Journal of Welding and Joining

The Korean Welding and Joining Society (대한용접접합학회)
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Evaluation and Comparison of Weldabilities with Various Welding Processes on TMCP Steels

TMCP강의 용접 공정별 입열량에 따른 용접부 물성 평가 및 비교

  • Choi, Chul Young (School of Materials Science and Engineering, Pusan National University) ;
  • Ji, Chang Wook (School of Materials Science and Engineering, Pusan National University) ;
  • Kim, Hyoung Chan (Dongnam Regional Division, Korea Institute of Industrial Technology) ;
  • Nam, Dae-Geun (Dongnam Regional Division, Korea Institute of Industrial Technology) ;
  • Kim, Joungdon (Research and Development, Hanchang Engingeering) ;
  • Kim, Soon Kook (Department of Advanced Materials Engineering, Dong-Eui University) ;
  • Park, Yeong-Do (Department of Advanced Materials Engineering, Dong-Eui University)
  • 최철영 (부산대학교 재료공학과) ;
  • 지창욱 (부산대학교 재료공학과) ;
  • 김형찬 (한국생산기술연구원 동남권지역본부) ;
  • 남대근 (한국생산기술연구원 동남권지역본부) ;
  • 김정돈 (한창엔지니어링 기술연구소) ;
  • 김순국 (동의대학교 신소재공학과) ;
  • 박영도 (동의대학교 신소재공학과)
  • Received : 2014.02.03
  • Accepted : 2014.02.24
  • Published : 2014.02.28
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Abstract

This paper has an aim to evaluate microstructure and fracture toughness of TMCP steel weldment applied for off-shore wind tower with the focus on the effect of heat input on the weldment with various welding processes; FCAW(13kJ/cm and 30kJ/cm), SAW(62kJ/cm), and EGW(177kJ/cm). Based on experimental results developed from this study, it was found that the impact toughness of top side for TMCP steel weldments with heat input up to 62 kJ/cm satisfied the required minimum value except the EGW(177kJ/cm). The heat input and microstructure are the main factors of impact toughness. The heat input of 13kJ/cm on back side with low heat input increased the amount of grain boundary ferrite which has low impact toughness, and heat input of 177kJ/cm on top side is significant enough to produce the austenite grain growth. The compositions and sizes of inclusions which are the dominant factors for the formation of acicular ferrite were analyzed by OM and EDS. As the heat input increased, the inclusions also grew and a nucleation site decreased. The size of nonmetallic inclusions and the crack width was nearly similar, therefore the inclusions were related with the crack propagation.

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References

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