Does anyone know of any PAUT equipment that allows you to define velocity as a function of angle? I believe that Olympus PipeWIZARD V4 has this capability, but beyond that I'm not aware of any regular sort of, "field portable" PAUT set that permits you define velocity as a function of angle (a "velocity vector", if you will).

Last year I came across this problem first hand while inspecting welds on TMCP pipeline steel. Ed Ginzel and I got a sample, and figured out a very simple way to calibrate for it using two phased array probes in pitch-catch, placed on the pipe material. It was much more common than we thought. I fear they may be many PAUT crews out there looking at "melting S-scans", and plotting defects incorrectly. This is something that we hope (one day ) to be integrated into field portable PAUT equipment (hint hint my PAUT OEMs!).

The first paper explains the procedure:
“Calibration for Anisotropic Effects on Shear Wave Velocity for Improvements of Weld Inspections in TMCP Steels”

Then we published two more papers because we simply couldn't stop ourselves (too interesting!):
“Visualisation of Acoustic Birefringence”

“Velocity determination using time-stops in photoelastic imaging”

I also did a video explaining the simple calibration setup:
https://youtu.be/aPxKdGmMUmM