Melonite barrel treatment

[MontanaRifleman]

Thanks guys, I have not even shot the gun yet, I just gave it to my smith to chamber, thread and put the peaked on. So sounds like 3-5 shots is best? The cleanning sounds not so tough thanks for telling me your cleaning info elkaholic. I need to read more of the recent stuff, but are you guys still using mmi? What's the wait usuallyon one barrel?

Based on what my smith says and some other reading I've done, I'll go with H&M. I will be getting the actions and triggers done as well. I'll run a few down the tube until copper fouling is greatly dimmished. I'll use a light load of slow powder and heavy bullets for the break in. My smith wants me to give it an accuracy check before sending it off, so the break in will be par of that.

If you use Bore Tech to clean, do not use a brass or bronze jag. The Bore Tech will start eating them immediately and give a flase copper indication. I use nickle plated jags. To ensure all copper is out, on your last pass, stroke the bore a couple of times with the BTE and let it sit for about 40 min. If you get a white or very faint blue patch, you're done.

You might read this....

http://www.longrangehunting.com/forums/f37/bore-solvent-70001/

 

[calib]

Should I or could I do my brake and barrel in one piece?

I'll checkout that link and see what all in there. I am not excited about 6 weeks to get my stuff back, where is h and m at?

 

[MontanaRifleman]

All pieces to be treated should be disassembled. Last I talked with H&M, they were turning barrels in 4-6 days plus shipping time.

 

[calib]

Ok, can you pm me some contact info

 

[MontanaRifleman]

Their contact info is here...

H&M Metal Processing: What is Black Nitride?

 

[shortgrass]

I contacted H&M a couple of years ago and was quoted a "batch charge" of about $200, whether I had one barrel or a dozen. Have things changed there? MMI charges me $60 per with a discount if I send more than 3 or 4 at a time.

 

[MontanaRifleman]

I contacted H&M a couple of years ago and was quoted a "batch charge" of about $200, whether I had one barrel or a dozen. Have things changed there? MMI charges me $60 per with a discount if I send more than 3 or 4 at a time.

H&M quoted me $100 per barrel and $200 per gun to include action and any other steel parts. The 2 biggest reasons I am going with them is reports that their final finish is very good and they also will do any action.

 

[Cold Trigger Finger]

I finally got the time to read this whole thread.
I only have 1 more? about the treated barrels which I will prolly have to talk to the company about.
Extreme cold weather shooting and whether the extra hardness can lead to shattering or if it is tough/ resilient. -50°F kinda cold.

 

[Pdvdh]

I don't think it's an issue. If the barrel steel will survive -50F use without Melonite treatment, it should also survive use in those temperatures with Melonite treatment.

Melonite Processing

""Melonite Processing: Melonite QPQ

Melonite™ and Melonite QPQ™ are thermochemical processes intended for the case hardening of iron based metals. These processes are categorized as molten salt bath ferritic nitrocarburizing. During these processes, nitrogen, carbon, and small amounts of oxygen are diffused into the surface of the steel, creating an epsilon iron nitride layer (e - FexN).

A degraded form of this nitride layer (gamma prime: g' - Fe4N) is obtained during plasma or gas nitriding. The nitride layer is composed of two principle zones. Zone 1, called the compound or "white" layer, extends to a case depth of ~0.0004" to 0.0008". The compound layer is porous, which lends to the lubricity of the finish, and hard (~700HV to 1600HV). Zone 2, called the diffusion zone, extends to a case depth of ~.004" to 0.008".

In addition, small quantities of substrate carbon are pulled from deeper within the substrate toward the surface. The diffusion zone demonstrates a decreasing gradient concentration of carbon and particularly nitrogen as the gradient extends deeper into the surface of the substrate. This property yields a tough outer surface or shell, yet allows the material to retain ductility, thereby lending to the overall strength of the material.""

 

[Cold Trigger Finger]

OK. Thanks. I like the corrosion resistant part of it also. Tho I will be dealing with stainless steel. And I might have the bolt and action done also.

