? about S30V

S

sc_rebel1957

Joined
Aug 19, 2002
Messages
1,605
I have a question about the switch to S30V by alot of makers from 440V.
From Crucible steel's website there's a quote that only S90V surpasses S60V in toughness and corrosion resistance, I know there's gotta be a reason for it, just curious because I'm no metal expert and want to learn all I can from people who know. thanks, Ron
 
Yeah, the S90V is a hell a lot harder to machine too. I think it has a quite high Carbon content, and even higher Vanadium content too.
 
Originally posted by sc_rebel1957
I have a question about the switch to S30V by alot of makers from 440V.
From Crucible steel's website there's a quote that only S90V surpasses S60V in toughness and corrosion resistance, I know there's gotta be a reason for it, just curious because I'm no metal expert and want to learn all I can from people who know. thanks, Ron
Click to expand...
Don't sweat it... they just need to update their site.

S90V and S30V both pretty much surpass S60V in every measurable way... only downside to S90V is that it is more expensive, more difficult to grind, finish, and heat treat (austenizing temp above what many people's ovens can handle w/o upgrade). And S90V isn't as tough as S30V.

S30V is tougher than any other stainless knife steel, including D2 (borderline stainless & a tool steel). Crucible says that in transverse Charpy C-Notch testing, S30V is 4x tougher than 154Cm and 440C. That is a big jump, and transverse toughness means S30V is much more resistant to chipping and breaking in blades where side loading is a real condition. Crucible's goal was "A2 level of toughness in a stainless with good abrasion resistance". Well, some say S30V approaches A2's toughness, but so far I think I'm hearing it falls maybe a bit short, but S30V is still a notable achievement.

S30V's abrasion resistance is on par with S60V (quite good) and is well below S90V, but this is based on the kind of repeatable lab test called pin or cylinder abrasion, where they rub metals together and see which one looses the most "weight" in metal dust. A good indicator, but not really the most directly applicable test for knives (where often both direct fine abrasive wear and, maybe more importantly, microchipping or macrochipping are dulling mechanisms).

S30V can be run significantly harder than S60V for a given toughness level, and so will make a better all around knife blade since it'll resist edge rolling (a primary dulling mechanism compared to abrasive wear for most daily applications of a knife).

S30V's corrosion resistance is, per Crucible's data sheet, "equal to or better than 440C in various environments"... jury out on how it compares with S60V and S90V, but they're all close, and it's "a stain resistant steel", and should waaaay exceed D2, and exceed ATS-34 by comfortable margin. If the 440's aren't corrosion resistant enough for your application, you must go to a lower edge performance 420 stainless or straight to Talonite/Stellite, or something else like Titanium.

Per Crucible, S30V's CATRA edge retention (cutting of standard paper stacks embedded with silica, sand) is 145% of 440C and about 121% of 154CM.

Even Bob Dozier (!), not an easy convert from D2 for some good reasons, has indicated that S30V cuts "as well" as D2 on such tests.
Bob Dozier from www.dozierknives.com discussion forum http://www.dozierknives.com/cgi-bin...board.cgi?s=3f50b74808fdffff;act=ST;f=1;t=209

I use the powder metals just to give my customers something different with out changing what I do. By this, I mean that I do not [want to] change from [an] air harding steel [for heat treating reasons]. As for the S30V, it cuts about as good as my D2 in cutting machine tests. I don't think cutting paper with sand in it is a good test but that is the only testing that I have done with the S30V. Bob D.
Click to expand...
D2 is Bob's workhorse, and it is a great slicing blade choice at a reasonable price. He also uses A2 for bigger knives (tougher). For Bob to even offer S30V is a significant statement about S30V (he never offered S60V or S90V from what I know).

Summary: S30V is the best balanced stainless knife steel going (balance of toughness, corrosion resistance, ability to be run hard, abrasion resistance). It's a small to medium improvement over all of these steels:
D2
ATS-34 / 154CM
BG-42
S60V
VG-10
S90V is a better edge holder than S30V but sacrifices toughness (more susceptible to chipping).

Here are a couple of threads where Ed Severson of Crucible posted something related:
http://www.bladeforums.com/forums/showthread.php?s=&threadid=176554&highlight=s30v
http://www.bladeforums.com/forums/showthread.php?s=&threadid=208043&highlight=s30v
 
I know the stain resistance is at least slightly better than 60V.On my 60V military I had seveal light rust spots to pop up after a week of carry in the hot hummid weather and sweeting on it too,they wiped off easally with miltec-1.On the 30V all I have notice is one or 2 very small rust spots that wiped off with my finger.
 
