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4130 High Pressure Piping

4130 High Pressure Piping

4130 High Pressure Piping

(OP)
I am trying to determine a wall thickness a tubular / pipe of 4130 material that has a design pressure of 15,000 psi at 100 F.

I am using B31.3 for process piping and am trying to apply equation 34a of the high pressure piping design section K304.1.2.

The criteria states that "for heat treated austenitic stainless steels and certain nickle alloys" apply the equation.

My question is this:

1.) Does SA 4130 pipe classify as a nickle alloy?

Thank you in advnance.

RE: 4130 High Pressure Piping

I believe that your material you mention really is A519 - Gr 4130......is that correct ?

I believe your code of record should be ASME B31.3...(or it's international equivalent)

If so, please be aware that A519-4130 is not listed as an accepted material in Appendix A

RE: 4130 High Pressure Piping

(OP)
Yes it is A519-4130 material. I am trying to use the B31.3 equation (34a) from Chapter IX:

t = (D-c)/2 x [1 - e^(-p/S)]

Would this equation apply for A519-4130? I am using an allowable stress of 2/3 x Sy as mentioned in Chapter IX for "other materials".

Thank you.

RE: 4130 High Pressure Piping

(OP)
I have used the B31.3 pipe thickness calculation both from Chapter II, part 304 (normal piping) and from Chapter IX, part K304 (high pressure piping).

I have attached my calculations, and I am getting a thicker section of piping from the normal piping equation than I am from the high pressure piping equation.

This does not seem to make sense to me, as I would expect the high pressure piping would have a higher safety factor.

Am I missing something here?

Thank you very much!

RE: 4130 High Pressure Piping

Yes you're missing something. Review e.g. Becht's book on Process Piping: The Complete Guide to ASME B31.3, Third Edition. It's, amongst others, in the eq.'s used.
Have you used table K1 for high pressure piping and table A1 for normal piping wall thickness calcs?

RE: 4130 High Pressure Piping

(OP)
SA519-4130 is not a standard material grade listed in either of the B31.3 stress tables (A or K).

I am using the B31.3 allowable stress S for "other materials". I am using the lesser of St/3 and 2/3 Sy.

Is the high pressure (chapter IX) safety factor supposed to be less than the low pressure (chapter II) safety factor?

Thanks.

RE: 4130 High Pressure Piping

I believe (but am not 100% sure) the governing stress distribution in thick walled pipe is different, hence why the standard B31.3 require t/D<6 is not applicable.
For thick walled pipe, you get (I think it's called) membrane stresses.
The safety factor may be less due to that reason, but also for another reason,
so Im not 100% sure. Yet again, read Becht's book.
I think it'll point you in a better direction than my blurred can do now ... ;)

RE: 4130 High Pressure Piping

engpes,
If you are using High Pressure piping equation the allowable stress basis is different to the general values in ASME B31.3 Read the full extent of the High Pressure chapter and you will see!!!

RE: 4130 High Pressure Piping

(OP)
I purchased Becht's guide and it shed quite a bit of light on the design basis. Thank you very much!

This has helped tremendously!!!

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