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Anti-Seize Compound

There's no one "best" anti-sieze for all material combinations. I prefer a stiff high solids moly di-sulfide grease for most purposes but special applications may require some discretion. Some high confidence applications may mandate a specific anti-sieze when conventional wisdom would indicate a more efficatious choice - graphite in alcohol for stainless studs interferance fitted to tapped holes in a stainless casting forming a pressure boundry for one example.
 
Steel fasteners in to alumininium? copper A S works for me, in fact copper works for most combos - anythings better than nothing ;)

I only use nickel base AS in very high temp applications ( turbo charger bolts?) or where specified.
 
Steel fasteners in to alumininium? copper A S works for me, in fact copper works for most combos - anythings better than nothing ;)

I only use nickel base AS in very high temp applications ( turbo charger bolts?) or where specified.

If the assembly is liable to get wet I would not use a copper-based anti seize compound with aluminum...

Nickel based is ok for most other applications.

On nuclear work we used graphite-in-distilled water (F.A.: ethanol would have been nicer, but I found out several years ago that ethanol can corrode and eat through 304L tubing).

Arminius
 
"On nuclear work we used graphite-in-distilled water (F.A.: ethanol would have been nicer, but I found out several years ago that ethanol can corrode and eat through 304L tubing)."

Zounds!! No kinnding!! What was the corrosion mechanism? I've heard of chloride corrosion, electrolysis, intergranulars etc but alcohol? CH2COOH etc? Where is the nasty ion?
 
"On nuclear work we used graphite-in-distilled water (F.A.: ethanol would have been nicer, but I found out several years ago that ethanol can corrode and eat through 304L tubing)."

Zounds!! No kinnding!! What was the corrosion mechanism? I've heard of chloride corrosion, electrolysis, intergranulars etc but alcohol? CH2COOH etc? Where is the nasty ion?

6,7 years ago I was working for a firm whose primary business was inspection of pressure vessels, piping, storage vessels, ship's hulls, etc. I was doing design and certification of lifting devices which did not really fit into the bigwig's business plans or insurance premiums.

Got to know the resident PhD metallurgist who was investigating this corrosion phenomenon... He'd never heard of this either and wrote a paper about his findings. I seem to recall that it appeared to be intergranular corrosion as the fissures appeared to follow the grain boundaries. It is possible that the ethanol contained a contaminant or that the steel was of questionable provenance.

Don't know if it got published in one of the metallurgical magazines or what.

If you have a need I could try to find the name of the metallurgist (he was Turkish and I forgot his name; but he was a capable individual).

Arminius
 
...(F.A.: ethanol would have been nicer, but I found out several years ago that ethanol can corrode and eat through 304L tubing).

Arminius

Absolute ethanol or denatured ethanol? Denatured ethanol can contain a variety of things such as aldehydes, ketones, pyridines and goodness knows what else, so a corrosion problem could be due to an additive not the ethanol itself.
 
I’m wary about chipping in here, as I’m only going to give half a story about a very complicated topic which has lots of ifs and buts.

Be very, very careful about using any ‘anti-seize’ compound on critical applications. I’m not going to attempt to define ‘critical’ or to recommend any products, but be aware that in hot, wet conditions, many of the organic ingredients of these compounds can break down to produce organic acids. These can initiate stress corrosion cracking (intergranular) of steel fasteners. It is true that hot, wet conditions alone can result in SCC, but it is much more likely when lubricants are present, and worst of the lot are compounds containing moly disulphide or copper. This is a big problem on things like valves on high pressure/high temperature steam or water systems, where many potentially dangerous failures have occurred. Fasteners have become wet through steam leakage, cracks have initiated and propagated, and the fasteners have failed. Many companies in the power generation industry have strict controls on the use of lubricants for this reason.

Graphite in water, as mentioned by Armenius, is widely accepted, although as can be imagined its effectiveness as a thread lubricant is not as good as the more obviously slippery compounds. There is also a very limited range of proprietary lubricants that are accepted, but I can’t quote names and numbers.
 
I don't think I'll ever run into that stress crack problem in any application I'ld be involved with. I use nickel and copper-based compounds for most any applications. I use copper mostly for very long-term applications like splines inside a dozer. I always keep the nickle-based in my toolbox for stainless and aluminum.
 
