Tool Steel Reference Graphs

flatgrinder

flatgrinder

Joined
Dec 20, 2005
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Here's a compilation of Crucible's "Tool Steel Comparagraph" that I put together with the most common steels used by us stock removal knifemakers, thought it might be useful for you other makers out there:

P.S> Anyone made a knife from CPM 9V yet? If you did, how was the edge retention?
 
um....can you define the abstract terms "Toughness" and "Wear resistance"? Is that like Tensil strength and edge retention or something?
 
i was going to try 9v but could not get it in barstock the size i could use
some setel smasher would have to forge it down
i did get some 10v but have not tested it yet i do know 3 v is nice stuff and have made few knives out of it
it holds a nice edge and at 59-60 i have not chiped on anything short of chain links
yep that messed up the edge but the banding straps didnt hurt it when i had to brake out my mill choped cut and pryed the crate to see how it would much it would take
i ll let you know about the 10v when i get some finished
butch
 
toughness is the ability to resist deformation under impact testing.

wear resistance has to do with the ability of the steel to resist degradation due to cutting abrasives.

Both are important to edge-holding...which is the "larger umbrella" in this case...
 
also just remembered that i that chart is the ont im thinking about all the different steels are at different Rcs
if i am right that would be showing 10v at 60 and the 9v at 54 and 3v at 58
just so you know
that they are all not the same hardness thats why im tring out 10v not 9v
butch
 
From reading multple posts I had an impression that O-1 is one of the best steel for knives out there. This chart shows that it has very little wear resistance.
Is it right?
 
Where does CPM125V fit into that chart info? I'm curious if anyone has ever done a edge retention comparison between D2 and A2?
 
I thought it was interesting in that Crucible claims that S30V has a toughness that is comparable to A2. However, according to their data, it is more in line with D2.

Maybe this addresses the info. we've all been getting where S30V has experienced "chipping?"

I think the charts are fairly representative of the various properties. From my own experience and testing S30V will outcut D2 -it produces a sharper edge and a longer lasting one.

Interestingly, I recently used two brand new Benchmade Griptilians to slice up some carpet, same blade shape and size (one in D2 and the other in 154CM) -and surprisingly the 154CM blade outcut the D2 version. I always thought D2 had the "edge" when it comes to "holding an edge forever" -but according to the chart and my personal experiences -other steels have outperformed it. Don't get me wrong, I like it, it's good -but in this day and age, there seems like there's better.

Anyone like 10V and S90V?
 
alexmin said:
From reading multple posts I had an impression that O-1 is one of the best steel for knives out there. This chart shows that it has very little wear resistance.
Is it right?
Click to expand...

O1 is good, sharpens easily, produces a very sharp edge, but will be outcut by D2 and generally by anything that has higher wear resistance. However, HRC counts too. So if you have an O1 blade hardened to HRC63 vs. a D2 blade hardened to HRC 54, the O1 will last longer. As always, there are other variables (heat-treat, grind profile, method of sharpening, etc.) that have to be taken into account.
 
i hope that next week i ll have something to say about cpm10v
im grinding out a spyderco para blade so i can do some back to back testing
im going to shoot for 62Rc and realy see what i can do with it
i have a small bit of s125v im just waitiing to find the right folder for so that will be later on
 
Daniel Koster said:
toughness is the ability to resist deformation under impact testing.
Click to expand...

Impact toughness, which is usually displayed in those graphs is resistance to fracture, there is often little deformation. One shot numbers are fairly useless, better than nothing, but what you actually want is something like this :

http://www.panix.com/~alvinj/graph1095.jpg

and this :

http://www.panix.com/~alvinj/graphA2vsO1.jpg

wear resistance has to do with the ability of the steel to resist degradation due to cutting abrasives.
Click to expand...

There are several ways to measure this, adhesive is often used on steels because they are often used to cut other metals, this isn't likely relevant to knife steels. There is also a big problem in relating the performance of a 0.1 micron strip of steel on an edge to a 1 cm block of steel in various materials tests, carbide issues for example can prevent acute edges from actually forming in some steels at low angles.

Wilson has made and tested knives out of 125V.

-Cliff
 
flatgrinder said:
I thought it was interesting in that Crucible claims that S30V has a toughness that is comparable to A2. However, according to their data, it is more in line with D2.

Maybe this addresses the info. we've all been getting where S30V has experienced "chipping?"

I think the charts are fairly representative of the various properties. From my own experience and testing S30V will outcut D2 -it produces a sharper edge and a longer lasting one.

