은계 필러메탈 브레이징 접합부의 특성 분석

이순길,이화인,손진오,하광일,구본흔,Soon-Gil Lee,Hwa-In Lee,Jin-Oh Son,Gwang-Il Ha,Bon-Heun Koo 한국재료학회 2023 한국재료학회지 Vol.33 No.5

As a filler metal for lowering the melting point of Ag, many alloy metal candidates have emerged, such as cadmium, with zinc, manganese, nickel, and titanium as active metals. However, since cadmium is known to be harmful to the human body, Cd-free filler metals are now mainly used. Still, no study has been conducted comparing the characteristics of joints prepared with and without cadmium. In addition, studies have yet to be conducted comparing the typical characteristics of brazing filler metals with special structures, and the joint characteristics of brazing filler metals with available frames. In this study, the characteristics of junctions of silver-based intercalation metals were compared based on the type of filler metal additives, using a special structure, a filler metal sandwich structure, to protect the internal base metal. The general filler metal was compared using the structure, and the thickness of the filler metal according to the thickness was reached. A comparison of the characteristics of the junction was conducted to identify the characteristics of an intersection of silver-based brazing filler metal and the effect on joint strength. Each filler metal's collective tensile strength was measured, and the relationship between joint characteristics and tensile joint strength was explored. The junction was estimated through micro strength measurement, contact angle measurement with the base metal when the filler metal was melted, XRD image observation, composition analysis for each phase through SEM-EDS, and microstructure phase acquisition.

구리-알루미늄 이종재료의 브레이징 특성 향상에 관한 연구

정호신(HO-SHIN JEONG),배동수(DONG SU BAE),고성우(SUNG WOO KO) 한국해양공학회 2001 韓國海洋工學會誌 Vol.15 No.3

One of the most important considerations to braze Cu-Al dissimilar materials is control of brittle metallic compound which makes it difficult to obtain a sound brazed joint. Nowdays, several attempts were made to control the metallic compound. But effective method for controlling metallic compound was not established. In this point of view, commercially pure aluminum and copper were used as base metal and Al-Si-X and Zn-Al-X alloy systems were developed as filler metal. Brazing was carried out to find optimum conditions for Cu-Al dissilmilar joint.<br/> The results obtained in this study were summarized as follows:<br/> 1) The joint brazed by Al-Si-X filler metal showed good brazeability and mechanical properties. The tensile strength of the joint brazed over solidus temperature was more than 90% of Al base metal. Especially, the joint brazed at liquidus temperature was fractured in the Al base metal.<br/> 2) Fluorides fluxes(a mixture of potassium fluoro-aluminates) were used to improve surface cleanliness of base metal and wettability of Al-Si-X filler metal. It was melted at the temperature about 10℃ lower than that of the filler metal, and made appropriate brazing environment. Therefore, it could be a proper selection as flux.

피스톤 크라운용 단강에 인코넬 718 용접재료로 용접된 용접부의 특성 평가

이성열(Sung-Yul Lee),문경만(Kyung-Man Moon),정재현(Jae-Hyun Jeong),이명훈(Myeong-Hoon Lee),백태실(Tae-Sil Baek) 한국해양공학회 2016 韓國海洋工學會誌 Vol.30 No.4

The combustion chamber of a diesel engine is often exposed to a more serious wear and corrosion environment than other parts of the engine because its temperature increases as a result of using heavy oil of low quality. Therefore, repair and built-up welding methods must be performed on worn or corroded parts of the piston crown, exhaust valve, etc. from an economical point of view. In this study, Inconel 718 filler metal was used in repair welding on the groove of a forged steel specimen for a piston crown, along with built-up welding on the surface of another forged steel specimen. Then, the corrosion characteristics of the weld metal zone for the repair welding and the deposited metal zone for the built-up welding were investigated using electrochemical methods in a 35% H2SO4 solution. The deposited metal zone indicated better corrosion resistance than the weld metal zone, showing a nobler corrosion potential, higher impedance, and smaller corrosion current density. It is considered that metal elements with good corrosion resistance were generally included in the filler metal, and these elements were also greatly involved in the deposited meta by built-up welding, whereas the weld metal consisted of metal elements mixed with both the filler metal and base metal elements because of the molten pool produced by the repair welding. Finally, it is considered that the hardness of the weld metal was increased by the repair welding, whereas the built-up welding improved the corrosion resistance of the deposited metal.

