C69???

I talked to Spike at QuesTek, the Ferrium C69 will not be available until September. In the tec data sheet it discription is Utra-Hard Case-Hardened Core. composition Fe/Bal., Co/ 27.8-28.2, Ni/ 2.9-3.1, Cr/ 5.5-5.2, Mo/ 2.4-2.6, v/.015-.025, c(core)/ .09-.011. Need someone with a Metalurgy skills to review and advise.

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INDIAN GEORGE
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[This message has been edited by indian george (edited 02-17-2001).]
 
Ferrium C69 was the subject of a big <a href="http://www.bladeforums.com/ubb/Forum64/HTML/001664.html">thread</a> in the Blade Discussion Forum, with yours truely being one of the main contributors to said thread.
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Well amend that to 'one of the subjects'. It rambled about a bit.

How I see it: is that Rc69 edge chip resistant? Slowly driving it in a precise linear fashion into another knife edge may not be the best measure of how tough it is. It also requires that the knife be gas or plasma carburized.
 
<font face="Verdana, Arial" size="2">Originally posted by indian george:
composition Fe/Bal., Co/ 27.8-28.2, Ni/ 2.9-3.1, Cr/ 5.5-5.2, Mo/ 2.4-2.6, v/.015-.025, c(core)/ .09-.011. </font>
Click to expand...

This is interesting.

Ferrium C69:
------------
Cobalt: 27.8 - 28.2%
Nickel: 2.9 - 3.1%
Chrome: 5.0 - 5.2%
Molyb: 2.4 - 2.6%
Vanadium: 0.015 - 0.025%
Carbon: 0.09 - 0.11%
Iron: 60.765 - 61.795%


By contrast, Talonite looks something like this:

Cobalt: 49.6 - 56.1%
Nickel: 3.0%
Chrome: 28.0 - 32%
Molyb: 1.5%
Vanadium: 0%
Carbon: 0.9 - 1.4%
Iron: 3.0%
Silicon: 2.0%
Manganese: 2.0%
Tungsten: 3.5 - 5.5%


Ferrium uses iron as the base metal matrix, like most steels, instead of Cobalt as in Talonite.

Ferrium has very little carbon for carbide formation, hence the use of case hardening to increase surface hardness.

From a knife blade perspective, the case hardening might be problematic... case hardening is really just a surface treatment. It is the approach used on some handgun trigger action parts.

Problem is, in the case of a knife, if you sharpen the edge once or more, you scrub off that outer surface layer of "hard stuff" created by the case hardening process...the carbides created by the carburization of the outer surface. Then you expose the soft metal underneath.

Now, I'm not a metallurgist, and I have lots to learn. At this stage, knife blades tend to be made out of either:
1. hardenable material, usually martensitic steels or hard ceramic matrix... or ...
2. moderately hard matrix (Cobalt/Chrome) loaded with carbides... Stellite or Talonite.

Perhaps one way around this to some degree with Ferrium would be to try Buck's approach to Carbo-nitriding... bevel the edge on one side only. When you sharpen, you sharpen the bevel, but leave the hard surface treatment on the back/unsharpened side to create the hard, cutting edge.

Interesting post on Ferrium 69. Thanks for the links.
 
Some raw text from the QuesTek page:

Overview of Properties
Core hardness = 50HRC
Surface hardness = 69HRC

Description
Ferrium ™ C69 is a member of a new class of
case-hardened steels which utilize an
efficient nanoscale M2C precipitate
strengthening dispersion. Ferrium ™ C69
combines a tough ductile core with an ultra-hard case that can achieve hardness levels
greater than 69 HRC, promoting high wear
and contact fatigue life.

Ferrium ™ C69 is the product of an ongoing research and development program with the objective of reducing weight of components by as much as 50% over those manaufactured using conventional high performance alloy steels.

This document contains results obtained from
several prototypes of Ferrium ™ C69. Commercial scale quantities are currently available. Please contact us with your production requirements.

FerriumTM C69 Advantages
=========================
Ferrium ™ C69 combines surface properties
superior to those of conventional caburized
steels with a flaw tolerant core. These
surface properties allow either higher
contact stresses at an equivalent life or
significantly longer wear life at the same
contact stress when compared to existing
carburized steels. Thermal resistance of C69
is a consequence of the high stability of the
strengthening carbide and ensures hardness
will be maintained to temperatures in excess
of 800ºF. High hardenability allows gas
cooling, which reduces the distortion that
normally results from quenching. Ferrium ™
C69 can be heat treated to an intermediate
case hardness of 60 HRC, providing
grindability equivalent to current high
performace alloys, and then tempered to 69
HRC case hardness with extremely low
distortion.

Processing
Ferrium ™ C69 can be processed using
typical forging and machining operations. Once the approximate geometry has been achieved, Ferrium ™ C69 can be plasma or gas carburized (gas carburizing requires a preoxidation treatment) by a typical boost and diffuse cycle.

A solution treatment, gas cool, and 575ºF
temper provide a 60 HRC case for finish
grinding if needed. In this condition,
grindability is similar to conventional
carburized steels such as AISI 8620 and 9310.
A final temper at 900ºF produces the ultra-hard 69 HRC wear resistant surface and tough core with minimal distortion. If needed, nitriding can be also completed during the tempering to increase surface hardness beyond 69 HRC.

Final shot peening is recommended.

Rolling Contact Fatigue
Contact fatigue properties of Ferrium ™ C69
are compared to standard M50. The fatigue
test is a standard 3 ball on rod NTN RCF test
using a contact stress of 786 ksi. The results demonstrate that Ferrium ™ C69 exhibits a longer fatigue life at a given failure rate (or, conversely, a lower rate of failure at a specified fatigue life) than alloy M50. The data suggest that at a failure rate of 10%, the fatigue life of
Ferrium ™ C69 is more than an order of
magnitude longer than that of M50.

Wear
The test results from a Falex wear simulator
are shown. A dramatic reduction in wear rate
is demonstrated by the advanced Ferrium ™
C69 alloy over that of standard commercial
grade AISI 8620. Whereas wear depth for
C69 appears to level off in the sub-micron
range after approximately one hour of initial
wear, the wear depth for components made
from conventional AISI 8620 steel (through
hardened to 56-58 HRC) is greater after one
hour and continues to increases with time.

Availability
Ferrium ™ C69 is available in custom bar sizes and billet forms. Please contact QuesTek Innovations, Evanston, IL with your
production requirements or to obtain
information about other QuesTek alloys and
materials design services.

 
Aw, never mind. Should've read the thread Grant refers to first.

I've always heard that most any steel like material harder than Rc62 get brittle. Certainly pure tungsten carbide machine tool bits are very brittle.

Hence the beauty of Stellite/Talonite... embed super hard carbides in only a moderately hard (Rc42-48) matrix. Gets to abrasion resistance anyway.
 
Tempered martensite in alloy steels actually results in a system not totally unlike Talonite. Carbides precipitate out from the martensite during the temper, letting the matrix relax into softer ferrite. The type of carbides depend on what the steel is alloyed with. Ferrium C69 forms Mo2C, the V-containing CPM steels form VC. Not so sure what others do.

Carbides in tempered alloy steels are nano-scale (10E-9 meter) while carbides in Talonite I am guessing are more on the micro-scale (10E-6 meter).

I am confused as to why Talonite reads so low on the Rc scale given the edge holding people report it can give.
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