D-2 E, more test results

R

Rob Simonich

Big Bear
Joined
Oct 3, 1998
Messages
2,294

OK, now you are wondering what D-2 E is? I am not going to call this stuff D-2 Mod anymore,
but D-2 Enhanced. I can call it whatever I want right? Christina and Bob may slap me down
for that, but oh well! Anyway, here are 3 test blades and results from cutting and destructive
testing. The top 2 have the same heat treat, and the bottom was cryoed, but heat treated the
same.

All blades had about the same edgeholding abilities, the cryoed blade held the edge the longest
slicing 62 feet of corrogated furniture cardboard, 2nd was the cross grain at 58 feet, and third
was the top blade at 55 feet. I quit cutting when the knives lost their hair popping ability, all
were still quite sharp, and would still scrape hair, just wouldnt easily shave. (Pretty unscientific
huh?) All blades were hammered through 16d nails and the edge flexed over steel rod with no
chipping. The cross grain knife had the least damage from hammering it through the nails, with
2 swipes on each side bring the edge back to normal. All blades had a tiny bit of edge rolling
from the nails. From previous testing of D-2 at the same hardness, I am finding the D-2 E to be
tougher. Edgeholding is about the same, maybe a bit better but I am not sure.

Breaking blades. (whos says knifemakers dont break blades?) I was surprised at the results
here. The cryoed blade shattered into 5 pieces when it broke at 33 deg. The cross grain blade
broke at 33 deg as well, but broke not at the tip but at a stress point in the handle where
there was a botched laser cut as the picture shows. All blades were flexed to 25 deg and
retuned to true. These are stout little knives and literally "tough as nails"

View


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www.simonichknives.com
 
Wow, do you think the one point of RcH that the cryo-ed blade had made all the difference in edge holding and brittleness?

I am really looking forward to the Pikuni. In time for Christmas?
 
Could be many things I suppose, but that is the thing that certainly sticks out the most. I am curious as well and when I get some more blades I plan on trying the same tests with an un cryoed blade at 60 Rc and see what happens...... Also remember that the cryoed blade flexed the same amount as the un cryoed blade, but when it let loose it detonated! It more points to the cryo to me, not the hardness. The grain structure in the break looks the same to me with a strong magnifying glass. Wish I had a microscope!

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www.simonichknives.com
 
Have you performed similar tests with other steels such as ATS-34 or Talonite? How would they compare? Its interesting that the cryo treated blade broke in so many pieces. Is it because the cryo treat stressed the steel?

Its interesting info. Thanks for posting it.

Cheers,
Damon
 
Rob
Nice test. The D2 e look like its a winner.

Did you figure the percentage of gain from the cryo?

Also the cryo from my understanding did what it was suppose to do.



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Web Site At www.darrelralph.com
 
Damon, I did have a Talonite blade cryoed and seen no difference at all. I have done other tests with ATS-34, A-2, BG-42 etc. Results have sometimes been mixed. I dont have the time to type it all out, I still use 2 fingers!
biggrin.gif
I do know cryo can be bad or good, sometimes I think it causes thermal shock and can do no good. I try to take them down slow, first freezer, then dry ice, then slow dunk in LN. Never had a blade detonate like that one. By the way, to break the blades, all were clamped 1" from the tip.

Darrel, didnt figure the actual percentage of gain from the cryo, I want to replicate the test again with 2 blades of the same hardness. I will do that as soon as I get some more blades ready. The one that was interesting to me was the cross grain blade. It was just as tough or even tougher than the cryoed blade, and cutting with it I noticed it seemed a bit more toothy if you know what I mean, but could have just been me!

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www.simonichknives.com

[This message has been edited by Rob Simonich (edited 09-30-2000).]
 
Sounds like the cryo might be stressing the steel because it is three steps, freezer, dry ice, and liquid nitrogen. Maybe a controlled gradual drop in temperature would work better? I'm just guessing. I thought cryo was a way to temper metal using cold. I'm glad your testing the new D2 to see what its capable of. Can't wait to see the new REKAT model and hear the results of your further test.

Cheers,
Damon
 
Rob, a question: is it possible this stuff is *highly* sensitive to small variations in heat-treat, such as 1 Rockwell's worth or so?

That's sorta the impression I'm getting from the above. If so, maybe REKAT needs to be warned to be extra-careful about the production-grade heat-treat/temper/cryo(?) processes used?

Jim
 
I wonder if you will see any gain with a blade hardened to the same rc on the cutting. Sure will be interesting to find out how a blade will act at the same RC with and without the cryo. Damb the cross grain one results look interesting.
 
Damon, actually a three step cryo is much better than a straight room temp dunk in LN. The outfits that have the controllable cryo tanks are the best, they can control the speed of the quench and there is no thermal shock.

Jim and db, I heat treated all the blades the same, so I am guessing the cryo had a lot to do with the blade in question. I will take an uncryoed to 60 rc and repeat the tests, that should tell the tale. Not to worry about the production REKAT heat treat, I spent quite a bit of time on the phone with the heat treaters and they are up to date!



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www.simonichknives.com
 
Hey Rob
Call Doug at crusible for an ineresting story about cryo in a test performed on steel.

Your results look like they tell the tale .

What percentage of performance improvement do you feel should be reached to make it worth the extra treatment?

Jim is right when you get up higher in the rc scale one point makes a big difference because of the scale that the hardness goes up with each point of hardness.



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Web Site At www.darrelralph.com
 
A guess on why hard steel items would 'shatter', like the blade above. It's similar to breaking glass with the right frequency, such as a singer breaking a goblet with a sustained note of the right frequency. In this case the right frequency for shattering the steel is that produced by the blade itself breaking. The 'right' frequency should be the primary resonant frequency.
 
Hey Darrel can you give us a summary of the Crusible cryo story?
I do wonder if a cryo treated blade at 60 rc will act the same as a 60rc blade with no cryo.

[This message has been edited by db (edited 10-04-2000).]
 
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