VG-10 and its standing in this group.

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I know a bit about steel.

To my mind VG-10 is tougher and more stain resistant than ATS-34, but does not hold an edge as well. To me it sits between 440c and ATS-34. Do you think thast is right? Is it just that VG-10 is often used with a lower Rc than ATS-34?

If VG-10 is so similar to ATS-34, Gin1, 440c, 10a et al. Why is it out there? What is VG-10 better at? I like it as a steel, but would like to understand it better.

Thanks all!

W.A.

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Old Knife Guy

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I think hardening figures into this as much as composition. I had always thought that VG-10 was one of those new 'super steels,' like BG-42 and CPM-440V. However, I had a Paragon ATKO-8 made out of ATS-34 that must have been hardened to 62 or 64 Rc. It was almost impossible to sharpen. Personally, I like 154-CM hardened to 59 Rc. My wife likes her Kershaw Boa of CPM-440V at 64 Rc because she doesn't want to be bothered by sharpening and stropping.--OKG
 
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I don't have any other high-end stainless blades to compare my Fallkniven F1 to, but it compares favorably in edge holding to Carbon V, in my experience. VG-10 has a dose of cobalt, which is supposed to enhance the qualities of the other alloying elements. I don't see cobalt in any other stainless alloys. The heat treat is doubtless another factor; there must have been something impressive about VG-10 to make Fallkniven switch from ATS-34. The Fallkniven website has some interesting information about the strength of this steel.
 

Burke

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Asking why a certain steel is out there is like asking why there are Fords, Chevys, and Porsches. They all do the same thing, they just do it a little differently, and some are better at different parts of it. As you say above, General, (and I'm not sure you're right that it holds a lesser edge than ATS-34), it is similar to a whole host of other stainless, high-quality steels. But it is different in some ways, as you note, and that is why it's out there.
 
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I have two VG-10 Spyders, and I find it to be a better edge holder than ATS-34, but slightly (only slightly) harder to sharpen.
 

Sal Glesser

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Hi General. We tested VG10 for about 6 months before we made the Moran from it. It tested very well in edge retention and corrosion resistance, better than most stainless steels that we've tested.

440C was better than VG10 in corrossion, as was MBS26. ATS34 was not as good.

Very little tested better in edge retention.

Old knife guy. Hate to disagree, but CPM440V will peak out a Rc62, but it cracks like glass at that hardness. 64 is not possible. Even 58 is too high. We found better edge retention and toughnesss is achieved at 55/56 in CPM440V.

sal
 

Old Knife Guy

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To Sal Glesser: You may be right about the Rc of CPM-440V. My wife's Boa is an early one, and it arrived with concoidal fracture divots on the bevel--very hard to polish off. The up-side is that the knife does not require sharpening as often as our other knives; due to my wife's side business, we are always getting packages with fiber tape on them. My wife is a 'slasher.' As I had mentioned, we had a Paragon that was even harder to sharpen, which is why my first post centered on the hardening issue to begin with. My use of a pocket knife is not in the 'survivor' genera. I trim thread, I open envelopes, etc., and I feel I get good service from the mundane high carbon stainless steels of modest hardening.--OKG
 
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Originally posted by Old Knife Guy:
My wife is a 'slasher.'

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Could'nt let this pass without notice, could I?
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I get some pleasure from finding a relentlessly peaceful use for a combative looking knife.
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SALTY

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Sal: Thank you for sharing your information regarding VG-10. There are things that you do that assist all of us in understanding and appreciating the tools (toys) of our hobby without merely hyping your own products. Thank you.
 

Sal Glesser

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Hi Nimrod. Thanx for the kind words. An old timer names Socrates convinced me long ago that truth was the highest value. I've had a few other teachers (Al Mar, Edward Deming) that convinced me the development of humankind is based on "shared knowledge".

Our brains are no larger than they were in Plato's time, but the ancient Greeks could not have put a probe on mars. 2500 years of "shared knowledge" does in truth create more than the parts.

sorry for the rant.

sal
 
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Nice one Sal, love those little insights. Makes this (sometimes) dull group a little brighter!
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W.A.

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"To strive to seek to find and not to yield"
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Ranger motto

[This message has been edited by The General (edited 11-24-2000).]
 
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I have two spydercos and some fallknivens in VG-10. I also have some bokers in 440C steel and quite good deal of knives in ATS-34.

Basing on my experience I can evaluate:
1. Edge hold is slightly better for ATS-34, 440C and VG-10 holds edge practically equally. It is difficult to consider precisely, a lot depends on edge geometry.
2. Corrosion resistance is better for 440C and VG-10, I can't say which of both is better but both are certainly better than ATS-34.
3. Impact resistance and ability to take side pressure on the edge without chipping is the best for VG-10, slightly worse for 440C and far worse for ATS-34.
4. I didn't consider difference in sharpening easy between these 3 steels noticeable enough to put them in certain order. Subjectively I like to sharpen VG-10 the most of them.
Of course all these evaluations are very subjective, a lot of factors can influence edge hold excepting blade steel. This depends even on what you are cutting. Here I have tried to make some comparison test and I have obtained quite funny results.

