal and welding consumable.

• 한국주조공학회지
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• 제11권5호
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• pp.392-397
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• 1991

This study has been performed to investigate the austempering heat treatment response and mechanical properties of a high carbon(0.9%), silicon(1.5-4.5%)-alloyed cast steel, with a chemical composition similar to that of the matrix of a ductile cast iron. Tensile and hardness tests were used to evaluate the effects of a wide variety of austempering heat treatment variables. SEM metallography and X-ray measurements of stabilized austenite were also performed for all the specimens employed. The austempered microstructures which contain up to 39% stabilized austenite were obtained. Mechanical properties and microstructures depended primarily on the austempering time and temperature. The optimum mechanical properties were obtained at the chemical compositions of 0.9% C and 2.5% Si.