A phased array ultrasound roller probe for automated in-process/interpass inspection of multipass welds

Non-destructive inspection of multi-pass welds for defects is traditionally performed once all layers have been deposited and the sample is at ambient temperature and therefore can lead to complicated and expensive rework, reduced throughput and higher lead times. By performing inspection either as the weld is deposited, or between weld passes, it is possible to identify defects earlier in the process and rectify them. Traditional ultrasonic inspection is severely limited in this application due to the high temperatures associated with the welding process and therefore, the authors describe a novel high-temperature ultrasound phased array roller probe to perform robotically delivered in-process inspection of multipass welds. The new roller probe is able to operate at temperatures up to 350 °C and perform angled weld inspection using 55° transverse waves. The wheel probe's endless rotation enables continuous inspection and makes it well suited to integrate within automated environments commonly employed for high integrity multipass welding applications. The probe demonstrated capability to detect calibration side drilled holes at room temperature and artificial defects embedded into a real weld at high temperature. The experimental results indicate potential to industrialise this prototype in the future.