INFI, is tough steel?

L

lovemysteel

Joined
Jul 1, 2015
Messages
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I found this by search and it seems like this may be steel I am looking for. I have not seen steel like this. How is corrosion resistance? I read threads and it seems very tough.

I found this:
This was listed in 2002:

V .36% Vanadium
Cr 8.25% Chrome
Fe 87.79% Iron
Co .95% Cobalt
Ni .74% Nickel
Mo 1.3% Molybdenum
C .5% carbon
N .11% Nitrogen

But in 2009 it change to this:

Element Weight %
Carbon C 0.64
Silicon Si 0.63
Chromium Cr 8.12
Molybdenum Mo 0.85
Vanadium 0.33
Iron Fe 89.43

So INFI can change and remain INFI? Later INFI seems

I found Mod A8

Carbon, C 0.50 %
Chromium, Cr 8.0 %
Iron, Fe 88.35 %
Manganese, Mn 0.45 %
Molybdenum, Mo 1.3 %
Silicon, Si 0.95 %
Vanadium, V 0.45 %

So new INFI is similar to Modi A8? Seem like very tough steels.


Seems like INFI is steel I want. Do they make folding knives from this steel?
 
INFI is a proprietary steel used by Busse alone. I believe the exact makeup and heat treatment are secret. There are no INFI folders (yet? )
 
Also, the corrosion resistance is excellent, although not technically a stainless...I'm sure others will be able to give more info on this.
 
The INFI I own does corrode. But not in a sense that it pits, more light surface stains than anything. From the perspective I stand at....rusting steel is good steel. I do not feel that the qualities that I choose for blades are even available in a stainless. INFI IS THE WAY TO GO!
 
INFI is tough stuff. I love how easy it is to keep an edge. Beat the hell out of it and hone it back. It doesn't seem to ever chip.
 
I have one or two particular blades i 'beat' on and never clean regardless of what im doing. I have never had any corrosion of any sort on my infi blades. They are unargueably the most robust, toughest blades i have dealt with to date.

The metallurgical analysis you have provided may indeed be what it is in the beginning, but with heat treatments and cooling solutions and other tricks, the material they come up with may be very different. At that point its all about microstructure, how homogeneous the material is as well as the amount of impurities. The simple fact is their method is proprietary no matter if they tell you what the steel is or not.

If i were to guess, the steel would be dangerously close to being defined as a stainless, with a microstructure that lends itself to lowered corrosion resistance with low carbon content to further increase corrosion resistance and ductility. There are other elements that can lend themselves to increase hardness (especially with treatments and cooling solutions/tempering). Regardless, the steel is dangerous any way you look at it.
 
I just came in from beating on an ASHBM for about 3 hours, hacking branches up to 5 inches thick. I came in ran some water down the blade to get the tree chunks off of it and then sliced my tomato for my lunch with it. I don't know how but this stuff gets sharper the more you use it, and I have never had rust on any infi that wasn't double cut bead blasted. Never any pitting just staining.

If you buy, you won't go back to whatever you were using even if you believe it to be superior now, INFI will change that.
 
Infi is great steel regardless of blade lenght. From big choppers to smaller fixed blades, it just works.
 
INFI is great performing steel. Buy one and never return to this board otherwise you'll end up with more than you "need"--just ask my wife. :foot: :D
 
NuclearSwine said:
INFI is a proprietary steel used by Busse alone. I believe the exact makeup and heat treatment are secret. There are no INFI folders (yet? )
Click to expand...

^^^ This. Proprietary. Secret. And can change under the hood as they experiment and improve various characteristics of the steel. The chemical makeup alone does not determine all characteristics, heat treat contributes as well. And yes, INFI is incredibly tough steel (toughest I've seen).
 
As far as we know, INFI is a custom steel alloy, commisioned by and made exclusively for Busse Combat. The composition is proprietary, but anyone can sacrifice a blade and pay for their own metalurgical analysis and then post it here. AFAIK, Jerry has not disputed any posted compositional data.

lovemysteel, can you please post links to those threads you found that report the composition? Thanks.

