TMCP강의 용접 공정별 입열량에 따른 용접부 물성 평가 및 비교 (Evaluation and Comparison of Weldabilities with Various Welding Processes on TMCP Steels)

서지정보

· 발행기관 : 대한용접접합학회
· 수록지 정보 : 대한용접접합학회지 / 32권 / 1호 / 6 ~ 14페이지
· 저자명 : 최철영, 지창욱, 김형찬, 남대근, 김정돈, 김순국, 박영도

초록

This paper has an aim to evaluate microstructure and fracture toughness of TMCP steel weldmentapplied for off-shore wind tower with the focus on the effect of heat input on the weldment with variouswelding processes; FCAW(13kJ/cm and 30kJ/cm), SAW(62kJ/cm), and EGW(177kJ/cm). Based on experimentalresults developed from this study, it was found that the impact toughness of top side for TMCP steelweldments 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 onback 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. Thecompositions and sizes of inclusions which are the dominant factors for the formation of acicular ferritewere analyzed by OM and EDS. As the heat input increased, the inclusions also grew and a nucleationsite decreased. The size of nonmetallic inclusions and the crack width was nearly similar, therefore theinclusions were related with the crack propagation.

영어초록

This paper has an aim to evaluate microstructure and fracture toughness of TMCP steel weldmentapplied for off-shore wind tower with the focus on the effect of heat input on the weldment with variouswelding processes; FCAW(13kJ/cm and 30kJ/cm), SAW(62kJ/cm), and EGW(177kJ/cm). Based on experimentalresults developed from this study, it was found that the impact toughness of top side for TMCP steelweldments 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 onback 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. Thecompositions and sizes of inclusions which are the dominant factors for the formation of acicular ferritewere analyzed by OM and EDS. As the heat input increased, the inclusions also grew and a nucleationsite decreased. The size of nonmetallic inclusions and the crack width was nearly similar, therefore theinclusions were related with the crack propagation.

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