• Journal of Welding and Joining
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• v.34 no.5
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• pp.70-76
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• 2016

In this study, Microstructure and tensile properties in arc brazed joints of 1000MPa grade DP steel using Cu-Si insert metal were investigated. The fusion zone was composed of Cu phase which solidified a little Fe and Si. The former phase formed due to dilute the edge of base material by arc, although Fe was not solid solution in Cu at the room temperature. Cu3Si particles formed by crystallization at $1100^{\circ}C$ during faster cooling. After the tensile shear test, there are no differences between the brazed joint efficiencies. The maximum joint efficient was about 37% compared to strength of base metal. It is better than that of arc brazed joint of DP steel using Cu-Sn filler metal. Fracture position of all brazing conditions was in the fusion zone. Crack initiation occurred at three junction point which was a stress singularity point of upper sheet, lower sheet and the fusion zone. And then crack propagated across the fusion zone. The reason why the fracture occurred at fusion zone was that the hardness of fusion zone was lower than that of base material and heat affected zone. The correlation among maximum load and hardness of fusion zone and EST at fractured position was $R^2=0.9338$. Therefore, this means that hardness and EST can have great impact on maximum load.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.34-39
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• 1997

With the development of semiconductor devices, adaptation of microcontroller prevails in industrial area. But in arc welding industry, there has not been much progress in adoption of microcontroller technology. There fore, this paper shows the application of digital control technology to welding machine. This paper presents the design of microcontroller that is appropriate for three phase $CO^2$ gas metal ar welding machine. By using microcontroller in $CO^2$ gas metal arc welding machine, the overall cost can be reduced compared to analog type one. Also TMS370C850 microprocessor is used as overall micrecontroller for the arc welding machine.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.185-188
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• 2006

The sea water pipe of engine room in all kinds of ships is being surrounded with severe corrosive environment. Therefore it's leakage part due to corrosion is inevitably prevented by various welding method. In this case corrosion property of welded zone may be considerably different by each welding materials. In this study corrosion resistance of the welded zone of sea water pipe with some welding materials such as shielded metal arc welding materials, inert gas arc welding materials was investigated with electrochemical method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.558-561
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• 2002

A CCD camera with a laser strip was applied to realize the automation of welding Process in GMAW. It takes relatively long time to process image on-line control using the basic Hough transformation, but it has a tendency of robustness over the noise such spatter and arc light. The adaptive Hough transformation was used to extract the laser stripe and to obtain specific weld points In this study, a neural network based on the generalized delta rule algorithm was adapted for the process control of GMA, such as welding speed, arc voltage and wire feeding speed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1219-1220
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• 2012

• Proceedings of the KWS Conference
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• v.43
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• pp.251-253
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• 2004

• Proceedings of the KWS Conference
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• 2001.05a
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• pp.36-39
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• 2001

• Proceedings of the KWS Conference
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• 2001.10a
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• pp.45-48
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• 2001

• Journal of the KSME
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• v.34 no.2
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• pp.78-87
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• 1994

이 글에서는 아직까지 우리나라의 기술수준이 낙후되어 있고 앞으로 개발의 여지가 많은 건설중 장비, 조선산업 등에서 많이 사용되는 중후판을 대상으로 하는 보호가스 아크용접(GMAW ; Gas Metal Arc Welding)자동화에 관하여 서술하고자 한다.

• Journal of Welding and Joining
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• v.33 no.3
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• pp.68-74
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• 2015

Superduplex stainless steels are important materials to the oil and gas industry, especially for off-shore production. TIG welding of super duplex stainless steels to obtain the optimal phase balance between austenite and ferrite is mainly achieved by controlling the cooling rate and the weld chemistry. The latter depends on the filler wire chosen and the shielding gas used. If TIG welding of superduplex stainless steels is performed with argon shielding gas only, then nitrogen gets lost from the weld pool, which can result in a ferrite-rich weld metal, with an inferior corrosion resistance than parent metal. In the present study, nitrogen permeation model from the shield gas which gets into the weld metal in DCEN-TIG welding has suggested. This plasma stream model shows characteristics of permeation of nitrogen ions into the molten metal due to the strong physical effect of plasma stream which formed by the arc pressure rather than the permeation of nitrogen ions caused by electric effect.