조선용 항복강도 390MPa급 고장력 TMCP 후판의 재현 열영향부 충격인성에 미치는 용접 입열량의 영향

• Published in: 대한용접·접합학회지 Vol. 42; no. 3; pp. 292 - 297
• Main Authors: 심호섭(Ho-Seop Sim), 김기혁(Ki-Hyuk Kim), 성준호(Joon-Ho Sung), 하려선(Ryeo-Sun Ha), 임경택(Kyeong-Taek Lim), 김도형(Do-Hyung Kim), 홍현욱(Hyun-Uk Hong)
• Format: Journal Article
• Language: Korean
• Published: 대한용접·접합학회 01.06.2024; 대한용접접합학회
• Subjects: 기계공학; Heat input; TMCP; Toughness; Simulated heat-affected-zone; Microstructure
• ISSN: 2466-2232; 2466-2100
• DOI: 10.5781/JWJ.2024.42.3.7

In this study, the influence of heat input on the microstructure and toughness of the simulated heat-affected zone (HAZ) of YP390 MPa grade steel with a thickness of 80 mm was investigated. The weld coarse-grained HAZ was simulated using a Gleeble 3500 simulator, with heat input levels ranging from 30 to 650 kJ/cm. Following the HAZ simulation test, the microstructures and Charpy impact properties were examined. For heat inputs ranging from 30 to 50 kJ/cm, the microstructure consisted of bainitic ferrite/acicular ferrite, resulting in an impact toughness exceeding 200 J at -20 ℃. Conversely, in the higher heat input range of 130 to 650 kJ/cm, the simulated HAZ exhibited a lower impact toughness value due to the formation of coarse grain boundary ferrite. A high proportion of acicular ferrite with minimal grain growth was found to be the key metallurgical factor contributing to the improvement of impact toughness. KCI Citation Count: 0