Interestingly, I recently used two brand new Benchmade Griptilians to slice up some carpet, same blade shape and size (one in D2 and the other in 154CM) -and surprisingly the 154CM blade outcut the D2 version. I always thought D2 had the "edge" when it comes to "holding an edge forever" -but according to the chart and my personal experiences -other steels have outperformed it. Don't get me wrong, I like it, it's good -but in this day and age, there seems like there's better.

Anyone like 10V and S90V?
Click to expand...
They originally hoped that S30V would have the toughness of A2, they don't claim that it does nor have they ever. Their data sheets have never claimed it. They originally tried to reach it, and told Phil Wilson so, who then wrote that that's what they were going for in his articles in Blade. In his articles he wrote that it seemed to reach toughness close to A2, though he had done little testing on toughness (according to him).

The problems with chipping are overblown IMO. It definitely isn't universal, and from talking to members of Crucible, the incidents they have investigated were gross neglect of the user (as in screwing up the blade by heating it up or something), or poor heat treatment by the maker, and Crucible tried to correct those problems. S30V's toughness is pretty close to D2, from talking to people at Crucible (who can give a little more information than the 25-28 ft. lbs. Charpy-C in the data sheet). They say that 440C and 154-CM get 25-28 ft. lbs. as well, but that isn't true. 154-CM gets 16 ft. lbs. at 60 Rc and 440C gets 16 ft. lbs. at 58 Rc. S30V gets 26 ft. lbs. at 58 Rc, and D2 gets around 22 ft. lbs. at 60Rc (these values seem to vary a little). These are all approximate and some of them might not even be in data sheets on the internet (most notably the S30V). Charpy-C seems to back up real world toughness of knives pretty well, whereas wear resistance doesn't always equate to higher edge retention.

In my opinion, S30V is equal to D2 in all areas except corrosion resistance, where S30V is of course better. I think that D2 holds an edge a little better and is a little tougher than 154-CM however, this is backed up by Wayne Goddard's rope cutting tests and Charpy-C values.

Makers seem to shy away from S90V because of the difficulty of finishing, and because of the difficulty in sharpening by the user. I have also heard maker's say that in the real world, the extra wear resistance provided by S90V compared to S30V isn't really needed, and that you'll be sharpening your knife before you get to the number of cuts you can get from S90V anyway, most recently from Phil Wilson, through my dad.
 
butcher_block said:
i do know 3 v is nice stuff and have made few knives out of it
it holds a nice edge and at 59-60 i have not chiped on anything short of chain links
yep that messed up the edge but the banding straps didnt hurt it when i had to brake out my mill choped cut and pryed the crate to see how it would much it would take

butch
Click to expand...

I thought about making a camp or survival knive out of CPM 3V. How hard was that stuff to work, grinding wise? It sounds like the results were worth the effort.
 
Larrin said:
The problems with chipping are overblown IMO. It definitely isn't universal, and from talking to members of Crucible, the incidents they have investigated were gross neglect of the user (as in screwing up the blade by heating it up or something), or poor heat treatment by the maker, and Crucible tried to correct those problems.
Click to expand...

There have been lots of problems with S30V chipping on very light use, usually there is always one actually active. The main problems are cutting cardboard and plastics, hardly gross neglect especially considering the focus of the steel was toughness according to Barber and the same people are cutting those materials with steels S30V was supposed to be superior to. Even the more demanding cutting such as light chopping is well within the expected use of the steel considering its promotion and the types of large knives it used for. It they are also all heat treat problems then it seems odd considering again that the steel was designed according to Barber specifically for ease of heat treatment by knifemakers.

The problems have also been reported across many different knives from different makers, Benchmade, Spyderco, Camillus, and Reeve, and have been so common that people have returned a defective knife (Ritter Grip) and got another one which was also defective and chipped. The frequency of problems reported is extremely high compared to the number of problems reported with say VG-10 for the same types of uses. Some of the problems have been solved with repeated sharpening, pointing to possibly burnt edges, others have persisted and blades even from Reeve have been found to have performance inferior to 420HC and matched by AUS6A by different indepentant users - and actually reported on Reeves forum with no public statement of refutation of expected performance.

Makers have also stated that S30V is both as tough as and tougher than A2 and its transverse toughness has been promoted by Crucible as comparable to "many high toughness tool steels", D2 isn't a high toughness tool steel, it is one of the more brittle tool steels.

