Ultrasonic Testing (TOFD) of Welding

[stormtx]

Has anyone used "time of flight diffraction (TOFD)" UT method to inspect welding of the pipe? We're inspecting a weld connecting two 36"pipes that have different thicknesses (constant internal diameter) together. Is TOFD capable to inspect this condition? I'm concerned about 2 issues:
1. Lateral wave might not be able to travel through uneven surface.
2. It can be difficult to calculate the depth of the defect.

Thanks in advance

 

[apiguy]

I believe regular shear-wave (angle-beam) examination should suffice;if you are looking for weld quality. TOFD is a more advanced method that will serve your purpose as well. I would recommend angle-beam inspection simply as a go-no-go approach, then pending results of that examination, TOFD if critical sizing of defects is desired.

The APIGUY....

 

[unclesyd]

Just remember there are UT operators and there are operators in the business.

I would take apiguy's advice, stick with shear-wave if possible. At present I'm not enamored with the TOFD inspections that I've witnessed. It has been mostly problems with the operator as there is nothing wrong with the process if used properly.