We would agree pretty much with RDangerer. Our tests do differ a little in some areas.

We found that S30 V was better than S60V in abrasion resistance by about 30% (at optimum knife blade Rc). S30V also was about 13% better than D2 in abrasion resistance. S90V was superior to S30V by another 15%-25% depending on edge angle. (We make out own mules, heat treat to factory spec, use our own CATRA (calibrated anually), our own dedicated technician, consistant edge angles (lazer goniometer) and optimum hardness).

We found that S30V was only slightly better that S60V in corrosion resistance. Nowhere close to 440C. (Govt approved Q-Fog tsting).

sal
 
Please, Sal, answer this once and forewer:

Is CPM S30V better cutter then CPM S60V (CPM 440V)?

Other words is abrasion resistance (30% better for CPMS30V) directly affects edge retention? May be it is - cuts better and easyer to sharpen.

Thanks, Vassili.
 
Hi Vassili. In my opinion, and in our testing, yes. That's why we switched. We seek the best and always have. In fact a serrated S30V blade had an almost level graph on the CATRA. A serrated S30V will seem to stay sharp a VERY long time. I think this is becasue of the extra toughness over S60V.

Cuts better, but not easier to sharpen.

"Hard to dull, hard to sharpen. Easy to dull, easy to sharpen". The steel does not know at which angle its surface is being abraided.

(Edge geometry might affect possible adjustments in sharpening speed).

sal
 
Thanks a lot Sal. This is the simple answer I need.
So it is not just tougher but also holds edge better then CPM S60V. Is it because of 0.2 Nitrogen in it?
Thanks, Vassili.
 
Thanks to all that replied to this post, I'm just a few months away now of attempting my 1st custom made folder and I value any information on subjects which in the end may affect my design.

About all I lack now is a heat treating oven and experince.

I plan on starting with a frame lock type folder in a steel easier to work with such as 154CM then maybe tackle the harder to work with metals.
Thanks, Ron
 
I'm not a metalurgist, but I think so. Crucible says the spec calls for up to .2% but they usually only get .1%. Kinda like the spec for 440C is 1.0% - 1.2% carbon, but I have never seen 440C with over 1.0%.

sal
 
How does S30v compare to BG-42 ?

I remember being quite excited when it looked like Spyderco would be going to BG-42 (Ocelot and rumours of a Lil' Temperance switch down the line).
I personally liked BG-42 over CPM-440v. Ok it is a bear to sharpen, but I liked the feal of what I percieved as an edge that could take a better polish, and on un-scientific tests it seemed to hold an edge longer without the brittleness associated with 440v.
 
Originally posted by Sal Glesser
We would agree pretty much with RDangerer. Our tests do differ a little in some areas.
Click to expand...
Sal, thanks for weighing in. And for being so diplomatic! :o

I always enjoy hearing from someone who chooses to do as much controlled testing as possible in leading a production knife business! In fact, I often cut/paste Sal's summary lab results into word files for storage. Which I'll do with what follows:
Originally posted by Sal Glesser
We found that S30 V was better than S60V in abrasion resistance by about 30% (at optimum knife blade Rc). S30V also was about 13% better than D2 in abrasion resistance. S90V was superior to S30V by another 15%-25% depending on edge angle. (We make out own mules, heat treat to factory spec, use our own CATRA (calibrated anually), our own dedicated technician, consistant edge angles (lazer goniometer) and optimum hardness).

We found that S30V was only slightly better that S60V in corrosion resistance. Nowhere close to 440C. (Govt approved Q-Fog tsting).
sal
Click to expand...
Any time Sal can chime in with repeatable tests from laboratory results, for goodness sakes, give that substantial weight. I certainly don't do any controlled testing. The CATRA is as good a laboratory tester of knife blades as I've heard about. Many of the tests that Crucible performs are more generic industry standard, like the Charpy and abrasion tests. And while they definitely have merit and are excellent indicators, they are often performed on chunks of metal that don't resemble knives.

I don't mean to sound so authoritative ... just trying to summarize what I have read and distilled down, for the original thread poster, along with what I find from informal testing (using a knife in "around the house and in the field" type conditions).

