ASME Section II Allowable Stress Question

[RVAmeche]

Hi,

I have a ASME Section II, Part D, Table 1A allowable stress question. I'm looking at an old 2013 binder we but I don't think these stress values have changed in recent editions based on the values I'm seeing in software.

I'm looking at SA-312 TP316L allowable stresses at 600F and there's four rows showing this spec/type. The primary difference (outside the stresses) appears to be the notes, but I'm looking to make sure I'm understanding why the stresses vary.
[ul]
[li]Product Form - Smls & wld pipe, Allowable Stress @ 600F = 14.0 ksi, Note G5[/li]
[li]Product Form - Smls pipe, Allowable Stress = 10.4 ksi[/li]
[li]Product Form - Weld pipe, Allowable Stress = 11.9 ksi, Note G5[/li]
[li]Product Form - Weld pipe, Allowable Stress = 8.8 ksi[/li]
[/ul]

Note G5 appears to basically say these higher stress values may result in greater deformation. The other notes don't appear to be anything affecting the stress values.

Am I correct that the only difference is the G5 note and the potential for greater deformation? Otherwise, outside of the seamless/welded differences, I'm not sure what the differences are impacting the allowable stress since they're all SA-312 TP316L.

 

[SnTMan]

RVAmeche, many of the stainless steels and I believe some of the non-ferrous metals have Note G5 applied. As you noted the G5 materials can experience greater deformation. This can cause for example leakage in gasketed components lke body flanges. Use of the lower allowable non-G5 materials is commmon for these components or any component where the deformation may be a problem.

Now to your four lines:

Seamless & welded pipe, G5: Higher allowable, BUT see notes W12 & W14 for welded pipe. Welded pipe may need a joint efficiency applied. You will see that detialed knowledge of the manufacturing process used is needed to apply the correct joint efficiency.

Seamless pipe, non-G5: Lower allowable version of the above seamless pipe.

Welded pipe, G5: Higher allowable welded pipe. Note these allowables are 85% of seamless version, see note G24

Welded pipe, non-G5: Lower allowable version of the above. These allowables are also 85% of seamless version lower allowables, see note G24.

Note that only the higher allowable, seamless / welded version is permitted for Sec III work. Note G21 restricts use for Sec I work.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[RVAmeche]

Thanks for the confirmation!

 

[r6155]

It is not a responsible practice to work with the old 2013 edition.

Regards

 

[RVAmeche]

Sorry I should've said I know the stresses have no changed. We're not working from 2013 it's just a binder I had handy.