Working Pressure @ Certain Temperatures

Working pressure is always the pressure that the system pushes on you and not what the temperature regulates.

If you meant to find the allowable pressure related to the temperature you might want to correlate similar material in the code regarding content and tensile strength to the one you have. But this is just a rule of thumb. Which material in particular are you interested in?

Yes, sorry, I meant the allowable pressure. I was looking for the pressures for AISI 4140 material.

On another note, when you mean pressure are you refering to the ksi value as in tensilte loading? Otherwise you need to take into acount the geometry. As for pipes this means the size will have to be taken into consideration.

For the materials mentioned in the B16.34, you can see what design pressures you can use at temperatures ranging from -29 till approx. +500°C.
I am a little at a loss however, if the material the customer wants is not mentioned in the B16.34.
Where can I find then the design pressure at a certain temperature.

Body & shell materials must comply with ASME and ASTM material standards for chemistry and strength.

Why would the customer want a non-compliant material in their design?

Don't exactly know why they want it, but they want it and we have to deliver.
An other material (perhaps more suitable) would be the ASTM A522 type I. This one is also not mentioned in the B16.34. Where could I find the data for this material?

I'm beginning to think you are fishing, or very new to the party.

Certified test data and certification of a material to a recognized standard cam only be obtained from the material supplier.

How will the facility insurance carrier react to a vessel built with uncertified materials. What assurance will you give them your customer that the vessel is safe to operate, if you are using uncertified materials of construction?

Who, in your organization, will sign off on the legal documents certifying the safe operation of the equipment?

Good luck.

How about discussing this project with the Engineer/Surveyor for the company that will be supplying burst/collapse indemnity insurance cover for the vessel? Like, right now and by telephone? <sigh>

I am under the impression that my question is a bit overrated. I know what I need to know because I had the good sense of asking the customer (and their engineers) what the numbers should be. I just was wondering if I could find these data somewhere for myself in the future. I am not that stupid that I just guess what it should be, was just trying to get some advise from more experienced people. I thought that was the purpose of forums. Apparently I was wrong. Guess this thread can be considered closed now.

Perhaps some clarity of question would have helped.

First you say, "where I could find working pressures belonging to certain temperatures if the material is not mentioned in the ANSI B16.34"

"sorry, I meant the allowable pressure. I was looking for the pressures for AISI 4140 material."

"Don't exactly know why they want it, but they want it and we have to deliver"

"I know what I need to know because I had the good sense of asking the customer (and their engineers) what the numbers should be."

"I just was wondering if I could find these data somewhere for myself in the future."

I would think that the specifying entity (your customer) could provide such data as justification for asking you to use it, and would be happy to help you understand their reasons for requesting these specific materials.

To me, that would be good engineering practice.

Sorry to see you go.

You confusing the terms "pressure" and "stress."

I think AISI 4140 is a material commonly used for shafts, not a plate for use in making pressure vessels.