I do, however, try not to exaggerate. So while I may say "S30V is on par with S60V in abrasion resistance", I'm trying not to overhype S30V. Gosh knows we get enough hype of blade materials on these forums.

If Sal says S30V wins the CATRA by 30%, I'd take Sal's testing over my summary from personal use and reading (I choose not to make time to conduct any controlled testing, since I'm knee-deep in renovating a house. Even if I did, it wouldn't be nearly so repeatable as are CATRA and Q-Fog!)

By the way, I should have attributed what I typed in quotes... it came from a Crucible data sheet:
Crucible data sheet
S30V's corrosion resistance is "equal to or better than 440C in various environments"...
Click to expand...

I'll edit my earlier post to attribute sources on a couple things I typed.

While Crucible tries to be fairly straight forward in offering comparisons, they can't help but be proud of their products (rightly so), and so some marketing can't help but creep into their literature at least a bit. And corrosion resistance is somewhat dependent on heat treat methodology also.

I have little need for the super corrosion resistant stuff like Talonite. My knife needs haven't been able to discern appreciable corrosion differences between S30V, S60V, and S90V. They all do fine for me. In fact, my main, hard-use folder around the house is in M2, and I only rarely have to fingernail scratch, or resharpen a small rust spot off the edge. For hunting blades, I prefer a good stainless. For big choppers, a carbon steel.
 
Sal, a couple more questions if you have the time:
Originally posted by Sal Glesser
We found that S30 V was better than S60V in abrasion resistance by about 30% (at optimum knife blade Rc). ... consistant edge angles (lazer goniometer) and optimum hardness).sal
Click to expand...
Twice you referenced "optimum knife hardness". Can you elaborate on how you find this balancing point ... I'm assuming it's a balance between hardness/edgeholding & toughness? Or do you just let the CATRA tell you where optimum hardness/toughness balance is? I.e., if toughness suffers at higher hardness enough that microchipping produces lower CATRA results, is that the way you find "optimum"?

And more specifically, what is optimum, in your opinion, for these:
S90V
S60V
S30V
BG-42
D2
ATS-34
VG-10
Originally posted by Sal Glesser
We found that S30V was only slightly better that S60V in corrosion resistance. Nowhere close to 440C. (Govt approved Q-Fog tsting).
sal
Click to expand...
I'm assuming you mean that 440C significantly exceeds S30V in the Q-Fog testing.

One more question: The CATRA involves cutting standardized stacks of paper that are impregnated with silica... I'm assuming this is like fine sand. It would seem like the CATRA would not induce much in the way of side loading on a blade's edge, it would slice with perfect perpendicularity, and so the blade edges would not "roll". Rather, they would dull by impaction and abrasive wear, but perhaps also a micro level of chipping (which is where material "toughness" would pay off in edge retention). Would the CATRA testing protocol therefore give some perhaps somewhat skewed preference for high carbide-bearing steels (wear resistant) over those that can be run hard for roll and impaction resistance along with toughness (say, O1).
 
I've found S30V more corrosion resistant than ATS-34, but not 420V or BG-42, having used all those steels at work, where the knives are frequently soaked in sweat for hours on end, and cleaned later. Never had even a speck of rust on my 420V DDR CF EDC...
Since I've been reading this thread, and am apparently bored out of my skull, just for the sake of curiosity, I've got a plastic platter sitting here with lemon juice on 4 S30V knives, and one each of 420V/S90V and BG-42, with an AUS-8 Deerhunter for comparison.
Pretty scientific, huh?:p

I used to work in a lab where we did salt spray testing. Wish I still had access to that equipment, my coworkers would think I'd lost my mind:D

edit: also very curious to hear the "optimal hardness" for the steels Rob listed.

...dang it, there's a Calypso Jr. in my pocket. Should have juiced up some VG-10, too.

edit:
~4 hours later, none of the knives is showing any hint of corrosion from the lemon juice (it just dried, and left a gooey film), which surprises me, since it makes a visible difference on carbon steel very quickly, and I expected, well....something, after a pretty short time. Guess I'll leave them overnight, and see what happens.

edit:
almost 11 hours from starting, it has become obvious that lemon juice isn't much of a test, but it sure leaves a clean blade when you rinse and scrub off the residue.
Now all I need is another bright idea:rolleyes:
 
My original intent wasn't to question Spyderco's judgement on which steel to use.
I'm here to learn all I can about knives and to quote rd I wasn't (sweating it). Ron
 
Originally posted by OwenM
...just for the sake of curiosity, I've got a plastic platter sitting here with lemon juice on 4 S30V knives

~4 hours later, none of the knives is showing any hint of corrosion from the lemon juice (it just dried, and left a gooey film),
Click to expand...