Since INFI is proprietary, it can be anything Jerry wants it to be, as he has made no public promises about the composition. It seems to me that he is free to tweak and adjust the formula and heat treat as he sees fit, within some parameters around maintaining the toughness and keeping warranty claims in an acceptable range.

There have been several posts over the years by old school hogs regarding their impression that old INFI seemed to hold an edge better than newer INFI. We know that way back when, the blades were hardened to Rc ~ 62, and later that was backed off to Rc ~ 58. It could simply be that effect that people are seeing. As the average user (or even the above average user) will never stress a blade to anywhere near it's limits, one could speculate that Jerry determined that INFI was overengineered for what it need to be and do, and backed off to a more reasonable range.

Only Jerry knows for sure, and he ain't talking.

OTOH, most customers seem to be very happy with their knives.
 
lovemysteel said:
I found this by search and it seems like this may be steel I am looking for. I have not seen steel like this. How is corrosion resistance? I read threads and it seems very tough.

I found this:
This was listed in 2002:

V .36% Vanadium
Cr 8.25% Chrome
Fe 87.79% Iron
Co .95% Cobalt
Ni .74% Nickel
Mo 1.3% Molybdenum
C .5% carbon
N .11% Nitrogen

But in 2009 it change to this:

Element Weight %
Carbon C 0.64
Silicon Si 0.63
Chromium Cr 8.12
Molybdenum Mo 0.85
Vanadium 0.33
Iron Fe 89.43

So INFI can change and remain INFI? Later INFI seems

I found Mod A8

Carbon, C 0.50 %
Chromium, Cr 8.0 %
Iron, Fe 88.35 %
Manganese, Mn 0.45 %
Molybdenum, Mo 1.3 %
Silicon, Si 0.95 %
Vanadium, V 0.45 %

So new INFI is similar to Modi A8? Seem like very tough steels.


Seems like INFI is steel I want. Do they make folding knives from this steel?
Click to expand...

Yes, INFI is the steel you want for any situation.

Yes, the chemical composition has changed, it now has no Cobalt, Nickel or Nitrogen in it. I remember the big talk being about Nitrogen in the 90's and no one could figure out how the steel had it. In fact I even had one of mine tested and the place that tested were dumbfounded about N. The old INFI was expensive and probably not worth the extra cost and removing a few elements and dropping Rc a few points kept the steel tough(maybe even tougher) and reduced costs. If you think about the cost and availability of a BM today vs a BM in 1999, the BM's of today are a bargain. The new stuff appears to be closer to Modified A8 per your chart. I don't mind that, because it is Busse's HT that makes the difference. 80+ hours plus a deep cryo is unbeaten in the industry. INFI still has no Manganese which is one of the most common elements in steel. There has to be a reason for that. INFI does not have hi levels of Vanadium because it reduces toughness but allows harder edges. This is what CVPM3V has more of. So on paper 3V should not be as tough as INFI and in reality I am pretty sure that is the case. Edge holding wise they might be close, but INFI's edge wil roll not chip.

Thank god I am not on the forums that often, otherwise I would be broke with 500 pieces of INFI.

The only other maker to use a steel as close to INFI was Johanning in his mod 11 and that was known to be an incredibly tough knife. No one else uses anything like it. There was a company in europe that made a Bohler steel blade of something similar to A8 but I saw one suffer massive failure on light batoning. Heat Treat matters.
 
Guy, you do not have to destroy a blade to determine the composition. It can be done without destruction. I can test any blade any time with no damage. It must be bare steel though.

And I did verify a while back that the composition had changed. I just wonder where OP got his data from since I never published anything, but I have not been on the forums and it may have been in some thread.
 
In compare to spring & jack hammer steels , what do you guys think INFI? still tough or tougher?
 
dingy said:
In compare to spring & jack hammer steels , what do you guys think INFI? still tough or tougher?
Click to expand...

Jack hammer bit steel is tougher, but corrodes quite readily. One of those is called S7. Swamp Rat and (especially) Scrapyard used that steel with the Busse heat treat protocol, and called it SR-77.

INFI is a steel that's all about compromise. It is extremely tough (there ARE tougher), and fairly corrosion resistant (but not quite stainless), while still being able to take and maintain a really good edge. It is easy to sharpen too. Any other questions? :D
 
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