I Tested the Edge Retention of 48 Steels

[Larrin]

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

 

[rob]

Thanks Larkin. Jeepers, this test would of been a huge amount of work.

 

[MontezumaBoy]

Excellent Larrin - I am always impressed with the thoroughness of your work plus I really enjoy your writing style that keeps me informed & entertained throughout. Very very cool ... a tremendous effort (as always)!

 

[inferno]

really surprised by the minimal difference between blue super and 1095

 

[Barmoley]

Many surprises and excellent work. The surprises is why this work is so important, good to have some solid data to make better decisions.

 

[inferno]

i see you said that the machine could take other media. I think it could be interesting to test steels similar to the most common japanese, like 1095 instead of white and some steel similar to blue2 and the blue super and test them with different media like the one you suggested, rope and cardboard. or maybe even some rubbery foamy plastic, or cotton/hemp/jute cloth.

i get the feeling that there actually is a difference in "edge retention" at home (with food) with blue vs white. could be minor though.

sure that edge retention might not be just abrasive wear but could be minor rolling/chipping etc etc but for the end user the result is the same, the knife feels dull.

 

[Ruso]

Acidity of food contributes to the edge degradation. Hence blue holds edge better in food prep than white.

Great work as usual Larrin!

 

[inferno]

but i think the blues are so low alloyed it might not make a difference vs white regarding corrosion resistance. could be wrong though.

 

[Eloh]

Yeah, cool work, i cant say that these figures reflect my experience with kitchen knives at all though. Aeb L with more Edge retention than 1.2562?

too many variables to get useful results for kitchen knives i guess, still interesting though.

 

[HRC_64]

but i think the blues are so low alloyed it might not make a difference vs white regarding corrosion resistance. could be wrong though.

Hitachi recommends using blue for kitchen knives. White steels are only recommended for tools (like chisels). Presumably the difference is that tools never see water or acids, whereas everyday reality in the kitchen is full of both.

 

[Bert2368]

That is an amazing piece of work.

As others, I would love to see similar tests run with non abrasive impregnated materials more similar to clean veges and/or boneless meat- but the required time and test media volumes for those higher wear resistant steels could be an issue... What could the test medium be?

I finally became a patreon supporter after skimming through this.

 

[Hz_zzzzzz]

but i think the blues are so low alloyed it might not make a difference vs white regarding corrosion resistance. could be wrong though.

I do notice huge difference between white 2 and blue 2/1/super in cutting tomatoes. The blues cut multiple times more tomatoes than white 2 and I've got 4 knives in white 2 so far given its popularity and they all perform similarly for acidic produce.

 

[HRC_64]

HT appears critical to performance for AEBL, and a good HT really delivers...

 

[Larrin]

That is an amazing piece of work.

As others, I would love to see similar tests run with non abrasive impregnated materials more similar to clean veges and/or boneless meat- but the required time and test media volumes for those higher wear resistant steels could be an issue... What could the test medium be?

I finally became a patreon supporter after skimming through this.

I bought some rope that fits the machine a couple days ago. I plan on testing a limited number of the knives to look for differences.

 

[tostadas]

Amazing work! Cant wait to see more

 

[inferno]

I bought some rope that fits the machine a couple days ago. I plan on testing a limited number of the knives to look for differences.

i got an idea. when doing these lesser abrasive materials well all know it can ages to see any results at all.

most people will not run the knives duller than a certain point. they just pull out the stones when the knives starts feeling dull.
so my idea is this. and i think it reflects how people actually use the knives.

sharpen up to maybe 3-4-5k. cut 1 or 2 stacks of regular copy paper/hemp cloth/hemp rope, then test the sharpness with your bess tester.

 

[Panamapeet]

Could you maybe elaborate on your ability to heat treat each steel to bring out its maximum potential, and the relevance of this study considering those abilities?

 

[Larrin]

Could you maybe elaborate on your ability to heat treat each steel to bring out its maximum potential, and the relevance of this study considering those abilities?

I have a PhD thesis about heat treating and a job where I optimize the heat treatment of steel. I have done several heat treating studies on different knife steels that are published to the website. There is a section of this article about the effects of heat treatment on the cutting behavior.

 

[Panamapeet]

I have a PhD thesis about heat treating and a job where I optimize the heat treatment of steel. I have done several heat treating studies on different knife steels that are published to the website. There is a section of this article about the effects of heat treatment on the cutting behavior.

That’s all very impressive! However, how do we know that you have practiced what you know? I don’t mean to be a party pooper, but all this study confirms is that the specific pieces of steel you have tested give these results...

 

[Ruso]

I am somewhat surprised with 440C performance especially at the lower hardness. I would say it will be at the bottom of the chart. :/

 

[inferno]

I am somewhat surprised with 440C performance especially at the lower hardness. I would say it will be at the bottom of the chart. :/

you should check out the vg10... the most hated steel on the forum.
i kinda like it though.

 

[RDalman]

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.

 

[Ruso]

you should check out the vg10... the most hated steel on the forum.
i kinda like it though.

While it was somewhat unexpected the result of VG10 tbh but it did not surprise me as much as 440C

 

[Barmoley]

That’s all very impressive! However, how do we know that you have practiced what you know? I don’t mean to be a party pooper, but all this study confirms is that the specific pieces of steel you have tested give these results...

So what you are saying is that no study or comparison can ever be done because you will always deal with specific pieces of steel that give specific results? The heat treat data is in the article.

 

[Larrin]

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.

If you give me some examples along with your heat treatment I can tell you the thought process and what differences might arise.

 

[RDalman]

If you give me some examples along with your heat treatment I can tell you the thought process and what differences might arise.

I'm sorry that's not a discussion I want to have. I believe we might have different preferences and that's all fine.

 

[inferno]

While it was somewhat unexpected the result of VG10 tbh but it did not surprise me as much as 440C

i think 440c got a bad reputation because people have ran it too soft, like 50-55hrc. or that that it has quite coarse carbides and supposedly, "cant be sharpened to a fine edge". d2 has very big carbides too. but i took my yoshikane skd santoku to 12k, no problem there really. it got truly scary sharp.
and according to internet lore i shouldn't have been able to do that. "theory" and practice seems to differ i guess.

and its probably just like all other steels. if you do it properly, it will be good. at least good enough for most people and uses.

 

[Larrin]

There’s nothing wrong with 440C, it tested about as expected for edge retention.

 

[M1k3]

Great article! I'm surprised by some of the results. Like 1095/52100 being close to blue super/1.2562. And A2 being so close to them.

 

[inferno]

Great article! I'm surprised by some of the results. Like 1095/52100 being close to blue super/1.2562. And A2 being so close to them those.

i think the machine runs the stuff way past what most people on this forums would call dull and resharpen.