Titanium nitrided bores?

20 April 2003, 14:10

hit-em

My company is envolved with hard chroming & nitriding stamping draw dies for the Automotive Stamping Industry. These are the dies that stamp out most of the sheet metal on vechiles.
In regards to surface treatements the major difference between hard chroming & nitriding is one is a coating "Hard Chrome", the other is a penetrant "Nitride".
In regards to Nitriding there are two different process's we use:
1.Nitriding which has a surface hardness of 58-62 RC.
2.Ion-Nitriding which has a surface hardness of 58-62 RC, but has a surface layer of what is called a White Layer which has ceramic qualities that aid's in it's lubricity.
Both process's are considered a high heat process, after Ion-Nitriding the dies have a very rough surface that needs to be stoned & polished before going back into the press.
The intial hardness of 58-62 RC for a Ion-Nitrided piece is only a few thousands deep, from there hardness will drop off. Basically what you have after Ion-Nitriding is a case hardening process with lubricity due to the ceramic qualities of the White Layer.
Dies will rust after treatment, most dies are cast iron or cast steel.
These stamping dies will see a tremendous amount of friction & heat due to the forming of sheet metal, more then any rifle barrel would see in normal shooting.
Both process's do quite well in that enviroment. I have seen dies with over a million hits before needing to be processed again.
I've often thought to Ion-Nitride my receivers & bolts, but to Ion-Nitride or Nitride my barrel to help with corrosion or enhance the life of my barrel would be a waste of time & money.
The chance of warpage would be too great. I've seen inserts that weigh over 50lbs that where Nitrided that had to be squared up again afterwards due to warpage from the high heat.
The only way I would surface treat a barrel bore is with a low heat process, but I just don't see the benefits versus the cost.

22 April 2003, 20:55

Pyrotek

quote:
I'm still looking for supporting evidence for the blanket statement that even nitrided or nitrocarburized surfaces will not resist throat erosion any better than untreated steel

InfoSponge,

How come you don't get the logic of the argument in this thread? The entire argument is dedicated to see if nitriding is better than CHROME plating, not plain steel. Of course nitriding is better than untreated steel, but if it's not better than chrome, which in due time cracks and peels off, then why spend the nitride money for the effect of chrome?

IF NITRIDE LAYER PEELS OFF ABOUT AS SOON AS CHROMED LAYER DOES, THEN THERE'S NO POINT APPLYING NITRIDE IN THE BORE.

For he who does not believe the so-called "heat cracking" phenomenon, see here :

http://www.gradientlens.com/majorapps.asp#Shooting

See "Bore Wear" for heat cracking image

See "The Condition Of A Used Barrel" for image of chrome plating peeling/cracking (Source from another magazine indicates the image is of a chrome plated AR-15 barrel after several thousand round)

Pyrotek

22 April 2003, 22:38

InfoSponge

quote:
Originally posted by Pyrotek:
How come you don't get the logic of the argument in this thread? The entire argument is dedicated to see if nitriding is better than CHROME plating, not plain steel.

Pardon me, but I don't believe the discussion was that narrow.

quote:
Of course nitriding is better than untreated steel, but if it's not better than chrome, which in due time cracks and peels off, then why spend the nitride money for the effect of chrome?

I'd love to see the data supporting your "of course". I haven't seen any reports specific (or really even very close) to nitriding or nitrocarburizing applied to rifle bores. I can see arguments to be made for both its advisability and inadvisability. What I'd really like to see is hard data.

I don't think nitriding or nitrocarburizing will create a magic, never-fail surface in firearm bores. However, if nitrocarburizing can provide a surface that performs at least as well as untreated steel (regardless of how it compares to chrome -- and, incidentally, chrome plating is frequently more expensive than nitriding), then it may be worthwhile. I say that simply because from the pricing data that I have been able to gather so far, it looks like nitrocarburizing with post oxidation may well be cost competitive with rust bluing by hand. If that is the case, then you can get the same aesthetic finish while simultaneously getting much improved corrosion resistance for no additional cost over rust bluing. If this nitrocarburizing process will also improve throat life or leave it unaffected, then you might as well do it, 'cause to mask out the throat so that it will remain untreated will add a small amount of cost.

quote:
IF NITRIDE LAYER PEELS OFF ABOUT AS SOON AS CHROMED LAYER DOES, THEN THERE'S NO POINT APPLYING NITRIDE IN THE BORE.