-Cliff
 
zcostilla said:
I thought about making a camp or survival knive out of CPM 3V. How hard was that stuff to work, grinding wise? It sounds like the results were worth the effort.
Click to expand...
it worked like a dream after i had been working with 440c and ats34
3v and 10 v are the only non SS that i have worked with so i can compare it to say O1 or 5160 i can say this with good belts the 10v that im grinding seems just as easy as ats34 that i was working
you can realy remove steel with a grinder on 3v
 
butcher_block said:
it worked like a dream after i had been working with 440c and ats34
3v and 10 v are the only non SS that i have worked with so i can compare it to say O1 or 5160 i can say this with good belts the 10v that im grinding seems just as easy as ats34 that i was working
you can realy remove steel with a grinder on 3v
Click to expand...

I am sure it is a stupid question, but did you have to anneal it first, or does it come soft enough to grind?

Zac
 
Cliff Stamp said:
There have been lots of problems with S30V chipping on very light use, usually there is always one actually active. The main problems are cutting cardboard and plastics, hardly gross neglect especially considering the focus of the steel was toughness according to Barber and the same people are cutting those materials with steels S30V was supposed to be superior to. Even the more demanding cutting such as light chopping is well within the expected use of the steel considering its promotion and the types of large knives it used for. It they are also all heat treat problems then it seems odd considering again that the steel was designed according to Barber specifically for ease of heat treatment by knifemakers.

The problems have also been reported across many different knives from different makers, Benchmade, Spyderco, Camillus, and Reeve, and have been so common that people have returned a defective knife (Ritter Grip) and got another one which was also defective and chipped. The frequency of problems reported is extremely high compared to the number of problems reported with say VG-10 for the same types of uses. Some of the problems have been solved with repeated sharpening, pointing to possibly burnt edges, others have persisted and blades even from Reeve have been found to have performance inferior to 420HC and matched by AUS6A by different indepentant users - and actually reported on Reeves forum with no public statement of refutation of expected performance.

Makers have also stated that S30V is both as tough as and tougher than A2 and its transverse toughness has been promoted by Crucible as comparable to "many high toughness tool steels", D2 isn't a high toughness tool steel, it is one of the more brittle tool steels.

-Cliff
Click to expand...
I have had no problems with chipping personally; however, I might just be lucky. Looking at the numbers, though, it is hard to imagine S30V having any problems with toughness. It has about the maximum amount of molybdenum before it starts to form molybdenum carbides, for added toughness. It has relatively low carbide volume, which equals higher toughness. It has the minimum of chromium, chromium reduces toughness as the percentage gets higher. It has the minimum of carbon (it's still very high because of the vanadium carbides it has to form). It has some nitrogen added, which generally increases toughness. And of course, it is made with the powder metallurgy process which makes the carbides uniform in shape and distribution, and much smaller than conventionally cast, and reduces the grain size as well. Warren Osbourne, in his searches for a "chopper" steel, says that S30V was the best stainless that he used, but still didn't have the toughness that he could get out of a tool steel (which is only to be expected). By the way, his favorite is CPM-M4.

I'd almost think that someone has made it "cool" to say that S30V has chipping problems, and that everyone is a bunch of hypochondriacs, or maybe heat treatment and edge geometry is somehow poor accross the board whenever the maker uses S30V.
 
flatgrinder said:
Here's a compilation of Crucible's "Tool Steel Comparagraph" that I put together with the most common steels used by us stock removal knifemakers, thought it might be useful for you other makers out there:
Click to expand...
The only gripes I have with your graph are that A2 is tougher than O1, even on Crucible's charts. O1 is 30 ft. lbs. at 60 Rc and A2 is 41 at 60 Rc, and the second is you didn't list any hardnesses. It can be a little difficult to see what hardness they're saying it is at on their charts. My guess is most of them are 58-61 like it says (edit: like it says on Crucible's charts, not yours), but the CPM-M4 and M2 are probably closer to 63 Rc, and the 9V at 53-55 Rc.
 
I'm certainly no hypochondriac, but I've found that S30V chips badly in normal use. I didn't realize that others had experienced the same problem until I recently checked out some threads in the "Knife Testing and Reviews" forum. It is a major disappointment for me, and has certainly not lived up to it's billing from my personal experience.

As far as the chart goes, it doesn't seem to correlate very well with my personal experience, either. 440C is as wear resistant as D-2? C'mon now, let's deal with reality in the knife world. D-2 is twice as wear resistant as O-1? Not for me, it isn't. The toughness part seems to trend correctly, but I haven't found the differences to be as great between some steels as the chart implies.

Todd

edited to add: Like Larrin points out, the Rockwell numbers could certainly skew the results, and could be the cause of the apparent inaccuracies.
 
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