Why Through Hardening Matters

[Jeep]

My guess is they will do both -- 17's for Green side ops (they are free from large Brit Army) - and 19's and 26's for times where the larger gun is not applicable.
The same way that they and the Canadians had 228s and 239's for certain missions.

As I expect the S&W M&P will win the Cdn trial - I would expect that they will pick up the 9C and Shield for those roles. Unless Glock finally released their MRDS Slide - I see most entities going M&P CORE who have a domestic CT requirement - as shooting in a GasMask - the MRDS kicks ass.

That makes sense. I've never tried to aim a pistol in a gas mask, but I've done it with other weapons (iron sighted--this was before red dots came out) and accuracy tended to be significantly degraded. If the Canadians go with the M&P maybe Glock will get off the dime--which would be nice for the rest of us.

[tomr]

LL, to go on just a little....

Perhaps you didn't see it, but back in post #74, I'd already reported this from a Google search:

"So, I just Googled H&K P30 and got to Wikpedia, where I found this quote,

"The cold hammer-forged barrel has hexagonal right-hand polygonal rifling while the slide, having both front and rear serrations, is made from a solid bar of nitro-carburized steel. Besides metals the P30 makes extensive use of impact-resistant polymers to reduce weight and production costs.

Major metal components like the steel slide are treated with a protective surface treatment. Heckler & Koch refers to this treatment as the "HE" (Hostile Environment) finish, which is an extremely hard, nitro-gas carburized, black oxide coating. It aids resisting wear and corrosion, including exposure to salt water, making the pistol particularly suitable for individuals carrying the pistol concealed as the highly chloride-resistant finish allows the pistol to better endure the effects of perspiration. and

Curiously and I guess its understood, different people contribute to Wikpedia, But isn't a "slide made from a solid bar of nitro carburized steel" and the steel slide treated with hostile environment finish an extremely hard, nitro-gas carburized black oxide coating double dipping? I believe nitro carburizing is not the older carburizing/case hardening. But beyond that I don't know what it is. Whats the base steel alloy that gets this treatment? Is it through hardened?"

I went on and looked up Nitro carburizing, but did not include that, for brevity's sake. Hence my questions at the end.

[Drang]

Green side ops

Not to derail the discussion, but could I ask you to define this term? It doesn't seem to mean what I first thought it did.

[Tamara]

But isn't a "slide made from a solid bar of nitro carburized steel" and the steel slide treated with hostile environment finish an extremely hard, nitro-gas carburized black oxide coating double dipping?

I think what you're seeing there is an artifact of the writing at Wikipedia and not the actual manufacturing process. Pretty sure they don't case-harden the stuff before they machine it.

[tomr]

I think what you're seeing there is an artifact of the writing at Wikipedia and not the actual manufacturing process. Pretty sure they don't case-harden the stuff before they machine it.

Perhaps I wasn't clear, according to the other Wikpedia piece - the one I went to after the H&K one, where I looked up nitro carburizing, it was explained case hardening - the older process we've discussed before, (and Ive actually done) is not the same as nitro carburizing. After reading that article I didn't feel like I knew a heck of a lot more about what nitro carburizing actually was, hence the questions I added in the post your refer to. I was hoping, Bill as busy as he is, would notice and comment.

So while no one would carburize, (alternate term for older process)/case harden then machine, because nitro carburizing is theoretically at least "different" (?) maybe for THIS process they do? I'm trying to find that out.

To, and I believe you are correct, this is an artifact of Wikpedia reporting. By double dipping, I meant whoever wrote this couldn't mean it somehow was both the method of fabrication of the base part metallurgy AND the finish employed after. I was being a bit snide (without the appropriate post icon) about what was written and thought it confusing at best.

Sorry for the confusion and hope this helps.

[Tamara]

Perhaps I wasn't clear, according to the other Wikpedia piece - the one I went to after the H&K one, where I looked up nitro carburizing, it was explained case hardening - the older process we've discussed before, (and Ive actually done) is not the same as nitro carburizing.
...
To, and I believe you are correct, this is an artifact of Wikpedia reporting. By double dipping, I meant whoever wrote this couldn't mean it somehow was both the method of fabrication of the base part metallurgy AND the finish employed after. I was being a bit snide (without the appropriate post icon) about what was written and thought it confusing at best.

Sorry for the confusion and hope this helps.

Here's the page from Bodycote, with whom we'd worked in the past, on nitrocarburizing. It is not incorrect to refer to it as case-hardening.

I hope this helps you; I'm no engineer, though.

[tomr]

Here's the page from Bodycote, with whom we'd worked in the past, on nitrocarburizing. It is not incorrect to refer to it as case-hardening.

I hope this helps you; I'm no engineer, though.

That helps, thanks. Sounds like it is indeed another form of surface hardness treatment. Wonder if its what Mavic used on their "ceramic" coated bicycle wheel rims - particularly as there was some discussion of plasma deposition with those, (a variation discussed at Bodycote) - I digress. So, it's a form of surface hardening that brings elements other than just carbon (carburizing/case hardening) to the mix. To what end I wonder.

Back to through hardening, and the better, (in my mind at least) steels required to enable that, assuming Wikpedia is right about H&K, I wonder what base steel they use for slides and barrels under the nitrocarburizing? Any ideas?

Or horror of horrors, is H&K no better than Glock in this regard?

[JV_]

Coatings are pretty far out of my area of expertise, but I've read that the Mavic coating is plasma electrolytic oxidation (keronite).

[tomr]

Coatings are pretty far out of my area of expertise, but I've read that the Mavic coating is plasma electrolytic oxidation (keronite).

Thanks JV, sorry I brought that up.

Tamara and anyone interested, re-read Bodycote's website, couple things intrigue and seem worth posting, (ill edit a bit)

1. "Nitrocarburising
Nitrocarburising is a variation of the case hardening process. It is a thermochemical diffusion process where nitrogen, carbon, and to a very small degree, oxygen atoms diffuse into the surface of the steel part, forming a compound layer at the surface, and a diffusion layer. Nitrocarburising is a shallow case variation of the nitriding process. This process is done mainly to provide an anti-wear resistance on the surface layer and to improve fatigue resistance.

Excellent scuffing and seizure resistance;
Fatigue properties improved by up to 120%;
Considerably improved corrosion resistance;
Good surface finish;
Negligible shape distortion;
Predictable growth characteristics; and
Alloy substitution - plain carbon steels replacing low alloy steels."

This latter item infers a base metal superior to the low carbon steels typically used for old fashioned case hardening and maybe some higher Rockwell through hardening is present? When case hardening we used only carbon, (don't know how pure it is) completely covering the parts in a metal box that is sealed to keep oxygen out. This is different.

2. "Process details
Nitrocarburising is carried out at sub-critical temperatures and involves the diffusion of nitrogen and carbon into the surface of carbon steel to give a somewhat harder case and soft core with a very thin compound layer on the surface.
The compound layer is wear and corrosion resistant and yet is not brittle, unlike its counterpart in the nitriding process. Since it provides an essential part of the properties required from the process it must not be removed by subsequent machining. Below the compound layer, the thin case significantly enhances the fatigue resistance of the component."

I'm particularly curious about the last sentence. Wonder if the heat effected zone from welding is a fair analogy? As in there's a bit of transition from hardest outside to less hard but still some as move to inside??

Most importantly what does all this get us?

[KevinB]

Not to derail the discussion, but could I ask you to define this term? It doesn't seem to mean what I first thought it did.

Field operations -- originally in some units with domestic CT missions they wore a lot of black (Brit SAS influence) so field ops where green side.