In a root scan, the scanning direction is parallel to the weld and the probe is positioned at a fixed distance from the center of the weld. A beam at 70° is usually the best for this type of scan.
- The probe is placed on a 15 mm plate
- The beam should land in the middle of the root
- The distance from the beam exit point to the center of the weld called the index offset or stand-off is calculated
- The two index offsets are marked on the part5.The part is scanned from both sides
A magnetic strip or a ruler placed behind the probe is a useful tool to ensure straight line scanning.