I simply don't agree. There are more factors to be considered than your oversimplification takes into account.

23 April 2003, 10:39

Pyrotek

Whatever you say, InfoSponge. Only people who know what they are talking about is capable of "oversimplification". This discussion hasn't been broad and shouldn't be.

Now you back nitrocarburization into a blueing substitute as long as it does not affect bore durability...you don't seem to see it as a bore treatment anymore, are you finally convinced that durability of hard surface treatment IS dependent to material underneath? Please say yes so I can take a vacation.

Do show respect and be grateful to others' intellectual capability, without above response from other members, you will probably still have undue faith in the nitrocarburization for bore idea.....having a misunderstanding for indefinite amount of time in life, should upset the intellectually-keen type like you. True intellectuals challenge and destroy their own misunderstanding, not to carry it on and superimpose on others. Know how much you don't know.

If you propose an idea and want to make your statement strong : seek and provide hard evidence yourself, if one is unwilling to believe in others then he'll just have to be on his own.

I feel that I have learned little from you and that I am not obliged to make you believe anything more, I shoulda wisely retire from this conversation like Axel did. If you truely want to find out more, then like Axel said, find out yourself. That's all I want to say.

A spongeful of info,
can't absorb no more,
if it thinks it's full,
only after it is willing,
to give up those bad info,
will it siphon even more.

23 April 2003, 20:35

InfoSponge

Pyrotek,

I'm sorry that you seem to take what I intended as a purely technical discussion as some sort of personal affront. You make take a vacation anytime you wish, and I will gladly retire from further correspondence with you on this subject.

23 April 2003, 23:49

John Y Cannuck

Sounds like a job for Saeed, and his crew of experts!
[Big Grin]

24 April 2003, 10:26

Pyrotek

quote:
I'm sorry that you seem to take what I intended as a purely technical discussion as some sort of personal affront

Got you! Look back into my posts, I never said I feel insulted, but why do you think I am insulted? If I am the one that "take" your purely technical words as insults, then why should you be sorry, you pity me or you subconciously feels guilty because you know you talk with a flavour? Don't say sorry unless you mean it.

If you are truely sorry, as a way to make up to me, why don't you provide some technical data that compares nitrocarburized steel surface against untreated steel, or against chrome plated surface? Seeing that you are eager to learn, you must have found it already. HEY! IF THAT'S TOO MUCH WORK FOR YOU OR YOU DON'T WANT TO SHARE HARD EARNED KNOWLEDGE, SEND ME A TAPE OR SOUND FILE WITH YOU READING YOUR ENTIRE MESSAGE(QUOTATION INCLUDED) IN A SEVERE BRITISH ACCENT, WE CAN CALL IT A EVEN.

I am not offended by you(you never can, have seen many like you), I am actually a little entertained, more if I can get that tape.

24 April 2003, 15:37

pjh421

Hasn't Blackstar made a business out of this? I believe they (at least at one time) offered a bore surface hardening process that was supposed to extend the accuracy life of a barrel.

Paul

29 April 2003, 06:01

<Axel>

To all of you nitriding proponents. I did a little research through the archives.

Steel - SAE 4140
Nitriding temperature: 950 F
Dissociation: 25%
Nitriding time: 50 hours
Core hardness: 25.6 Rc (avg)
Surface harness: 53.1 Rc (avg)
Effective case depth: 0.127 mm (0.005")

Steel - SAE 4140
Nitriding temperature: 950 F
Dissociation: 25%
Nitriding time: 50 hours
Core hardness: 35.2 Rc (avg)
Surface hardness: 61.4 Rc (avg)
Effective case depth: 0.356 mm (0.014")

Remember that all heat treatment and tempering MUST be completed before nitriding! Also, the tempering temperature used MUST BE GREATER than the nitriding temperature to maintain strutural integrity during nitriding. Rc 35 is about all the harder that 4140 can achieve and be tempered above the nitriding temperature.

Nitriding is a DAMNED expensive method for creating a wear resistant surface. Wear does not begin to be significantly affected until surface hardness approaches Rc57.

Nitride away, but at least you have been warned.

Infosponge, this is REAL data taken from REAL steel shafts. There is NO cyber world dreaming going on here!

FINAL NOTE. THE RC VALUES ARE CONVERTED FROM RN-15.

Axel

[ 04-28-2003, 21:03: Message edited by: Axel ]