• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
• /
• pp.96-97
• /
• 2014

The purpose of this study is to analyze the adhesion strength of metal spray coating system in steel using high-frequency arc metal spray method. For the purpose the experimental factor such as surface roughness was selected at 3 levels. As a result of experiment, it appeared that high-frequency arc metal spray method had higher adhesion strength than existing metal spray method. Especially, Al-Mg showed the highest adhesion strength than other metals. In case of surface roughness, the higher roughness steel has, the higher adhesion strength appeared.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2016년도 추계 학술논문 발표대회
• /
• pp.50-51
• /
• 2016

Ozone is a strong oxidizing materials in the advanced water treatment facilities. However, due to such a strong oxidation, Ozone eroded waterproofing/corrosion on the concrete surface and caused performance degradation. Therefore, in this study, permeability experiment of metal spraying system by concrete surface treatment was conducted.

• 한국건축시공학회지
• /
• 제14권6호
• /
• pp.505-513
• /
• 2014

본 연구에서는 전기화학적인 시험 및 CASS Test(염수분무시험)을 실시하여 중방식도장 시험체와 용융아연도금 시험체, Zn-Al 시험체와의 비교를 통해 Zn-Sn 금속용사의 방식 성능을 평가하였다. 시험 결과, 전기화학 시험을 통하여 Zn-Sn / Zn-Al 상온금속용사 시스템 공법의 방식원리는 방식전위에 의하여 확보되는 것을 확인하였으며 강구조물의 방식 공법으로서 상온금속용사 공법은 용융아연도금 공법과 중방식 도장공법과 비교하여 매우 우수한 방식성능을 가지고 있는 것이 CASS 시험을 통하여 검증되었다. 특히 Zn-Sn 금속용사와 Zn-Al 금속용사를 비교해본 결과 그 방식성이 현저하게 차이가 있지는 않았으나 Zn-Sn(65:35) 비율의 시험체가 가장 우수하였다. 또한 중방식 도장은 손상된 부분에서 현저하게 녹이 발생하고 도막이 박리되지만, Zn-Sn / Zn-Al 상온금속용사 시스템 공법은 갈바닉 희생방식에 의하여 매우 높은 부식 방지 특성을 가지고 있음을 확인 하였다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2015년도 추계 학술논문 발표대회
• /
• pp.34-35
• /
• 2015

Recently, introduction of Advanced water treatment facilities has been increasing due to serious domestic water pollution. Ozone is a strong oxidizing materials in the advanced water treatment facilities. However, due to such a strong oxidation, Ozone eroded waterproofing/corrosion on the concrete surface and caused performance degradation. Therefore, in this study, permeability experiment of metal spraying system by concrete surface treatment was conducted.

• 동력기계공학회지
• /
• 제10권2호
• /
• pp.93-98
• /
• 2006

Metal matrix composites(MMCs) reinforced with ceramic particulates are receiving increasing attention because their high specific strength, low coefficient of thermal expansion and excellent wear resistance. Especially, Al-based composites(AMCs) have been widely applied for the aerospace and automotive industries. Such composites are mainly fabricated by the cast, powder metallurgy and infiltration process. In this study, SiC particulate reinforced Al-based composites were fabricated by thermal spray process and their wear behavior were investigated. Composites with different spray parameter were fabricated by using flame spray apparatus. Microstructure and wear behavior of the composites were observed by scanning electron microscope(SEM) and electron probe micro-analysis(EPMA).

• 한국분무공학회지
• /
• 제17권3호
• /
• pp.128-133
• /
• 2012

The present study aims to examine the influence of flame spray distance on the thermal behavior of micro-metal particles and the morphological characteristics of $Ni_{20}Cr$ layers coated on the preheated SCM415 substrates by using the conventional flame spray system. Commercially available nickel-based $Ni_{20}Cr$ particles with a mean diameter of $45{\mu}m$ were used. In addition, CFD simulations using a commercial code (FLUENT ver. 6.3.26) were conducted to estimate temperature and velocity distributions of the continuous and discrete phases before impact on the substrate. From FE-SEM images of coated layers on the substrates, it was observed that as the spray distance decreased, the metal particle morphology showed splash-like patterns and such a short stretch shape, resulting from higher particle momentums and the impact of partially melted particles. Moreover, it was found that the spray distance should be considered as one of important parameters in controlling the porosity and the adhesion strength.

• 한국분무공학회지
• /
• 제14권2호
• /
• pp.71-76
• /
• 2009

The aim of this investigation is to study the effect of the high injection pressure on the dimethyl ether (DME) spray characteristics injected through a common-rail diesel injector under various ambient pressures. In order to investigate the effect of the injection pressure and ambient condition, the common-rail injection system with two high pressure pumps and high pressure chamber pressurized up to 40 bar were used, respectively. Spray images of DME fuel obtained from a visualization system composed of high speed camera and two metal halide lamps as the light source. From the obtained images, the spray behaviors such as a spray development process, spray tip penetration, spray width, and spray cone angle were measured for analyzing the DME spray characteristics under various experimental conditions. It was found that the spray development slowed as the ambient pressure increased and spray tip penetration at injection pressure of 90 MPa is longer than that at 50 MPa. In addition, the spray width at the end stage of injection decreased under the atmospheric conditions due to the evaporation property of DME fuel, and DME spray shows narrow spray cone angle according to the injection pressure increased.

• 한국분무공학회지
• /
• 제14권3호
• /
• pp.109-116
• /
• 2009

The purpose of this study is the experimental and numerical investigation on the DME spray characteristics in the combustion chamber according to the injection timing in a common-rail injection system. The visualization system consisted of the high speed camera with metal halide lamp was used for analyzing the spray characteristics such as spray development processes and the spray tip penetration in the free and in-cylinder spray under various ambient pressure. In order to observe the spray characteristics as a function of injection timing, the piston head shape of re-entrant type was created and the fuel injected into the chamber according to various distance between nozzle tip and piston wall in consideration of injection timing. Also, the spray and evaporation characteristics in the cylinder was calculated by using KlVA-3V code for simulating spray development process and spray tip penetration under real engine conditions. It was revealed that the high ambient pressure of 3 MPa was led to delay the spray development and evaporation of DME spray. In addition, injected sprays after BTDC 20 degrees entered the bowl region and the spray at the BTDC 30 degrees was divided into two regions. In the calculated results, the liquefied spray tip penetration and fuel evaporation were shorter and more increased as the injection timing was retarded, respectively.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
• /
• pp.1225-1228
• /
• 2001

The purpose of this study is to develop for finishing method of concrete structures applying metal spraying system. In the experiments, the pull out tests were conducted using the specimen which was applied by various surface treatment of concrete substrate. As a result, it was confirmed that the adhesion strength of metal spray was effected by surface condition of concrete and the construction of primer or the coarse surface agent to the concrete substrate is very effective to the new finishing method of concrete for the metal spraying system.

• Journal of Welding and Joining
• /
• 제13권2호
• /
• pp.115-121
• /
• 1995

As the metal transfer in the GMAW process affects the weld quality and productivity, the mechanism of molten formation and detachment has been investigated at various welding conditions. The force balance and pinch instability models have been widely used to analyze the metal transfer in the globular and spray modes, respectively A new approach is proposed in this work by minimizing the energy of molten drop system. Effects of the surface tension, gravity, electromagnetic and drag forces are considered with no presumed molten drop geometry. Effects of various welding conditions on the metal transfer are explained. The results show that the proposed mode can be applied to the globular and spray transfer modes. When compared with other models, results of the proposed model show better agreements with the available experimental data, which demonstrates the validity of the present model.