infi

knif3buy3r

knif3buy3r

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May 30, 2009
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how does infi compare to s30v or s3v or cpm M4? tell a rookie about infi? thanks kids!

Eric aka Knif3buy3r!

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In large knives which for chopping risk burrs from hitting stones/nails/even concrete the edge is more likely to roll than chip out....and it is a lot easier to sharpen than those steels you mentioned .... for smaller blades "sharp is sharp" IMO and edge holding simply depends on the heat treatment quality and hardness ... Infi has an excellent heat treatment ... it holds an edge very well ... but so do other steels ... Infi mainly beats most steels if used in very hard/damaging risk applications ...
 
http://www.bladeforums.com/forums/showthread.php?t=210505&highlight=cpm

http://www.bladeforums.com/forums/showthread.php?t=194854&highlight=benefit+powder

Jerry Busse said:
Matti S.,

Good question! We have explored this very question. Powdered metallurgy can offer some very strong benefits in certain ares of knife performance. However, it is not possible to take the same analysis from a smelted steel and transfer it to a powdered construct and achieve an improvement. Carbide dispersion is very good and can therefore greatly affect the amounts of carbide formers that are included in the mix. If we wanted to achieve the same level of performance as INFI in some areas, the analysis of the PM would look nothing like that of INFI.

Thanks,

Jerry
Click to expand...

in general, most of the super-alloy powder metallurgy steels will have greater wear resistance then infi because they are harder with a smaller more uniform grain structure. however, infi has a smelted steel matrix with nitrogen as a hardener instead of high carbon: it's able to take high lateral loads without breaking and it maintains maleability even at high hardness.

Consider the very idea, the reason why infi exists. It was meant to be indestructible by hand at the highest hardness possible. This means that the edge has to mash, dent and roll before it chips. None of the steels you just mentioned had this as a goal in their development, and thus don't provide it in their final form. Expect them to have a harder stiffer edge at high hardness with longer wear resistance on harder materials - but also expect them to chip, fracture, break and (sometimes) explode in a hailstorm of shrapnel long before infi does.

in infi's defense though - you may find that it does equally well or better on soft materials like wood.

http://steel.keytometals.com/default.aspx?ID=CheckArticle&NM=204
Abstract:
The effect of nitrogen on mechanical properties is the result of interstitial solid solution strengthening by the free nitrogen; precipitation strengthening by aluminum and other nitrides; and grain refinement due to the presence of nitride precipitates.
Nitrogen absorbed during steelmaking results in interstitial solid solution strengthening and grain refinement, both of which increase hardness.
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Wow, great responses, Thank-You, learning a lot! Best, Eric aka Knif3buy3r -

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p.s. cool topic!
 
Wow, great responses, Thank-You, learning a lot! Best, Eric aka Knif3buy3r -

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p.s. cool topic!
 
The ability to remove small dents without having to reprofile the edge is pretty amazing at the hardness INFI is heat treated to. The corrosion resistance is very good for a non-stainless steel especially with its strength and toughness.
 
I am no steel expert, but all the knives I have made of s30v and other powder formed steels ( I believe that is the correct terminology ) are very brittle. Like for instance the very tip of my xm-18 broke off when a buddy of mine dropped it on a tile floor. They don't flex under pressure, they snap.

INFI is very hard, I believe it's 60 on the mo scale without being brittle. When the edge is very polished, it may loose some of that edge toothy-ness, so you may be push cutting more than a saw motion slicing, but that is a VERY small trade off for the durability and ease of edge maintenance. A very thick bladed infi knife with still out slice a knife of the same thickness made of the CPM steels.

I've had several knives of the cpm steels, that were very polished and would glide through paper like butter, but man they WOULD NOT slice rope worth a !@#, and you could rub that blade on your skin and not get cut. A knife made of INFI with the same properties and polish would still bite into rope, and slice into you if you were to rub it on your skin.
 
iamtoast said:
The ability to remove small dents without having to reprofile the edge is pretty amazing at the hardness INFI is heat treated to. The corrosion resistance is very good for a non-stainless steel especially with its strength and toughness.
Click to expand...

