• Proceedings of the KWS Conference
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• 2006.05a
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• pp.130-132
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• 2006

• Proceedings of the KWS Conference
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• 1999.05a
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• pp.63-67
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• 1999

• Journal of Welding and Joining
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• v.17 no.3
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• pp.96-101
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• 1999

Microstructures and mechanical properties of weldments were studied for EH36 TMCP higher-strength hull steel with electrogas welding jprocess. In case of a newly designed EH36 TMCP steel for large heat input welding process, the Microstructures of HAZ shows more narrow width of grain coarsed region than that of conventional EH36 TMCP weldments, the amount of acicular ferrite, which is beneficial to impact toughness, increased while the amount of grain-boundary ferrite decreased. Charpy V-notched impact tests show that a newly designed EH36 TMCP steel weldment satisfies all the requirement of specifications, especially at the fusion line +2mm where the conventional EH36 TMCP steel fails to exceed the requirement.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.200-202
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• 2004

용접이 진행되는 아크 범위 내에 용접재료로서 아크를 일으키지 않는 여분의 Wire를 삽입하고자 하는 시도는 이미 여러 용접 Process 에 응용되어 행해진 바 있다. (중략)

• Proceedings of the KWS Conference
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• 2007.11a
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• pp.124-126
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• 2007

The study was performed in order to develop high efficient Electrode Gas Welding with additional solid wire by means of a surplus heat source. This technique can be reduced welding heat input in the weldments, welding speed can be increased over 30%, and mechanical properties can be more excellent than traditional method.

• Journal of Welding and Joining
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• v.14 no.1
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• pp.68-74
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• 1996

The microstructure of HAZ and the mechanical properties in weldments such as hardness and toughness were studied for mild steel and AH36 grade TMCP steel, as increasing heat input with electrogas welding process. The results of this study can be summarized as follow: 1) In the HAZ of mild steel, the width of coarse grained zone was larger than that of the nomalized zone, however in the case of TMCP steel, the nomalized zone was wider than the coarse grained zone. 2) The grain size of HAZ become coarse with increasing heat input. And at the same heat input, the grain size of TMCP steel was more coarser than that of mild steel. 3) According to the change of heat input, the deviation of hardness values was not significant, and the maximum values of hardness was not in HAZ but in the weld metal. And the hardness values in root part was higher than in face part. 4) Even though the HAZ grain size of mild steel was larger than that of TMCP steel, the impact values for mild steel was higher than those for TMCP steel, and the impact values in face part was higher than those in root part.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.5
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• pp.482-487
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• 2007

The container mobilization of material resources has increased continually owing to international economy growth and overseas trade increase in recent years. There are large amounts of order received for container carriers which are the biggest in the world ranging from 8,000 TEU to 10,000 TEU or above The very large container carriers have minimum thickness of sheer strake, upper deck and hatch coaming about $65mm{\sim}90mm$. Therefore, this study is performed in order to develop vertical welding process with high deposition rates applicable to thick plate above 65mm thickness. Electrogas welding process with 1 pole and 2 poles has been developed to apply to vertical joint with thick plates in the shipyard. In this paper, it was explained that the relationship of cross section to various groove types and executed that electrogas welding for thick plates. The mechanical tests were carried out to verify the soundness and effectiveness of EGW.

• Korean Journal of Metals and Materials
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• v.47 no.3
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• pp.195-201
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• 2009

This paper is concerned with effects of Mn and heat-input on the mechanical properties of EGW welds. Four different kinds of welding consumables were fabricated by varying Mn contents such as 1.3, 1.5, 1.7, 2.0%Mn and each consumable was welded for EGW on four heat-input conditions between 190 and 340 KJ/Cm. Mn contents were decreased as heat-input increases and alloy elements (C, Si, Ti, B, Al) to deoxidize easily also revealed similar tendency to Mn. Their microstructure, Charpy impact property and strength were investigated, and it is found that Charpy impact property and strength exhibit a strong dependence on change of microstructure by Mn contents and heat-input. The increase of Mn contents or the decrease of heat-input made the microstructure fine and increase volume fraction of acicular ferrite, thereby leading to the great improvement of Charpy impact property and strength. In case of single EGW, optimum Mn contents are over 1.7% for the toughness and strength.