• Journal of Advanced Marine Engineering and Technology
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• v.36 no.2
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• pp.294-301
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• 2012

Shipbuilding industry has used a lot of $CO_2$ gas as a shielding gas for arc welding and thus, development of welding equipment which can reduce the amount of $CO_2$ gas is requested widely. Therefore, this study is focused on the examination of optimum welding torch distance of Tandem welding system as a fundamental study for the optimum shape design of torch nozzle. $CO_2$ shielding gas distribution and welding bead shape formation by the torch distance are examined. Results show that according to the torch distance variation, most effective shielding gas layer can be formed and quantitative determination of the optimum torch distance can result in the reduction of $CO_2$ shielding gas consumption.

• 대한공업교육학회지
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• v.33 no.1
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• pp.282-296
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• 2008

Present automobile robot welding use $CO_2$ inert gas as a shielding fluid. The inert gas is spreading out and consumable. This present welding mechanism interfered with the welding nozzle. After welding several places have welding defects. Therefore, to reduce the $CO_2$ inert gas and to avoid interference with the material and to increase production modified nozzle which composed of cap and tip are needed. Suggested modified nozzle assembly composed of two stages i.e. $1^{st}$ and $2^{nd}$ stage. At the second stage it has 8 holes which is 3mm of diameter around the circumference. On the base of experimental results the inert $CO_2$ gas discharge reduced to 47% and welding defects decreased also. Modified two stage welding cap can be applied to the present robot welding machine and save the prime cost.

• Journal of Welding and Joining
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• v.1 no.1
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• pp.6-12
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• 1983

탄산가스 아아크 용접법은 다른 용접법에 비해 전자세 용접의 기능, 용접능률의 우수성, 생산적인 측면에서의 뛰어난 경제성으로 인해 중공업 분야에서 그 적용 추세가 증가일로에 있다. 당사( 현대중공업)에서는 1981년에 탄산가스 아아크 용접법이 현장 구조물 시공에 최초로 적용된 이래 꾸준히 증가하여 보편적으로 시용되는 용접법 중위 하나가 되었다. 탄산가스 아아크 용접법의 여러 가지 장점을 적극적으로 이용하기 위해서는 탄산가스 아아크 용접시 발생하는 결함의 원 인을 분석하여 결함을 최소화하는 대책이 강구되어야 한다. 탄산가스 아아크 용접시 발생하는 결함의 빈도를 조사하여, 빈도수가 많은 결함의 원인을 분석하고 그 방지대책을 세우는데 본고의 목적이 있다.

• Journal of Welding and Joining
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• v.12 no.1
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• pp.51-58
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• 1994

Amount of spatter, welding conditions and welding costs were investigated for MAG welding. $CO_2$, Ar+18%;$CO_2$ and Ar+8%$O_2$ were used for shielding gases. As results, arc characteristics and appropriate range for welding were obtained. Amount of spatter in Ar+18%$CO_2$ gas welding was 20% of that of $CO_2$ welding, and Ar+8%$O_2$ was 10% of that of $CO_2$ welding. Therefore by using Ar+18%$CO_2$and Ar+8%$O_2$ gases, welding costs could be reduced compared with $CO_2$ welding due to avoiding spatter.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.1
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• pp.13-18
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• 1998

In this study. the fatigue lives of two kinds of specimens made by $CO^2$ gas weld were assessed. The materials for two kinds of specimens were taken out of the virgin carbon steel tubes and the used carbon steel tubes respectively. As a result, it was found that the fatigue lives of two groups of specimens were in the same order of magnitude.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.57-59
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• 2004

$CO_2$ 용접은 다른 용접에 비하여 와이어와 보호가스의 가격이 저렴하기 때문에 재료비 측면에서 매우 경제적이라는 장점이 있다. 그러나 $CO_2$ 용접은 타 용접에 비해 스패터 발생량이 많다는 문제점이 있었으나, 최근 파형제어 기법의 개발로 스패터 발생량을 SCR용접기에 비하여 80%이상 향상된 인버터 용접기가 개발되었다. (중략)

• Journal of Welding and Joining
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• v.13 no.1
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• pp.127-137
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• 1995

The possibility of new GMAW process using economic shielding gases including CO$_{2}$ gas was investigated on the effect of shielding gas on weldabilty. In the optimum welding condition using 600A power source, FCAW process showed low depositions rate, 114 g/min at 300A, but new GMAW using other mixed shielding gases exhibited high deposition rate, 208-224 g/min at 450A. TIME gas, Ar+CO$_{2}$ gas and Ar+CO$_{2}$+O$_{2}$ gas as a shielding gas were able to be used to the very high welding current(450A), moreover TIME gas and Ar+CO$_{2}$ gas showed the highest arc stability among shielding gases studied in this experiments. The weld penetration was performed by axial spray transfer mode of weld droplet. On the basis of workability, weldability and economic point of view, Ar mixture (80%Ar+20%CO$_{2}$) gas was recommended as a shielding gas for the development and application of new GMAW process. This shielding gas showed the low spatter, good weld quality, stable arc and low cost at the region of high welding current.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.535-541
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• 2013

The present study was carried out to investigate the effects of welding parameters such as current, voltage and shielding gases on the bead shape, microstructures and hardness. It was confirmed that bead height was lowered and bead depth was increased with increasing voltages while height, depth and width of beads increased with welding currents. The hardness of weld metals with Ar+10% $O_2$ and Ar+20% $CO_2$ was low due to the formation of grain boundary and polygonal ferrites while that of weld metals with Ar+2% $O_2$ was high due to the presence of acicular, bainitic and sideplate ferrites.

• Proceedings of the KWS Conference
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• v.43
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• pp.52-54
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.290-291
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• 2002

스틸 판재 4KW CO2 레이저 용접시 발생되는 플라즈마 특성 연구를 위하여 용접 품질에 중요한 요인이 되는 용접속도, 주입가스 양, 판재사이의 갭을 변화시키면서 실험을 하였다 발생된 분광학적 스펙트럼을 측정하였고 플라즈마광의 세기를 광파이버를 이용하여 측정하였다 플라즈마 패턴 특성을 알기 위하여 1000 frame/sec의 고속 디지털 카메라를 이용하여 플라즈마 영상을 측정하였다 그 결과, 용접속도가 빠를수록 상단에서 발생되는 플라즈마 광의 세기는 커졌으며, 주입가스의 양이 적을수록 플라즈마광의 세기가 강하게 측정되었다. 또한 판재 사이가 넓을수록 발생된 플라즈마가 판재 사이로 분출이 되면서 그 세기가 감소되는 현상을 보여주었다. 이러한 결과는 2차원 플라즈마 영상실험의 결과와 일치함을 보여주었다. 따라서 표면에서 발생되는 플라즈마 광의 세기는 레이저 용접시 중요한 요인이 되는 침투깊이를 추정하는데 중요한 정보가 되며 레이저 용접 품질에 대한 실시간 모니퍼링이 가능함을 확인하였다.