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

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

• Proceedings of the KWS Conference
• /
• 1995.10a
• /
• pp.176-179
• /
• 1995

• Proceedings of the KWS Conference
• /
• 2004.05a
• /
• pp.200-202
• /
• 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
• /
• 2006.10a
• /
• pp.75-76
• /
• 2006

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

• Journal of Welding and Joining
• /
• v.14 no.1
• /
• pp.68-74
• /
• 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 Welding and Joining
• /
• v.26 no.5
• /
• pp.66-73
• /
• 2008

Welding work in pre-erection or erection stage of shipbuilding construction to be carried out in flat and vertical upward position mostly and Electrogas welding(EGW) is actively applied especially for vertical butt joint of thicker steel plate recently. In this study considered how to develope and improve mechanical properties of weld metal and HAZ in high heat input welding processes such as EGW and Electroslag welding(ESW) with its welding equipment in order to extend the application range to the longitudinal members and hatch coaming parts of container ship. Some components of welding system and parameters were modified to get the faster travel speed and reduce weld heat input, and also by adding additional filler rods or tubes increase the amount of deposited weld metal. With the test get some good date can apply to actual fabrication work and recommend items to manufacture welding materials make better. Above all things it's a fruition that to prepare the possibility of application of ESW to shipbuilding construction which fill up the gap of stoppage days of more than 20 years.