Corrosion Resistance of 410 and 4140

[Carburize]

12 Cr stainless and 4140 are popular alloys for handgun barrels. During use, the barrels pick-up lead and copper from the projectiles and need to be cleaned. One of the cleaning methods I have heard about involves soaking the barrel in a 50/50 mixture of vinegar and hydrogen peroxide. Does anybody know if this mixture would have any harmful effects on either of these alloys, particularly in terms of pitting?

 

[mcguire]

The 410 won't pit unless there is a chloride present, so you're safe there. Neither will it be corroded in a general sense by this mixture.
Carbon and alloy steels, such as 4140, are attacked by acetic acid at all concentrations. The attack will not take the form of pitting. The corrosive attack during cleaning should be negligible if you're a quick cleaner.

 

[rustbuster1]

I wonder why you wouldn't just polish up a piece of each metal and dunk it in the cleaning process you intend to use. Close examination will show you if any harm arises. I suspect none of the sloultions you mention will cause real corrosion but they may etch the carbon steel.

This appraoch falls under the rubrick of "One test is worth 100 opinions."

 

[Carburize]

Under normal circumstances I would agree completely but when all one has is the part to clean the alternative to "no test" is to gather the 100 opinions.

 

[mcguire]

Maybe the best of all is to get onto Eng-tips.com and find out from someone who has already done the test.

 

[stonerabroad]

the data i've got for 410SS and vinegar says it's resistance up to 70F is good (in a concentration of 100%)gut the carbon steel is not so good at any concentration over 8%.

as for the peroxide...carbon steels aren't recommended at any concentration at any temperature. the 410 is good up to 90F.

so...i'd recommend testing out a sample as well, if possible.

 

[mcguire]

Hydrogen peroxide is harmless to 410 up to boiling at any concentration. It IS safer to test. We all give advice, but in the end you're responsible, so take precautions.

 

[Carburize]

Two components cleaned using the mixture - it worked like a charm -

 

[shooter45]

How do I tell the difference between a stainless steel barrel and a 4140 one??

 

[rustbuster1]

To Shooter 45 - put a drop of 10% or so nitric acid on the barrel at a suitable place - 4140 will produce a green spot 410 will do nada.