Toughness testing of AEB-L, Niolox, CPM-154, 19C27, 40CP, and D2

Excuse my ignorance but what is it in the composition of the steel that makes up the carbide volume? These threads are some of my favorites, even if i dont fully understand them yet
 
valknut said:
Excuse my ignorance but what is it in the composition of the steel that makes up the carbide volume? These threads are some of my favorites, even if i dont fully understand them yet
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First is the amount of carbon, second is carbide forming alloys like niobium, vanadium, tungston, molybdenum, chromium, and some lesser known alloys.

Hoss
 
So with AEBL is it the fact that it only has .67% carbon with the higher amount if chromium that gives such fine carbides?
 
Okay. Now it gets complicated. You guys have to figure out what the sweet spot is for all of these steels. :D
 
Wow what a great thread! Would love to see CPM-3V throw in here too :p

Thanks for the effort anyway.
 
Interesting test.
But you didn't give the steels cyro treatment.
How would that have influenced the results?

Also to me stainresistance is an important feature. How do the steels compare there?
 
Hengelo_77 said:
Interesting test.
But you didn't give the steels cyro treatment.
How would that have influenced the results?

Also to me stainresistance is an important feature. How do the steels compare there?
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OP already stated that he use cryo after quenched for every steel he tested...
 
Larrin said:
There are a lot of steels out there without any reported toughness values. And comparisons between toughness results from one company usually can't be compared with another company, often because they use different testing methods. So we collected together an eclectic group to compare. AEB-L is known for its high edge stability and toughness but as far as I know there aren't any toughness numbers out there. Niolox is a European steel with V and Nb additions which has been pushed before as an "enhanced wear resistance" AEB-L. Everyone knows CPM-154, of course. 19C27 is made by Sandvik but has 1% carbon so its carbide volume is much higher than the 12C27 and 13C26 steels. 40CP is our representative of Carpenter powder metallurgy stainless steels. And D2 is of course the well known tool steel. All of these steels were heat treated using a cryo treatment directly after the quench followed by a double temper. I also added in the CruForgeV testing that we did as a comparison, but I'm too lazy to link to that thread. The austenitizing and tempering temperatures were as follows:
AEB-L: 1950, 350
Niolox: 1975, 350
19C27: 1950, 450
CPM-154: 1950, 450
D2: 1870, 450
40CP: 1925, 350

Anyway, AEB-L is by far the toughest, and its reputation is well founded. Niolox did not do as well as hoped. 19C27 and CPM-154 have similar toughness, around half that of AEB-L but better than 40CP, Niolox, and D2. There still isn't much out there with toughness between AEB-L and 19C27/CPM-154. There are just so many more options when it comes to non-stainless tool steels. Oh, and D2 is confirmed to be overrated.

gOuh6Zl.png
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Hello, Larrin, thank you for your great tests.

Just curious how did you select your steel samples. Did you used Rolled sheet or flat bar with length direction parallel to the rolling direction? How do you think using a steel cut from a big block, not sheet, will affect toughness?
 
This excellent thread let us think why doesn’t more people uses AEBL in they Knives, and insists in using D2 and other silly (in my opinion, at least) things in “hard use” Knives. The answer seems clear to me: because is cheap and associated to cheap knives (13c26 is used in pretty cheap knives) with poor heat treatment. Let us not forget PHD Roman Landes uses AEBL in most of his high performance kitchen knives.
 
valknut said:
Excuse my ignorance but what is it in the composition of the steel that makes up the carbide volume? These threads are some of my favorites, even if i dont fully understand them yet
Click to expand...

Compare AEB-L composition with this from REX-121

Carbon 3.4% ..............................................0.67 %
Tungsten 10.0%............................................ :thumbsdown:
Chromium 4.0%.............................................13 %
Molybdenum 5.0%.......................................... :thumbsdown:
Vanadium 9.5%.............................................. :thumbsdown:
Cobalt 9.0% ................................................... :thumbsdown:
Sulfur 0.03% (0.12%)*.................................0.015 %
 
hugofeynman said:
This excellent thread let us think why doesn’t more people uses AEBL in they Knives, and insists in using D2 and other silly (in my opinion, at least) things in “hard use” Knives. The answer seems clear to me: because is cheap and associated to cheap knives (13c26 is used in pretty cheap knives) with poor heat treatment. Let us not forget PHD Roman Landes uses AEBL in most of his high performance kitchen knives.
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People with PhD’s don’t know everything. :) But I agree Roman has good taste in stainless steels.
 
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hugofeynman said:
Hello, Larrin, thank you for your great tests.

Just curious how did you select your steel samples. Did you used Rolled sheet or flat bar with length direction parallel to the rolling direction? How do you think using a steel cut from a big block, not sheet, will affect toughness?
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If the charpy samples were the same thickness than the biggest difference would be the amount of reduction in forging. More forging/rolling leads to reduction in carbide size and reduction of segregation. This would show up most apparently in transverse toughness tests but would be seen in longitudinal tests as well which is what we performed. If we used full size charpy specimens from the block that would also change our values even if they were both normalized by cross section because of the change in triaxiality, but I’m struggling to find an easy to understand link to post about triaxiality to explain what I’m talking about.
 
AEB-L @62 RC (ht by Peters) lawnmower toughness test:

N1Gyuyi.jpg


Never did get the whole story on how the knife and sheath got under the lawnmower. The blade, right at the edge deflected a hair which I was able to straighten and sharpen out, back to about 98 percent. The sheath not so much:

2OcNxfS.jpg


Built the guy a new sheath for free cause it was a good story:

6g0TGIG.jpg


Standing nearby may not of been the thing though, I don't know.
 
I asked Brad Stallsmith a while back how much it would cost to do the Hoss style multi stage HT on AEB-L and he said double price because it involves two trips through the vacuum furnace. With what have discovered about those still available even if slight performance gains available with this old, simple steels, I am thinking that extra cash is probably worth it at least on bigger kitchen knives where you can justify the extra cost. Hence my semi-serious question about the "sweet spot" for ome of these steels. So of the work that knife makers have done over the past decade or two on some of these steels have moved a few them from the "old timey" category to the "preferred steel" one. W2, 52100 and AEB-L are good examples, but obviously not the only ones.
 
The 40CP toughness is interesting also because 440XH/XHP and 20CV are likely worse, and those steels have occasionally been advertised for their toughness. CPM-154 looks pretty good though.
 
Larrin said:
The 40CP toughness is interesting also because 440XH/XHP and 20CV are likely worse, and those steels have occasionally been advertised for their toughness. CPM-154 looks pretty good though.
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Do you believe CPM-3V will has the toughness live up to the hype? or at least would it be any tougher than AEB-L?
 
shqxk said:
Do you believe CPM-3V will has the toughness live up to the hype? or at least would it be any tougher than AEB-L?
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By all indications the toughness of 3V should be pretty good. However, whether it would have superior toughness to AEB-L is hard to predict. The two have similar carbide volumes, but AEB-L carbides are smaller which should improve its toughness. But AEB-L is a stainless so the high chromium in solution likely somewhat reduces its toughness. Other interesting comparisons would be Bohler and Uddeholm grades like Vanadis 4 Extra, K490, and K890, since they show in datasheets and papers having superior toughness due to their 3rd gen PM process.
 
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