How to Heat Treat AEB-L in the Home Shop

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DevinT

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Jan 29, 2010
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Because AEB-L keeps popping up in several threads I'll post how I do my treatment of this steel.

I highly recommend that you make 5 test coupons, heat the first one to 1900'f and plate quench, second to 1925'f, third one to 1950'f, 1975'f, 2000'f. This will give you a starting place for what temperature to use.

Repeat this test with 5 new test coupons except do a sub-zero or cryo quench after the plate quench. With each set of test coupons measure the HRC and you should find a peak hardness at a specific temperature for your furnace. It is also good to break each of the test coupons and see grain size and toughness differences.

All furnaces are different, each will have a different soak time and or temperature required, even two ovens of the same make can be different.

I prequench at 1725'f after soaking for 20 minutes, plate quench. I also use 321 foil to wrap blades in.

Second quench I run two ovens one at 1550' and the other at 1950-1975'. Place blade in preheat oven and stablize temp, soak for 15 minutes move to austenitze temp oven and plate quench after 8 minutes in furnace.

Cryo quench right after plate quench, continuous cool down. With an extended cryo there will be some nano sized carbides that precipitate, slightly better wear resistance with a slight decrease in toughness.

This is a very simple steel, don't try and complicate the heat teatment. See attatchments from Uddeholm. The carbon content will vary some on this steel, I've seen 64.5 hrc on some batches but not all get this hard. Happy testing and heat treating.

Hoss
 

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So after the first quench at 1725 if you don't have 2 ovens is there anything wrong with letting the blade/s sit will the oven cools to 1550 then letting it soak at that temp then ramp to 1950-1975 for final quench?
 
It is better to go straight into the furnace at aus temp, ~1975, grain will grow if left in there that long.

Hoss
 
Yes thanks so much! I am going to be picking up a HT oven that was made for me over the holidays so this couldn't have come at a better time.

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Rehardening is different than prequenching. Prequenching at lower temps produces more carbides which pin the grain boundries refining the grain after the second quench.

Hoss
 
DevinT said:
Rehardening is different than prequenching. Prequenching at lower temps produces more carbides which pin the grain boundries refining the grain after the second quench.

Hoss
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Ok Thank you for the clarification. It was an honest question as I just had a shipment of Aeb-l arrive from aldo's, and have been scouring the net for heat treat info. Having read everything google could provide, I hadn't heard about a double quench, but you are the stainless expert so I appreciate the help.
 
I'd just like to add that I talked to Devin awhile back about heat treating 52100 and he told me to do the same test with the coupons (different temps than AEB-L of course). It only took a few hours and I learned more doing that than I have the past 4 years of knifemaking. You can see how higher temps break easier while middle of the road temps make the blade tougher while zeroing in on the exact temperature for your specific kiln/forge/whatever. Good stuff.
 
Hoss, do you think that prequench cycle also deals with any issues cause by the steel being spheroidized in that it gets the carbides/matrix into a more useful condition for hardening into a good hard, cutting edge as opposed to a chunk of steel that is easy to grind a machine?
 
Thank you Hoss, you get nothing from telling us this. It is much appreciated. I have done a couple of fillet knives out of the stuff, so I don't know a ton about it, but I have never heard of pre quenching. Thanks!
 
There are others doing a prequench. It does put the steel in a good condition to austenitize from.

Hoss
 
Thank you Hoss. So with a single oven doing the prequench at 1725 and then the 1950-1975 quench. Am I losing anything by skipping the 15 minute soak at 1550?
 
Not much, the purpose of the preheat is to spend less time getting to the full aus temperature reducing grain size.

Hoss
 
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