• Journal of Welding and Joining
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• v.23 no.6
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• pp.37-42
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• 2005

Most of the welding steel plate structures have complicated mechanical problems such as rolling directional characteristics and residual stresses caused by manufacturing process. For the enhancement of reliability and safety in those structures, therefore, a systematic investigation is required. SS400 steel plate used for common structures was selected and welded by FCAW butt-welding process for this study, and then it was studied experimently about characteristics of fatigue crack propagations with respect to rolling direction and welding residual stress of welded steel plates. When the angles between rolling direction and tensile loading direction in base material are increased, their ultimate strength not show a significant difference, but yielding strength are increased and elongations are decreased uniformly. It is also shown that fatigue crack growth rate can be increased from those results. When the angles between welding bead direction and loading direction in welded material are increase, fatigue crack growth rate of them are decreased and influenced uniformly according to the conditions of residual stress distribution. In these results, it is shown that the welded steel plate structures are needed to harmonize distributed welding residual stress, rolling direction and loading direction fur the improvement of safety and endurance in manufacture of their structures.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.42-46
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• 2000

In this paper, joints of Cu-1Cr-0.1Zr alloy to STS316L were performed by friction welding method. Cu-1Cr-0.1Zr alloy is attractive candidate as nuclear power plant material and exibit the best combination of high sts good electrical and thermal conductivity of any copper alloy examined. The stainless steel is a structural material who alloy acts as a heat sink material for the surface heat flux in the first wall. So, in this paper, not only the develop optimizing of friction welding with more reliability and more applicabililty but also the development of in-process rear quility(such as strength and toughness) evaluation technique by acoustic emission for friction welding of such nuclear component of Cu-1Cr-0.1Zr alloy to STS316L steel were performed.

• Journal of Welding and Joining
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• v.29 no.4
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• pp.41-47
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• 2011

GMA welding process is a production process to improve productivity for the provision of higher welding quality of material. These includes numerous process variables that could affect welding quality, productivity and cost savings. Recently, the welding part of construction equipment had frequent failure of major components in the welding part of each subsidiary material due to shock which is very poor according to the welding part. Therefore, the implementation of sound welding procedure is the most decisive factor for the reliability of construction machinery. The data generated through experiments conducted in this study has validated its effectiveness for the optimization of bead geometry and process variables is presented. The criteria to control the process parameters, to achieve a good bead geometry. This study has developed mathematical models and algorithms to predict or control the bead geometry in GMA fillet welding process.

• Journal of Welding and Joining
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• v.19 no.2
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• pp.151-159
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• 2001

• Journal of Welding and Joining
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• v.31 no.4
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• pp.13-16
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• 2013

In this research, laser cladding characteristics were investigated for various filler metal feeding methods such as powder, cold wire, and hot wire feeding. Appropriate parameter window, deposition rate, material efficiency and dilution for each filler feeding method were evaluated with same laser power and cladding speed range. Laser powder cladding has wider process parameter window but higher material efficiency and lower dilution were achieved by laser wire cladding. Among these feeding methods, laser hot-wire cladding showed best efficiency in material usage and deposition rate.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.5
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• pp.469-476
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• 2009

Hard facing overlay welding in high chromium carbide is a representative way of extending the fatigue life or recompensing damage, because workpiece surface is uniformly overlay-welded by alloy material. In general, grinding process is currently used for finish due to hardness of weld material. The development of tool material, such as PCBN, has made it possible to use turning instead of grinding. There are many advantages of hard Owning, as lower equipment costs, shorter setup time, fewer process steps, higher material removal rate, better surface integrity and the elimination of cutting fluid. In this paper, machining characteristics and cutting performance are examined to investigate turning possibility of overly welding in high chromium carbide.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.426-430
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• 2008

Hot shear-welding is a process of bonding two plates together by using shearing stress in a controlled manner. This study dealt with the hot shear-welding process of two aluminum plates. These two plates were piles up in the shear-welding mold. Due to the shearing stress, these two plates were cut off longitudinally, and meantime they were welded together. During this process the control of the surplus material flow is very important, and it can be realized by designing the overlapping length and the shape of the cavity. The commercial software Deform-3D was employed to predict the effect of these two factors. The overlapping length and the shape of the cavity that presents the optimum design was then developed to get a good shear-welding process.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.43-48
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• 2003

The problem of welding stresses and fatigue behavior is the main concerns of welding research fields. The residual stresses and distortion of structures by welding is exert negative effect on the safety of mechanical structures. That is, expansion of material by high temperature and distortion by cooling during welding process is caused of tensile and compressive residual stresses on welding material, and this residual stresses reduce fracture and fatigue strength of welding structures. The accurate prediction of residual stress and relaxation due to loading and post weld heat treatment of weld zone is very important to improve the quality of weldment. In this study, a finite element modeling technique is developed to simulate the relaxation of residual stresses due to loading and post weld heat treatment of weld zone. The accuracy of finite element models is evaluated based on experimental results and the results of the analytical solution.

• Proceedings of the KWS Conference
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• 2003.11a
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• pp.103-105
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• 2003

Currently, duplex and superduplex stainless steels are widely used for piping system in offshore unit because of its excellent combination of strength and corrosion resistance properties. Also, the usage of duplex and superduplex stainless steel is steadily increasing with getting into step with development of offshore industries. In spite of excellent merits in mechanical and chemical properties of base materials, sometimes stringent requirements in welding procedure qualification and fabrication of duplex class material have regulated not only the application of various high-efficiency welding processes but also applicable welding parameters. This study is focused on hardness requirement which is known as one of the most stringent factor in duplex class material welding and this study aims to evaluate the effects of cutting and welding methodology on hardness values of duplex and superduplex stainless steel weldments.

• Journal of the Korean institute of surface engineering
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• v.42 no.1
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• pp.34-40
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• 2009

In the study, it was carried out dissimilar metal welding on materials for Al ship. The electrochemical and mechanical characteristics evaluated for specimen welded by ROBOT. The hardness of welding zone is lower than those of heat affected zone and base metal. At the result of tensile test, the specimen welded with ER5183 welding material presented excellent property compared with ER5556. The polarization trend for the base metal and welding metal showed the effects of concentration polarization due to oxygen reduction and activation polarization due to hydrogen generation. At the Tafel experiments result, the corrosion density in welded with ER5183 welding material presented the lowest value.