Stainless nuts siezing on stainless studs...antisieze..

Pablo · Jun 9, 2004

We are breaking a number of studs or having a number of PEM studs spinning, due to the nuts siezing WHILE IN FREE SPIN mode. In other words, we aren't talking about overtorquing, misthreading, etc.

There is some literature (and some old mech's knowledge) about stainless steel hardware having this issue...galling and siezing.

Anyone knowledgeable on this condition?

I am considering recommending some anti-seize compounds. Any best for stainless?

XS650 · Jun 9, 2004

You're not the first person that has happened to.

Use a nickel type anti-seize, don't use a copper based one.

Google one of the nati-seize mfrs like Fel Pro or Permatex and you should be able to get some specific recomendations and more info.

Sounds like maybe the parts were dry and spun at high speed? In any case, use the right anti-seize.

Kestas · Jun 9, 2004

I'm a metallurgist, and I can categorically say that stainless steel is known for its galling when compared with plain carbon steel. But you don't have to be a metallurgist to know that. Most machinists recognize that stainless steel is "gummy". Use antisieze compound on the threads. Are you sure there weren't burrs on the threads that could've caused this?

XS650 · Jun 9, 2004

quote:

Originally posted by Kestas:
Are you sure there weren't burrs on the threads that could've caused this?

That's often the cause of a seizure on initial assembly. But, burrs are a fact of life, so it's best to always use the right anti-seize on a stainless on stainless threaded or pressed joint.

RB Shannon · Jun 9, 2004

quote:

I'm a metallurgist, and I can categorically say that stainless steel is known for its galling when compared with plain carbon steel.

Kestas, Why is that? Could it be that the chromium oxides on the surface are easily wiped off.
BTW we use Locktite Marine Grade anywhere there isn't any danger of food contamination and it seems to help. If I remember correctly we use 316ss bolts.

Pablo · Jun 9, 2004

Thanks for the GREAT replies. I also need to know WHY?

Kestas · Jun 9, 2004

The question WHY is the stuff of dissertations. I can only guess it may have something to do with the diffusion process causing microwelding or lack of adherence of the chromium oxide (good call, Shannon).

1sttruck · Jun 10, 2004

A general guideline to minimize galling is to use dissimilar materials, which could include just different hardness levels.

I almost always use anti-seize on lug nuts and spark plugs.

Cutlery is a hobby, and I notice that the typical softer stainless (it tends to be more brittle at a given hardness than tool/carbon steel) produces more of a burr when sharpening than tool or carbon steel, and that the burr can be hard to remove if the steel is too soft. It seems 'gummy'. I'll guess that it's due to the type of and amount of carbide formation.

Rick in PA · Jun 10, 2004

Don't forget to check the quality of the nuts (PEM hardware is typically good quality, so I wouldn't be woried about them). We had hardware problems at work and traced it to bad nuts, probably some low quality imported junk. Got a new batch of nuts and that fixed the problem.

rpn453 · Jun 10, 2004

quote:

Originally posted by XS650:
Google one of the nati-seize mfrs like Fel Pro or Permatex and you should be able to get some specific recomendations and more info.

That's probably the best place to start to get the right compound for your specific application.

I've got an old can of Never-Seez that I usually use on anything aluminum, stainless, or titanium. If it's a low temperature application, I've never had a problem by just using a petroleum grease on the threads. The anti-seize will probably last longer and work better though. I worked as a bike mechanic for a few summers and I've seen a lot of stripped threads. I've never stripped or seen a thread become stripped with these materials though if there's grease or anti-seize on them.

ChrisW · Jun 10, 2004

Link

I came across this webpage a while back. intersting to me.

Shannow · Jun 10, 2004

Working in the power industry, I'm not a huge fan of "Stainless" Steels.

Joints don't want to come unstuck, anything in electrolytic contact with them dissolves, chlorine casues it to fall to pieces, and a score with a carbon steel scaffold tube will cause our "stainless" ash hoppers to corrode.

I'd rather use it for decorative than mechanical fasteners. But in high temp, high pressure applications (1000F, 2500psi), sometimes you just don't have a choice.

(At least it's not Chrome Moly Vanadium steel like my steam mains are)

labman · Jun 10, 2004

quote:

Originally posted by ChrisW:
Link

I came across this webpage a while back. intersting to me.

--

One of the few positive postings on Teflon additives I have seen on BITOG. thanks for posting the link. I notice he didn't test one of my favorite lubes, powdered graphite.

