explanation of graph please

K

KenH

Well-Known Member
In reading the thread "Your thoughts on carbon steel edge retention on hunting knife" there was a post to a graph from this link:

http://www.nsm-ny.com/index.cfm?fuseaction=page.display&page_id=27

On this graph I see 440C is actually rated "almost" the same as the "magic" S30V steel with:

440C - Toughness = 2, Wear resistance = 2.5; while S30V =Toughness = 2, Wear resistance = 3

As I understand, Toughness is resistance to edge chipping in use, while Wear resistance would be ability to hold an edge in use. Now why isn't 440C more popular if it has the same toughness as S30V, and only 1/2 point less wear resistance? I guess that depends on some extent how much difference is there in 1/2 point?

Looking at the graph if a person could combine the wear resistance of S125V with the toughness of 3V he'd have a true "Magic" steel.

Comments please.

Ken H>
 
My guess is 440C sales dwarfs S30v and S35vn combined. It might be the most popular knife steel in the world for production knives after 420 (production kitchen knives).

440C is good steel and this chart shows that. (What is missing on this chart is corrosion resistance.) The deal is that for a few dollars more, on a custom or higher quality folder/fixed knife you can get a bit more performance -- at a bit more, sometimes quite a bit more cost.

It wasn't that long ago that ATS-34 was considered the best in the custom world. 154-cm is basically the same thing and you can see how 440C stacks up to that.

The chart scale is all relative performance and does not show specific cutting test data. s35vn will significantly out cut 440C, on the order of 20% to 30%. That is a pretty big performance gap up.
 
That's sorta what I was thinking Boss - I just wished confirmation of my thinking. I've only made 1 or 2 blades of 440C, and had I nothing else I would have been pleased with 440C.

Ken H>
 
Toughness has many different meanings -and you can pick and choose your data.

s30v.jpg

S30V looks pretty good now doesn't it. This snip also explains some of the "toughness" differences. By the way the change from 2.5 to 3.0 you references can be viewed as 'only half a point' - or as a 20% improvement.

Having said all that, S30V is no fun to finish. :rolleyes:

All our steel choices have their strengths and weaknesses. That applies equally to stainless and to carbon / tool steels. We all have our favorites, but I'd hope we'd all be willing to make an informed choice about the right material for the job. Embrace it. We have incredible choices.

My 2 cents
 
Thoughness is the ability to resist sudden loads (impacts), and wear resistence is the ability to whitstand abrasion.
Holding an edge is more of a function of thoughness+ strenght and thus the stability of the matrix. You loose the edge from chipping or rolling.
With alloy steels it boils down to the small dimensions and omogeneity of the carbides, so if the overall makeup of the steel leads to those properties you get an holding edge.
Wear resistence is a bit misleading when comparing 2 steels, other things comes first and have more weight.
 
Now that graph shows S30V in a MUCH better manner vs 440C. Thanks for the graph, that's the kind of info I was looking for.

Stezann, your explanation is what I was thinking, just glad to have confirmation.

Ken H>
 
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