While we are on the subject, I vacuum heat treat beryllium copper contact springs in a 304 SS fixture. The fixture is held together with a bunch of 1/4-20 SS studs with SS nuts, one between each spring. Using a heater under the fixture caused problems because the cover plate expanded faster than the main fixture and tore things loose, so I put up to 800 amps through the fixture, using it as its own heater. The temperature is held at 600 F for an hour. I use Never Sieze on the nuts, but still have a few losses from galling each run. The vacuum is as high as I can get with a diffusion pump, necessary because oxidation makes a patina that is very difficult to remove and they are silver plated afterward. I need something that will not contaminate the vacuum or the parts, although that is not too serious because outgassing of the metal limits the vacuum while the heat is on to something around a micron.

Any suggestions?

Bill
 
I don't know of any ethanol compound that attacks 304 SS. Even elevated temps on everything still makes is an acceptable choice. What Armenius is describing almost sounds like sensitization, but that usually occurs at above 1000F which would be unusual for any ethanol compound.

All most all of our stainless and steel products get put together with Lub-O-Seal nickal anti-seize compounds. For aluminum, most of the time we use ENC coated fasteners. If they are not available (extremely rare), we use a product call No-Ox.

Our oxygen service products require a non-metalic, non-grease, no melt compound.

Nuclear is another story. What worked 30 years ago is probably not going to work now. We are writing all new assembly and cleaning proceedures for nuclear products. Most of our stuff was assembled with Lub-O-Seal NM-91, but that will probably change. They are so picky, we have to be careful of what material our fixtures are made from.

Bill, Look at the Lub-O-Seal website, they probably have something for you.
http://www.lub-o-seal.com/products/manufactured/mfg_products.html#antiseizes

JR
 
Put a couple of turns of PTFE thread tape around the fastener. I kid you not. Have used this with great success with fasteners subject to salt water.

It works by isolation and lubrication.
 
Ah, Mark, you’ve just reminded me:

Xantho01.jpg


Take a marine engine, built in the 1850s, sink it in warm, shallow sea water in 1872. Leave it for 120+ years. Scrape tons of concretion off. Identify the nuts, heat them with a torch, and unscrew them. Go to your local fastener store, get some British Standard Whitworth nuts, and screw them straight on the original bolts to hold the engine together while you carry on dismantling.

Joseph Whitworth knew what he was doing, 150 years and 10,000 miles away. Standardisation would have been a good thing, if it had caught on.

The engine was in the SS Xantho, and was investigated in a superb archaeological undertaking, and can now be studied in the shipwreck museum in Fremantle, Western Australia.

The lubricant? Tallow.

They used it on the crankshaft journals as well. They were OK, too.
 
I’m wary about chipping in here, as I’m only going to give half a story about a very complicated topic which has lots of ifs and buts.

Be very, very careful about using any ‘anti-seize’ compound on critical applications. I’m not going to attempt to define ‘critical’ or to recommend any products, but be aware that in hot, wet conditions, many of the organic ingredients of these compounds can break down to produce organic acids. These can initiate stress corrosion cracking (intergranular) of steel fasteners. It is true that hot, wet conditions alone can result in SCC, but it is much more likely when lubricants are present, and worst of the lot are compounds containing moly disulphide or copper. This is a big problem on things like valves on high pressure/high temperature steam or water systems, where many potentially dangerous failures have occurred. Fasteners have become wet through steam leakage, cracks have initiated and propagated, and the fasteners have failed. Many companies in the power generation industry have strict controls on the use of lubricants for this reason.

Graphite in water, as mentioned by Armenius, is widely accepted, although as can be imagined its effectiveness as a thread lubricant is not as good as the more obviously slippery compounds. There is also a very limited range of proprietary lubricants that are accepted, but I can’t quote names and numbers.


At the power plant I work at we are in search of a better anti seize product for steam applications. Do you have any suggestions on what works well inside steam turbines, valves etc? What we have now does not work very well and normally during outages we end up drilling or spark erosion the bolts and studs out and we would like to get a way from that if we can.

Thanks
 








 
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