Stellite

N

Nebulae

Joined
Aug 24, 2009
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O.K. So learn me up on this. I have been trying to find out as much as I can about this material, and I have found it is very difficult to find information, and sources. I realize that Stellite was popular in the early 2000s, and it is not a replacement for steel, but I just want to play with the stuff, and learn about it. Everyone has heard about Stellite 6k, 6B, but there are dozens of other varieties that look like they have desirable properties, but I cant find much data on them, much less a source.
Look at Stellite 100
you can find some data here -stellite 100 seems to be very cool, 63Rc, but how tough?

Why is Stellite so expensive, so hard to find info on, and so hard to get. I have gotten tungsten carbide, and other materials realitivly easily, and reasonably cheaply. I haven't seen anything so elusive-Which is part of why I want it!
 
Stellite 6K and 6B are cobalt based materials. 6K will Rc at about 47
and 6B at about 51. Neither is hard enough for a general purpose
utility knife. These materials excell at cutting softer materials like
fabric or flesh. They are difficult to grind, and require carbide tooling..
They tend to be ductile, and were used as signal mirrors on battleships
during WW2.
These are the two more commonly used for knives....not familiar with
Stellite 100.
 
Signal mirrors? that is a weird use, I wonder why? from what I have heard it doesn't finish well.
 
I asked the same question of the Cabot Corp Rep. ( They
made Stellite then...early 70's). He said it would take a high
polish, and not shatter when struck by a bullet.
 
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I have a little piece of tantung G, also a cobalt alloy, interesting physical characteristics...

Mechanical Properties
Rockwell C hardness
60.0-63.0
Brinell hardness: 479 at 1200°F
Transverse Rupture Strength
300 x 10³ psi
(almost twice that of other cast alloys)
Compressive strength:
400 x 10³ psi
Youngs' Modulus:
41 x 106 psi

Tantungs* low co-efficient of friction makes it an ideal cutting/slicing material.
 
so is this in the same family as dendritic cobalt which is still used in knives? I know dendritic cobalt has amazing stainless properties (it isn't steel so I guess that's why) but will not take a real fine edge due to the large crystalline structure.

This is a great topic, sure has peaked my interest in non-steel metals for knives.


-Xander
 
Most of the stellite products are used in the high temp, high pressure environment of Jet turbine engines. the reason you are having so much trouble finding info is that most of the good stuff is classified as TOP SECRET by the DOD. since it's used in the fighter/bomber engines. I have a Haynes Corp (another stellite manufacturer) about 15 minutes away from my home. many of my friends work there. anyone cought sneaking stuff out are terminated on the spot, and subject to much worse charges than petty theft. (upto and including treason) anyway I digress. There are some "knifeguys" in the factories but they aint producing except for themselves. Another cobalt based product you may have an easier time finding is Talonite. AKS used to stock it but I dont think they have it on there website anymore. might be worth giving them a call though. They might have a few pieces still kicking around their shop. :D

Jason
 
I'm a knife user, not a maker. I have used several stellite 6k and talonite knives, Blackwoods, Simonich and Rinaldi. They are fairly soft and will roll an edge, but they will keep a working edge for a long time if you are careful. There was talk about the material's "lubricity", but the scientific basis for that isn't that clear to me. I use it mostly for harsh salt water environments ( extended ocean kayaking) and it does excel for general use in that context, although chopping isn't the best idea. the materials' main uses are industrial, as I understand it, but i don't pretend to be anything approaching an expert.
I hope that helps in some way.
 
OH that explains it. I knew they did allot of Engine parts, but I didnt put 2 & 2 together.
looking into tantung, but it looks more brittle than steel.
 
Stellite is much like Talonite in how it works and cuts and in its properties I think. I understand Stellite is the more difficult to grind of the two. Both are difficult to grind though regardless of which is the more difficult one to work. I bought some Talonite from Chuck Bybee a few years ago and gave the blade made from it to my son in a folder. Just enough to make a 3" blade for a folder was surprisingly expensive.

After working with it I can say that the material is for lack of a better term, 'strange' and by that I mean its just one of those things you have to look at for what its good for and what it is not good for. On the one hand it holds an incredible edge, yet on the other well, not so much. Its non magnetic and it has extremely high corrosion resistance but you have to, as HJK said, be careful about how you use it. The material its made up of, call it the matrix is soft but its filled with carbides which are hard. It may Rockwell test as softer than you would think could work but the carbides within the matrix are very hard and they do the cutting and they are why it has a high wear resistance and is difficult to work, drill or grind.

