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Thread: S&W Melonite coated barrel vs Noveske chrome lined barrel.

  1. #191
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    Quote Originally Posted by constructor View Post
    Do you think Melonite is 70 Rockwell .005 thick and it turns to butter just on the other side of the .005"? How about 69, 68, 67, 66 until it gets to the center between the bore and the outside at apx 60Rockwell and then it starts getting harder again . Most barrels are only 48 Rockwell all the way through with a thin hard layer of chrome on the bore only. As soon as the chrome is worn or eroded away the 48 Rockwell barrel steel is eroded much faster than a Melonite heat treated barrel.
    very interesting point!!!

    NorthDakota: No problem. I too am very interested to see what happens in the next few years. I know you understand but i just wanna repeat myself that I'm not saying that the S&W barrel is superior to the Noveske. In fact, i would assume the opposite. As the thread developed it kinda turned into a NTC vs. CL debate and in general i do feel NTC is better based on the research myself and others have done. Hell, the Smith barrel might be or at least close to what they claim it to be. I just dont know.

    Ring: Man you got some nice rifles. Does SBN= salt bath nitrocarburization?

  2. #192
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    Quote Originally Posted by BAC View Post
    That sounds like a very bad idea, given that gun barrels are designed to contain and direct rapidly expanding gases (i.e. explosions). Ceramics aren't traditionally good at high-impact applications, and a thirty round magazine of 50k psi per round is somewhat high-impact...


    -B
    Ok, yeah i figured it was just some BS. Although he was claiming that it had already been done with phenomenal results but the cost made it not even worth considering.

  3. #193
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    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 alloys the material to retain ductility, thereby lending to the overall strength of the material.

    Resulting properties from these chemical and structural composition changes are increased surface hardness, lower coefficient of friction, enhanced surface lubricity, improved running wear performance, increased sliding wear resistance, and enhanced corrosion resistance. Naturally, the alloy of the substrate will influence which properties are principally affected and to what extent they are affected.
    Our heat treat company told us the longer the parts are heated the deeper the tempering goes and that includes Melonite/QPQ or carburizing but the carburizing like we use on our bolts can go deeper than the QPQ with the core of the bolts target hardness around 50-55 for maximium toughness. The surface .010 deep of 4150 treated by QPQ is corrosion resistant, very slick and tough to drill even with carbide bits. To check the barrels, we sent out a cut off where a barrel had been shortened to 14.5" the core(center) was 57-60C. Some 416R stainless barrels that are high in sulphur are as low as 30C, the hardest chromelined 4150 barrel we have found was 48C. The lands in a typical barrel are only .004" high so the Melonite completely penetrates the thickness of the lands . I can cut the chrome out of a chamber with a carbide reamer easy, it is not possible to cut a Melonite chamber without damaging the reamer.

  4. #194
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    Excellent information!!! I knew the first part but the last paragraph was something I didn't know.

    I just called it NTC because I know some companies like Swiss Arms are supposedly using a gas instead of a salt bath so I just started saying NTC to "cover it all" more or less.

    ETA: Looking through the S&W 2011 catalog and noticed that their not only offering melonite on their cheap sport model but their also using the same melonited 5R barrel on their "premium model" M&P 15T.
    Last edited by Dirtyboy333; 07-12-11 at 01:46.

  5. #195
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    Ring: Man you got some nice rifles. Does SBN= salt bath nitrocarburization?
    yes,,,,,

  6. #196
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    Quote Originally Posted by constructor View Post

    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 alloys the material to retain ductility, thereby lending to the overall strength of the material.

    [/FONT]
    That's good to know, as I thinking that maybe the steel would become somewhat "brittle", or whatever, due to the high RC.

  7. #197
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    Quote Originally Posted by constructor View Post
    To check the barrels, we sent out a cut off where a barrel had been shortened to 14.5" the core(center) was 57-60C. Some 416R stainless barrels that are high in sulphur are as low as 30C, the hardest chromelined 4150 barrel we have found was 48C. The lands in a typical barrel are only .004" high so the Melonite completely penetrates the thickness of the lands . I can cut the chrome out of a chamber with a carbide reamer easy, it is not possible to cut a Melonite chamber without damaging the reamer. [/FONT]
    That's impressive. I thought that chrome lining gave a higher Rockwell hardness than melonite.

  8. #198
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    Ceramics - Strange Properties for a "Glass"

    Quote Originally Posted by Dirtyboy333 View Post
    Was at my local gunshop talking to the local "expert" about NTC vs. CL and he was making several points (as have been mentioned here) to why he prefers NTC over CL. After discussing it he then mentioned something about ceramic barrels that "would not be affected by heat, best barrels ever, blah blah". He also stated that they are WAY to expensive to produce but theoretically perfect.

