• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.93-93
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• 2010

We developed friction welded bimetallic sleeve for 220kV aluminum conductor XLPE cable. Not only friction welded bimetallic sleeve for Termination(EB-A, EB-G) but also friction welded sleeve for Joint of Al to Cu conductor was developed regardless of this project. Generally, friction welded sleeve used to connect Al conductor cable to Cu conductor cable and used for improvement of mechanical property of terminal by offer the copper side of friction welded bimetallic sleeve at the Termination. Connection method for Al-Cu conductor has mainly used friction welding at the solid state, because it is difficult to connect by using conventional welding method. this investigation introduces development of friction welded bimetallic sleeve by friction welding and test result of 220kV Al conductor XLPE cable and accessories using friction welded sleeve.

• Journal of Welding and Joining
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• v.12 no.1
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• pp.80-93
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• 1994

The microstructure and fractography of the friction welded joint of Al to Cu have been investigated in order to understand the formation of intermetallic compounds and their effects on the failure in tensile test of the joint. The variation of welding pressure did not affect significantly the tensile strength of joint. However, the tensile strength of joint decreaed as welding time increased. The thickness of reaction layers of welded joints was several micro-meters and mainly composed of intermetallic compounds of $CuAl_2$, $Cu_9Al_4$ and Al+$CuAl_2$. The thickness of $CuAl_2$, $Cu_9Al_4$ was increased with welding time. However, $CuAl_2$ was gradually changed to $Cu_9Al_4$ which caused the decrease of tensile strength . Even though the morphology of fractured surfaces depended upon the welding time, the failure occurred along $CuAl_2$ intermetallic compound itself or between $CuAl_2$ and $Cu_9Al_4$ in most cases.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.207-210
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• 2003

The purpose of this work is to find an appropriate welding approach for rotor assembly of a marine turbocharger. The friction welding and laser welding of dissimilar materials, IN713LC and SCM440 were investigated. The quality of the welded joints obtained from two welding processes was evaluated by microstructure observation, micro-hardness and tensile tests. The friction welded joint indicated a good bonding structure in the weld interface. On the other hand, the laser welded joint showed the weld defects and non-welded area in the weld interface.

• Journal of Ocean Engineering and Technology
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• v.2 no.2
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• pp.112-121
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• 1988

A study on friction welding of carbon steel bar (SM45C) to chrome molybedenum steel bar(SCM4) is examined experimentally through tensile test, hardness test, microstructure test and fatigue test. so, this paper deals with optimizing the welding concitions and analyzing various mechanical properties about friction welds of SM45C to SCM4 steel bars. The results obtained are summarized as follows; 1) For friction welded joints of SM45C to SCM4 steel bars, the total upset(U)increases linearly with an increase of heating time ($t_{1}$) till 6s. 2) The determined optimum welding conditions are heating time ($t_{1}$)2s, upsetting time($t_{2}$), 3s, heating pressure($p_{1}$), 4kgf/$mm^{2}$(39.2MPa), upsetting pressure($p_{2}$, 8kgf/mm$^{2}$(78.4MPa) and rotating speed(N), 2, 000rpm when the total upset(U) is 3.4mm, resulting in a computed relationship between the joint tensile strength .sigma.$_{t}$ (kgf/mm$^{2}$and the total upset U(mm); .sigma.$_{t}$ =$0.21U^{3}$ - $3.38U^{2}$ +17.03U + 66.00 3) As the elongation is increased more and more, the fracture position becomes away from weld interface and the fractures are similar to those of SM45C. Fracture is taken place on SM45C side. 4) The weld interface of two dissimilar materials is mixed strongly, and the heat affected zone is about 2.0mm at SM45C while about 2.7 mm at SCM4 side. Therefore, the welded zone and heat affected zone are very narrow, comparing with those of the joints welded by the other welding methods. 5) The fatigue strengths at N=10$^{6}$ cycles of SM45C, SCM4 and friction welded joints are 23kgf/$mm^{2}$, 33kgf/$mm^{2}$(220.5 MPa), and 22.5kgf/$mm^{2}$(220.5MPa) respectively, and fracture at friction welded joint takes place at the side of SM45C. 6) The hardness of the friction weld interface is 3 times higher than that of base metal. 7) Fatigue strength of friction welded joint is higher than that of base metal. 8) Notch sensitivity factor of friction welded joint is lower than that of base metal.