Ag계 Filler Metal을 사용한 YSZ와 STS430의 브레이징 접합시 Ti, Sn의 함량 변화가 접합강도에 미치는 영향

이기영,박현균,Lee, Ki Young,Park, Hyun Gyoon 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.1

In Ti active brazing of YSZ to STS 430 using Ag-Cu Filler Metal, the effect of Ti contents on the shear bonding strength were investigated together with the effect of brazing temperature and holding time. The addition of Ti in Ag-Cu Filler Metal increased the bonding strength up to 4.68% Ti, followed by the decrease with further addition. This seems to be caused by formation of TixOy at the reaction layer. Brazing temperature was optimized at $960^{\circ}C$ among a given temperature ranges. The addion of Sn to Ag-Cu filler metal brought the decrease of its melting temperature its melting temperature without a significant decrease of bonging strength.

Transient liquid phase diffusion bonding for micro PCD tool fabrication

Bawi Jeong,Jeongwoo Park 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.10

In this study, K30 (W 90 wt%, Co 10 wt%) and DX5 (W 84 wt%, Co 16 wt%) tungsten carbide were used as base metals for transient liquid-phase diffusion bonding (TLPDB). The filler metal was MBF20, a type of nickel alloy used to minimize the residual stresses that occur due to the differences in the expansion coefficients of the metals. MBF20 contained B, Si, and Cr, which reduced the melting point of the nickel alloy and enhanced its mechanical properties. The base metal and filler metal surfaces were cleaned by mechanical polishing and cleaning. Diffusion bonding was performed under vacuum at 1,000-1,500 K under low pressure than buckling load conditions. The microstructure on the localized bonded surface was analyzed using scanning electron microscope (SEM) and optical microscopy. Result of no significant change was observed in the diffusion bonding in the low-to-mid temperature range due to insufficient filler metal or base metal dissolution at the bonding site. However, at high temperatures, the filler completely melted and bonded to the base metal on both sides. Our results showed that temperatures approaching the recrystallization temperature were required to provide high-quality welds for ultra-precision joints and micro polycrystalline diamond (PCD) tool fabrication.

BNi-2계 삽입금속에 의한 SUS304 스테인리스강 접합체의 강도와 조직에 미치는 브레이징 온도의 영향 : Ni기 삽입금속에 의한 브레이징 접합성의 기초적 검토(II)

이용원,김종훈,Lee, Yong-Won,Kim, Jong-Hoon 한국재료학회 2007 한국재료학회지 Vol.17 No.3

A plate heat exchanger (PHE) normally uses vacuum brazing technology for connecting plates and fins. However, the reliability of high temperature brazing, especially with nickel-based filler metals containing boron the formation of brittle intermetallic compounds (IMCs) in brazed joints is of major concern. since they considerably degrade the mechanical properties. This research was examined the vacuum brazing of commercially SUS304 stainless steel with BNi-2 (Ni-Cr-B-Si) filler metal, and discussed to determine the influence of brazing temperatures on the microstructure and mechanical strength of brazed joints. In the metallographic analysis it is observed that considerable large area of Cr-B intermetallic compound phases at the brazing layer and the brazing tensile strength is related to removal of this brittle phase greatly. The mechanical properties of brazing layer could be stabilized through increasing the brazing temperature over $100^{\circ}C$ more than melting temperature of filler metals, and diffusing enough the brittle intermetallic compound formed in the brazing layer to the base metal.

Ultrasound-assisted brazing of Cu/Al dissimilar metals using a Zn-3Al filler metal

Xiao, Y.,Ji, H.,Li, M.,Kim, J. Scientific and Technical Press ; Elsevier Science 2013 Materials & design Vol.52 No.-

