Stainless question
Is it possible to get a stainless pistol to look like a bright stainless and if so....how?
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In the 1950's, I didn't see any stainless weapons. I was told that this was due to stainless parts and gears tending to bind and stick to each other. Then in the 1960s, a surface treatment (iodine based?) was developed which allowed stainless weapons to function.
My question is how thick is the treated surface? Can enough wear be put on a stainless steel weapon so that the parts start to bind?0 -
I am not a machinist. I have heard a different reason.
Customers:
Cost. In our more conservative generations we would provide sufficient care to prevent rust before they would spend money on a stainless gun. A blued gun can be hunted in bad weather if properly cared for after exposure.
Manufacturers:
Cost. The stainless alloys are VERY hard on tooling bits. To machine stainless cheaply there needed to be a supply of cheaper/more durable tooling/lubricants.
As an example, the tooling and the demand for Titanium is now a market reality. May expect to see the availability and cost of titanium receivers/accessories to increase over the next several years.
I have NEVER heard of an iodine coating on the bearing surfaces of stainless arms. On bearing surfaces (trgger sears, locking lugs)stainless is said to gall more than carbon alloys. A trigger job on a blued/carbon trigger will be easier to smooth and last longer than a trigger job on stainless components.
The plus: stainless is REPUTED (I don't know) to resist flame cutting/barrel erosion better than carbon alloys. So it makes a better revolver frame or magnum rifle barrel.0 -
The problem with the early stainless guns was a matter of alloy selection. The early AMT guns were notorious for galling and had to have big gobs of thick grease on the slide rails to function. As newer 'stainless' alloys were developed and the use of dissimilar alloys in the same gun was implemented, the galling problems went away.
Scrappy Doo sleeps with the fishes.0 -
What is galling?
J. Patrick Tatum0 -
Maybe Country gunsmith can confirm this description..as I understand it.
You know how rubbing two pieces of carbon steel together will polish them?..even if they are of different hardness or alloys?
Well, stainless, at least before the solutions that 'smith refers to in his post, would result in a surface resembling what happens when you try to smooth silicon or latex chaulk with your finger-after the caulk has started to set up...it peels back gobs instead of fine shavings.
SEMPER FI0 -
I don't have anything to add, except to say that I thought this was a very interesting question and line of responses. Thanks all.
Sako Fan0 -
mowart,
"Can enough wear be put on a stainless steel weapon so that the parts start to bind?"
Here is a sort of working definition or rather a basic description of galling:
As pressure builds between the contacting and sliding surfaces, protective oxides are broken, possibly wiped off, and interface metal high points shear or lock together. This cumulative clogging-shearing-locking action causes increasing adhesion. In the extreme, galling leads to seizing - the actual freezing together of the surfaces.
Galling is a severe form of adhesive wear that shows up as torn areas of the metal surface. Galling can be minimized by decreasing contact stresses or by the use of protective surface layers such as lubricants (where acceptable), weld overlays, platings, and nitrided or carburized surface treatments.
The firearms industry came to this understanding a little slowly and then only because of severe customer complaints and firearm failures to function. A good example as pointed out was the AMT line of semi-auto pistols where the slides seized to the frames. The bolt action rifles weren't guiltless either, when bolt lugs seized on the lug seats. These failures resulted in the use of dissimilar steels when contact surfaces were involved such as stainless steel receivers/chrome moly bolts and stainless slides/chrome moly frames with semi-autos. Greater attention was also paid to sophisticated lubricants for these contact surfaces.
Best.
I forgot to add the part about iodine:
The basic resistance of stainless steel occurs because of its ability to form a protective coating on the metal surface. This coating is a "passive" film which is resistant to further "oxidation" or rusting. The formation of this film is instantaneous in an oxidizing atmosphere such as air, water, or many other fluids that contain oxygen. Once the layer has formed we say that the metal has become "passivated" and the oxidation or "rusting" rate will slow down to less than 0.002" per year (0,05 mm. per year).
