• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
• /
• pp.1138-1139
• /
• 2006

The present study has shown that the effect of boron and phosphorus in Ni-Cr-Si-X alloy to interfacial reactions and bonding strength of diamond-steel substrate, and the influence of various construction parameters on the formation of the topography of the tool. And these factors are required to making a good brazed tool. The microstructures and phase change of the brazed region were analyzed into SEM, EDS. According to the electron probe microanalysis, while brazing, the chromium present in the brazing alloy segregated preferentially to the surface of the diamond to form a chromium rich reaction product, which was readily wetted by the alloy.

• 한국안광학회지
• /
• 제12권4호
• /
• pp.15-18
• /
• 2007

티타늄과 그 합금은 경량성, 우수한 기계적 성질 및 내식성 때문에 주요한 안경테 소재로 사용되고 있다. 본 연구에서는 안경테 소재로 사용되고 있는 순 티타늄(P-Ti)과 ${\beta}$-티타늄(${\beta}$-Ti)에 대하여 전기저항땜질 장치를 이용하여 접합조건의 변화에 따른 접합부의 특성 변화에 대하여 조사하였다. P-Ti 및 ${\beta}$-Ti 모두 접합부 근처에서 경도값의 감소가 나타났으며, 이는 전기저항열에 따른 결정립의 조대화 때문이다. 결정립 조대화에 의한 경도의 저하량 및 저하된 부분의 크기는 ${\beta}$-Ti 보다 P-Ti에서 크게 나타났다.

• Journal of Mechanical Science and Technology
• /
• 제16권9호
• /
• pp.1078-1083
• /
• 2002

Ceramics are significantly used in many industrial applications due to their excellent mechanical and thermal properties such as high temperature strength, low density, high hardness, low thermal expansion, and good corrosion resistive properties, while their disadvantages are brittleness, poor formability and high manufacturing cost. To combine advantages of ceramics with those of metals, they are often used together as one composite component, which necessiates reliable joining methods between metal and ceramic. Direct brazing using an active filler metal has been found to be a reliable and simple technique, producing strong and reliable joints. In this study, the fracture characteristics of Si$_3$N$_4$ ceramic joined to ANSI 304L stainless steel with a Ti-Ag-Cu filler and a Cu (0.25-0.3 mm) interlayer are investigated as a function of strain rate and temperature. In order to evaluate a local strain a couple of strain gages are pasted at the ceramic and metal sides near joint interface. As a result the 4-point bending strength and the deflection of interlayer increased at room temperature with increasing strain rate. However bending strength decreased with temperature while deflection of interlayer was almost same. The fracture shapes were classified into three groups ; cracks grow into the metal-brazing filler line, the ceramic-brazing filler line or the ceramic inside.

• 열처리공학회지
• /
• 제23권1호
• /
• pp.3-9
• /
• 2010

Titanium and its alloys were brazed in the range of $850-950^{\circ}C$ within 10 min. of brazing time using expensive infra red or other heating methods. However, brazing time needs to be extended to get temperature-uniformity for mass production by using continuous belt type furnace or high vacuum furnace with low heating rate. This study examined effects of holding temperature for 60 min, on microstructure and mechanical properties of titanium alloys. Mechanical properties of titanium alloys were drastically deteriorated with increasing holding temperature followed by grain growth. Maximum holding temperatures for CP (commercial pure) titanium and Ti-6Al-4V were confirmed as $800^{\circ}C$ and $850^{\circ}C$, respectively. Both titanium alloys were successfully brazed at $800^{\circ}C$ for 60 min. with the level of base metal strengths by using Zr based filler metal, $Zr_{54}Ti_{22}Ni_{16}Cu_8$.

• Journal of Welding and Joining
• /
• 제31권4호
• /
• pp.7-12
• /
• 2013

The dissimilar welding between magnesium alloy and steel sheet was required in automobile industry to increase the strength of the dissimilar joints. Laser brazing is one of the good joining processes for Mgsteel dissimilar joint. In this study, the effect of coating materials was evaluated on the laser brazing for the dissimilar joint between AZ31 and coated steels such as Zn, Sn and Ni. Diode direct laser was used to braze the lap-edge joint with Mg600 filler wire and Superior #21 flux. The wettability was best on Zn coated steel. The interlayer was formed at the interface between brazement and steel for all coating materials. The strengths of brazed specimen were 146.5N/mm, 204.6N/mm and 101.6N/mm for Zn, Sn and Ni coated steel respectively.

• 한국안광학회지
• /
• 제8권1호
• /
• pp.47-52
• /
• 2003

티타늄 안경테의 땜질을 위하여 땜납의 종류에 따른 접함을 행하고 접합부의 성분분석 실험을 통하여 납재가 접합부 성능에 미치는 영향을 조사하였다. 최적의 조건을 알아보기 위하여 X-ray micro-analysis (XMA)법으로 접합부 성분 분석과 가열방법에 따른 땜질 강도 변화를 분석하였다.

• 한국레이저가공학회지
• /
• 제17권1호
• /
• pp.7-12
• /
• 2014

The dissimilar welding between magnesium alloy and steel sheet was required in automobile industry to increase the strength of the dissimilar joints. Laser brazing is one of the good joining processes for Mg- steel dissimilar joint. In this study, AZ31 magnesium alloy and Zn coated steel dissimilar joint was brazed using diode direct laser with Mg600 filler wire and Superior #21 flux. The wetting of Mg filler wire on Zn coating was very good because of the formation of eutectic phase with low melting temperature. The strength of the brazed joint between AZ31 magnesium alloy and Zn coated steel was 131.3N/mm. The fracture occurred at brazement.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
• /
• pp.1130-1131
• /
• 2006

We found that the """interface reaction between Ni-based alloy bond, diamond, and steel core is very critical in bond strength of diamond tool. None element from metal bond diffuses into the steel core but the Fe element of steel core was easily diffused into the bond. This diffusion depth of Fe has a great effect on the bonding strength. The Cr in steel core accelerated the Fe diffusion and improved the bond strength, on the other hand, carbon decreased the strength. Ni-based alloy bond including Cr was chemically bonded with diamond by forming Cr carbide. However, the Cr and Fe in STS304 were largely interdiffused, the strength was very low. The Cr passivity layer formed at surface of STS304 made worse strength at commissure in brazing process.

• 설비공학논문집
• /
• 제15권11호
• /
• pp.957-963
• /
• 2003

The present work was conducted to investigate the air-side thermal-hydraulic performance of the brazing fin-tube heat exchanger. Pressure drop and heat transfer coefficient for a plain and a louvered fin configuration were compared numerically and experimentally. It was found that the heat transfer characteristics for the plain fin were similar to the developing flow in the rectangular channel. The louver fin showed about twice better heat transfer coefficient than the plain fin. Previous empirical correlations presented by Davenport, Sunden and Svantesson, Sahnoun and Webb, Chang and Wang, Achaichia and Cowell, and Kang were compared with the present experimental data.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 1999년도 특별강연 및 추계학술발표대회 개요집
• /
• pp.259-262
• /
• 1999