I own a FS MP .40 1.0 that was made November 2015. Was S&W still using the Melonite process then, or had they gone to the new Armornite process?

They are the same my friend... just different trade name. it is a process of SBN (salt bath nitriding) that hardens the surface of the metal and makes it much more corrosion resistant and have a higher lubricity.

There are a couple different ways of doing the process itself and some differnt combos of recipes but the end result is very similar. This metal hardening has a lot of different names in the industry. SBN, Melonite, Armornite, Tenifer, QPQ, Nitride to name a few. there are some different processes that change the level of protection and hence the quality of the job like QPQ (quench, polish,quench) that gets run through the salt bath, pulled out and polished and then run through the salt bath again. this is the one process that gives a very smooth look and some of the more basic processes tend to have a rougher look.

apparently S&W isn't using the melonite term anymore because of legal issues. copyright stuff or something

__________________
Equal opportunity shooter

Ah, a rose by any other name is still a rose.

Very eloquently spoken sir, I tip my hat to you!

__________________
Equal opportunity shooter

Ah yes. The debate over Melonite and Armornite. Some of my buddies had been arguing this point for weeks so while we were at the range I called S&W then placed my phone on speaker and asked the lady what the difference is. She politely stated it's the same thing but S&W wanted to ™Armornite.

We were told in a M&P pistol recert that the company had decided they wanted to stop paying more for a nitriding process for which they had to pay royalties (trade name), so they decided to buy the equipment and start doing it themselves. It started a couple years ago, give or take, depending on the guns. I seem to recall seeing the M&P Bodyguard using the new in-house process first (name change), before the rest of the M&P pistols and rifles.

FWIW, consider that they can do the process for an outside gun company's products, and the other gun company can call the process whatever name they may wish for their guns when they market them.

There's big business in being able to provide this sort of process, and S&W has been in the business of providing such services, as well as forging and heat treat, for some time. They'll quickly recoup their investment and attract even more business among the industry.

I apologize for being fuzzy on remembering some details, but it all starts to blur together after a while. Not counting the 8 classes/recerts I've attended for the 3rd gen's, SW99/P99's and revolver (and we won't count the Sigma and SW armorer class), I've been through 5 M&P pistol armorer classes, 2 M&P rifle classes and a Shield class. I recently turned down a chance to do another rifle armorer class at no charge, but since I'm no longer having to support them as an armorer, and have already been through 2 Colt classes and an "outside" AR (retired FBI armorer) class, I didn't have the interest. The things you hear in the different classes, and during calls to the factory now and again, all start to get mixed together in the memory. Fortunately, I also have a lot of notes, even if I didn't always date them, so I can sometimes figure out where/when I was told something.

__________________
Ret LE Firearms inst & armorer

I only hope they know what they're doing. The nitriding process is such that if you fudge it you can really screw up the metal. You're dealing with a pretty delicate balance of temperature to case harden the steel without messing up the temper of the core.

__________________
Equal opportunity shooter

Their engineers have been studying it since it was first used on the Sigma, and then the 5906 Militar, going back some years. (I remember reading about a former S&W engineer writing about how they realized their different stainless alloys required a different version of the process, and the inherent difficulties involved.) Then, they used it for some of their special LE runs of 4566's, and then the SW99's.

As I recall, due to the stainless steel they used, the version used on their guns was the Melonite QP, as the QPQ (a finishing Quench) wasn't appropriate for stainless.

Done improperly, as you mentioned, the process can reduce the inherent corrosion resistance properties of the stainless steel. (You might remember initially reading about some oxidation issues occurring with some slides in the early days of the M&P's, when they were outsourcing batches of slides and barrels?)

Now that the company owns the equipment and has direct control over the whole process, they can exert more QC over all aspects of the process. Same reason they own their own forging and heat treat facilities, and hold the patent on alloying Scandium to aluminum for their guns, and more recently bought the plastic manufacturer they've used for many years, and bought TC Arms (so they could own their own high quality rifle barrel manufacturing equipment, which was moved to Springfield).

As I was given to understand their decision, it wasn't a quick, off-the-cuff decision, nor was the initial investment cheap. It's apparently been a long time coming.

__________________
Ret LE Firearms inst & armorer

That's good, makes me feel a bit better about it. I wasn't gonna lose any sleep over it but the treatment on the 1.0's was really nice and it would be a shame if the 2.0's was inferior. It seems to be pretty good bit only time will tell. I did notice right away though that it was different in some way. Can't quite put my finger on it but it's not the same as my 1.0's.

__________________
Equal opportunity shooter

Before I sold my Glock 17.4 I was on a few Glock websites. They were stating the same thing about the Gen 4 finish. They stated it was nothing like the Gen 1-3 finish on prior Glocks. So, it seems that S&W is not the only gun manufacturer with the Melonite Blues.

A rose, by any other name, would smell as sweet.

In the years since I've been attending Glock armorer classes (5 classes/recerts), they've mentioned that they've changed the finish a few times.

I think in the first class I attended they just referred to it as a type of phosphate finish. It wasn't given much attention, as they were more interested in teaching us how to maintain, service and repair the guns, instead of keeping them looking "pretty".

The hardening treatment (not the same thing as the surface finish) was originally Tenifer (apparently the QPQ version of the process), but in the last couple of years the company has changed it (at least for US produced guns) to a process they only identify as "nitration".

