Stainless Steel Rusting

[rem_kujawa]

I have a question I shot my rifle about two weeks ago,cleaned it and then put it away.Well I have a match coming so I got it out and noticed that there was some rust forming on the barrel right after the action.I thought it was no big deal got out the rust and blue remover,well that turned it a dark black color.It took me about two hours of rubing it with steel wool to get the stain off.How can I prevent this do you guys still put a light cloat of oil on the barrel?

Jon

 

[Preacher]

Your best bet is to always apply a light coat of oil on all exposed metal parts before putting them away, even on so called stainless steel.
S/S will rust, not as quick as Moly but it sure will rust if your not careful.......

 

[TRECustom]

Rem; don't know if it's what happened, but sweat is very corrosive. It and blood will rust many stainless steels. It's one of the things I hate about shooting in hot weather. I hate to handle my guns or drip on them when I sweat. It really helps to just wipe them good with a wet rag, dry and wipe on a light coating of gun oil.

I think most stainless barrels are made from type 416 stainless, and it is generally pretty corrosion resistant, but not when exposed to sweat, blood, or chlorates,,corrosive priming) and some other electrolytes.

Just a possibility, Tom

 

[steveyrock]

The only stainless that won't rust is food grade.That aside' Preacher is correct in that stainless does not rust as chrome moly but it will get slight surface rust which is harmless really except in a polished barrel bore.

 

[Spotcheck_Billy]

Surgical,medical) grade stainless won't rust either, at least I hope that it won't

I believe that as a rough rule of thumb the more magnetic stainless steel is the more prone it is to corrode.

 

[kells81]

Wanna see some rusted stainless, Go to cabela's in Ft. Worth, every stainless gun they have on the used gun rack is rusted, weirdest thing I have ever seen. I picked up a Win mod 70 Heavy varmit and was gonna buy it till I noticed the rust on the SS barrel.

 

[rudedog]

I have notice that stainless steel pipe where i work in calif., left outside for months,does not seem to rust very much at all.This is 304,308,316 stainless.But let it touch some chrome-moly,or some carbon steel,and it will get surface rust all most over night,maybe not that quick, but in a week you"ll see a lot of surface rust.

 

[Rustystud]

There is a big difference in 300 series stainless and 400 series stainelss.

They are alloyed for different purposes. They machine different also.

Rustystud

 

[rem_kujawa]

Ok,
Im pretty sure its 416 stainless.who knows what got on the barrel in those two weeks.Its a new gun and I dont think that it has left my hands since it arived.

Jon

 

[TRECustom]

I'm still betting on sweat, but I did have a problem with very light general surface rusting on a sandblast finish heavy stainless barrel. I hunted about a week getting rained on, then drying out and getting rained on again. Other than being sure it was dry at night, I didn't wipe it with oil or anything. It's still on there, but I'm going to rework the barrel and I'll clean it up then. I've also seen light rust on stainless AR-15 barrels that have been out in weather for awhile.

Different subject. You mentioned using rust and blue remover and it turned your barrel dark. I've got to try that as a poorboy way to darken stainless. What do you think?

Tom

 

[rem_kujawa]

I wouldnt it was not that great of a color.

Jon

 

[ConnorExum]

oxidation is not easily overcome. The acids in our skin and perspiration are possibly the greatest issues to over come. White Gloves Boys...

 

[ccg]

As mentioned before, 300 series is more corrosion resistant, 400 series can be heat treated.

 

[Jacob]

This is how it goes. I found this on the web and I confirm that it is true. I was close to getting a Material Science minor and we had to learn all this stuff. I new that stainless had corrosion resistance by way of passivation but forgot most of the rest of it. When I was reading this it all came back. Here it is.

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 resists further "oxidation" or rusting. The formation of this film is instantaneous in an oxidizing atmosphere such as air, water, or 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's created when oxygen combines 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
* 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're also soluble, active ions; the basis for good electrolytes, the best conditions for corrosion or chemical attack.

 

[Jacob]

More on 416SS. It is a Martensitic SS. The composition,by % weight) of 416 is 0.15 carbon 12-14 chromium and the rest iron. It lacks the ~10% nickel that makes the 300 series more corrosion resistant in atmospheric conditions.