Stainless Steel Threads -- locking and galling?

Thread Starter

cmartinez

Joined Jan 17, 2007
6,624
MOD NOTE: This is an off-shoot of another unrelated thread and is being split off in case anyone would like to discuss it further.

Thread lock? Here, each color has different strength or application.


View attachment 98633
Sometimes, the last thing you want is for threads to lock... especially when dealing with stainless steel fittings:

Loctite--Silver-Grade-AntiSeize-2A1-ba.jpg
 
Last edited by a moderator:

#12

Joined Nov 30, 2010
18,167
to prevent stainless steel threads from seizing is to use two different grades of stainless for nut and bolt.
That sounds like something a mechanical design engineer would never think of or design into a product. I suppose some of them know about this, but if I ever saw it in the real world, I didn't know what I was looking at. Is this common practice? Is it just one of those things one picks up over the years, and most people don't know?
 

JohnInTX

Joined Jun 26, 2012
3,903
(defensively) Gopher started it.:eek:
I pick up new information where I find it. That is a priority for me. If this kind of Thread Locking belongs in a different Thread, it won't be the first one the Mods split for me. In fact, it won't be the first one the Mods split for me in the last 24 hours!:D
OT maybe but @GopherT has a point, according to Fastenal. If you want to continue in a new thread let us know.
 

Attachments

WBahn

Joined Mar 31, 2012
24,970
That sounds like something a mechanical design engineer would never think of or design into a product. I suppose some of them know about this, but if I ever saw it in the real world, I didn't know what I was looking at. Is this common practice? Is it just one of those things one picks up over the years, and most people don't know?
My guess is that the galling of stainless steel is a topic that few people know much about unless they have had need to work with stainless steel, in particular threads, in a situation in which galling was an issue. Then, whether engineers, technicians, or mechanics, they learn about the issue and the common tricks to deal with it.
 

Thread Starter

cmartinez

Joined Jan 17, 2007
6,624
My guess is that the galling of stainless steel is a topic that few people know much about unless they have had need to work with stainless steel, in particular threads, in a situation in which galling was an issue. Then, whether engineers, technicians, or mechanics, they learn about the issue and the common tricks to deal with it.
What I'd like to know is the why of this phenomenon... is it a chemical thing? or does it have to do with the alloy structure or some other physical forces?
 

WBahn

Joined Mar 31, 2012
24,970
What I'd like to know is the why of this phenomenon... is it a chemical thing? or does it have to do with the alloy structure or some other physical forces?
Different materials have different wear characteristics due to different surface physics. A lot of factors come into play. Aluminum is notorious for galling, as are most allows of stainless steel. If you have extremely clean steel (don't know how sensitive to alloy composition it is) plates in contact with much pressure at all and try to slide them they will cold weld to each other.

Surface physics is, in general, an extremely complicated field that we are always learning new things about and that many of the things we have learned how to exploit we don't really know what the true underlying phenomena are.
 

Thread Starter

cmartinez

Joined Jan 17, 2007
6,624
Surface physics is, in general, an extremely complicated field that we are always learning new things about and that many of the things we have learned how to exploit we don't really know what the true underlying phenomena are.
That should make it an extremely interesting subject for any materials engineer looking for an appropriate theme for his thesis and disertation.
 

WBahn

Joined Mar 31, 2012
24,970
It is a VERY active field of research in many disciplines. Physics, Metallurgy, Materials Science, just to name a few. Papers are constantly being published and there are numerous opportunities for students at all levels (undergraduate to post-doctoral) to be involved.
 

#12

Joined Nov 30, 2010
18,167
I ran across a TV show about 3 this morning that focused on the idea that surfaces are where chemical interactions take place, like, life didn't arrange itself in a soup, it arranged itself on a surface.

ps, I have no intention of proving that TV show was correct or that God said, "Let there be surfaces". It was just a TV show with an interesting perspective.
 

Thread Starter

cmartinez

Joined Jan 17, 2007
6,624
I ran across a TV show about 3 this morning that focused on the idea that surfaces are where chemical interactions take place, like, life didn't arrange itself in a soup, it arranged itself on a surface.

ps, I have no intention of proving that TV show was correct or that God said, "Let there be surfaces". It was just a TV show with an interesting perspective.
It does make sense.... after all, every physical contact between 3D bodies occurs in either 1 or 2 dimensional surfaces.
 

#12

Joined Nov 30, 2010
18,167
It's counter-intuitive to me. All 3D bodies can bump into other 3D bodies, and there is more movement in a soup because surfaces in a fluid tend to have a stagnant layer on their surface. Just saying, if it's true, it's news to me. Like, molecules bump into each other and bind together better if they are holding still? I have doubts.
 

wayneh

Joined Sep 9, 2010
16,125
Molecules yes, but living things all have membranes that define self from non-self. Inside from outside. A lot goes on at that interface, especially in us mammals. Our membranes have ion channels, molecule receptors, all sorts of things.

Still, I'm not sure it's all that useful to focus on surfaces. Anything involving DNA replication, for instance, takes place in soup.
 

joeyd999

Joined Jun 6, 2011
4,287
I've always considered it fascinating that life tends to occur "on the margins" (macro view). For example, at the interface between land and air, land and water, and water and air.
 

nsaspook

Joined Aug 27, 2009
6,586
I've always considered it fascinating that life tends to occur "on the margins" (macro view). For example, at the interface between land and air, land and water, and water and air.
The surface is where the greatest energy kink usually exists. Where things are kinky is usually where the fun begins.;)
 

joeyd999

Joined Jun 6, 2011
4,287
The surface is where the greatest energy kink usually exists. Where things are kinky is usually where the fun begins.;)
Interesting you bring up energy.

Another of my fascinations is that life only exists at very low energies -- equivalent to temperatures between, roughly, 273K to 325K in a universe where temperatures span from close to 0K to millions of K.

In fact, in my estimation, most matter in the universe exists either very close to 0K or at temperatures much greater than 10,000K. This makes it surprising that life happens in such a narrow band.

Of course, this can be explained away by the antrhopic principle: life exists in such a narrow range only because we exist here in that range to ask the question.

More substantially, the binding energies of the organic molecules that support life are so small that they could not organize to support life at higher temperatures. Even more so are the all important weak hydrogen bonds that mediate the interactions between, and govern the processes performed by, such organic molecules.

Still, you'd think the universe would come up with another class of "organic" molecules that could organize at the higher temperatures and energies at which most matter in the universe exists.

Sorry for pulling this thread so far off topic!
 
Last edited:
Top