Allowable Stress for Unknown Carbon Steel Material for Manhole Plate on a Pressure Vessel

Danger Will Robinson . . . .

what is that supposed to mean?

Try this.

Proceed with great caution at your own risk. People's lives could be at risk based upon the assumptions made.

As far as plate goes, SA-36 would probably be the most conservative assumption. In the absence of mill-cert documentation, though, you're shooting in the dark.

Cast materials include cast iron (CI), ductile iron (DI), and cast steel (CS, but that might be ambiguous with carbon steel). DI is often used for compressor and valve body castings. I'm not expert on this, and I haven't seen any posts in some time from Milo, the "resident metallurgist" on CR4.

<,,,pressure vessel with flat bolted heads on both sides (Design Pressure 160 psig and Design Temperature 450 F)...>

There should be a written scheme of examination and a series of periodical test reports in pursuit of continuing burst/collapse indemnity insurance cover on the equipment. That's where to start. Again.

"No azia5333 is an island."

Given the test pressure applied to the vessel on those reports it is possible to calculate the stress that each bolt is experiencing. If that figure exceeds the figures quoted for materials in any mechanical handbook, and Kempe's Engineers' Yearbook any edition springs immediately to mind, then the equipment will not be insurable.

That's it, in a nutshell.

<...Unknown Carbon Steel Material...know it is carbon steel...>

There are a lot of unknowns on a vessel that has a <...Design Pressure 160 psig and Design Temperature 450 F...>!

Where are the records for this vessel, please?

<...The service is steam at 150 psig and 366 F. The size of the drum is 120" X 42" dia...>

If this is the same vessel as in the earlier thread it is unconscionable that such a vessel is in service without a single test record in place for burst liability insurance cover purposes!

However, if that is the case then please ensure all other CR4 readers are at least 500m away before its use.

Amen. Hence my reference to Lost in Space.

How did the calls go, please?

No one else in this forum apart from the Original Poster will accept liability should this vessel fail. It can’t be delegated-out. The risk can only be farmed-out to an insurance company.

Got it?