In welding, your AWS CWI or SCWI is the cert that is most usable.
Alternate NDT training is hard to find-been looking myself.
I am a current AWS CWI, but wanted to find more in depth training. Still looking, by the way.
After your CWI, which seems to be the basic certification, join the ASNT.
From what I have learned, you can train to ASNT, but can't certify unless an employee of a company with a ASNT quality control program.
Anyone who can shed light on this subject-please let us know!!
Good Luck
brande