    Have you heard of this or is this just gunshop BS?

    ETA: a google search turned up a little bit about ceramic but it was all for coatings. He was talking about the entire barrel being ceramic with no steel.
    Ceramics are "glass" - long molecular chains that are essentially an extremely viscous liquid as it flows continuously.

    However, I have in my possession a ceramic ball that handles phenomenal compressive loads. Surely, it's geometry plays a role but still... I placed the ball on smooth concrete, took a sledge hammer and whacked it. Expecting the results to differ from what the manufacturer claimed I wore a protective face shield. When I opened my eyes I saw the black ball had sunk INTO the concrete floor leaving a perfect hemispherical divot.

    Later, I read of ceramic ball bearings for use in race motorcycles and u can purchase a set for your bike to decrease rolling resistance - and absorb ridiculous loads (though the bearing race may not fare as well).

    My point is that advances in metallurgy and material sciences is continuous. I don't doubt a ceramic barrel can be made. It will probably be a ceramic composite initially (just as we have MMCs - Metal Matrix Composites). The other material would be added for toughness; how much would have to be determined experimentally and studying phase diagrams.

    One would think that a pistol barrel would be first on the public market (as well as a research project) since it's much shorter and has to deal with less powder charge/pressure, etc.
    "One cannot awaken a man who pretends to be asleep..."

  9. #199
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    Quote Originally Posted by rsilvers View Post
    I never think of Chile and Poland as having good firearms innovations.
    [/Patriotic rant mode ON]

    In Poland we had a few, mostly in 1918-1939 era but also when our engineers worked for UK during and after WW2, but I must admit that 50 years of Soviet occupation greatly harmed this - this time firearms development was reserved for Soviets. Only Czechoslovakia break out from this (and they are still leading in firearms development in area). Now, guys at FB Radom (former "Łucznik" aka "11"), Military Technology University and Military Armament Research Institute have they bright days as well. Like with using NC process instead of CL or like with MSBS rifle prototype, where you can go from classic to bullpup and back in few minutes just by exchanging lower receiver and adding cheek rest over top rail (Youtube video with 1 generation working prototypes)

    After 1989 we are quite capable, especially with new technologies (non firearms example: http://www.marssociety.org/home/pres...untitledpost-2 http://urc.marssociety.org/home/urc-...011finalscores).

    [/Patriotic rant mode OFF]



    Going back to original "flamewar" CL vs NC. Example of Sako TRG sniping riffles with NC barrels is excellent. It is Polish Army standard DMR (I know that using bolt action as DMR is retarded). Those rifles just seem to go and go and go. Despite conditions, maintenance and strange selection of ammo used. My TRG-22 was not that abused, but seemed to take my "rust chamber" storage quite well. Anyway, for those application NC beats CL in very crucial aspect - NC does not add material - it penetrates into making layer of hardened surface but does not change dimensions. This way it is does not affect accuracy of barrel by changes of coating thickens and there is not need to calculate dimensions toleration for process.

    As to safety of processing material on finished barrel. I was researching this issue when I was going to ad PVC coatings on my custom STI 2011 pistol at Oerlikon Balzers Coating. I was consulting their engineers as well as STI (to get info on steel they use). High temperature processes can affect crystalline structure of steel and also can change element dimensions (warp it).

    What I learned is that most important is that temperature used for coating or nitrocarburising process used on element must be lower (at least 20C as minimum) than last stress relief temperature used in steel hardening process. So if one does not know what steel is used and how it was treated going blind into NC process can be asking trouble. It is also important to remember that surface hardening provided by NC will not cure using poor steel for barrel as much as CL does. NC layer, while harder than CL layer, is not going into material as deep as CL goes over it.

    It is best to consult firearms manufacturer to get info on material properties and work with people who know what they do. As always...

    BTW European companies (mostly from EU, but Swiss also) go from salt bath nitrocarburising to gas or plasma nitrocarburising due to new environmental protection regulations. Those regulations practically killed all king of traditional "bath" coatings (also for chrome, nickel, etc.). Green fundamentalists have strong position ad European Commission.
    Montrala

    I'm sponsored competition shooter representing Heckler&Koch, Kahles, Hornady and Typhoon Defence brands in Poland, so I can be biased

    http://montrala.blogspot.com

  10. #200
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    Thought I would post a few short comments;

    Salt bath nitrocarburizing (QPQ) does give about 20% better barrel life then chrome.

    LWRC does Salt Bath Nitrocarburizing to their barrels which will help barrel life as stated above. Plus the black finish works very well for those that like or need a black or dark finish.

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