Fiber laser welding is considered an effective joining process for cryogenic storage structures because of its high welding speed, narrow heat-affected zone, and low thermal deformation. In this study, butt welding was performed on 10 mm-thick SUS316L plates using a fiber laser system, and the distortion behavior according to welding conditions was experimentally evaluated. The main process variables were laser power (4.0 and 4.5 kW) and welding speed (36–54 mm/s), and five welding cases were investigated. Distortion was measured at multiple locations on the welded specimens, and heat input was calculated from laser power and welding speed. The results showed that, under the 4.0 kW condition, distortion increased as welding speed decreased and heat input increased. At a constant welding speed of 48 mm/s, increasing the laser power from 4.0 kW to 4.5 kW caused a slight increase in distortion. Among all conditions, the 4.5 kW-54 mm/s case showed the largest distortion. In addition, identical heat input conditions did not always produce the same distortion level, indicating that welding distortion was affected not only by heat input but also by the combination of laser power and welding speed. These results provide basic data for the prediction and control of welding distortion in fiber laser butt-welded SUS316L for cryogenic hydrogen storage tank applications.

Abstract
1. 서 론
2. 실험방법
    2.1 실험 소재
    2.2 실험 방법 및 조건
    2.3 변형량 측정 방법
3. 실험결과 및 고찰
    3.1 용접 속도 영향
    3.2 레이저 출력 영향
    3.3 출력 4.5 kW 조건에서 속도 변화
4. 결 론
후 기
References

• 김재웅(Korea Institute of Industrial Technology, Docter, Korea Institute of Industrial Technology) | Jae-Woong Kim Corresponding author
• 김영현(Korea Institute of Industrial Technology) | Young-Hyun Kim
• 하을용(Korea Institute of Industrial Technology) | Eul-Yong Ha