LT-FH, a low temperature C-Mn steel, was utilized to compare the bending and impact properties of various specimens based on welding method. The property-comparison out of welding method was accompanied by performing bending and impact tests under the standards of the “Classification Society” for manufactured structures for LPG tank applications. In order to acquire the property-comparison on the given test specimens, flux cored arc welding (FCAW) and submerged arc welding (SAW) were utilized to weld the given test pieces. The specimens used for the bending and impact tests were prepared by precise fabrication using both lathe and milling machines. First of all, no cracks were observed on the root part of the bent specimen when the bending test was performed. In addition, when evaluating the effects of impact property related to the weld metal and heat affected zone, the SAW results differed little compared to FCAW. Actually, with respect to SAW, the weld metal showed twice as high impact toughness as the heat affected zone. The results of the impact test confirmed that ductile fracture occurred via microstructural mechanism including lots of dimple microstructures, which means that immediate plastic deformation was produced during the Charpy impact test.

Abstract
1. 서 론
2. 실험 방법
    2.1. LT-FH 강재에 대한 용접
    2.2. 선급 규격 굽힘 및 충격시편 제원 검토
    2.3. 선급 입회용 굽힘 및 충격시험 준비
3. 결 과
    3.1. 굽힘 및 충격시험용 시편 전경
    3.2. 굽힘시편 가공 시 용접 비드 상부 단차 검토
    3.3. 굽힘시험시 맞춤형 지그 설비의 사전 제작
    3.4. 굽힘 및 충격시험 수행
4. 고 찰
    4.1. PWHT 온도변화에 따른 강재의 미세조직 변화
    4.2. 굽힘시험 후 굽힘강도, 응력-변위 검토
    4.3. 용착금속 및 HAZ 관련 충격인성 결과치(FCAW↔ SAW)
    4.4. 용착금속 및 HAZ 관련 개별 충격결과치 비교(FCAW ↔ SAW)
    4.5. 용착금속 및 HAZ 관련 미세조직 분석
    4.6. 충격시편의 파단조직 및 연성파괴 분석
5. 결 론
Acknowledgement
References
<저자소개>

• 이기열(군산대학교 조선해양기자재연구센터) | Ki Yeol Lee (Shipbuilding and Ocean Equipment Research Center, Kunsan National University, Kunsan 54150, Republic of Korea)
• 송창규(현대중공업 군산조선소) | Chang Gyu Song (Kunsan Yard, HD Hyundai Heavy Industries, Kunsan 54001, Republic of Korea)
• 문병영(군산대학교 조선공학과) | Byung Young Moon (Department of Shipbuilding Engineering, Kunsan National University, Kunsan 54150, Republic of Korea) Corresponding author