FWIW, the small steel parts like the frame rail tab (fixtures), FP, FP safety plunger, trigger bar and locking block have been said to receive a Teflon nickel plating (to help resist corrosion), and the some other small parts get some sort of a black finish (slide stop lever, slide lock lever), which has varied quite a bit from one time to another.

The trigger coil springs and locking block pins have received changes to hardening and finish over the years, too.

There are always going to be ongoing production revisions and refinements, manufacturing changes, updates to materials, etc, and trying to keep up on all of the reasons for all of them (even if the companies would provide reasons ) can become distracting from simply keeping the guns properly serviced, maintained and running.

__________________
Ret LE Firearms inst & armorer

The Hi-Point guys just call theirs Black Power Coat.

As it has been explained to me, and I think those who did the explaining were in the know, Tenifer, Melonite, Armornite, Tenifer, QPQ, etc., etc., are all "proprietary" variations of a salt bath nitriding (SBN) process -- as has been explained above. The colored coating (which typically matches the frame) is a different finish, and THAT is what most folks really complain about; that cosmetic coating, which is somewhat wear resistant, is applied AFTER the SBN process is completed.

Personally, one option I'd like to see used more often is the application of a PVD coating applied over their through-hardened stainless steel. Dunno if they're out-sourcing that, though. It's used on some of the specialty M&P pistols (Viking Tactical) and the cylinders for some of the revolvers, like the M&P 340/360's.

It has some advantages.

PVD Coatings

__________________
Ret LE Firearms inst & armorer

I don't know what you mean by "through-hardened." As I understand it, the SBN process is a bit like case-hardening: it creates a relatively thin but harder, more rust- and scratch-resistant surface but doesn't greatly change the rest of the metal below the surface. That's supposedly good -- as if it were hardened all the way through, it could be a problem (making the metal almost brittle.)

I wish gunmakers would just come up with a cosmetic layer that was either very durable, or easily touched up with additional material (like a car touch-up paint) from the gun maker.

That's their basic heat treat of their forged stainless parts. I only use that term as it's what's been used in some descriptions by the company in classes, discussing their basic hardening without (or before) any FSB nitrocarburizing.

The first time I asked about it I was told that they essentially use a double heat treat process that isn't as shallow as the zone tempering used by some European gun makers.

Then, in the slides and barrels which also receive an additional surface heat treat, meaning a FSB/nitrocarburizing process, they get a harder boundary layer resulting from that hardening process.

__________________
Ret LE Firearms inst & armorer

Indeed, most gun slides and a lot of other gun parts are actually through hardened. It's just that they go through a second process to relieve some of the stress caused by the first process so it's not brittle. I believe the second process is called annealing. Basically they heat the piece to a red hot state and then quench in oil (dip in oil to cool off rapidly) and this makes the metal really hard but brittle. Then they heat it up again to a little cooler but still fairly glowing temp and then let it air cool. Temperatures used and type of quench medium (i.e. water, oil, air) depends on the type of metal used. Only after all this do they then go through the nitriding. I guess "technically" nitriding isnt really a case hardening... because it's a chemical conversion process that happens to be done with pretty hot solution instead of strictly through a heat treating process like real case hardening. I guess I should stop calling it that.... It's just easier

__________________
Equal opportunity shooter

Actually, nitriding IS a form of case hardening. Case hardening is a term that describes the RESULT of a hardening process (an encasement of softer metal) rather than the PROCESS.

Case hardening is done so that the surfaces of somewhat softer metals (through-hardened to a lower level of hardness) can stand up to abrasion and other forms of wear. Gun makers realize that a bit of flex is necessary for many metal applications, even guns. (If receivers, handgun frames, car frames, or bridges didn't flex and rebound a bit under stress, they'd eventually break!)

The following Wikipedia link offers an explanation of the various hardening processes now used and mentions flame/induction, carburizng, nitriding, cyaniding, carbonitriding, and ferritic nitrocarburizing. A number of those processes use chemicals to create the heat that changes the metal, or are used with heat to get the desired results. The type of metal being treated also dictates the process used. Case-hardening - Wikipedia

Some of the older forms of heat-based case hardening, seen in beautiful old rifles and handguns, used chemicals (based on the types of woods added to the heat source) to change and enhance the appearance of the metals being hardened by the heat.

That makes sense. I guess I was right in the first place! Shouldn't have doubted myself I guess.

Thanks for that link too... I like learning more about that kind of stuff.

__________________
Equal opportunity shooter

when i scratched away the fde cerakote on my gun slide, underneath it was a silver color. i'm assuming it's a nitrided steel surface?

I am betting they don't nitride the cerakoted slides. Probably just stainless you are seeing there. Not real sure cerakote would stick very well to a nitride coating.

Rosewood

That would be correct according to Smith and Wesson. They say the cerakote is done over their amornite (nitride/melonite). Remember that nitride doesn't have to be black... that's just one of the last steps of the process where they can use a different chemical bath to give it the black color. Usually nitride without the black adds a bit of a grey hue to the base metal so it can vary depending on the exact steel alloy used. CZ had a gun that they did the slide in what they called "white nitride" which was just nitride without the black oxide treatment.

__________________
Equal opportunity shooter

Well, I assumed wrong. Their webpage does indeed state that the FDE slide is stainless with armornite.

Learn something new every day.

Rosewood