I Tested the Edge Retention of 48 Steels

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Its worth also looking back here to AEBL--A steel not really "lknown" for its edge retention...

According to this test, however, the best AEBL can be differentiated from the worst with the existing setup. A key question is this because good aeble is really good, or if the bad aebl is just really bad?

And can we get this kind of variance in other low-carbide steels (stainless or not) just from heat treat? Expecially blue/blue super etc one would think maybe could be separated form white, just like o1 seems to underperform 1095.
 
i'm guessing there is no incorrectly HTed steels in this test. probably all of them were HTed better/more suitable than all big brands HT them.
 
HRC_64 said:
Any test that is demanding of the steel like this one is going to lump all those steels together and make them look like "losers", which people's ego gets caught up in their "team" not winning.
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i dont think most people actually care that "their favorite steels" ranked low. almost all people on here know god damn well these low alloyed steels basically suck for abrasive resistance.

and i actually dont think people have steels that is like their "favorite team". i have favorite knives. and its usually knives i have put my own handles on.

my own favorite steels, and they probably all suck in this test is: blue2, aus8 and vg10. because they have have a good balance of properties. and i get those properties when i buy almost any off the shelf knife. no magic needed. i have never tried a bad blue 2 knife. they are all good.

the only real supersteels imo is blue2 and mac's aus-8 :) but i'm probably alone thinking that. and i dont care because for me these are the best tradeoffs.
 
Larrin, i don’t pretend to understand everything you write but I do appreciate all your hard work. Is the paper used for the test standardized in some way? Couldn’t you get a “bad batch”. Did anything from the test surprise you at all? Also does the machine cut straight up and down ? Just curious. Thanks for any answers. And thanks again for your work. I know it took a long time. And it’s never easy when your wife is angry!
 
I want to apologize I havent taken the time to explain myself better. I do applaud all the work and found the experiment and it's findings really interesting. But also feel like Iggy was pointing out, it might not be great as using for relevancy for kitchen knives edge retention. I did react to the chosen heat treatments, because I believe other, or more optimized heat treatment temperatures would show exponential curves in this catra test, like the aeb-l does. And also I would venture to believe many steels are at a low level of catra performance comparing it to itself with a harder heat treat. If that is the case (that many steels are tested at what might be bottom range of a exponential chart-curve hardness wise) the study could have looked different I would believe.
Still, I found the study interesting!
Since I don't want to contribute I should maybe not have said anything, but then this is a discussion board, and like Bryan mentioned, studies/experiments should really stand to be discussed.

For my heat treatments I don't think I do anything special really. I just don't share exact temps I have come to use for a couple of reasons. One is I don't want to give alot of work away to be copied or potentially misused/misreferenced. And also, I don't want to open for being critiqued by people who might have the opinion, or be invested in the opinion, that using some temperature or the other would be very bad theoretically. For me as a knifemaker it's best to just have it like that, that if customers enjoy the knives I make performance, that's what matters.
 
I spent many years on an audio forum. Any time someone posted a listening test of any kind you knew the thread was destined for quarantine. No matter how good of a double blind test was done if someone’s own equipment lost the test the test was flawed.

I’m a very new knife maker and don’t really know anything about steel but I’m guessing the same thing is in some ways happening here. If someones favorite steel didn’t do well or it doesn’t compare favorably to their own beliefs the test is flawed in some way. I’m wondering, does the medium you’re cutting through really make a difference on the edge retention of different steels? It seems to me it shouldn’t matter what you’re cutting through when determining edge retention, what matters is how many times it takes to get through it. Other than the the huge variable of heat treating each steel to its best state this test seems to be very informative of edge retention of different steels.

One question for Larrin, I’m curious why 15n20 wasn’t included in this test? I didn’t think it was that obscure of a steel?
 
Predicted wear resistance of 15N20 would be close to 8670, maybe a little less.

Hoss
 
15n20 can be hardened to much higher than 60 hrc though, so you might get another 10% on this test while doing that. you can get 62-64 after temper if you want.

i'm guessing the reason it wasn't tested it that there was no real confirmed virgin 15n20 to test. i can get it here in sweden as 3mm plates but this might not be the case in the US. its probably not.

one thing i reacted on is that uddeholm caldie is about as "good" as 1095 in this test but in practical reality it would be on the order of, most likely 3-10x, as durable and long lasting as a blade steel made out of 1095. at high hardness.

we used to make shearing knives out of caldie @ 61-62hrc for a plant that used it as "knives" to chop rebar. because this was the steel that lasted the longest. i think we re-machined them every 2 weeks or so. 1095 would have lasted maybe 2-10 seconds in this environment. so it is what it is.
 
