Ultrasonic testing, in which a transducer sends sound pulses of roughly 1 to 10 MHz into the part through a couplant and the instrument displays reflections from flaws and boundaries. Angle-beam UT is the standard check for structural CJP welds and is very good at cracks and lack of fusion. Phased array (PAUT) and time-of-flight diffraction (TOFD) add imaging and sizing without the radiation hazard of RT.
UT tech called a reflector at 1.2 inches deep on the flange weld, mark it and gouge it out.
Also heard as
- ultrasonics
- shear wave
Related terms
RT
Radiographic testing: imaging a weld's interior with X-rays or gamma rays on film or a digital detector.
CJP
Complete joint penetration: a groove weld that fuses through the full thickness of the joint.
Lack of fusion
Weld metal that failed to fuse with the base metal or a previous pass at some boundary.
CWI
Certified Welding Inspector: the AWS inspection credential, and the usual job title for the person checking welds.