ASME B31 Allowable Stresses 1

[pipesvessels1]

How do I calculate the allowable stress of a particular material that is not listed within ASME B31.3 or ASME IID.

I am particularly interested in ASTM A350 LF6 Cl.2 @ 210F.

Can anyone please help.

 

[TVP]

I am not familiar with the requirements for "process piping" according to ASME B31.3, so it may be beneficial to provide some additional details on the definition of allowable stress. Is there a fatigue requirement? Fracture toughness is apparently something you are considering. Why is this? Low temperature service? Corrosion environment?

The mechanical properties of the steel alloy outlined in ASTM A 350 LF6, class 2 will not change appreciably from ambient temperature to 210 degrees F, with much emphasis on appreciably. Which heat treatment were you considering? I would expect the precipition heat treatments to provide the most stable mechanical properties as temperature increases, but again, 210 degrees F is not really considered elevated temperature.

 

[AEF]

A350 is a forging spec. If your fabricating a standard forged fitting go to the applicable spec., such as B16.5 and determine the working pressure by the class (A350 LF6 Cl.2 is listed as a group 1.2 material in B16.5). If your using the material for some other aplication, go to B31.3 Chapter IV, 326.1.2 or 326.2.2
Good Luck!

 

[ppk]

Try

http://www.matweb.com

, there you can find practically all specs. of materials.

 

[reichertc]

If you look in B31.3 302.3.2 d-f, there is a full listing of what the allowable stresses are based upon. I would expect that you could use the design bases to determine allowable stresses for unlisted materials. Please note that there are modifications to this paragraph in both the 2000 and the 2001 addendas to the 1999 code, so you'll want to be using whatever one is applicable to your project. I'd list off the bases for stresses, but this paragraph is about a page long, and I wouldn't want to give incomplete info. There is a note at the beginning of the paragraph that says "These bases are the same as for BPV Code, Section VIII, Division 2, given in Section II, Part D..." so if you can track down either B31.3 or the BPVC you should be able to find this info.

You may be able to use the bases to justify using the allowable stresses from another material based upon the comparable properties...

I haven't personally done any of this, but it would seem to be a logical approach to the problem.

Hope this helps.

 

[pipesvessels1]

Thanks for your suggestions.

In ASME B31.3(2002)302.3.2 (f)it suggests multiplying the the SMTS by the ratio of the Tensile strength at temperature to the tensile strength at room temperature.

This is confusing as I require the tensile strength of the given material at the particular temperature to find the tensile strength of the given material at the particular temperature?

Unfortunately,still lost?

 

[teodoro]

Hi

I'd like to know max pressure the Carbon steel(A352 Gr LCC) and AISI 316 are able to withstand when temperature is below - 60°C for Rating 300 and 600.

Thanks

Teo