I Tested the Edge Retention of 48 Steels

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Very good article. However most of the steels listed there are more utility knife centered and not for kitchen knives. Interestingly SG2 a powder steel which is staineless and easy to sharpen seems to be the best choice for kitchen knives.
The high alloy ones (supersteels with lots of Chrome and Vanadium carbides) although have better edge retention, would probably eat through the whetstones to sharpen not to mention thin.
They make diamond/CBN bonded stones that behave more like water stones with resin and Vitrified bonds.

They have been around for 5 years now.
@JBroida
 
Heat, quench and temper? Or maybe he just beats the metal with unicorn bones until the edge is hard enough to be chippy?

yes of course.
just wanted to point out that NO or almost no makers publish how they HT the steel. hell some dont even tell you what steel they use.
 
I think everyone appreciated the research even the guys who commented. I believe that it's natural to debate and question ideeas. It prooves thought process and active synapses. If we all agree all the time it means there is no base for new ideeas or questions. Had Einstein not question the classical laws of physics would we have the theory of relativity?
And the questions were quite good. Meaning that it might be a good ideea to take each steel to its highest supported HRC and test how many cuts it can perform. I mean same steel at 65 HRc will have better edge retention than 61 hrc ( while more brittle). Let people debate because it's healthy it's not criticism ( no one said the study was stupid) it was just points for improvement.
 
yes of course.
just wanted to point out that NO or almost no makers publish how they HT the steel. hell some dont even tell you what steel they use.
Off the top of my head, I can think of one maker that has a Definitively Thorough knowledge about optimal HT for a variety of the steels Larrin mentions... Maybe he and Larrin have talked? :cool:
 
i think you're missing the point. what i meant is that the HT procedures are usually secret. no makers publish their HT specs. so why should Dalman be forced to do that?
 
i think you're missing the point. what i meant is that the HT procedures are usually secret. no makers publish their HT specs. so why should Dalman be forced to do that?
No. But I was probably too indirect. Just look at what I bolded.

Edit--Of course I agree. It's absurd to ask that Larrin ask a variety of different makers known for their HT recipes for their recipes and then duplicate these recipes and then publish them.
 
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i think you're missing the point. what i meant is that the HT procedures are usually secret. no makers publish their HT specs. so why should Dalman be forced to do that?
DT is not Dalman but Devin Thomas - and because I am “your father”.
 
For The moment I only have questions :
why cryo for all steel ? i know nothing about SS but 1.2519 ? 1.2442 ? super blue ?
Why austenize 2442 and 2519 at 800 and the other 830 ?
why temper 149 and the other 200° ?
10 and 15 minute soaking, what thickness at edge before quench ?
no big deal here but all the differences in the process make huge difference in the knife »performance« .
 
This is an amazing article. I like that you threw in the graph showing toughness as well. Anecdotally, I think your results make sense with my kitchen knife experience in some ways. I have always thought my VG-10 knife had surprisingly good edge retention, but it definitely shows visible damage to the edge far more than my White #2 or Blue #2 knives.

Perhaps the takeaway here is not that we should buy all the ZDP-189 knives, but that we place a greater value on toughness and ease of sharpening than we think we do.
 
Sorry, I misunderstood your comment since it was after DT post.

I got the impression that the idea is not to get the “secret sauce” of the HT, but that Dalman (Just as an example) could create a blank to Larrin specs and HT it the way he does it. Then this blank could be tested and compared to the current data. I think it would super awesome if many makers would do it and we got a data with S30V vanilla, s30v Spyderco, s30v Benchmade etc
 
I think complaining about CATRA testing is really mis-placed. In order to get any test standard to be useful, there has to be a basic or baseline that still forces variance over the correct range.

IF we stick XYZ in this machine you need to force measurable variance (repeatable, measurable, scaled etc) in a specific way: ie quickly, consistently, with realized range easy to measure etc.

The special test medium is almost surely designed to solve some problem related to this.

If you recall back when ATK did chef knives they tried to dull the knives nd could't actually do it. They resorted to CUTTING ON GLASS or something stupid to "force variance" in an accceptable window of time to get results they could talk about.

That being said, it would be interesting to devise an "acid resistance" protocol,
and see if one can empirically validate /dimensionalize variance along that axis.

That is to say, without altering the CATRA setup, to maybe "dope" the blades with acid exposure and then run them thru the test.

The practical problems here is you might need to find/validate the correct chemicals and correct proportions and timings etc. That could be complex/expensive/hassle so the fact this wasn't done isn't a flaw, its maybe better thought of as possible next steps or extensions of the analysis.

Anyways, thanks OP for the test/results/writeup...
and the many commenters on this thread

Its a good discussion :chef:
 
I think complaining about CATRA testing is really mis-placed. In order to get any test standard to be useful, there has to be a basic or baseline that still forces variance over the correct range.

IF we stick XYZ in this machine you need to force measurable variance (repeatable, measurable, scaled etc) in a specific way: ie quickly, consistently, with realized range easy to measure etc.

The special test medium is almost surely designed to solve some problem related to this.

If you recall back when ATK did chef knives they tried to dull the knives nd could't actually do it. They resorted to CUTTING ON GLASS or something stupid to "force variance" in an accceptable window of time to get results they could talk about.

That being said, it would be interesting to devise an "acid resistance" protocol,
and see if one can empirically validate /dimensionalize variance along that axis.

That is to say, without altering the CATRA setup, to maybe "dope" the blades with acid exposure and then run them thru the test.

