Acceptance criteria

[tekari123]

Dear All,

what is the acceptance criteria for visual & radiography test for suck back as per ASME B31.1

Kindly reply.

 

[XL83NL]

Suck back? You mean a concave root surface, or suckup, like in B31.3 fig 341.3.2 (e)?
For B31.1, refer to chapter VI, para 136.4.2, table 136.4.1 and para 136.4.5.
I think for RT, your answer is in 136.4.5 (A.5)

 

[tekari123]

thank u. can u also pl. tells us the acceptance criteria for suck up per ASME section I.

 

[XL83NL]

I suggest you refer to sect. I, and if you cant find it yourself, specify how we can help you further.

 

[stanweld]

B31.1 is quite subjective regarding "abrupt change in density." Advise performing density checks adjacent to and through the flaw to clearly indicate the abrupt change.

Section I does not address.

 

[gtaw]

If you do not know the proper terminology, you cannot find the criteria in any code, ASME or other.

Best regards - Al

 

[tekari123]

Density difference can only be found through RT, but before doing the RT, on what criteria the weld can be visually accepted for concavity?

Best Regards,
Alok

 

[DekDee]

Alok,
I cannot find anything for visual requirements for concavity - only excess reinforcement.
Density of a radiograph in a concave root is relative to the amount of reinforcement on the outside of the pipe.
Measure the concavity, measure the reinforcement at the same spot externally.
Subtract the concavity from your wall thickness then add the reinforcement measurement.
If the total is less than your wall thickness the weld should fail RT.
Hope that helps,
Cheers,
DD

 

[stanweld]

tekari123,
Per ASME B31.1, Root concavity is only addressed under 136.4.5 Radiography. Per 136.4.2 Visual Examination, root concavity is accepted by non-inclusion therein. DON'T MIX UP REQUIREMENTS. If you visually observe root concavity that has an abrupt dimensional change and the weld is subject to RT, you can probably assume that the radiograph will exhibit an abrupt change in density and will be subject to classification as a defect. Again it is quite subjective.

 

[DekDee]

stanweld,
I based my response on B31.3 which is pretty clear cut on how to judge root concavity.
What I would like to know - how the hell do you quantify an "abrupt" change in densities ?
Cheers,
DD

 

[stanweld]

DekDee,
I knew that you were basing your recommendation on B31.3, which is much more objective than B31.1. Abrupt change in density is open to subjective interpretation; that is why I recommended density checking across the flaw in disputes of interpretations.

 

[JR97]

DekDee,

When I review radiographs the standard I use to judge abrupt change in density is if the condition could mask a potential defect. Admittedly that is just as subjective as the base wording. If I believe the change in density is gradual enough that I would be able to spot a crack right at the transition I will accept the radiograph. On the other hand, if the radiograph goes from 4.0 density to 1.8 within 1/32 inch, the area cannot be interpreted, and the area requires blending to ease the transition.

Hope this didn't muddy the murky water any more!

JR97