recommendation for anti-seize?
recommendation for anti-seize?
(OP)
I am designing a pressure vessel that will be using Inconel 718 bolts due its strength retention at the design operating temperature of 550C. Preliminary testing has shown a problem with galling when torquing the bolts with dry threads, so I am considering using anti-seize to prevent galling.
I did a search on anti-seize in the forum and came across a statement that using the wrong kind of anti-seize can be disastrous. No specifics were offered, but I gathered that the problem lies with the anti-seize compound "baking" at high temperature and becoming a solid, like epoxy maybe.
So is that simply a problem with using anti-seize that is not rated for the temperature, or is there more to it than that?
Any recommendations? As I said, the operating temp is 550 C, the bolt material is Inconel 718, and the bolts are 1-8 UNC and will be preloaded to 31,000 lbs each for the hydrotest, and 20,000 lbs for design temperature and pressure.
Thank you.
I did a search on anti-seize in the forum and came across a statement that using the wrong kind of anti-seize can be disastrous. No specifics were offered, but I gathered that the problem lies with the anti-seize compound "baking" at high temperature and becoming a solid, like epoxy maybe.
So is that simply a problem with using anti-seize that is not rated for the temperature, or is there more to it than that?
Any recommendations? As I said, the operating temp is 550 C, the bolt material is Inconel 718, and the bolts are 1-8 UNC and will be preloaded to 31,000 lbs each for the hydrotest, and 20,000 lbs for design temperature and pressure.
Thank you.





RE: recommendation for anti-seize?
RE: recommendation for anti-seize?
I-718 is used for critical nuclear bolting, so I'm sure EPRI has something to say on the matter; try searching there.
https://www.epri.com/
"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
RE: recommendation for anti-seize?
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P.E. Metallurgy, Plymouth Tube
RE: recommendation for anti-seize?
RE: recommendation for anti-seize?
I actually have a bucket of 718 bolts in my office that were all lubed with nickel, and exposed to temps <400 F. Almost every one of them had to be cut. I really ought to throw those out...
Nathan Brink
RE: recommendation for anti-seize?
http://proceedings.asmedigitalcollection.asme.org/...
RE: recommendation for anti-seize?
I've just had terrible luck with nickel antiseize in general. I'm all about moly disulphide lubes myself, but that's a little toasty...
Nathan Brink
RE: recommendation for anti-seize?
Nickel antiseize on nickel alloy bolting does not compute, but if metengr says to try it, I'd test it.
There are some versions with lead and lead oxides that were used historically; you can still find the stuff in industrial supply catalogs.
Oh and yeah, don't trust automotive engineers when it comes to PVs, what do they know, just building millions of very high temperature, million-cycle loaded pressure vessels operated by amateurs in every environment known to man. MY personal experience with Inco 718 bolting doesn't come from nuke plants, it comes from rocket and jet engines and their associated R+D, so by all means ignore my silly ideas. FWIW, OP you mentioned testing and I think that is the wisest thing said in this whole thread.
RE: recommendation for anti-seize?
Spray can BN is even better, but it is also soft and the coating is fragile. It is very slick though.
We also used it in the lab. But we had a good control over cleanliness and application.
For long term high temp stuff we used to favor solver platting the bolts.
We would use them up to 1550F (850C), and it is reusable.
Avoid anything with lead, tin, sulfur, cadmium, zinc or any other low melting point element.
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P.E. Metallurgy, Plymouth Tube
RE: recommendation for anti-seize?
"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
RE: recommendation for anti-seize?
RE: recommendation for anti-seize?
Regards
r6155