• Journal of Advanced Marine Engineering and Technology
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• v.17 no.4
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• pp.38-48
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• 1993

A study on friction welding of stainless steel bar(SUS431) to chrome molybdenum steel bar(SCM21) was accomplished experimentally through analysis for relations among friction welding conditions, tension test, hardness test, microstructure test and acoustic emission test. The results obtained are summarized as follows ; 1. Through friction welding of SUS431 bar to SCM21 bar, the optimum welding condition by considering on strength and toughness was found to be the range of heating time of 3-5 sec when the number of rotating speed of 2000rpm, heating pressure of 10kg/$mm^2$, and upsetting time of 4 sec. 2. Quantitative ralationship was identified between heating time($T_1$, sec) and tensile strength (${\sigma},\;kgf/mm^2$) of the friction welded joint and the relation equation is $\sigma$=52.62$T_1{^{0.06}}$. 3. Through AE test, quantitative relationship was confirmed between heating time($T_1$, sec) and total AE(N, counts) during welding, and the relation is computed as follows ; N=30413.6$e^{0.06T1}$. 4. It was confirmed that the quantitative ralationship exists between the tensile strength of the welded joints and AE cumulative counts. And the relation is computed as the following ; ${\sigma}$=16.37(ln N)- 116.4. 5. When ONZ=36500-41500 counts by $OT_1Z$=3~5sec, it was identified by experiment that the range of welded joint tensile strength is 55.6-57.7kgf/$mm^2$/ whose joint efficiency is more than 100%, and it was experimentally confirmed that the real-time nondestructive quality(strength) evaluation for the friction welded joints could be possible by acoustic emission technique.

• Proceedings of the KWS Conference
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• 2001.05a
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• pp.120-121
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• 2001

• Journal of the Korean Society for Heat Treatment
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• v.34 no.6
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• pp.309-314
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• 2021

Due to the superior corrosion resistance and mechanical properties of TiAl alloy at high temperature, it has been utilized as a turbine wheel of a turbocharger. The dissimilar metallic bonding is usually applied to combine the TiAl turbine wheel with the SCM440 structural steel which is used as a driving shaft. In this study, the TiAl and SCM440 joint were fabricated by using a friction welding technique. During bonding process, to suppress the martensitic transformation and the formation of cracks, which might reduce a strength of the joints, Cu was used as an insert metal to relieve stress. As a result, the intermetallic compounds (IMCs) layer was observed at TiAl/Cu interface while no IMC formation was formed at SCM440/Cu interface. Since understanding of the IMCs effects on the mechanical performance of welded joint is also essential for ensuring the reliability and integrity of the turbocharger system, we estimated the nanohardness of welded joint region through nanoindentation. The relation between the microstructural feature and its mechanical property is discussed in detail.

• Proceedings of the KWS Conference
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• 2000.10a
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• pp.192-195
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• 2000

This paper describes a fundamental investigation of the friction welding condition for pure copper/pure titanium and the effect of friction time, upset pressure on the mechanical and metallurgical properties of friction welding. Under the constant upset pressure, the tensile strength make a little difference with an increase in friction time. At the constant friction time, the tensile strength increased with an increase in upset pressure. The tensile fracture of Cu to Ti joint occurred in Cu base material near interface.

• International Journal of Korean Welding Society
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• v.2 no.1
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• pp.62-66
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• 2002

The Friction Stir Welding (FSW) is a new joining method that was developed at The Welding Institute (TWI) in England in 1991. It applied heating by the rotational friction and material plastic flow. It was developed as a new joining method to solve the problems of epochally in the welding of Al alloys. In the study, 6000series of Alloy composed of Al-Mg-Si, one of the Al alloys that are utilized for shipbuilding and construction, is selected as a specimen and the numerical is executed against the welded zone of FSW. The material used in this study had the unique properties of strength and anti-corrosion, but since the welded joint of this material is easily softened by the welding heat, FSW is executed and the numerical analysis is carried out around the joint. To examine the mechanical behaviors and properties, F.E.M analysis is executed and the developed thermal-elastic-plastic finite analysis are used.

• Journal of the Korean Society for Heat Treatment
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• v.32 no.2
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• pp.79-85
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• 2019

To investigate the influence of heat treatment on the growth intermetallic compounds (IMCs) at the joint interface of friction-welded Cu-Al, several heat treatments are performed at three different temperature with different times. The experiments reveal three different IMCs layers which are significantly influenced by atomic diffusion of Cu and Al with heat treatment conditions. Since the formation of these IMCs layers can affect mechanical properties of friction-welded Cu-Al interfaces, the relationship between the microstructure of IMCs layers and the tensile strength is analyzed according to heat treatment temperature and times.