RDalman said:
I did react to the chosen heat treatments, because I believe other, or more optimized heat treatment temperatures would show exponential curves in this catra test, like the aeb-l does.
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57 blades were completed in total, more blades can always be created and added to see more data.

RDalman said:
I don't want to open for being critiqued by people who might have the opinion, or be invested in the opinion, that using some temperature or the other would be very bad theoretically.
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Yes, all the heat treatment is shared openly in the study for science and is open to scrutiny from all people of any background.

It is a complex subject. Scrutiny in some cases may be due to a misunderstanding of how some features work.

RDalman said:
I don't want to contribute I should maybe not have said anything, but then this is a discussion board, and like Bryan mentioned, studies/experiments should really stand to be discussed.
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Scrutiny without constructive feedback or wanting to help isn't very helpful.

Discussion works best if information is shared.
 
inferno said:
one thing i reacted on is that uddeholm caldie is about as "good" as 1095 in this test but in practical reality it would be on the order of, most likely 3-10x, as durable and long lasting as a blade steel made out of 1095. at high hardness.

we used to make shearing knives out of caldie @ 61-62hrc for a plant that used it as "knives" to chop rebar. because this was the steel that lasted the longest. i think we re-machined them every 2 weeks or so. 1095 would have lasted maybe 2-10 seconds in this environment. so it is what it is.
Click to expand...

This is a very good example of why studies like this are very useful and important. Taking your anecdotal evidence as an example. You don't really know if 1095 would last 2-10 seconds in your example or if caldie would last 3-10 times as long, a huge range by the way, but let's say you are right and it lasts 5 times as long. Well, wear resistance of caldie in this test is similar to 1095, but it so happens that at the same hardness it is about 5 times as tough as 1095. Could it be that in your application with "knives" to chop rebar, low toughness and not wear resistance is what causes failures? I don't know but looking at results of different testing that was done you could probably arrive at an explanation and pick the steel that would work best for you. Take A8Mod as another steel that is used in chipper blades, it too is not very wear resistant, but also very tough and it is used in a similar application, so wear resistance is probably not the main failure mode in such applications. If you wanted a steel that would give you similar toughness, but was also more wear resistant you would go for CPM-3V for example, cost not being an issue. So you can see how useful this and other studies are to make good decisions of steel choice for different applications.

Disclamer: Everything said in the above example is just a thought experiment, it has nothing to do with reality of chipper or rebar blades and definitely has nothing to do with kitchen knives or how steels relate to them. no claims of CPM-3V being superior to A8Mod for chipper or any other blades should be taken or inferred.
 
Rapid failure vs 2 weeks would be an indication of chipping or deformation.
 
yeah it was just an approximation. but i guess caldie (and maybe even calmax) would be at the very top (with 3v) of the "carbon" steel hill when talking practical longevity of an edge, talking all regular types of "wear" combined kinda, both for folders and kitchen knives. it might not be very far ahead of some of other steels but they probably would come out ahead. thats what i'm guessing at least.

i'd buy a max hardened 3v kitchen blade in a heartbeat if i could. but now im probably forced to make it myself instead :)
 
You can buy a Z-Wear kitchen knife at around 63 that will give you the practical longevity you are looking for with max hardness 3v, just saying.....

This is unrelated to this discussion
 
According to the Crucible datasheets the toughness of 3V starts to fall off around 62 Rc. For 62+ Rc CPM CruWear might be a better choice. Pushing a “tough” steel to higher hardness levels doesn’t always work out well If it’s not optimized for higher hardness.
 
Human nature.. It's funny how we want take a well thought out product and try to adapt it to something outside of the roll it was designed for, even while other products already exist to fill that roll.
I bet some of the metallurgists look at how bladesmiths (in general) are choosing and treating their steels, and see this:
25iecv0wsu821.jpg

but-why.gif

Step aside blade steel, move over ball-bearing steel... Now I want to make a knife out of a high quality injection moulding die. Specifically one made from CPM-15V, obviously tempered lower than advised (duh).
Thanks guys... :LOL:
https://www.crucible.com/eselector/prodbyapp/plastics/plasticapptitle.html
HTB1WmeOPXXXXXb9XVXXq6xXFXXXI.jpg
 
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Barmoley said:
You can buy a Z-Wear kitchen knife at around 63 that will give you the practical longevity you are looking for with max hardness 3v, just saying.....

This is unrelated to this discussion
Click to expand...

cool!
 
