VG-10 vs. S30V

Orthogonal1, lets get terminology correct. Steels have grains and that is measured as grain size. That has nothing to do with carbide size and distribution. Crucible's CPM method has been around since about 1970. It's a proven method and benefits the knife maker and user by being easier to grind and sharpen and capable of taking a high polish .The European powder metal system is similar. S30V is now readily available , CPM154 is becoming more so ,and CPM D2 is becoming available. Try them they're great !
Disclaimer - all this assumes proper HT and edge geometry !!
As a metallurgist I understand all this !My working knives include Sebenza, agrussell One Hand CPM154, Fallkniven TK-1 [SGPS] and U2.
 
BOTH are great steels... but it is not just enough to choose the steel, one must choose the maker as well.

Personally, I have every confidence in the likes of Spyderco and CRK. In my experience they can get the best out of the steels they employ.

I also believe that edge geometry plays a big part in the sharpness of a knife, and in how easy - or difficult - it is to sharpen.
 
mete said:
S30V is now readily available , CPM154 is becoming more so ,and CPM D2 is becoming available. Try them they're great !
Disclaimer - all this assumes proper HT and edge geometry !!
As a metallurgist I understand all this !My working knives include Sebenza, agrussell One Hand CPM154, Fallkniven TK-1 [SGPS] and U2.
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Have S30V, CPM D2, and SGPS knives. I like the CPM D2, and SGPS knives pretty much, S30V I think is a good steel (not too happy calling it a "super steel" though).

So, as a metallurgist, which metal would probably have the larger grain size, S30V or VG-10? And further, which of the two noted metals will probably have the larger and harder carbides?
 
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I call SGPS, S30V ,M4 and a few others 'super steels ' because they have large amounts of very wear resistant carbide formers especially V. Note that VG-10 has a small amount of V which is to keep the grain size small.I would expect S30V and VG-10 to have similar small grain size. Carbide grain size should also be very similar. We don't care about carbide hardness but we want carbide wear resistance. Carbides in increasing wear resistance , are Fe,Cr, Mo,W, V.
 
Does not the hardest constituent material in the steel, the carbides, determine what can be used to sharpen the edge to the greatest degree of sharpness?

If the stones used have a hardess less than or approximately equal to the hardest constituent of the steel, say the carbides, I would think the the carbides would be likely to be ripped out rather than eroded during sharpening.
 
orthogonal1 said:
I was under the impression that those pictures showed concentration, i.e. distribution, and not actual grain size.
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knarfeng said:
And it was my understanding that those were photo micrographs that show actual grain size.

I believe one of our staff metallurgists at work has worked with PM steels on a prior job. He is on travel this week, but should be back Monday the 13th. I will ask him then. I might also try a couple of the other metallurgists who might know, even though they have not directly worked with the stuff. Then I would not have to resurrect what next Monday will be a dead thread.

Best
Frank
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mete said:
Orthogonal1, lets get terminology correct. Steels have grains and that is measured as grain size. That has nothing to do with carbide size and distribution. Crucible's CPM method has been around since about 1970. It's a proven method and benefits the knife maker and user by being easier to grind and sharpen and capable of taking a high polish .The European powder metal system is similar. S30V is now readily available , CPM154 is becoming more so ,and CPM D2 is becoming available. Try them they're great !
Disclaimer - all this assumes proper HT and edge geometry !!
As a metallurgist I understand all this !My working knives include Sebenza, agrussell One Hand CPM154, Fallkniven TK-1 [SGPS] and U2.
Click to expand...

Just to complete. Although the one metallurgist at work who has the most experience with PM steels is still on travel, I did find that one of the other metallurgists has also worked with PM steels in the past. I asked about the effect of the PM process on carbide size.

He said that is possible to end up with smaller carbide particles through the PM process in addition to the finer grain structure, though he added that it is not guarranteed as the rest of the processing must be correct.

So I suppose it is not guarranteed that S30V will have smaller carbides than D2, but it is quite possible.

Best,
Frank R
 
I was thinking carbide size would be dependent upon heat treatment amongst other things.

I have come to think of S30V as simply a more stainless D2 due to the similarities in the edge most of the knives I have in the respective metals are taking with my sharpening routine. Admittedly, most of my S30V knives are Benchmade and Microtech, as are a good percentage of my D2 knives. I have sharpened knives for friends, though, so I have experience with other maker's knives in the noted steels.

Most of my knives in the noted metals seem to take a relatively "toothy" edge. I have three D2 knives that excell at taking a fine edge - two custom and a BM pre-production and one S30V that does such also (that come to mind, at the moment).

Of course, one could continue down the carbide road and determine the constituent make-up of the carbides and whether these carbides are harder than the average sharpening implement - running on the theory that carbides can be pulled out of the edge, making a rougher final edge. Probably mixing carbides with grains, there.
 
Would this help:
Carbidehardnesses.jpg


So you are saying that perhaps the toothy edges are left by using a sharpening medium that is softer than the carbides? That seems reasonable to me, although I don't have your user experience with those steels.

Following that hypothesis, this chart would imply that the only way not to get a toothy edge on either S30V or D2 would be to sharpen with diamond. Both S30V and D2 have enough Vanadium in their makeup to form significant amounts of Vanadium Carbide and diamond is the only commonly found sharpening medium that is harder than Vanadium Carbide.
 
That is along the lines I'm thinking, i.e. that S30V and such are best sharpened with diamond abrasives. Diamond stones should cut the tougher carbides versus the carbides eroding the the stones (say common ceramic stones).

