Infi steel?

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David Stifle

David Stifle

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I've heard a ton of stuff, primarily on the swords subforum, on how tough infi steel is. Baton through bricks, cut through steel pipes, so on. How much of this is hype, and how much is well founded facts? What the heck is it anyway? I've never seen it for sale, so I assume it a tradmarked steel. Just curious.
 
There is certainly some hype and marketing going on there, but I believe there is more to the product than grind and hype. While it is true you can grind a piece of 1070 into a cold chisel than can cut a concrete block in half without gross edge damage, there is no single grind you can form it where it can push cut paper, slice up melons, bend 90 deg in a vise and come back mostly straight and still chop a concrete block in half without gross edge damage. Think about that for a second. Busse did his homework and developed a very good heat treat for a well chosen alloy that pairs well with the geometry he uses to make a very durable knife.
 
Nathan,

It sounds like an impressive steel, do you know what is is? Is it a 10XX, a stainless? Any idea what makes it so durable?
 
It's a nitrogen steel. Similar in toughness to CPM3V. It's not all hype. Geometry plays a part but Infi is the real deal.
I have the specs and comps to CPM3V and a couple other steels bookmarked on my laptop. I'll try to add them later.
 
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No hype.
INFI is some of the best stuff out there.
I was skeptical too, until I got some INFI.
 
Sam Salvati said:
Any steel can do all that if you grind it like a cold chisel.
Click to expand...

Well, almost;)

I am not a metallurgist, but I have some experience with some amazing steels and some amazing knives. I would suggest something that a lot of people in the know would probably agree with...that is there are many factors to what makes a phenomenal knife, and many of these factors if left unchecked will render the knife FAR less than phenomenal. One of those factors is steel/alloy, another is geometry, and there are others;)

The concept that there is one ultimate steel that will lead to the greatest performance (bar none) and it is unique to a single maker, who also has every other aspect of knife making completely perfected, is a little hard to digest. There are a LOT, and I mean a LOT of entities out there working very hard to develop new alloys....and a lot, and I mean a LOT of VERY knowledgeable makers out there working with these alloys and constantly pushing this industry forward.

I would suggest that the "greatest" is a very mobile target;)
 
In my opinion,The propeties of steel depend on two factors: chemical composition and metallurgical quality.

in the alloy design of INFI,first the carbon is reduced to about 0.5%, it can get high toughness that will stiil provide sufficient hardness.second, about 0.18% nitrgen was introduced into the steel which can enhance not only corrosion resistance but also toughness . third, about 0.5~1% nickel was added and nickel is the most effective element to improve toughness. Fourth, because of nickel can lower MS critical point that may result in more residual austenite, 1% cobalt was introduced to fill in the gaps,because coblat is is one of the few elments that raise the MS critical point, and the tempered martensite turn more tough when nickel/coblat are added in steel together.Fifth,chrome was hold at 8% and molybdenum was hold at about 1%, than form a certain quantity of carbide to get wear resistance ,however the carbide is not too large to harm toughness.in conclusion,the alloy design of INFI is very clever .

Even so, alloy design is only one side,the metallurgical quality of steel is also very important which is determined by the technological process,but so far I still do not know the manufacturing process and equipment of INFI, so I have no comment.
 
Thanks for elaborating Yushu!

I'm can never get enough information when it comes to metallurgy. Always fascinating when people who know(as opposed to me) share their knowledge.
 
I have a geology degree, so I studied chemistry and the properties of compounds, what happens in a melt as it cools, grain size and all sorts of things for 4 years. So I know a little about what's going on in a blade; I'm not a complete noob. I've been getting into knives pretty seriously for about the last 12-18 months and recently gave Busses a try. I read every bit of info I could find about them.

I got a FBM and was using it to clear a few scrub brush small trees in my back yard. There is limestone directly under our soil here, so there's some loose limestone and chert in the soil. My FBM did contact the soil and a few rocks (limestone and chert) a few times. I was working outside for about 30 minutes. When I inspected the blade, I was a bit shocked. I didn't expect to see any chips. I saw three chips that were about 2-3mm long and parts of the edge that were just obliterated. I thought I'd see some folding, possibly, that could be straightened up with a hone. I took some pics of it and resharpened it on a EdgePro Professional, removing the chips. It took about 90 minutes to get the edge back; it's a big blade. My own take away from this experience was that the steel is human, not superhero-like. I had a 23 degree edge profiled on the FBM. This may be too acute if you think you might be impacting rocks hidden in the dirt. I still like INFI steel just fine and have plans for buying several more, but I'll be a bit more careful in the future and not expect that I can swing the blade into anything and it will escape with just some minor folding.

