ASME Fasteners Vs SAE Fasteners

[TBP]

Is there any cross-referencing for B7 studs/bolts & 2H nuts and SAE Gr 5 & Gr 8 bolts and nuts for flanged joints under codes like ASME B31.1? I see huge numbers of the SAE grades (usually 5 because they're cheaper) in all kinds of industrial steam and compressed air piping (flange bolts). I was reading some steam trap manufacturer's literature today (very well known brand name in North America) and they list the fasteners for their float & thermostatic traps as "Gr 5".

I don't think ASME and SAE grades of fasteners are (or should be) interchangable, but I've been wrong before. Any thoughts?

 

[John3p]

Interesting question.

I'm not sure what we can infer from this, but the Machinery's Handbook lists identical head markings for:

SAE - Grade 5 & ASTM A449
SAE - Grade 8 & ASTM A354 Grade BD

I'd be interested in a more definitive answer. A well defined problem is half solved.

 

[TBP]

Hi John3p:

Thanks for considering my question. I have a small "IPT's Industrial Fasteners Handbook" The ASTM A-193 bolts/studs info for pressure piping flanges is in a whole different section of the book from the SAE stuff. The A-193 table includes data on chemical composition for studs, maximum operating temperature, elongation, etc. It lists grades as B7, B7M, L7, L7M, etc. Nuts are 2H and 2H heavy hex. All of the piping books I have (Grinnell's "Piping Design & Engineering", Nayar's "Piping Handbook" etc) only refer to A-193/A-194 type material. None makes any mention of SAE grade fasteners, that I can find.

In spite of my question, in 25 years of working in powerhouses and working with pressure piping systems, I can think of no catastrophic flange failures (on systems running 300 PSIG steam or less) that can be traced to SAE fasteners. Having said that, I still don't think the SAE grades meet code in these applications.

Just in passing, this little IPT book (ISBN 0-920855-06-7) is extremely useful. Nuts, bolts, screws, gaskets, o-rings, rivets, adhesives, concrete anchors, shaft keys, all kinds of threads (including pipe), etc. It's pretty hard to go wrong for under $20. I originally ordered "Pipe Trades" and "Metal Trades" from them, and was so impressed, I bought the rest of the set. There are 10 in all. There's not much for formulas, but if you're involved in plant maintenance or construction, the amount of information in these is incredible.

 

[John3p]

TPB,

Thanks. I'll look into acquiring that little IPT book. A well defined problem is half solved.

 

[iven]

Well in accordance with our State Boiler Inspector it has to be H-7 and B-2 per code. This was for the fasteners on the pressure operated relief valves. He also pointed out that the valves were remanufactured at the same plant as the original manufacture and that this was not an acceptable code condition for a new installation.
Iven, with egg on my face.

 

[TBP]

I don't think you should feel that you have egg on your face, Iven. I've posted this question on a couple of boards, and got very limited response. I suspect that there are now a number of people quietly checking flange bolts in their plants, and what's on the shelf in their stockrooms. Some of those people will likely quite nervous about what they've found.

At least you have an inspector that will give you an answer. The inspection authority here is just maddening to deal with. They'll bend over backwards to dodge providing a direct answer to anything.

 

Gentlemen,

I hate to bring reality into this because it really is an interesting technical question.

However, the real answer is that because it is a administrative jurisdictional matter you cannot arbitrarily use the SAE bolts in a Power Plant. It ain't for nothing that we have Standards. The local building Code (directly or indirectly) calls for B31.1 to be the design Code of record. This makes it (B31.1) the law. That being the case, you cannot deviate from the requirements of B31.1 without breaking the law. B31.1 addresses the use of unlisted materials in paragraph 123.1(C) of Chapter III. The committee will review applications for including materials that are not listed on an individual case basis. The mechanism exists for you to "ask". If it is worth taking your time to do it, you can have B31.1 decide. An Authorized (or commissioned) Inspector (AI) has no choice to make in this matter. The Code defines "good practice" in this case (and the jusisdiction makes it the law) and if the AI is to be true to the jurisdiction (state, commonwealth or province), and the law the answer is "no".

Best regards, John.

 

[butelja]

Another consideration aside from the binding legal requirement already pointed out is that SAE fasteners have much more wide open metallurgical requirements. They also consider mechanical properties at room temperature only, with no allowance or consideration of mechanical properties at elevated temperatures.

 

[TBP]

Thanks for your input, John and butelja. I concur totally. The pressure piping code requirements here are as good as anywhere. However, inspection & enforcement is a joke, and has been for years. I have been after the inspection authority for over 5 months to clarify my question. I'm tired of being "high-bid" on piping jobs by the slim margin that doing things like using the correct grade of fasteners, and machining the raised faces off 150# flanges so they can be bolted to 125# flanges represents.