The make up is also why its not particularly good for cutting harder materials. The carbides do the cutting as I said but if you are cutting in things harder the carbides get pulled out of the softer matrix of the blade so you end up with a rolled edge or micro chips missing from the edge from this happening and what it amounts to is that you have to be careful what you use it on. If you are cutting paper or flesh well heck the stuff will clean out the roll of paper or do all the deer in the deer camp in a skilled hand but if you hit bone, or use it in between for something else that knocks the edge some you'll soon find that the edge is degraded in one of several ways. It can roll, or deflect and it can chip from carbide loss.

One of the other things, at least with Talonite is that its a very slick feeling material. It almost seems to slide through as opposed to slice through things. I've not compared it to Stellite for cutting similarities and that material is very hard to find so thats why. I think talonite is very similar though for the most part and you can find more on it. It is very expensive also though, as I said so be prepared to spend some bucks for even a very small amount.

STR
 
I have a fair bit of experience with David Boye's Dendridic Cobalt bars. It is somewhat similar.Even though you can't really get it screaming sharp, it slices soft tissue and things well, but will not retain and edge against harder things like wood cutting. Its biggest advantage is its non-corrosive nature ( and no HT).
I made up several fighter/survival models a while back for a special order. Beyond that order, and a couple dive knives,I have never had much luck with selling cobalt blades. I have three or four finished blades in the cabinet that I haven't put handles on yet.
 
JasonSCarter said:
Most of the stellite products are used in the high temp, high pressure environment of Jet turbine engines. the reason you are having so much trouble finding info is that most of the good stuff is classified as TOP SECRET by the DOD. since it's used in the fighter/bomber engines.

Jason
Click to expand...
Curiouser and curiouser. Jason may be exactly right. It seems information about the lubricity of cobalt is "under lock & key":
http://www.eng-tips.com/viewthread.cfm?qid=81517&page=229
 
After working with it I can say that the material is for lack of a better term, 'strange' and by that I mean its just one of those things you have to look at for what its good for and what it is not good for. On the one hand it holds an incredible edge, yet on the other well, not so much. Its non magnetic and it has extremely high corrosion resistance but you have to, as HJK said, be careful about how you use it. The material its made up of, call it the matrix is soft but its filled with carbides which are hard. It may Rockwell test as softer than you would think could work but the carbides within the matrix are very hard and they do the cutting and they are why it has a high wear resistance and is difficult to work, drill or grind.
Click to expand...

This is exactly why I want to both use, and make /grind stellite, or the like, because it is different, and provides lots of exciting learning opportunities.

HJK I have heard that it has a low coefficient of friction, that it is closer to Teflon than steel.
here have a read lotsa good stuff http://www.azom.com/Details.asp?ArticleID=1723#_Talonite®_Compared_to apears to discuss everything except wear resistance
 
It's funny stuff alright. Stellite 6-K Rockwells in the mid forties, but you can't scratch it with a 60Rc file. It is used to make tool cutting bits which must resist high heat. It is used to make Sodium cooled valves for racing engines. The dendritic material is cast. The stock removal blades have no dendrites (macro-crystals). Talonite is a proprietary 6-B Stellite. It usually has a lower Rockwell hardness than 6-K. 6-K is more than twice as expensive as 6-B. The last prices I saw for Stellite were $265/lb. for the former and $100/lb. for the latter. You can scratch 6-B with a file. Really high end alloy steels usually sell for less than $50/lb.
 
Some people have tried forging Stellite but I don't recommend it. At 2,000° a hammer will not dent it. The Stellite alloys were specifically designed to be heat resistant.

We will carry Talonite again when the price comes down. The alloy is made in Asia and the devaluation of the US dollar has increased the price to where it is stupid expensive.

It is hard to describe the lubricity of Talonite. When I grind steel I put a stack by the grinder and work my way through the stack. When I stack Talonite the stack slides apart a few seconds after turning on the grinder. I've been cut many times by burrs on Talonite but I've never felt the cut once. Sometime I feel it graze my skin. A few minutes later I notice blood. It is a very different blade material.

One last point that was made previously. Talonite is not a general use blade material. It is excellent for some uses and poor for others. It works great for cutting meat or vegetables. It is terrible for cutting hard materials or chopping.
 
Thanks chuck, I emailed you if you haven't already seen it, but this answers my question, so no need to respond. any idea about a timline?
 
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