Here's an album with the pics of the FBM, the brush I was cutting and the area of the blade where the edge really took it on the chin.
http://www.flickr.com/photos/oldjimmyjohnjohn/sets/72157630091941718/

I'll try and directly link to one of the pics of the chips here:
7171260365_d0d02e2d5f_b.jpg
 
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{QUOTE}My FBM did contact the soil and a few rocks (limestone and chert) a few times. I was working outside for about 30 minutes. When I inspected the blade, I was a bit shocked. I didn't expect to see any chips. I saw three chips that were about 2-3mm long and parts of the edge that were just obliterated. I thought I'd see some folding, possibly, that could be straightened up with a hone. I took some pics of it and resharpened it on a EdgePro Professional, removing the chips. It took about 90 minutes to get the edge back; it's a big blade. My own take away from this experience was that the steel is human, not superhero-like.

Here's an album with the pics of the FBM, the brush I was cutting and the area of the blade where the edge really took it on the chin.
http://www.flickr.com/photos/oldjimmyjohnjohn/sets/72157630091941718/

I'll try and directly link to one of the pics of the chips here:
7171260365_d0d02e2d5f_b.jpg
[/QUOTE]

A real life experience. This is why I asked over on the Swords subforum if anyone had tried to duplicate the tests Busse did. Should that blade have chipped if in fact, it really could baton through concrete blocks, pipes, etc. ?
 
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Heres my piece of INFI, with a chuddy bear sheath package, no draggin this sweetie through the dirt though!

511.jpg
 
Nice looking knive, Greg. Hardly looks used, not even a few scratches. Guess I can't ask you if you have tried any of the Busse tests.:)
 
I have heard a LOT of discussion on here and other forums about Busse knives. What I have heard indicates that the INFI steel is probably not as tough as S7, but maybe a bit tougher than the other commonly used high impact knife steels like CPM 3V and L6. Now, I may be wrong about this, but what I have not been able to discern its ability to take and hold a fine edge, whereas we have a pretty good idea of those properties with CPM 3V (good) and L6 (not as good in the edge retention department). i have also heard the common "complaint" that Busse knives are so oriented toward toughness in their basic design, that the edge geometry is found wanting by some who expect a knife to cut well, hence the previous poster's "cold chisel" comment. It raises the question of how much toughness do you need? CPM 3V is generally considered to be rather good in the edge stability and fineness department and it does have perhaps 4-5 times the impact resistance even when compared to Crucible's newer S35VN super stainless, which was specifically formulated to be tougher than S30V. The CPM 3V gives up some abrasion resistance, but it is still substantially better than say A2 and even better than D2. What is different is that many makers take advantage of CPM 3V's properties to actually make guard use knives with thinner edges that cut better. if you want a "pry bar" knife, it certainly appears from all of the offerings on the market that you can do it much more cheaply by using one of the 10xx carbon steels, 5160 or L6 at lower levels of hardness like 56-57.
 
David Stifle said:
{QUOTE}

A real life experience. This is why I asked over on the Swords subforum if anyone had tried to duplicate the tests Busse did. Should that blade have chipped if in fact, it really could baton through concrete blocks, pipes, etc. ?
Click to expand...

I chopped through a cinderblock with a 5160 tanto with very minimal damage. The edge was not crazy thick and it was plenty hard too, probably 57-59rc. I never posted my results because I thought they were gratuitous and I don't like knife abuse... I was testing heat treat and wanted to see.

I have seen that video everyone speaks of where they chop through a cinderblock... there are sparks flying. I bet each spark was steel.

So yes, possible to not have a lot of damage, in fact that is not too hard to pull off with everything right. No damage at all... I doubt it!

There is a lot to all of this, not just the steel.
 
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