Maximum temperature for Material as per ASME Section II

[Soft2008]

For SA-540 B23 Cl.3 (2Ni–3/4Cr–1/4Mo) Bolt material, is it possible to use at design temperature of 390 deg C ?

For above material, maximum temperature limit is 371 deg C as per ASME Section II (Equipment designed per ASME Section VIII Div.1).
Equipment operating temperature 340 deg C and Original Existing design temperature 360 deg C which is no problem in operation because it meets the ASME.

However, I want to ask here is it completely prohibited to use bolt material SA-540 B23 Cl.3 at design temperature of 390 deg C ? for SHORT time 10-15 mins.. what would may happen to bolts at 390 deg C .does the bolt yield or may fail in those 10-15 mins?

As per plant operation Hazop and revamp study, process team asking to include a rare case where fluid with design temperature of 390 deg C may back flow and present in this for 10-15 minutes if pump blockage. Its not the original design case but they want to know sure the bolt would withstand this 390 C temp for 10 to 15 mins is back flow occurred.

It is difficult to replace bolts because of the site and current condition for this exchanger, so I am checking possibility to find ways for reuse of existing bolts.

 

[XL83NL]

In contrast to ASME B31.3, ASME VIII-1 doesn’t allow short term excursions above design. The limit in IID is a hard one. The only way to bypass that, afaik, is by using a code case.

Huub
- You never get what you expect, you only get what you inspect.

 

[SnTMan]

Soft2008, will the actual bolting temperature exceed 371 C during yuor short excursion? If not, you may be OK. Your design documents might state "Vessel designed for 390 C, bolting designed for 371 C", or words to that effect.

Regards,

Mike

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

 

[Soft2008]

SnTMan, Thank you.
I rechecked with our process team and actual bolting temperature have a very slim chance to beyond 371 deg C and they wanted us to cover 390 deg C design to bolt also. So it is needed to explore stretching the design temperature limit of IID if code case or exemption that may allow the bolt to operate at 390 deg C for those 10-15 mins only (390 deg C is not the continuous operation/design).

XL83NL, Thanks. Does ASME B31.3 allow such deviation ? please provide the clause number if you know. And please specify the code case number if available.
This deviation limit in IID is hard for our site situation. Bolts are applied in D type exchanger channel cover bolts which were securely seized to exchanger body over these years and bolt replacement is deemed to be difficult due to the short shutdown schedule. I am still rolling the pages of ASME code cases which may allow our bolt to work in 390 deg C because this case for that short time on 10-15 mins.