I was wondering if anyone has experience with doing any UT Examinations on Forged parts with ASTM standards. I just started this new position and I am heading up their new NDE department. I am experiecened in AWS and some ASME on welded connections but now I am jumping in head first with these Forged Rings. I/we will be doing PT, UT and eventually MT on these. We have a current complany doing all of our NDE and hopefully in a month I can take over that and start getting a couple trainees on board to start getting their hours. I have a Responsible Level III who has jsut started going over our procedures I have rough drafts for. After reading all of the the different specs and looking over all of the different standards I have noticed their a few things that as a UT tech I have never came accross. One example is a ID/OD ratio, not sure exaclty what this is but I am sure it is a calculation and it relates to thicknesses and the ID and OD. Depending on the ratio determines type and location of exam i.e. Shear or Longitudinal waves.
My company knows I don't have experience with this type of work, I just wanted to get a good feel for it and see if anyone has any comments. I do see a few areas for concern that the current contracted NDE firm that is doing our examinations.
As a rule of thumb, exclusive of any given standard, the base problem with ID OD ratio's is when it hits (or not) the ID surface. If it impinges upon the ID surface > critical angle you will get a bounce. If it impinges on the ID surface = critical angle, it will graze the ID surface, setting up surface waves, and other mode conversions on that surface, as well as passing part of the initiating beam on through the main body of the piece. If you hit it at < critical angle, it will shoot on through the body with only a bit of the beam spread catching the ID if anything.
Forgings are a PIA in that the grain structure is not isotropic but rather anisotropic. Your beam has a nasty habit of not traveling the imaginary straight line a lot of UT hands believe it to be. The near surface tends to be isotropic (the same in all directions), but further into the body of the forging, it tends to turn anisotropic (directionally dependent).
That would have more to do with utilization of Refracted L waves rather than the ID OD ratio. (that is only one of many concerns)
I am not normally negative, but you've bitten into something that's going to bite back if your not careful.