Larrin said:
According to the Crucible datasheets the toughness of 3V starts to fall off around 62 Rc. For 62+ Rc CPM CruWear might be a better choice. Pushing a “tough” steel to higher hardness levels doesn’t always work out well If it’s not optimized for higher hardness.
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of course you are right, the steels are made/optimized for a certain hardness range. and outside the design range there might be better options.

but if we look at most of the common japanese steels, SS or carbon they are pretty much all in the 10ft-lb range or less in your tests. so even at this "low" toughness usually its enough for most people. but if one could double that toughness and still have good hardness, well, i think this is a good way to go to increase "overall performance". because chipping is very common with high hardness kitchen knives. no matter what steel. if they are thin enough they probably will chip out sooner or later in my experience.

------------

btw a bit OT, i think i'm done with 1095 for my moras at work.

in sweden mora knives are multitools, its the most essential tool for any worker.
i usually do everything you are not supposed to do with a knife. hundreds of times a day. and have been for the last 20 years.

i scrape rust/paint/dirt/concrete/grease, deburr parts, chisel burrs away from hardened parts, general chiseling on steel, bend/pry stuff apart, puncture thinner materials (with a hammer), chop heavy duty shipping straps, clean surfaces, etc etc. but i also do maybe 5% actual cutting with it, opening boxes and such. and it still needs to be able to cut cardboard, tape and plastic bags at the end of the day.

i used to like the mora robust (because it has a bit shorter and a bit thicker blade than usual) but it would simply dull within a day or 2. and it usually chipped out. especially when chiseling stuff.

but now i have basically switched over to the orange/black companion stainless (12c27), and it chips out way less and i only have to sharpen it once a week. and it still opens the boxes. win-win.
------------

its usually thought that stainless is brittle and carbon is tough, but i find it to be the exact opposite most of the time.
 
Kippington said:
Human nature.. It's funny how we want take a well thought out product and try to adapt it to something outside of the roll it was designed for, even while other products already exist to fill that roll.
I bet some of the metallurgists look at how bladesmiths (in general) are choosing and treating their steels, and see this:
25iecv0wsu821.jpg

but-why.gif

Step aside blade steel, move over ball-bearing steel... Now I want to make a knife out of a high quality injection moulding die. Specifically one made from CPM-15V, obviously tempered lower than advised (duh).
Thanks guys... :LOL:
https://www.crucible.com/eselector/prodbyapp/plastics/plasticapptitle.html
HTB1WmeOPXXXXXb9XVXXq6xXFXXXI.jpg
Click to expand...

hehehe i'm gussing its gonna be fun forging that out to a knife shape :)
 
I thought it would be fun to show the cutting geometry the catra blades before I sharpen them.



Next batch of testing should be exciting.

Have some heavy hitters like Maxamet, also some lesser known steels like T15 and Rex 76.

Also some fan favorites like Rex45 (hap40) and XHP as well as the new SPY27 steel from Spyderco that's is stacking up to be a real SG2 killer.
 
inferno said:
The CATRA test results in extremely dull edges, you can run your finger along the edges with no fear of being cut.

... i never let any knife get so dull i cant actually cut myself with it. i resharpen it when i feel its not cutting well anymore.

(followed by some specific suggestions)
Click to expand...
Outside of whether those specific suggestions you went on to make are the best solutions (because I have no way of knowing if they would be), superficially it makes sense to me that in a dulling test, knife users are only interested in the part of the test that mimics our experience - the part from "fresh edge" to "subjectively seems like it needs sharpening". After a certain level of dullness, then regardless of technical terms I'd start to think of the remainder of the test as merely testing abrasion resistance rather than ability to hold an edge - because in knife user terms, that edge was already gone.

There may really be a useful number lurking here to be found, perhaps something like "Subjectively, how many microns is too wide to qualify as an edge, and might therefore signal the end of a test?"
 
Wear resistance is highly correlated to slicing edge holding. The curves of loss of cutting ability for different wear steels have similar slopes, so it doesn’t really matter at what point you stop the test. Relationship among steels will be similar. This is well explained here Which Steel Has the Best Edge Retention? Part 2 - Knife Steel Nerds follow the links for more.
 
When you run the test all the way to dull, you can analyze the data at any point you want. There is a cutting ability curve for every cut in the test. There isn't a difference in steel ranking if you stop at some subjective earlier point, however. There is just more scatter earlier in the test because it is more dependent on variability in sharpening.
 
You know how they say a picture is worth a thousand words. I had hoped the nice pictures wouldn't make my head hurt as much as the text. Maybe reading at gone 2:30am wasn't the best choice. It seems like choosing Blue Super for my latest knife acquisition may also not have been the best choice.
 
Blue Super is a good choice for higher wear resistance low alloy steel (for forging). Low alloy steels don’t have particularly high wear resistance but Blue Super is among the highest in its category.
 
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