Anyone ever heat treat AEB-L without cryo or sub zero?

I didn't see anything about a preheat in Verhoeven's procedure. I wouldn't want to hold it at high temperature any longer than necessary, so maybe you could preheat to say 1400 or so, then on to 1900. FWIW, preheat instructions from steel manufacturers usually assume you have a dedicated preheat oven and a different one for the final heat. I forgot about the home freezer stuff. You could do that. It wouldn't hurt I don't suppose, other than adding an extra step. If you do, go straight to the freezer from the plates for best chances of making any changes while in there. 250 F or 250 C? If it's F, that sounds low. I think the minimum recommended temp is 350 F.
 
I was going by the info in the link that mete posted in this thread from Alpha Knife Supply. In the graph it looks like 250F will give you about 61Rc with no sub zero quench.
Link to info
 
Reading a little more in Verhoeven's tests, the as quenched hardness was around 63 for a -140F cold treated blade, 62 for a room temperature quenched blade austenized at 1900F. Generally speaking, stainless steels are much more resistant to softening during tempering than plain carbon and low alloy steels. His experiment then also tempered the AEB-L at 380 F, with a hardness still above 60 HRc. All this is separated by just a couple of hardness points. If you can test hardness, try a piece after quenching, then after tempering at various temperatures. It only needs to be a small piece, maybe 1/2" square or so.

Edited to add: If you temper at 340-360, you can likely hit the 60 mark even without cryo, but the lower austenizing temperature of 1900 will be needed to control the retained austenite in the absence of dry ice or LN2.
 
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Thanks for the info. I will try the 1900F heat treat and 350F temper. Should I just put the knives in the oven at room temp and ramp it up to 1900F for 10 minutes (it will take an hour I'm guessing with my Evenheat 120V) or preheat it to 1400F and put the knives in then ramp it up to 1900F and leave them for 10 minutes? Or get the oven to 1900F and put them in for 10 minutes and quench?
 
That's tough for me to say. I don't know if going straight to 1900 then adding the blade would cause you any trouble. Many makers preheat then ramp. If it were me, I'd preheat the oven to 1900 and then add the blade, but my heat treating at home has been on much simpler steels with much lower temperatures, so take that for what it's worth.
 
Why spend lots to get the best , then not HT to get that best performance ??? Cryo not only reduces RA but permits the formation of fine eta carbides which also has cohesion with the matrix. That means it strains the matrix around the carbide increasing the strength ! I just posted in British Blades -I was happy to see there are makers there who appreciate cryo !
 
We use a dry ice/Acetone slurry for the sub zero quench on AEB-L. It works very well, in fact we use it on all stainless. I know it gets down to -106° at least because Ive checked it with a thermocouple before.
We preheat to about 1560° and hold for 5 minutes then ramp to 1975° and hold for about 10 minutes. Plate quench then straight into sub zero quench. A 375° temper and we get appx 62rc with this method.
 
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By preheating do you mean getting the oven up to 1560F and then putting the knife in it or putting the knife in the oven at room temp and heating it to 1560F and holding it there and then moving up to 1975F?
 
mete said:
Why spend lots to get the best , then not HT to get that best performance ??? Cryo not only reduces RA but permits the formation of fine eta carbides which also has cohesion with the matrix. That means it strains the matrix around the carbide increasing the strength ! I just posted in British Blades -I was happy to see there are makers there who appreciate cryo !
Click to expand...

I understand what you are saying and I do agree with it, but for a single small test blade it would cost me about $30.00 plus time (to drive back and forth) to sub zero quench it. Not worth it in my books. When I settle on a knife design I will use I will definitely go the sub zero route.
 
I made a small EDC type knife as a test and the heat treat seems to have turned out very well. I did a cutting test with 1/4" sisal rope (approx 224 cuts) and the edge was very easy to restore with a Spyderco Sharpmaker. I think this would be an excellent steel for the end user due to the ease of resharpening. At the end of the video I demonstrate how easy it is to bring the edge back. Truth be told, I was surprised.

[video=youtube;sdhOCjaLWlw]https://www.youtube.com/watch?v=sdhOCjaLWlw[/video]
 
Good test, and GREAT results. Did you use AEB-L for this blade? How did you heat treat? Cyro? OR non-Cyro?

I'm using AEB-L for the first time now and do plan to use dry ice for Heat treat. I've been using Sandvik's 14C28N as my steel of preference, but it's not available in the thin sizes I wanted for paring knives.

Thanks for posting your video - a very sharp blade that seems to be holding an edge very good, and just as important, easy to sharpen.

Ken H>
 
Thanks. I did use AEB-L for the test blade but I did not use the cryo or sub-zero treatment on it. Somewhere I had read that even -5 was beneficial, so I did throw it in the freezer after the plate quench. I was definitely impressed with the overall performance of this steel and especially the ease at which it resharpens.
 
It will be VERY interesting to see how much difference it makes between your -5F and a -105F freeze treatment. I've been using mostly 14C28N and did use 12C27 with a -5F freeze. The last blade I did was with dry ice on a 14C28N folder blade - I sure like it, but it's really hard for me to tell if there's any "big" difference between -5F and -105F treatment. I'm told there is, but my opinion (we all know about opinions), is a non-cryo'd blade can make a very good blade, better than the normal store bought blade for sure.

Please run the same test with the same type blade, using AEB-L with the only variable as the dry ice cyro and let us all see the results, and your comments on results.

Ken H>
 
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