Another metal fatigue Question

perry shooter

This is some pictures of my blued No.3 in 38/44 But I have a question about one I have in 44 Russian that is Nickle Has anyone beside me experienced Nickle embrittlement . I had a great S&W No 3 single action target model Top Break revolver with factory letter made in the 1880's it was factory Nickle after shooting with light target loads I cleaned this pistol and Then closed the action. when the latch closed The complete Rear extension to the barrel Broke off right at the place that the Barrel Forcing cone started . There was no visible gas cutting at this spot but it had been exposed to high pressure Gasses. Anyone have any comments about The fact that the Nickle plating Might have weaken the metal. Thanks all and Merry Christmas.
Perry Shooter



Thanks to locust Fork going far beyond the call of duty I am also the owner of one box each of the only Two factory loadings for this rare cartridge. the case looks to be empty but is actually loaded with Conical projectile Target load flush with case mouth and Galley load recessed half way down the case length

Thanks everyone who had posted earlier and also Machine Gun Moran. I just feel better now That I should have known this could happen to this model pistol. I still have not had right weather conditions ABOVE 60 degrees for this skinny old man ) to take pictures outside in good light So I can show the break. Trying to find a complete Barrel would be near to impossible [:(]as well as having this one repaired . Just an expensive lesson on my part[:(][:(]

tsr1965

perry shooter,

What exactly broke off? The nickel plating, or the whole barrel extension, inside the frame?

One thing that will erode steel, is chemical alterations...such as pickling for preparation for plating. But it would only alter the first few microns of the surface.

I would suspect, in your case, the decades of corrosive ammunition, that were used in it, to be the culprit. The forcing cone should see the highest pressures, of the burning curve. With that in mind, the byproducts of black powder contain both Hydrochloric acid, and sulpheric acid. Those, in gaseous form, and under high pressure, could in fact have the effect you describe.

Even though the exterior parts of the revolver were well cared for, the forcing cone, is about the toughest area to get surgically clean, after firing corrosive loads.

Merry Christmas to you, my friend!

Tim

iceracerx

Back in the 60's/70's that was called 'hydrogen embrittlement' and was common on plated hotrod parts (axles, spindles, etc).


What you described is a classic example of 'good' steel becoming brittle after being plated.

http://www.tau.ac.il/~chemlaba/Files/Electrodeposition/13208_02.pdf

perry shooter

Thanks guys Yes the complete Top section including the Latch still attached / ALL ONE PIECE broke off flush with the very rear of the Beginning of the barrel proper / forcing cone. The face of the break
looked to have very large grains almost like a broken piece Of cast Iron not deformed /bent at all just a Clean break. I purchased This item from a dealer that used to appraise Guns etc on Antique Roadshow now deceased. I really like the Grip back strap to trigger distance on The S&W No 3 Target and wanted to have something Different for Cowboy Action Matches. $4000. lesson learned [:(] I still have one in 38/44 and this is blued steel but am hesitant to shoot it

Bill DeShivs

If the problem was hydrogen embrittlement, it would have shown up a long time ago-when the gun was new.
Hydrogen embrittlement on large gun parts is practically a non-issue. I have nickel plated many guns and have never seen evidence of it.

v35

It's hydrogen embrittlement from hydronium ion in acid plating bath.
Nickel isn't the culprit.
The hydrogen can be driven off by heating.
I came across a S&W Russian with missing top strap and cylinder
In Korea and wondered what it was doing there. The break was in the
Same place. It was also plated.

Bill DeShivs

Well, that solves it, doesn't it? Two similar examples does not prove anything. There are many things more likely to cause those failures than the nickel plating. Guns have been commonly nickeled for well over 100 years. If this were a problem, it would be well known by now.

v35

It may.
Was that an honest comment ?
Are you an arbitrator or do you make the mistake of assuming knowledge doesn't exist beyond your own?
Embrittlement was the subject and a likely cause.
However, there are other metallurgical ando machine design aspects that could provide a conclusive determination.
Failure analysis and mechanical properties of steel and iron are big subjects and your wise crack adds nothing to the discussion.

machine gun moran

When a top-break is fired, the barrel tries to rotate around the pivot. This applies downward pressure at the rear of the top strap, against its mating frame surface. The stress then moves forward along the cantilevered top strap, and is localized where the top strap meets the barrel. This micro-flexion will eventually cause metal fatigue. It will become much worse and the process will be accelerated if any looseness at all develops at the juncture of the rear of the top strap where it seats on top of the frame. Heavy-recoiling guns will suffer from this much more frequently than the small-caliber ones.