Pablo · Jun 10, 2004

The Teflon link is interesting.

I notice he didn't really test many classical "good" anti-sieze compounds. I do wonder how they would have done....

Our are mostly 1/4-20 and #10-32 threads. It's mostly for appearance sake we use stainless. These are not supercritical structural applications in corrosive atmospheres, but they are high end comm power enclosures.

1sttruck · Jun 11, 2004

I'm not a big fan of using lubricants on fasteners unless it's called for, but I'm also assuming that the typical anti-seize compound isn't designed to be a typical general purpose lubricant. I would assume that a good general purpose lubricant would work better/longer at allowing nuts to spin up and down a threaded shaft multiple times, while I only expect the anti-seize to prevent the fasteners from seizing, and that I'll apply the compound each time I tighten the fasteners. In summary I DON'T want the world's best lubricant on all of my threads, I actually use a thread locking compound much more often than I do an anti-seize, and when I do use the anti-seize compound I would prefer lubrication to be incidental and minimal.

ChrisW · Jun 11, 2004

quote:

Originally posted by 1sttruck:
I'm not a big fan of using lubricants on fasteners unless it's called for, but I'm also assuming that the typical anti-seize compound isn't designed to be a typical general purpose lubricant. I would assume that a good general purpose lubricant would work better/longer at allowing nuts to spin up and down a threaded shaft multiple times, while I only expect the anti-seize to prevent the fasteners from seizing, and that I'll apply the compound each time I tighten the fasteners. In summary I DON'T want the world's best lubricant on all of my threads, I actually use a thread locking compound much more often than I do an anti-seize, and when I do use the anti-seize compound I would prefer lubrication to be incidental and minimal.

I've noticed that many times on anti-seize pacakges and tubes, it specifically states that it is not a high-speed lubricant; it says this on my tube of permatex (the gray stuff). This leads me to believe that it should only be used things that are tighted once and reapplied everytime it is taken apart and put back together as you have said. I am not aware of whether or not there are anti-seize compounds availible either from permatex or others that is a high-speed lubricant.

Titanium fasteners they reccoemnd the use of moly grease (maybe like CRC's stuff)or assembly paste under the "inch titanium hex flange nuts."

Pablo · Jun 11, 2004

Indeed, don't confuse a lube with an anti-seize. In fact some thin lubes make things WORSE (check out how WD-40 did!)

XS650 · Jun 11, 2004

quote:

Originally posted by 1sttruck:
I'm not a big fan of using lubricants on fasteners unless it's called for, but I'm also assuming that the typical anti-seize compound isn't designed to be a typical general purpose lubricant. I would assume that a good general purpose lubricant would work better/longer at allowing nuts to spin up and down a threaded shaft multiple times, while I only expect the anti-seize to prevent the fasteners from seizing, and that I'll apply the compound each time I tighten the fasteners. In summary I DON'T want the world's best lubricant on all of my threads, I actually use a thread locking compound much more often than I do an anti-seize, and when I do use the anti-seize compound I would prefer lubrication to be incidental and minimal.

Thread locking coumpound often accomplishes the same as an anti-seize, depending on the materials, because it seals the joint and prevents corrosion.

You are right about being concerned about anti-seize's lubricatiing qualities. It does act as a lubricant and will usually result in more clamping force than a normal nearly dry fastener.

The anti-seize manufacturers tech data sheet usually give enough information for a technically astute person to figure out how much to adjust the torque. A very few actually give a ball park torque reduction recommendation.

In reality, the avearage mechanic ignores the effects of grease or anti-seize on threads and assumes everything was OK because nothing broke.

Fortunately, automotive assemblies are usually designed to be maintained by mechanics of that talent level.

JohnBrowning · Jun 11, 2004

GM currently uses a lot of teflon coated hardware. I have often used moly EP grease on staniless hardware when I was out of antiseize and it worked just as well. If this for a large corperation a small study to determine if cheaply available moly EP grease will work could save a lot of money. True nichle anti-seize compounds are exspensive compared to moly EP grease.

Wich ever one your company ends up useing the torque speck will have to be modified to deal with lubed hardware.

IF you can get the supplier to coat them with anything like ZDDP,Teflon,Nickle,Moly etc that might be better then setting up shop to do this your self.

[ June 11, 2004, 06:45 PM: Message edited by: JohnBrowning ]

Stainless nuts siezing on stainless studs...antisieze..

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