The theory isn't mine, I just keep it mind. It seemed reasonable when I first read it and it would appear to explain some of the sharpening behavior some people (me included) have experienced. Then there is always the PFM factor of heat treatment added in to the mix.

The theory could partially explain why some people observe "inferior" steels performing better than the "superior" steels. Simply using the right media to sharpen the steel could change the resultant perception of which is the better steel.

Just trying to increase my understanding of the theory and see whether it has real-world merit.
 
Truthfully, I can't tell much difference between VG-10 and S30V when it comes to actual cutting....they both perform very well and they both seem to take equal effort to sharpen.

As for the notion that S30V is all hype....that's nonsense.
If S30V didn't perform better than previous blade-steels then makers like Buck, Chris Reeve, Benchmade, and Spyderco would not have adopted it.
Knife makers live and die by their reputations....they are not going to choose a blade-steel that's inferior to what they already have.
 
mete said:
I call SGPS, S30V ,M4 and a few others 'super steels ' because they have large amounts of very wear resistant carbide formers especially V. Note that VG-10 has a small amount of V which is to keep the grain size small.I would expect S30V and VG-10 to have similar small grain size. Carbide grain size should also be very similar. We don't care about carbide hardness but we want carbide wear resistance. Carbides in increasing wear resistance , are Fe,Cr, Mo,W, V.
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S30V should be finer than VG-10, but I don't know by how much. I can't remember the specs for S30V in microns off the top of my head, and don't know that I've ever seen them for VG-10.
I do remember Sal Glesser stating some years ago that S60V was the finest steel(grain size) that Spyderco had used at the time of his statement, which included VG-10. S30V is a bit finer than S60V, so it would follow that it is also finer than VG-10.
Personally, though S30V is technically "better", I'm not picky between these two, and like them both.
 
I have many knives in S30V, VG-10, AUS-8, and 13C26. I have a few in 154CM, ZDP-189, BG-42, and SG-2.
With the first 4 steels mentioned, I have some that are scary, hair-popping sharp, some merely sharp (all will push and pull cut telephone book paper easily). Of the second group of 4, I am able to make the SG2 and BG-42 and one of the 154CM blades ridiculously sharp. The ZDP I'm going to either get fine diamond hones or be prepared to spend a very long time with what I have to get them to where I'd like. All I use is a Sharpmaker w/ all 4 sets of stones, and a strop loaded with green compound.
My conclusion? The level of sharpness attained, and subsequent edge retention has nothing to do with the steels involved, but with my ability (or inability) to sharpen consistently.

Now as far as the OP's question, I find that S30V holds an edge slightly longer than VG-10, and my relatively uneducated guess would be that it might be a combination of grind, angle, and possibly heat treat seeing as he's comparing not only 2 different steels, but 2 different manufacturers as well
 
The toothiness of high carbide steels only shows up after some wear. Straight off the sharpening stone there is no toothiness whatsoever, the edge is much smaller than the size of carbides (0.4 micron edge despite 30 micron carbides). You can see it under a 1000x microscope. If you don't have a microscope you can run the edge over your thumbnail to check for toothiness.

I shave with a 440C razor, the carbides are as huge as it gets, but it makes no difference on the edge. After 2 weeks of shaving, the toothiness appears and is easily felt. I don't care, I just strop the razor on 0.1 micron diamond paste. Edge is restored and the toothiness never was an issue.

S30V doesn't seem to have much tooth to me, at least not compared to D2, 154CM, and 440C. VG-10 is somewhere in between the toothiness of S30V and those toothy steels. That said, different S30V perform very different so your mileage may vary.
 
All three are good steels that take and hold an edge well. If the knife is made by a quality company you will get a good heat treat and blade engineering that will perform. Most, myself included could never really tell the difference.
 
I have quite a few knives with S30V. My only VG-10 based knife is a Delica. Both my S30V knives, at least softer HT such as my Sebenza, as well as my Delica will lose the shaving sharp edge pretty fast. All of my S30V based knives still cut effectively even when the shaving edge is gone. The Delica really drops off in cutting ability much faster. It is indeed very easy to touch up but just does not maintain a working edge any longer than many of my 1095 based knives. Part of it may be the so-so grind geometry that I need to fix but so far I would pick 1095 over VG-10 any day.
 
tomsch said:
I have quite a few knives with S30V. My only VG-10 based knife is a Delica. Both my S30V knives, at least softer HT such as my Sebenza, as well as my Delica will lose the shaving sharp edge pretty fast. All of my S30V based knives still cut effectively even when the shaving edge is gone. The Delica really drops off in cutting ability much faster. It is indeed very easy to touch up but just does not maintain a working edge any longer than many of my 1095 based knives. Part of it may be the so-so grind geometry that I need to fix but so far I would pick 1095 over VG-10 any day.
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Yep, mirrors my experiences quite well.
 
Elen said:
Could it be that you're getting the VG-10 sharper, and that's why it seems to hold an edge better? I find VG-10 very easy to sharpen, and S30V not so easy.
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my experience has been pretty similar. vg10 is just takes a wicked edge effortlessly.
 
Vivi said:
Using knives with thicker edges, like the edges they come from with the factory, S30V seemed to lose a hair whittling sharp edge quickly for me but hold on to a somewhat sharp edge for a very long time.

Since reprofiling the S30V to a very acute edge it's been tremendously easier to get to the highest degrees of sharpness and holds that upper 5-10% of sharpness better.

It might be worth your time to take the Benchmade to 6-8 degrees per side with a microbevel if you're not happy with it's performance.

I can't say I've ever had VG10 outlast S30V in terms of edge holding.
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6-8 per side? Ho far backed up would that be on most benchmades? Let alone how unstable that would be.
 
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