Nitrogen in steel

Dmitry Platonov

Dmitry Platonov

Joined
Mar 19, 2002
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Researching this topic, I came up with interesting document:
http://mse.snu.ac.kr/msebk21/achievement/2006pdf/오규환/nitriding of steel.pdf
It indicates that it's possible to add considerable amount of nitrogen to steel in salt bath, using readily available nitrates. After 3 hours exposure average concentration of nitrogen in 0.4mm layer was 0.055%, which isn't low comparing to 0.11% N in INFI (as I read somewhere on the forums). So, Busse may use similar process to enhance steel with nitrogen during their 40h HT.
Main concern with nitriding is that nitrogen is mainly on the surface, while this study shows considerable diffusion into volume. I think if nitriding is done before quenching, soaking will level nitrogen percentage through cross-section great deal.
It would be interesting to do some nitriding of CPM 3V and compare it to INFI :rolleyes:
 
While this procedure sounds interesting, I think the advantage of this would be pretty much wiped out by the expense of holding the blade at 1050C for 40 hours (or even 3 hours). The cost of running a salt pot for a couple blades, as well as the toll on the equipment, would be a lot of money for a small gain.
Stacy
 
Sandvik has a steel with 3 % nitrogen !! Carburizing or nitriding adds more variables and cost .Not an efficient way of doing things.
 
Dmitry, on one of the forums I'm on there is someone who works for Sandvik.He mentioned it recently. I'll see if I can track it down.
The Korean report is interesting .I've now read it carefully. To explain to those who need clarification, there are two types of alloying.Where the alloying element has a significantly smaller diameter than the base metal [such as carbon] the alloying element fits between atoms in the matrix. If the alloying element size is similar to the base metal it substitutes for an atom in the matrix. In the report the nitrogen is substitutional.
No mention of the use of Ti and Al in the steel was made but they have an affinity for nitrogen .Al additions of about 1 % have been used for special nitriding steels.
 
mete said:
Sandvik has a steel with 3 % nitrogen !! Carburizing or nitriding adds more variables and cost .Not an efficient way of doing things.
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That's very interesting, I wish we could learn more.
 
No link from him to the actual steel thogh. THe metalurgists here are dying to look into it. (We mostly deal with iron, but what metal guy isn't turned on by this kinda reading.)
 
Fiddleback said:
No link from him to the actual steel thogh. THe metalurgists here are dying to look into it. (We mostly deal with iron, but what metal guy isn't turned on by this kinda reading.)
Click to expand...
And I've been unable to turn up anything through basic patent searches or Sandvik's website, though maybe I'm not looking hard enough.
 
TiN is that gold colored coating you find on some drill bits for example.
With powder metals many things are possible.Add the powders you want .These are then compressed and heated to bond them.
 
Thank you, mete! Uddeholm does have interesting steels, besides vancron 40 there are Vanadis 6 and Vanadis 4 Extra, which seems to be excellent choice for knife steel!
 
M Wadel said:
Could you get steel with "built in" Ti nitride?
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Yes.

During the Eighties, Sandvik Coromant developed a material to be in between high speed steel and cemented carbide in hardness, 70+HRc. The material was characterised as having extremely fine grained hard particles, average size around 0,1 microns, Ti nitride hard phase in a Fe matrix. The material was commercially introduced in solid endmills in 1990 under the name "Coronite". Due to production difficulty and the development of better PVD coated solid carbide, the material did not become a commercial success.

This said, for a long time I have been thinking how this material would work as a blade material. I would think that the fine grain size in a steel matrix would give a good balance between edge holding and toughness.

//Rickard//
 
Dmitry Platonov said:
Thank you, mete! Uddeholm does have interesting steels, besides vancron 40 there are Vanadis 6 and Vanadis 4 Extra, which seems to be excellent choice for knife steel!
Click to expand...

I have been wanting to try Vanadis 4X and 6 for years, but you can't get it in usable sizes, at least in the US. 4X is like CPM 3V on Steroids, twice as much Carbon and similar other chemistry.
 
Vanadis 4 Extra and Vanadis 6 do appear to be excellently balanced knife steels, but as Steve said ithey can't be purchased in knife sizes. My father has a round bar of Vanadis 4 Extra that I've always wanted to play with. In related news, there is a patent application out right now for a Vanadis 6 Extra that looks amazing.
 
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