Ultrasound-assisted brazing of Cu/Al dissimilar metals was performed using a Zn-3Al filler metal. The effects of brazing temperature on the microstructure and mechanical properties of Cu/Al joints were investigated. Results showed that excellent metallurgic bonding could be obtained in the fluxless brazed Cu/Al joints with the assistance of ultrasonic vibration. In the joint brazed at 400<SUP>o</SUP>C, the filler metal layer showed a non-uniform microstructure and a thick CuZn<SUB>5</SUB> IMC layer was found on the Cu interface. Increasing the brazing temperature to 440<SUP>o</SUP>C, however, leaded to a refined and dispersed microstructure of the filler metal layer and to a thin Al<SUB>4.2</SUB>Cu<SUB>3.2</SUB>Zn<SUB>0.7</SUB> serrate structure in the Cu interfacial IMC layer. Further increasing the brazing temperature to 480<SUP>o</SUP>C resulted in the coarsening of the filler metal and the significantly growth of the Al<SUB>4.2</SUB>Cu<SUB>3.2</SUB>Zn<SUB>0.7</SUB> IMC layer into a dendrite structure. Nanoindentation tests showed that the hardness of the Al<SUB>4.2</SUB>Cu<SUB>3.2</SUB>Zn<SUB>0.7</SUB> and CuZn<SUB>5</SUB> phase was 11.4 and 4.65GPa, respectively. Tensile strength tests showed that all the Cu/Al joints were failed in the Cu interfacial regions. The joint brazed at 440<SUP>o</SUP>C exhibited the highest tensile strength of 78.93MPa.

유사 조성의 모재분말과 Ni기 삽입금속 혼합분말을 사용한 천이액상확산 접합 시 모재의 용해현상

송우영,예창호,강정윤,Song, Woo-Young,Ye, Chang-Ho,Kang, Chung-Yun 대한용접접합학회 2007 대한용접·접합학회지 Vol.25 No.3

The dissolution phenomenon of the solid phase powder and base metal by liquid phase insert metal during Transient Liquid Phase bonding using the mixed powder composed of the modified GTD111(base metal) powder and the GNi3 (Ni-l4Cr-9.5Co-3.5Al-2.5B) powder was investigated. In case of the mixed powder contains modified GTD111 powder 50wt%, all of the powder was melted by liquid phase at 1423K. At the temperature between solidus and liquidus of GNi3, liquid phase penetrated into the boundary of the modified GTD111 powder and solid particle separated from powder was melted easily because area of reaction was increased. With increasing mixing ratio of the modified GTD111, it needed the higher temperature to melt all of the modified GTD111 powder. During Transient Liquid Phase bonding using the mixed powder composed of the modified GTD111 50wt% and GNi3 50wt% as insert metal, width of the bonded interlayer was increased with increasing bonding temperature by reaction of the base metal and liquid phase in insert metal. Dissolution of the base metal and modified powder by liquid phase progressed all together and after all of the powder was melted nearly, the dissolution of the base metal occurred quickly.

내부구조재를 가진 중공형 접합판재의 전단가공특성에서 틈새효과에 관한 연구

김지용,정완진,김종호,Kim, Ji-yong,Jung, Wan-jin,Kima, Jong-ho 한국금형공학회 2008 한국금형공학회지 Vol.2 No.1

While recent industrial structure is various, it is small quantity batch production structure, and products requiring of various functions are increasing. In order to improve the quality of the sheared surface in cutting of inner structure bonded sheet metal the cut-off operation is mainly investigated, which is the typical shearing process in sheet metal forming technology. The sandwich sheet metals considered have inner structure which is constructed in the form of crimped expanded metal and woven metal. The inner structure is bonded between solid sheet by resistance welding or adhesive bonding. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results we found that the influence of sheared position can be observed and explained clearly and this result can be utilized to get the better sheared surface.

Filler metal을 이용한 Stainless steel필터의 제조 및 통기도

배승열,안인섭,성택경,최주호 한국분말야금학회 2004 한국분말재료학회지 (KPMI) Vol.11 No.4

The application concept of using a fail safety filter on the filtering system is to prevent the particle leakage when the main filter element is broken at high temperature. In this study, the metal filters were fabricated by pressureless sintering method. The mixture of stainless steel powders and filler metal binder solved in the water solutions of 5% PVA was compacted to form the cylindrical filter without pressure. The compacted filter were sintered in the vacuum sintering furnace at 120$0^{\circ}C$ for 1 hour. The metal filter(produced with powder of 640-840 ${\mu}m$ size) having more than above 50% porosity, 500${\mu}m$ pore size, and permeability of 7.3${\times}$10$^{-11}$m$^{2}$ plugged within 2.5 minute to prevent the leakage of maximum slip particle size of less than 3${\mu}m$.