• Journal of Welding and Joining
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• 제30권6호
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• pp.15-20
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• 2012

Brazing technology has been widely used among bonding technologies because it enables to bond various metals, even ceramics, dissimilar metals, and give higher bonding strength, cost down, automation, etc. However, there are many parameters to achieve optimal brazing joint such as brazing alloys, brazing atmospheres, designs and brazing methods, etc. The brazing parameters affect seriously on the characteristic of final brazing products. Stainless steel is broadly used in high temperature applications, chemical industry, heat exchangers, muffler of vehicles, and so on. Accordingly, in this article, brazing alloys, forms of brazing alloys, brazing methods and atmospheres for stainless steel were described.

• Journal of Welding and Joining
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• 제25권1호
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• pp.30-36
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• 2007

A joining of dissimilar metal combination faces significant problems such as poor strength and cracking associated with brittle intermetallic compounds(IMC) formed. An application of laser allows low heat input; leading to less dilution and smaller heat affected zone. The $CO_2$ laser overlay was conducted on an AC2B alloy with feeding Fe-based powders. The overlay area was significantly influenced from the travel velocity rather than the powder feeding rate. The interface between the overlay and substrate consisted of the hard and brittle IMC($FeAl_3,\;Fe_3Al,\;Fe_2Al_5$), which initiating and propagating the crack. The reciprocating test for the slide wear was conducted on a multi-pass overlay experiment. Comparing with the multi-pass overlay with no overlap, the overlay with 50% overlap showed better wear resistance.

• 한국산학기술학회논문지
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• 제12권3호
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• pp.1070-1077
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• 2011

본 논문은 초음파 가공에 의한 용착성을 가공조건의 영향에 관하여 나타내었다. 한파장 혼의 최적화를 이용한 Ni-Cu 이종금속 박판의 용착성 평가는 초음파 가공 방법을 이용하여 확인된다. 초음파 가공변수 설정에 따른 인장시험을 통한 최적의 용착조건을 제시하였으며 SEM 사진과 EDX-ray 분석에 의한 용착성을 평가하였다. 실험적 연구는 초음파 가공 후 인장강도의 측정, SEM사진 분석으로 수행된다. 또한 가공시간, 가압력, 진폭의 가공변수들은 본 연구에 적용되었다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 추계학술대회 논문집
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• pp.101-108
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• 2000

In this paper, the real-time prediction of high temperature creep life was carried out for the friction welded joints of dissimilar heat resisting steels(SUH3-SUH35). Various life prediction methods such as LMP(Larson-Miller Parameter) and ISM(initial strain method) were applied : The creep behaviors of those steels and the welds under static load were examined by ISM combined with LMP at 500, 600 and $700^{\circ}C$, and the relationship between these two methods was investigated. A real-time creep life( $t_{r}$ , hr) prediction equation by initial strain($\varepsilon$$_{0}$ , %) under any creep stress ($\sigma$, MPa) at any high temperature(T, K) was developed as follows : $t_{r}$ =$\alpha$$\varepsilon$$_{0}$ $^{\beta}$$\sigma$$^{1}$ where, (equation omitted) for SUH3-SUH35 friction weld of =16mm and =20mm, respectively.

• 한국공작기계학회논문집
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• 제11권3호
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• pp.65-71
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• 2002

Friction welding has may merits such as energy efficiency, simple processing, etc. but it is difficult to obtain good welding at the welded interfaces and heat affected zone. It is discovered that stress singularity exists at the interferes and heat affected zone. The computer program based on boundary element method is utilized in this study. A mathematical model is implemented based on results from several experiments performed at and around the welded interfaces and heat affected zone of disimilar metals under static and dynamic loadings. This stay is to investigate the characteristics of the deformation and fracture behavior around interfaces for friction welded materials under static tensile load. Also, the stress distribution at the tip of crack is analyzed by using BU based on Kelvin's solution of 2-dimensional binding zone. The results of BEM are identical with those in case of considering interfaces of both heat affected zone. Also, stress singularity at the tip of interfaces appears when the elastic modulus ratio is 1.07.

• Journal of Welding and Joining
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• 제9권4호
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• pp.17-27
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• 1991

The direct brazing technology which could be used for the simplification of brazing process and the improvement of brazed joint quality was studied with $Al_2O_3$ and stainless steels. The brazing of $Al_2O_3$ to STS304 or STS430 was performed under different brazing conditions such as brazing filler metal, temperature, heating rate and brazing time. Microstructural observation and chemical analysis be SEM/EPAM were carried out to verify the quality of brazed joints. 4-point bending strength of brazed joints was also measured to find the optimal brazing conditions. The results showed that, in brazing of $Al_2O_3$, the mixed oxide layer resulted from the reaction between Ti in filler metal and oxide layer on the material surface to be brazed was found to be bery important for the joint quality. The width of oxide layer varied with the brazing conditions such as brazing time, heating rate and chemical composition of filler metals. The strength of brazed joints was more affected by the type of materials and their thermal properties than by brazing heat cycle.

