Shear wave ultrasonics testing calibration

[Agcd5150]

When performing a shear wave UT inspection on drill pipe tubes does the wall thickness of the test specimen (calibration standard) have to be the same thickness and diameter of the equipment being evaluated?

 

[Duwe6]

API, ASME, or EN?

 

[redpicker]

For API drill pipe, the calibration standard is defined as having the same nominal OD and wall thickness as the product being inspected. From your question I cannot determine if you are asking about new or used pipe, but I believe the only difference is the depth of the calibration notch (either 5% or 12.5% of the nominal wall thickness).

rp

 

[Agcd5150]

I should clarify what I am asking. I want to know if I calibrate my unit using a standard that has a wall thickness less than the parts that I am inspecting will the results of the inspection be inaccurate? Basically my shear wave unit is calibrated using a standard that has a wall thickness of .330" but the actual wall thickness of the tube being inspected is .362"

 

[redpicker]

Basically my shear wave unit is calibrated using a standard that has a wall thickness of .330" but the actual wall thickness of the tube being inspected is .362"

Your calibration will be in error. The gain setting you use to reach threshold on the 0.330 wall will be less than you would need for the 0.362 wall. This means flaws in the material will not give as high a signal, so you will accept indications that you would have rejected with a proper standardization.

The OD has to match, too, because you will not couple to the 4 inch pipe the same as you do on the 5 inch.

rp

 

[Agcd5150]

Thank you, that's what I needed to know..