The aim with this report is to describe the ultrasonic peening treatment of welded connections on Met Mast Module 5 structure carried out at HadFab workshop in Tranent, Scotland.
A description of the ultrasonic peening equipment, ultrasonic peening procedure and time requirement for the treatment are briefly presented.
Special consideration has been taken to inter-pass weld toe at weld face and weld spatter adjacent to weld root areas in the treated specimens.
Based on previous fatigue test of UP treated welds we assess the potential fatigue life extension for the treated specimens.
IIW Fatigue Recommendations classification of this detail is FAT 71. Our conservative estimate is that the specimens could be classified as FAT 151 after UP treatment.