Good Morning BankerQC,
I'm not disagreeing with you but AWS D1.1:2004 nails you down as a UT operator (without the Level III writing special UT procedures) as far as the equipment allowed.
for example...
6.22.7.1 Frequency. The transducer frequency "SHALL BE" between 2 and 2.25MHz, inclusive.
6.22.7.2 Transducer dimensions. The transducer crystal "SHALL BE" square or rectangular in shape and may vary from 5/8" to 1" in width and from 5/8" to 13/16" in height. The maximum width to height ratio "SHALL BE" 1.2 to 1.0, and the minimum width to height ratio "SHALL BE" 1.0 to 1.0.
6.22.7.3 Angles. The search unit shall produce a sound beam in the material tested within a +/- 2 degrees of "ONE" of the following proper angles: 70,60, or 45 degrees as described in 6.29.2.2.
We are basically told what to use rather than allowing us to use something more appropriate for the situation. The Level III that we were using here brought some sample plates with built in flaws for me to evaluate. Some of these were too near to the surface of this relatively thin plate for good resolution with the AWS mandated equipment. There are other sizes and frequencies and angles that would have worked much better, but we are locked in.
So I'm thinking those variables are not relavant to the original question, however if I'm off base, please correct me as I am still learning as I go.
John Wright