 

[JeffVN]

I talked with BAT directly before I had a BAT HR single-shot action done. It produced no problems, but could not have the bolt done because the bolt handle was/is not welded. I had the bolt finished with Ion Bond (suggested by BAT directly).

Jeffvn

 

[Trickymissfit]

I don't think it's an issue. If the barrel steel will survive -50F use without Melonite treatment, it should also survive use in those temperatures with Melonite treatment.

Melonite Processing

""Melonite Processing: Melonite QPQ

Melonite™ and Melonite QPQ™ are thermochemical processes intended for the case hardening of iron based metals. These processes are categorized as molten salt bath ferritic nitrocarburizing. During these processes, nitrogen, carbon, and small amounts of oxygen are diffused into the surface of the steel, creating an epsilon iron nitride layer (e - FexN).

A degraded form of this nitride layer (gamma prime: g' - Fe4N) is obtained during plasma or gas nitriding. The nitride layer is composed of two principle zones. Zone 1, called the compound or "white" layer, extends to a case depth of ~0.0004" to 0.0008". The compound layer is porous, which lends to the lubricity of the finish, and hard (~700HV to 1600HV). Zone 2, called the diffusion zone, extends to a case depth of ~.004" to 0.008".

In addition, small quantities of substrate carbon are pulled from deeper within the substrate toward the surface. The diffusion zone demonstrates a decreasing gradient concentration of carbon and particularly nitrogen as the gradient extends deeper into the surface of the substrate. This property yields a tough outer surface or shell, yet allows the material to retain ductility, thereby lending to the overall strength of the material.""

your post is interesting (data), and also makes one do some thinking. Nitride hardening is vary hard, and if done right doesn't change the metal's granular structure much if any at all. It's very hard (62rc-64rc) if done right. Yet most folks don't realize that as you cut thru the case the metal gets softer (typical for all case hardened metals). I would think they would at least be doing a .010" case in a high speed setup. You don't need the .025" case I spoke of elsewhere in a fire arm. The old ways used a liquid shot of cracked ammo gas to give you pure nitrogen gas into the heated metal. At best you could get about .015" case, and the parts ended up being very dirty. The newer plasma and gas setups use a typical 900 degrees in a semi vacuum. Parts come out looking like they've been glass beaded. The trick here is to make sure the parts are suspended correctly to aid in a total soak.

Now to add to the above, and from past experiences. I've found that not all metals behave the same in the nitride process. I've actually had them shrink as much as .0009", and have seen some steels grow that much as well. Why I simply can't tell you, and perhaps Flip might have a clue here. Still most of the time we always machined the part to size and ran it thru the nitride process without a hitch. I learned the hard way several times that not every lot of steel comes out the same. The first couple times I blamed the heat treat operator, but soon learned from my mentors to expect this as it was something that just happens from time to time. No one seems to know why to this very day!
gary

 

[elkaholic]

Gary...that's a little scary thinking your bore dimension could change by nearly a thou. It must not apply to Stainless or chrome moly or they couldn't do this. I was told by the experts that it will not change the dimension in the barrel hardening process at all. I will say this, however; I remember the muzzle brake requiring more torque to align as it previously did on the barrel? That could be just a residue problem though?.......Rich

 

[deadlift]

Hey Guys here's a quick recap of what I've learned after nitriding nearly 100 chambered barrels and actions over the last 3 years.
1) Some nitriding companies run the solution at the stress re-leaving temp, for our barrels that is 1050F and all you will end up with is a really expensive black barrel. If you are having this done by yourself get the S/R temp and save your self that headache.
2) Once this is done it will cut with carbide, its not fun or recommended but can be done ie, you ding the crown and need it re-cut.
3) We still don't fire anymore rounds down the tube than a final chamber dimension test fire. This works for us and has reduced the # of culls we have had after the process.
4) Any part you don't want permanently bonded together must be separate and marked either SS or CM.
And lastly we are using H&M for all a our nitriding
We do have our own process for break in/clean up after the fact.
Yes I have seen 3 barrels fail after being fired for accuracy then sent out to nirtide.
Hope this helps!
Chris
Benchmark Barrels