The practical problems here is you might need to find/validate the correct chemicals and correct proportions and timings etc. That could be complex/expensive/hassle so the fact this wasn't done isn't a flaw, its maybe better thought of as possible next steps or extensions of the analysis.

Anyways, thanks OP for the test/results/writeup...
and the many commenters on this thread

Its a good discussion :chef:

You're right, party pooper. Still would like to see an automated carrot cut test, for science and all.
 
You're right, party pooper. Still would like to see an automated carrot cut test, for science and all.
cutting-carrots.jpg


https://knifesteelnerds.com/2018/08/06/sharpness-vs-cutting-ability/
 
This wasn’t a study of heat treating like some of you are trying to make it in to.

Wear resistance is controlled mostly by carbides and hardness which is controlled by the chemical composition of the steel. Most of these test coupons were heat treated using the standard recommended heat treatments or something that would fit the test better.

There needs to be some follow up testing to determine if we can get some separation with optimum heat treats.

This was some very good testing but I’m afraid some of you lack the intelligence to learn anything from it.

I highly recommend that those of you with the biggest mouths do your own testing and then let us sit back and criticize your work.

Hoss
 
1: Knife making is a niche material use. There are a FEW kinds of tool steels I know of, plus some damascus, monosteel and pre laminated stock developed and made expressly for our favorite tool, the knife. Naturally, manufacturers of a steel developed for, say, punch press dies, roller bearings or truck springs will have processing recomendations developed in that light. It is unlikely one guy with a day job has had free time to personally experiment with making knives and optimizing heat treating for 40+ materials. YOU PEOPLE, collectively pretty much have.

2: Larin did a huge project because he is way into your favorite application- and you don't have to pay a dime to see the results. Should you thank him or complain about some of the details?

3: The methods chosen to treat the test pieces and data taken certainly were not perfectly in line with what dozens of makers have learned by experience. They are a nice big pile of (Free! Open source!!!) data, perhaps best viewed as a community resource to suggest FURTHER INQUIRY.

4: If your results vary, as many indicate? Kibitzing and complaining that he should have done what you do (and possibly also not wanting to publicly state what your techniques are as you consider that to be proprietary info?) is not constructive. A better response might be to contact Larin, ask if he wants to work on it, and if so, start fabricating test samples conforming to his physical specs, heat treat under your conception of optimum for kitchen or other knife uses and send them to Larin for testing.

5: Larin does this for a day job. I like my day job, but I don't do it for free anymore (although I did for 10 years while I learned the craft). Don't look the gift horse in the teeth, give it a tasty apple and say "good horsey!"
Well I’ve enjoyed this.
 
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How much is "drastically different?"
What are your expectations?
Any predictions?


Ok I came to think of one I don´t use, cpm m4. Why did you austenize it so low, and do the high temper you usually advice against? The hardness and catra result I think is very low, if you would have ran it much higher, like much much higher aus and got it to 65-67 hrc rangethe same temper, I believe it would have performed drastically different.
 
How much is "drastically different?"
What are your expectations?
Any predictions?
I have no experience with catra testing just heat treat experiments what I feel works well with the kitchen knives I make. And since I don't want to contribute that maybe I should have just cut off my post at kudos for the awesome work, which I do feel. I just wanted to note I thought the heat treats was a little odd for many steels. This was my original reply in the thread:
"Kudos for the work, awesome.
Not that it takes away anything or makes any difference here necessarily for this catra test, I was struck that across the board the heat treats I prefer on steels in the study that I use in knives are very different from the ones you used."
 
No big deal Robin, thanks for sharing, I was just curious, and the words "drastically different" in your other post caught my eye.








I have no experience with catra testing just heat treat experiments what I feel works well with the kitchen knives I make. And since I don't want to contribute that maybe I should have just cut off my post at kudos for the awesome work, which I do feel. I just wanted to note I thought the heat treats was a little odd for many steels. This was my original reply in the thread:
"Kudos for the work, awesome.
Not that it takes away anything or makes any difference here necessarily for this catra test, I was struck that across the board the heat treats I prefer on steels in the study that I use in knives are very different from the ones you used."
 
Recently I was able to acquire a used CATRA machine, so I heat treated just about every knife steel I had, made 57 knives with the help of knifemaker Shawn Houston, and tested them all to see which cut the longest. For a few of the steels I did multiple heat treatments to look at a couple variables and to see the effect of hardness. I also compared edge retention and toughness to see which steels have the best balance of properties. Testing the Edge Retention of 48 Knife Steels - Knife Steel Nerds

Really excellent study and report @Larrin ! Thank you!

One thing that I would've liked to see but understand it makes the graphs cluttered is for all three CATRA measurements to be plotted. It would be interesting to see the spread in measurement values. It's not entirely clear the procedure followed between the three measurements; was the same knife was resharpened between the measurements? Was the thickness behind the edge checked between tests and after resharpening and no significant increase was seen? Or does your other testing of cutting edge angles show that thickness behind the edge is negligible in the CATRA slicing test?

It's really cool to see some measurable values from standardized testing like this, regardless of the quibbles some people may have. May be of more interest over at Bladeforums shop talk since there is more discussion of steels with respect to knife usage. KKF has a very Japanese knife-centric audience, and for Japanese kitchen cutlery, it's very unlikely many of the favored makers/bladesmiths/shops will expand their steel offerings outside the steels they are used to forging or using especially considering how little spread in the CATRA values are seen between the low alloy carbon steels typically used.
 
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