Applicability study of laser beam butt welding for pipe structure maintenance with ultrasonic guided wave

Furusawa, Akinori   ; Nishimura, Akihiko  ; Torimoto, Kazuhiro; Takenaka, Yusuke*; Toyama, Ryoji*; Nakamoto, Hiroyuki*

The aim of this work presented here is to investigate the applicability of ultrasonic guided wave for evaluation of laser beam butt welding quality. First, laser beam butt welded pipes are prepared. Two pipes are jointed and continuous wave laser beam is irradiated on the line. The test pipes are divided into two groups according to the difference in laser welding quality. One group is fine quality welded, another group is poor. Second, ultrasonic guided wave testing experiment is performed on the pipes. Torsional mode guided wave is excited by Electromagnetic Acoustic Transducers. Finally, the experimental results are analyzed and issues are discussed. The reflection wave bullet from the poor welded line is clearly observed, whereas no reflection from fine welded line. It is found that the ultrasonic guided wave technologies have the potential for laser beam butt welding line evaluation.