• 한국기계가공학회지
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• 제20권8호
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• pp.18-24
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• 2021

Polymers, polymer compounds, are very moldable at low temperatures and have good strength against weight, and hence, are often used in the interior and exterior materials of cars. Owing to the increasing environmental problems, emission regulations have become stricter, which has increased the use of lightweight polymers as substitutes for metal materials. Therefore, as the use of polymer increases, extensive research is being conducted on the bonding technology of polymers, such as polyurethane and epoxy. However, the increased cost and environmental pollution by adhesives caused by the polymer manufacturing plant depend on the chemical composition or the manufacturer's mix ratio. To compensate for this issue, a laser beam is irradiated through a highly permeable polymer (PC) placed on top of an absorbent polymer (ABS) to transfer the laser output to the ABS polymer and fuse them at the interface. Moreover, enabling laser penetrating bonding by placing a stainless steel wire mesh between the two polymers can achieve improved bonding strength compared to conventional heterogeneous polymer bonding.

• Journal of Welding and Joining
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• 제35권1호
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• pp.26-33
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• 2017

This study aims to investigate the suitability of requirement for post-weld heat treatment(PWHT) temperature when different P-No. materials are welded, which is defined by ASME Sec. III Code. For SA-516 Gr. 60 and SA-106 Gr. B carbon steels that are typical P-No. 1 material, simulated heat treatment were conducted for 8 h at $610^{\circ}C$, $650^{\circ}C$, $690^{\circ}C$, and $730^{\circ}C$, last two temperature falls in the temperature of PWHT for P-No. 5A low-alloy steels. Tensile and Charpy impact tests were performed for the heat-treated specimens, and then microstructure was analyzed by optical microscopy and scanning electron microscopy with energy-dispersive spectrometry. The Charpy impact properties deteriorated significantly mainly due to a large amount of cementite precipitation when the temperature of simulated heat treatment was $730^{\circ}C$. Therefore, when dissimilar metal welding is carried out for P-No. 1 carbon steel and different P-No. low alloy steel, the PWHT temperature should be carefully selected to avoid significant deterioration of impact properties for P-No. 1 carbon steel.

• 수산해양기술연구
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• 제23권2호
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• pp.34-34
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• 1987

이종재 마찰용접재 강도특성과 초음파 반사계수와의 상관성에 관하여 실험적으로 연구한 결과의 요약은 다음과 같다. 1. 이종재 마찰용접 이음면에서의 초음파 반사계수를 펄스반사법에 의하여 측정산출할 수 있다. 2. 5MHz의 비교적 낮은 주파수의 탐촉자를 사용하므로써 시험편의 표면가공 오차를 무시할 수 있다. 3. 알루미늄과 스테인레스의 마찰용접에서는 용접조건으로 마찰가열시간이나 가열압력을 변수로 하였을 때보다 업셋가압력을 변수로 하였을 때 반사계수의 변화가 뚜렷하다. 4. 업셋가압력을 변수로 한 용접조건과 반사계수사이에는 선형적 상관관계가 있다. 5. 용접이음면에서의 이음인장강도와 반사계수와의 상관관계식을 정량적으로 도출할 수 있다. 6. 초음파 반사계수에 의해 이종재 마찰용접 품질의 비파괴적 평가가 가능하다

• 수산해양기술연구
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• 제23권2호
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• pp.80-85
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• 1987

이종재 마찰용접재 강도특성과 초음파 반사계수와의 상관성에 관하여 실험적으로 연구한 결과의 요약은 다음과 같다. 1. 이종재 마찰용접 이음면에서의 초음파 반사계수를 펄스반사법에 의하여 측정산출할 수 있다. 2. 5MHz의 비교적 낮은 주파수의 탐촉자를 사용하므로써 시험편의 표면가공 오차를 무시할 수 있다. 3. 알루미늄과 스테인레스의 마찰용접에서는 용접조건으로 마찰가열시간이나 가열압력을 변수로 하였을 때보다 업셋가압력을 변수로 하였을 때 반사계수의 변화가 뚜렷하다. 4. 업셋가압력을 변수로 한 용접조건과 반사계수사이에는 선형적 상관관계가 있다. 5. 용접이음면에서의 이음인장강도와 반사계수와의 상관관계식을 정량적으로 도출할 수 있다. 6. 초음파 반사계수에 의해 이종재 마찰용접 품질의 비파괴적 평가가 가능하다