Unlike aluminum or silver this passive film is invisible in stainless steel. It is due to the combining of oxygen with the chrome in the stainless to form chrome oxide which is more commonly called "ceramic". This protective oxide or ceramic coating is common to most corrosion resistant materials.
Halogen salts, especially chlorides easily penetrate this passive film and will allow corrosive attack to occur. The halogens are easy to recognize because they end in the letters "ine". Listed in order of their activity they are: fluorine, chlorine, bromine, iodine and astatine. These are the same chemicals that will penetrate Teflon and cause trouble with Teflon coated or encapsulated O-Rings and/ or similar coated materials. Chlorides are one of the most common elements in nature and if that isn't bad enough they are also soluble, active ions; the basis for good electrolytes, the best conditions for corrosion or chemical attack.
http://www.mcnallyinstitute.com/04-html/4-1.html
In essence, the stainless steel was treated with iodine to encourage the surface oxidation (ceramic) that prevented the galling.
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mo, these guys know stainless!! The only thing I could add is 9 brought up flame cutting - it's generally thought that stainless has a much higher melting temp than carbon steel. That's not true. The big difference is that stainless maintains it strength at high temp much better than carbon steel. When carbon steel is glowing red it's time to run. Stainless on the other hand has a good percentage of it's strength at those temps. The ss barrel should hold up better with rapid fire.
cbxjeff<P>It's too late for me, save yourself. <br>0 -
As they used to say, "you ain't driving your father's car anymore..."
Today's use of stainless composite/alloys efforts are far more advanced than earlier attempts at using "commonly" available materials of those days.
Should you check the early stainless steel for "magnetic" signature, or more importantly so, "rockwell" hardness, you will find both lacking, or very low.
Some of the "chrome/vanadium" alloys were a poor choice, and others such as the "monel" type, again, while good for marine purposes, failed miserably in firearms. Corrosion, while being the emphasis for its use, became a misleading subject.
Knife makers experienced the same problems, while trying to hold a sharp edge.
Ultimately, "CARBON CONTENT" became the actual cure. Now remember that steel is still steel, whether called stainless or not. The issue/question became, how much "stainless" did you want your alloy-steel to be? Previously used 300 and "early" 400 series stainless alloys were not the best choice for firearms. Now-a-days some of the "416 series" of stainless alloys are being used successfully.
The advantage of the "carbon charged/loaded" stainless formulas is its ability to be manageable/controllable where even "hardening" of the piece is needed, to enhance wearability and eliminate "galling" possibilities. Complete corrosion resistance took a back seat, both in knife making and firearms. Carbon content was the key that resolved the issue, and eliminated most galling, when the metal responded well to proper heat treating/hardening.
In conclusion, todays stainless steel alloys as used in most reputable manufacturers firearms, far surpases the average gun variety plain carbon steel, in both maintenance and durability. Machining, of course is more difficult with stainless. Wherever available all the tooling I use in my shop is "carbide", which is a must for tooling life, and speed of cutting.
Manufacturers found a long time ago that using different hardness in the slide and frame was essential to eliminate galling with any metals, and to promote resistance to wear, while guarding off embrittlement caused by too much hardening. Experience and paying attention to details paid off, for the benefit of us all.[:D][:D][:D][8D][8D]
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"If it ain't broke, fix it anyway... make it better!" (RadCat)0 -
Well!
RadCat and nononsense cleared this up for me. I like the details from guys who know what they are talking about. Thanks, it wasn't even my post.[:)]
I may copy and paste RadCat and nononsenses posts into Word. I save a lot of the stuff I get here!!!
SEMPER FI0 -
It was my understanding that due to the problems with stainless to stainless parts, some manufacturers used chromed carbon steel parts for the actions in stainless guns.
NRA Life Member0 -
I certainly want to thank all of the folks that contributed to this exchange of information. It is easily one of best I have run across on this forum. Once upon a time I looked up the composition of 416 stainless steel and I was really surprised at what I found. Stainless steel is usually defined as alloys that contain principally ickel and chromium as well as the iron and carbon. 416 stainless actually contains more manganese than it does nickel or chromium.
J. Patrick Tatum0
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