Shell from bar

[ElCidCampeador]

Hi,
Is it possible, according to ASME VIII Div.1, to make a vessel's shell from bar? Looking at UG-14 it seems prohibited. Thanks

 

[marty007]

You found the correct reference. You are allowed to build very small pressure vessels from bar, but only up to NPS4.

Cheers,

 

[ElCidCampeador]

Thank you marty007.

If I had a NPS8 vessel, could I use SA 479 316L for the shell? SA 479 seems referring only to bars, and for UG-14, as we discussed before, I couldn't use it. Am I wright? Thanks

 

[marty007]

That's how I would read it...

 

[XL83NL]

There's a code case on this matter where youre allowed to go beyond NPS4. Dont have access to CC's right now, I can look up tomorrow, but it's in the 2xxx range.

 

[ElCidCampeador]

Do you mean code cases 2155-2156? I've just found them...interesting. However, are these cases universally accepted? Who decides if they are suitable for applying? Simply an ASME inspector or may I ask to "upper floors" for an authorization? Thanks

 

[SnTMan]

ElCidCampeador, the jurisdiction generally has the say on application of Code cases.

To your OP, I have seen stainless bar at 10" diameter dual certified as bar / forging. You might look into that with your supplier.

Regards,

Mike

 

[K.P.M.]

Hey,
Go with 8NPS pipe. As per pressure select appropriate schedule.

Kejul_Mistry

 

[XL83NL]

Yes, CC 2156-1.

 

[ElCidCampeador]

Thank you all guys, but I have a problem.

I have this certificate, where it's written that the material is forging, but at the same time is "A 479": is it a contraddiction? How is it possible? If it is true, could I use it for shell and heads NPS8 without controls required by Code cases 2155-2156? Thanks

 

[SnTMan]

ElCidCampeador, your material is dual certified as forging / bar, it meets the requirements of both specifications. You may use it as either.

Regards,

Mike

 

[ElCidCampeador]

Understood. Anyway, do you think it's an error to indicate only as SA 479 in a drawing of a shell, even if is dual certified? Or does it depend on AI? Thanks

 

[XL83NL]

I would not list it as SA479, caus that would mean that A182 (i.e. forging) is not permitted per drawing, will you actually 'need' A182 to exempt the CC.

 

[moltenmetal]

Be very careful, as some materials say they're "dual certified", but comply only with the CHEMISTRY requirements of one spec or the other. It's an old trick, which is still in use because it is still effective as a means to sell material to unsuspecting victims.

The code case examination requirements, though logical and probably required for carbon steel bar product, seem to me excessive for modern austenitic stainless steel bar. They fall into the "better safe than sorry" category I guess. Simple rules are more likely to be followed, even if they are excessively restrictive for some materials.