I have had a good deal of discussions with Peter Hjortberger (Fällkniven) about knife strength. Peter has an obsession
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to make the strongest knives in the world and he really does this. Please visit "Test" section at his web site, you will find some interesting things there.
I'm quite sure that higher impact resistance and corrosion resistance of VG-10 caused Fällkniven to turn from ATS-34 to VG-10. Please take into consideration that fallknivens are designed to be work reliably in low temperature environment. Each steel is noticeably more brittle and less impact resistant at -30°C than at +30°C.

OKG,
Kershaw Boa has blade hardness like other their CPM 440V knives (Ricochet, Random Task, Avalanche) - it is 55-57 HRC. CPM 440V blade is somewhat harder to sharpen than ATS-34 or VG-10 one but for some another reasons than hardness. It is pretty hard to take wire edge away from properly hardened CPM 440V blade because the steel is not brittle. My Starmate is from first production run (with harder blade, 59-61 HRC) and it is easier to sharpen than Military or Boa with softer blades. But both Military and Boa hold their edges better.


[This message has been edited by Sergiusz Mitin (edited 11-25-2000).]
 
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Thanks Sergiusz, I will be trying out an A1 soon. I will post my results of this knife, and some others. I will look at practical use of such blades as the A1 and Ka-Bar D2 (my knife)Ontario Marine (my knife) and several others to be decided upon.

W.A.

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"To strive to seek to find and not to yield"
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Old Knife Guy

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To Sergiusz: Yes, I am confused. I thought the reason that some companies went from CPM-440V (s60V) to CPM-420V (s90V) was that it was TOO brittle. I had also heard that some blades got bad reviews because of hardening problems. And trust me, my wife's Boa is hard--way too hard. I have an Edge-Pro, and if you have trouble getting a burr with the 180 grit stone, that knife is hard! I have good quality Microtechs of 154-CM at Rc of 57 to 59. They sharpen fairly easily using only the 220 waterstone to form the initial burr. Additionally, the Boa leaves very little 'slag' on the stone to wash off, implying that very little metal is being removed. Having said that, I think the only real problem is careless handling over a cement floor. For my wife, she'd rather have a hard knife than do maintenance. Considering I have an early Boa, is it possible that Kershaw made some manufacturing refinements as time went on?--OKG
 
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OKG,
if you have trouble getting a burr with the 180 grit stone, that knife is hard! I have good quality Microtechs of 154-CM at Rc of 57 to 59. They sharpen fairly easily using only the 220 waterstone to form the initial burr. Additionally, the Boa leaves very little 'slag' on the stone to wash off, implying that very little metal is being removed
I have no problems to rise a burr on my Military and Boa. But it is somewhat tricky to remove it. Today is Sunday, I have some free time so I did sharpening comparison session with Boa, Military and Starmate. About 20 strokes on SPYDERCO Sharpmaker white stone's edge rose burr on each edge. Subjectively it was biggest on Military, next Boa and the smallest on Starmate. Next I tried to get rid of it, the simplest this was with Starmate, next Boa and the hardest to remove burr was with Military. My Military is sharpened to very thin edge, essentially it has 30 degree sharpening angle and only very, very edge is sharpened to 40 degrees. Maybe this causes difficulty to remove the burr...

Next, the extremely high wear resistance causes CPM 440V to leave very little deposit on sharpening stones per each stroke. This is not exactly the same as hardness. Please note that CPM 440V is not melted steel. All components are crumbled into very small particles, mixed and then heated to parch but not to melting temperature. This causes the properties inaccessible for melted steels. Carbon content is 2.15%, this is more than steel can contain by definition. The grain structure is quite different from melted steel: very hard carbide particles are embedded into relatively soft matrix.
This causes great edge hold because relatively soft matrix wears out exposing new and new hard cutting particles. This is the same principle Talonite utilizes.
High wear resistance causes some problems with sharpening. Edge blunting and sharpening basically is the same process, uncontrolled than blunting and controlled than sharpening - the only difference. No one steel is easy to sharpen and hard to blunt. As better the steel holds the edge as harder it is to sharpen. Of course here I'm speaking about only natural blunting what is caused with edge wear out only, no way about edge micro-chipping under side pressure.
Wow, too long post! Call me please if you are interested to discuss farther. I nave no intentions to bore anyone deadly
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Sal Glesser

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Hi OKG. To date, no company has used S90V (CPM420V) in production. It's good stuff, but to date, the grinding wheels are not yet developed. We made a run of "Q's" for Crucible that said "CPM420V" and were in fact that steel, but that is the only run done by a company to date. We used our 440V wheels, but they were clearly not ideal.

Spyderco began using CPM440V first in production. It took quite some time to develop the grinding wheels to be able to prodcution grind the material. Kershaw simply ordered our wheels from our supply company which saved a lot of time and money. The early Kershaw 440V pieces were too hard. Ken Onion knew of the harness requirements, but Kershaw did not. Ken and I spoke about the hardness when the Kershaw piece first came out and Ken immediately educated Kershaw on the material.

Hi Serg. The particles are not really crumbled, the molten steel is dropped (drop by drop) into a air chamber that is blowing hard. The drops or particles of molten steel swirl around as molten sparks in this air chamber until they drop into a vat of liquid nitrogen at the bottom of the air chamber. The particles are them frozen into the particler size. They are then compressed and heated (HIP) until the particles are fused, but as you say, not melted. the grain structure is very uniform.

sal
 
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