UT on thin stainless plate

[Jman69]

My customer requires a UT examination on all rolled plate and formed heads. Per ASME SA-435, the range of thickness is from .500 and above. I have a shell that is .375" and is being rolled and need to have it UT examined. I am being told that it cannot be done per this requirement. I cannot locate in the code what is required for material of this thickness. Any idea's?
Thanks, John

 

[fegenbush]

Please consult ASME SA-578 which allows for UT examination of plates down to 0.375" thickness.

 

[Jman69]

fegenbush, I made a mistake. It is .3125" thk. not .375". I did find SA-578 but it did not apply.

 

[JR97]

Jman69,

The problem with UT for loss of back reflection on thin plates is an issue with the test itself, not a matter of finding a spec that "fits". If a plate has a lamination the signal from the back reflection will disappear; replaced by the signal from the lamination. If the plate is too thin the visible separation on the screen between the position of the lamination response and the back reflection response will be too close together to see the shift, potentially resulting in the indication being missed by the operator. That said, I believe .312 plate can be successfully tested. A dual element transducer should be used to ensure the dead zone of the transducer does not extend to the probable lamination depth zone.

JR97