Another Newb question on AEB-L

Gliden07

Well-Known Member
If Im making a fillet knife do i need to Cryo the blank after heat treating. I ask because I've been reading that the fillet knives should be 57-59 HRC? If I Cryo the blade it will raise the hardness so I would have to temper it out more correct?? Asking for a friend!! LOL!!
 
I run my fillet blades just as hard as my hunting knives in AEB-L. I think there is confusion on fillet blades that they need to be softer to get the flex in them. This is not true. Almost all the flex comes from the geometry of the grind. With that being the case, why not have a harder blade?

Another thing with AEB-L, it is one of the toughest stainless steels. It is at it's toughest at 60 HRC. I could see running a blade softer if it is not a tough steel, say one known for being chippy, especially with a thin grind as that on a fillet knife. But I don't think you need to worry about that with AEB-L. I grind mine to a BTE of .005" and sharpen at about 12 degrees and have had no trouble with them.

Larrin Thomas on knifesteelnerds.com, has an article on AEB-L that is worth the read. His dad, Devin Thomas, from my understanding, is one of the most knowledgeable on using AEB-L.

I would definitely cryo. I use Devin's double quench method, cryo (liquid nitrogen but dry ice will do) and temper my fillet blades at 375 degrees.
 
Thank you Gentlemen! Thats why I asked! I eventually will do Nitrogen but spent all my money on Oven! LOL!!
 
Very little (if any) difference between cyro with LN and cold treatment with dry ice solution. All the RA conversion takes place above -95°F which dry ice solution does just fine. Even with a home freezer treatment of -5°F treatment will still get you 60 Rc hardness just fine.While LN treatment will improve the blade, you'll be surprised how good just the -5°F treatment blade will be.
 
I should have mentioned in my other post, you want to cryo as soon as possible after quenching. The longer you wait, the less retained austenite will be converted.

No worries I used a friends oven so I had to wait till the weekend. Now I have to wait till Monday to get the Dry Ice to do Cryo. Is it worth even doing after 48 hours?
 
According to this article from Larrin Thomas, I’m not sure if it would do much at this point.


I would be tempted to put them in the freezer as soon as you can, then do the dry ice treatment as soon as you get it.
The other option would be to requench, which would involve a lengthy time in the kiln to get the steel prepped for that. I think Devin Thomas recommends 12 hours at 1300 degrees. I’d have to double check that to make sure.
 
According to this article from Larrin Thomas, I’m not sure if it would do much at this point.


I would be tempted to put them in the freezer as soon as you can, then do the dry ice treatment as soon as you get it.
The other option would be to requench, which would involve a lengthy time in the kiln to get the steel prepped for that. I think Devin Thomas recommends 12 hours at 1300 degrees. I’d have to double check that to make sure.

I'll put them in freezer and do cryo tomorrow. This is my first attempt at SS other than some repurposed Kitchen knives. Needed to get process down for fillet knives I have sold. These 2 will be staying in my stable! Great article Gene thanks for the link!
 
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