The corrosion resistance of infi is due in large part to it's low carbon content. Because there's so little carbon (.5%) in INFI, only a small portion of the chromium content is tied up in chromium carbides, and part of carbon is also used by the vanadium and molybdenum content. If you look at the two compositions, infi and s30v, in how their chromium molybdenum and vanadium contents compare proportionally to their carbon contents, you'll notice that infi has surprisingly high looking chromium content.

infi:
Cr 8.25% Chromium
Mo 1.3% Molybdenum
Co .95% Cobalt
Ni .74% Nickel
C .5% carbon
V .36% Vanadium
N .11% Nitrogen

s30v:
Cr 14.00% Chromium
V 4.00% Vanadium
Mo 2.00% Molybdenum
C 1.45% Carbon


I went looking for the amount of chromium that's sapped up by chromium carbides, and how much of the carbon would be used for vanadium and molybdenum carbides, but I came up empty handed:grumpy:. I remember it being something like .1% carbon could utilize 1.0% chromium. If that IS the case, then there's only a small % of chromium left in s30v as free chromium. In infi there's somewhere between 1.5% and 3.25% chromium available for free-chromium: pretty close to what s30v and many other stainless steels offer.

Free chromium helps corrosion resistance by forming a "passivation layer" of chromium oxide on the surface of the knife where it's exposed to oxygen. Cr2O3 is passive because it it's a complete molecule, it's valence shell isn't +/- an electron so it doesn't seek out other elements to try make it neutral (like orange rust does).
 
Andrew Lynch said:
I think if you do some searches of the old posts in the Busse forum you will find the composition of INFI. It might surprise you.

The heat treat is very extensive. It's called "Transversion Wave" tempering or something. Jerry has said this:

"cryo treatment (-300/320 degrees) which was done in a dry, controlled, atmosphere. This process allows us to take our blades down to temp. over the course of 10 hours hold them at temp. (-300 degrees) for approx 50 hours, and then bring them back up to room temp. over the course of the next 10 hours at which point they receive 3 more, individualized, oven tempers"
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from: http://www.bladeforums.com/forums/showthread.php?t=219446&highlight=composition

I had not known of this post until just now while I was searching for the composition of infi.
 
Jack Shen said:
INFI is very hard, I believe it's 60 on the mo scale without being brittle. When the edge is very polished, it may loose some of that edge toothy-ness, so you may be push cutting more than a saw motion slicing, but that is a VERY small trade off for the durability and ease of edge maintenance. A very thick bladed infi knife with still out slice a knife of the same thickness made of the CPM steels.
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I dont think a thick knife will out slice a knife that is thinner--especially when its made of a very hard super steel. It will out chop one though. I think INFI is a great all round steel but I find the edge is lost pretty quick for things like carving. However, it sharpens up real easy.

In my experience, steel is key for hard work. I find toughness to be very important for chopping, battoning etc. I also find for slicing, super hard steels work best. I dont find any one steel wins in both types of knife use. However, I think INFI wins overall by having very high toughness and holds an edge reasonably. Thus, for a large knife, I think INFI is the best. For a small slicer type knife (EDC), you may be happier with another type of steel.
 
Hey Eric...you came to the right place for info about INFI. In terms of hard use fixed blades, you can't get better than Busse.

Btw...I believe I recognize your email addy from another forum...a green one. Welcome. :thumbup:

If you have any questions I can help with, don't hesitate to hit me here or there. ;)
 
Thanks Bro -

Will Do!

E or X ;>

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I'mGatMan! said:
Hey Eric...you came to the right place for info about INFI. In terms of hard use fixed blades, you can't get better than Busse.

Btw...I believe I recognize your email addy from another forum...a green one. Welcome. :thumbup:

If you have any questions I can help with, don't hesitate to hit me here or there. ;)
Click to expand...
 
INFI is very different than the steels you mentioned. I am new at this but here is my take. S30V needs to be super polished to avoid chipping. INFI also takes well to polishing but it doesnt chip it rolls. It is designed to hold a nice edge but roll before it breaks. That also translates to ease of sharpening which has alot to do with the carbides in the steel. I have many S30V knives that I have beat the piss out of and have eventually dulled and chipped. I have given my S5LE and BWM the same treatment and they take seconds to get sharp and do not chip. It comes down to what you are doing. If you are skinning critters all day or small chores that arent abusive you dont need the power of INFI. 154CM IMHO is perfect for this type of use and has a price tag to match. It is all just personal preference and you have to figure it out yourself. A good reference point on steels is getting a 154CM blade, an SR101 blade which is a high carbon tool steel and an INFI blade. I think you can find one of each in the market at any time. INFI is knife steel made for knives by Jerry Busse. S30V is knife steel made for knives designed by Chris Reeve. All of the rest are modified tool steels.

The point is to buy knives, try different makers and see how you like the steel.
That is my rant hope it makes some since.
Zach
 
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