Steel Question

R

Robert Ptacel

Joined
Feb 1, 2007
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Let's say you have two knives one in AUS-6 and the other in Vg-10 both at 58RC. Would the VG-10 because of superior ingredients have better edge retention? That is my way of thinking but I'm no metallurgist.
 
I think the relevant point is that AUS-6 probably can't be brought to the same hardness as VG-10. But then again, I'm no metallurgist either.
 
Yes. Hardness is only one factor, there's abrasion resistance, ductility, etc. All of which are influenced, if not based on, the specific alloy used.
 
The grind of the blade has very much to do with it, also.
 
Robert Ptacel said:
Let's say you have two knives one in AUS-6 and the other in Vg-10 both at 58RC. Would the VG-10 because of superior ingredients have better edge retention? That is my way of thinking but I'm no metallurgist.
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All other things being equal, yes.

I have a number of knives in different alloys each at a Rockwell hardness of 59. (I know they are 59 HRC because I had them each measured.) I have done side by side Manila rope cutting,after sharpening them all to a uniform 30° inclusive angle on a Sharpmaker, and taking them to equal sharpness. Because the fibers of the manila rope fall away, the rest of the blade shape does not matter. So this is a direct comparison of the performance of the alloys.

I found that VG10 does indeed hold an edge better than AUS8 when both are hardened to 59. I find I have some difficulty differentiating the performance of VG10, N690, and ATS34/154CM. But there is a definite difference between an alloy with 0.8% Carbon and one with 1% Carbon. Moreover, alloys containing small amounts of Vanadium (say about 0.15%) perform better than those that do not. It is said by metallurgists that small amounts of Vanadium act as a grain refiner and you end up with a finer grain structure and better properties. Looks like that is truth to me.

Frank R
 
Bill DeShivs said:
The grind of the blade has very much to do with it, also.
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I agree, I've found that the grind effects the edge retention much more than the type of steel the blade is ground from. I've got a kershaw wild turkey in aus-6 with a very thin flat grind, and it holds a sharper edge longer than my BM Rukus in S30V (which has a ridiculously thick grind). When looking at knives I focus more on the grind than the steel it is made of. I've had a bunch of knives with thick grinds and premium steels like ZDP or BG-42 that don't hold an edge for anything. I've also had knives with thinner grinds and steels like VG-10 or aus-8 that hold an edge great and are much easier to sharpen due to the fact that there is much less steel at the edge. I had my ZDP endura reground by Tom Krein and the increase in performance was incredible. Much easier to sharpen, takes a sharper cleaner edge, and hold it for a very long time.
 
AUS-6 is a poor knife steel while VG-10 is an excellent one .There's a world of difference between them !! I would never buy an AUS-6 but I have a number of VG-10 knives.
 
mete said:
AUS-6 is a poor knife steel while VG-10 is an excellent one .There's a world of difference between them !! I would never buy an AUS-6 but I have a number of VG-10 knives.
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I was just using those examples as two steels on opposite ends of the spectrum. I wanted to confirm if hardness or composition was more important.
 
I'm not an expert, but I can imagine that a very poorly heat treated and badly ground VG-10 blade will perform less then a perfectly ground and treated aus-6 blade.
I have and use a Paul Bos treated 420 HC Buck Vanguard that holds a better edge then a ATS-34 blade from another wellknown companie

I'll prefer VG-10 over aus-6 from known makers anytime..
 
Robert Ptacel said:
I was just using those examples as two steels on opposite ends of the spectrum. I wanted to confirm if hardness or composition was more important.
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Both are important.

Assume this:
Two blades: same shape, same edge angle
VG10 hardened to 56HRC
AUS8 blade hardened to 60HRC.
It is quite possible the AUS8 blade would outperform the VG10 blade in edge retention.
(This is unlikely to happen in real life. I know of no knife company that underhardens VG10.)

Now if we assume:
Two blades: same shape, same edge angle
VG10 hardened to 59
AUS8 hardened to 59
The VG 10 will outperform the AUS8 for edge retention.

This is why folks focus on heat treat so much and from buying from an established firm. Performance is not only a function of the alloy, it is a function of the heat treat.
 
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