Change A479 with A276 for pressure application 1

[bssem]

I was wondering if I could change Change A479 with A276 for pressure application (for SS316L material)? I have been told that A479 is suited for B&PV application and A276 for structural application. Could some one shed light on this topic?
Regards,
bssem

 

[iainuts]

Hi bssem. I'd be interested in a responce from someone here about this issue as well. Historically, we've used both A479 and A276 for pressurized applications, though not for pressure vessels of course. All pressure vessel material has to be code rated. So the A479 must be SA479 to use on a pressure vessel. Regardless, I'm unaware of any reason SA479 would be preferred over SA276. For non pressure vessel applications (ie: valves/piping/pumps) I'd be interested in knowing if A479 might be preferable over A276.

 

[08tramp]

Both of the materials are actually connecting bolting materials, and they are equally replacebale for each other as far as their UNS numbers match each other,s.

 

[bpss]

Thanks iainuts,

The interesting thing to add here for SS316L is:
1. Section II part D of the B&PV code does not rate SA276 (unlike SA479) for high temperature (pressure) applications.
2. The properties of the two specs. are so much alike (only the elongation for certian sizes of SA276 is precribed at a higher value).
How can one differentiate b/w the two? How can these spec. be so different - see 1 above and so alike see 2 above at the same time?

bssem

 

[metengr]

When the SA 276 material specification was submitted for ASME Section II review and endorsement it was for bars and shapes. This scope statement limits the use to non-pressure boundary applications (trim and internal support structure), it is as simple as that.

 

[iainuts]

Hi metengr. Both specs are for "bars and shapes" but SA479 then tacks onto the title "for use in boilers and other pressure vessels". Aren't both specs (SA276 and SA479) approved for BPV applications by virtue of their being SA grade material?

If a solid bar is bored out and used to contain pressure, does it need to be SA479, or doesn't it matter? And if it does need to be SA479, how does someone know that from reading either of these specs? Certainly one can't simply assume an intended purpose strictly from a title.

 

[metengr]

iainuts;
In reviewing the ASME B&PV Code, Section II, Part D, Table IA, the list of materials in this table can be used for pressure boundary applications, like SA 479. Materials not listed in this table are not permitted for use as pressure boundary material. SA 276 is a material that is is permitted for use by ASME B&PV Code, except only as support and trim function, and cannot be used for pressure boundary design applications.

 

[iainuts]

Thanks for that explanation.

 

[bssem]

Thank-you metengr for your input. It clarifies a few things for me.
However from the manufacturer of barstock and incomming quality (for machined products) points of view, what is the difference b/w making barstocks to either standard... are they both not hot or cold rolled products?

 

[metengr]

bssem;
Good question. If you perform a side by side comparison, you will see the ASME SA 479 provides specific information regarding heat treatment and grain size for austenitic stainless steel grades to assure maximum corrosion resistance in pressure vessel service. Also, review the Supplementary requirements in SA 479 versus none for SA 276.