Confusion on Flange Mat'l and codes (ASME VIII / ASME B16.5 / ASTM A182) - 410 Stainless

[awhicker84]

Hi,

Simply put, I have a compressor casing that needs a weld neck flange. Construction is per ASME VIII. THe casing is 410 CA6NM. I was looking thru our company's specs and noticed we don't have any martensitic stainless weld neck flanges called out (I was looking for 410). I start looking at ASME VIII and it calls out B16.5 for flanges. Then I look around at vendors that produce B16.5 flanges and realize they call out materials using ASTM A182 (among other mat'l specs). A182 has UNS 410 as an option, however 410 doesn't seem to be among vendors options.

So.. what's going on here and what am I missing. It seems 410 doesn't meet a spec, but I'm not sure which one. I don't have access to ASME B16.5. Does this have a section detailing acceptable materials? If so, is 410 not allowed?

Thanks and cheers,

 

[awhicker84]

Maybe nevermind, it looks like it is commonly produced?

B16.5 is a dimensional spec only, correct? It is somewhat confusing that we call out material from ASTM for a ASME part.

I would still like some clarification, if anyone has sort of a decision tree / selection process summary..

 

[XL83NL]

There’s so much to answer as your post implies you seem to know so little about this topic. So please bear with me, with all due respect.

If you don’t have a copy of B16.5, get one. Read it. B16.5 is for a lot more than dimensions.

Is the compressor designed as per ASME VIII Div1?
Do you have a copy of ASME VIII—1? It does list more options for flanges besides B16.5.

If the design doesn’t need to meet VIII-1, do you have a copy of ASTM A182? Do you understand what these codes and standards stand for?

There are a lot of people here willing to help, but with such background, it’s doubtful if the help you require meets the intent of the forums policy and their members contribution.

 

[SnTMan]

awhicker84, I can't confirm the to the latest edition B16.5, but in older editions 410 materials were not within the scope. This means B16.5 contained no pressure-temperature ratings that could be applied to flanges of 410 materials.

A B16.5 pattern flange of 410 material, if such existed, would have to have the P-T rating confirmed by other means, such as perhaps Sec VIII, Div 1, Appendix 2.

Regards,

Mike


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

 

[awhicker84]

Thanks Mike.

That's what I was shooting for. ASTM A182 does reference ASME BPVC IX. I think we are basically saying that other materials are "pre-approved", while 410 requires some additional calculations.

Thanks again

 

[XL83NL]

Why would a standard for forged materials refer to a (service) Code for welding (ASME IX) in this context?

 

[awhicker84]

Yeah, I found that odd. I'm just telling you what it references. You can check for yourself (I don't want to break any rules for sharing snipets of code). However, the actual code that gets referenced inside BPVC Section II is SA182, not A182.

I'll have to dig deeper. I was also surprised to see IX called out, but it made me feel more comfortable that ASME was mentioned in the spec. I saw one vendor site refer to their flanges as thus:

 

[awhicker84]

Maybe it is a mistake in the A182 spec?

 

[awhicker84]

I sent the question into the ASTM.org website. We'll see what they say about the IX reference. I've asked an API person a question before and was blown off. Those people have regular industry careers, so they probably just have "better things to do".

 

[XL83NL]

Do you own a copy of ASTM A182 or ASME Section II-A?

 

[awhicker84]

I realized what it was right after I typed this up and now I feel bad I submitted the question. The reference has to do with weld repairing during the casting / forging phase.

 

[SnTMan]

You can buy B16.5 pattern flanges made from PVC. They ARE NOT B16.5 flanges.

Regards

Mike

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

 

[awhicker84]

Right. I'm trying to get my hands on B16.5... trust me. We have a hardcopy, but I need a digital one.

Thanks for all the help

 

Although it appears not to be an option in this instance, be careful joining CA-6NM to SS410 - they have incompatible PWHT temperature requirements. CA-6NM would be severely damaged by PWHT at the higher prescribed temperature for SS410.

I have never encountered this combination, although I am expert in CA-6NM fabrication. I think the incompatibility could be overcome by safe-ending the SS410 with a buttering layer of 410NiMo weld.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."