6.3 Probe Positions with Respect to Weld Geometry
Ultrasonic Flaw Detection Tutorial
Weld inspection procedures usually require testing from two or more different locations on the test piece to cover the entire volume of the weld and to project sound waves in the directions required for generating reflections from common flaws. In all cases the probe must be scanned back and forth so as to project the sound beam through the entire volume of the weld. Specific procedures for a given test must always be established by the inspector, based on part geometry and test requirements.
Probe Positions for Weld Inspection
BUTT WELD
Primarily inspected from the sides using an angle beam probe, testing is done on both the left and right sides of the weld.
A secondary test with a straight beam transducer checks for laminar cracking in the heat affected zone. Testing is also done on each side of the weld.
T WELD
T WELDS also typically require inspection with both angle beam and straight beam probes, testing with an angle beam from both the flange and web and with a straight beam from the flange.
LAP WELD
Full penetration lap welds are commonly tested with an angle beam probe coupled to the upper plate.
CORNER WELD
Full penetration corner welds are commonly tested with an angle beam probe aligned both perpendicular to the weld and from a direction representing a small rotation from parallel.