I have a Darrel Ralph Arc Lite (big one, 4”) fixed blade. Bought it 2nd hand, didn’t know if it was S90V or D2. Darrel didn't mark the blade obviously. So I emailed him... Darrel said easiest way to check was to use lemon juice, like OwenM is doing with his experiment. (to be clear, D2 will show corrosion quickly, 420V won't).

Well, I thought the same thing… it dried, left gooey film… no corrosion after a few hours... so I let it sit for over a day (maybe 2 days?), no corrosion, must be 420V.

Well, when I removed the dried juice, there was discoloration… the steel turned a darker gray in the area where lemon juice was. Can’t remove it.

So you might want to use the juice as a "couple hour" type test, else risk permanent discoloration.
 
There is really nothing cast in stone, just accumulated data. We stopped listing Rc on our printed steel charts because of controversey and different opinions.

"Twice you referenced "optimum knife hardness". Can you elaborate on how you find this balancing point ... I'm assuming it's a balance between hardness/edgeholding & toughness? And more specifically, what is optimum, in your opinion, for these:
S90V
S60V
S30V
BG-42
D2
ATS-34
VG-10"

"Optimum" hardness for us is the hardest the steel can be and not be brittle (chip or break). In most cases, it is mfrs spec. S60V performed better at 56-57. At 58, it was brittle and at 63 it actually cracked when dropped, so we made our knives 56-57. S90V (a great steel) does well at high Rc, 61 is not a propblem, S30V is tougher at 56 but edges work better at 59-60 and toughness is still very good. Bg-42, we used Chris Reeve's specs and heat treating, 59-60, D2 we tested harder, 60-61 was ok, but we think optimal would be 59-60. Keep in mind that guys like Chris Reeve and Bob Dozier seem to get more performance from similar steels because of heat treat "tricks", but they're not huge differences. ATS-34 for us works best at 59-60, but it will get harder. VG-10 wil also go to 62 but works best at 59-60.

This is a very gray area to work in because there are so many variables. Heat treat greatly affects corrosion resistance as well. 440C at 59 has excellent corrosion resistance, probably the best stainless, but rusts badly if left annealed. Finding the "ultimate optimum" is difficult.

Also, the steels you listed are all great steels. Compared to each other is a little misleading because the differences are not that great. I would buy and use any of those listed with confidence. Compare S30V to 420 and you not even in the same game.

Keep in mind, our "opinions" are still just that.

"I'm assuming you mean that 440C significantly exceeds S30V in the Q-Fog testing".

yes

"One more question: The CATRA involves cutting standardized stacks of paper that are impregnated with silica... I'm assuming this is like fine sand. It would seem like the CATRA would not induce much in the way of side loading on a blade's edge, it would slice with perfect perpendicularity, and so the blade edges would not "roll". Rather, they would dull by impaction and abrasive wear, but perhaps also a micro level of chipping. Would the CATRA therefore give some perhaps skewed preference for high carbide-bearing steels (wear resistant) over those that can be run hard for roll and impaction resistance along with toughness (say, O1)".


The CATRA uses stacks of specially made paper (made in France for CATRA). As you say loads are generally perpenducular. There is some side force in that the paper is clamped on one side, but I don't think it's sigificant. It's a good test for abrasion resistance on a knife blade and is quite consistant. It does have its limitations.

I don't think it will give an indication of toughness, at least nothing major that we've discovered. We did find that the tougher steels seem to support serrations better.

We have recently purchased a Charpy tester, but have not yhet set it up.

sal
 
Excellent post Sal. One for my archives. Thanks for taking time to type up your experience and opinions, which carry a lot of weight with me.
 
I believe it is the sharing of information and cooperation between humans that has taken us out of the caves, and will bring us to the stars.

It is my pleasure (& responsibility) to share when possible. (also try to keep in mind that this info is always subject to question, I'm not always correct either).

sal
 
You must log in or register to reply here.
Back
Top