Tempering temp questions AEBL

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Grayzer86

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Jan 15, 2012
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Hi guys I'm back with another AEB-L question. I heat treated 12 blades and need to temper them but find conflicting tempering temps. I have written down that 325 should hit 61 but that seems low to me. I also can't recall where I got that number from when I wrote it down. Here's my process so far.

-Preheat kiln to 1965
-Place foil wrapped blades in kiln, allow to come back to temp
-When kiln and blades are at 1965, start 15 minute soak
-Pull blades and quench between 1x4x18 aluminum plates.
-Once I can handle, fully cool in water, remove from foil and place in dry ice and alcohol for an hour.

I don't have a hardness tester yet but they are damn hard and a Nicholson file won't cut at all. I'm struggling to come up with a tempering temp for these so am currently running a 325 cycle for an hour just to try to stress relieve them. 6 blades are fillets in .070, and 6 are hunters in .130. What would you recommend for temps and hardnesses for these? This is my first real attempt at AEB-L and I managed to lose all my info I had compiled somehow. I really appreciate any help anyone can offer here.

Lastly, I have some warps I need to correct. They were pretty good off the plates but warped a bit again when they went into the subzero. I have a straightening jig I made from angle iron, but I'm wondering if I would be better to clamp flat and temper, or overbend for the temper cycle. I could go straight and then overbend if needed, I'm just trying to save some time doing it right the first time.
 
Last edited:
AVigil said:
Take a look at AKS site
https://www.alphaknifesupply.com/shop/aeb-l-stainless-steel
Click to expand...

I did end up finding that chart but wasn't quite sure what to make of it since I am somewhere in the middle. They show 1940 without subzero and 1990 with subzero. I was pretty much in the middle and did the subzero, so I'm thinking I should be closer to the tempering scale for the 1990 with cryo. If I split the difference it looks like 350 should give me around 61-62.

For those that have used this, would 61-62 be ok for a fillet? Seems a bit hard to me. I would think I should be more in the 60 area.
 
Here is the definitive thread on HT'ing AEB-L by DevinT (Hoss).
https://www.bladeforums.com/threads/how-to-heat-treat-aeb-l-in-the-home-shop.1353014/

Personally, I usually temper 2 times at 2 hrs each around 375⁰F and come out 60 to 61 Rc which I think is good. I agree with you, 62 Rc just seems a tad hard to me.

This my summary of DevinT's heat treat info for AEB-L: any mistakes are my mistakes, NOT DevinT's mistakes)

Make 5 test coupons, heat the first one to 1900⁰F and plate quench, second to 1925⁰F, third one to 1950⁰F, 1975⁰F, 2000⁰F. 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.

After determining correct temperature to use, then use below.

Soak blade at 1725ºF for 20 minutes, plate quench – this is called the “Pre-Quench”.

Second quench with only one oven set at 1950-1975⁰F. Place blade in oven and soak (austenitze) for 8 minutes then plate quench with aluminum plates. Cool enough to handle, remove from foil and straighten if needed.

Sub-zero (dry ice) quench right after plate quench, continuous cool down. With an extended cryo (LN) there will be some nano sized carbides that precipitate, slightly better wear resistance with a slight decrease in toughness.

DevinT says: For HT'ing without dry ice, Lower the quench temp to 1925⁰F, keep the soak time at temp to ten minutes, quench in oil or plate quench, faster is better, put it in your freezer (-5ºF) right after the quench, this will keep the RA down. Temper at 325-350ºF

To anneal AEB-L wrap blades in foil, soak at 1350⁰F for 4 hours – does not require slow cooling. This is a very good condition to re-harden from. This is a simple sub-critical anneal to allow straightening before re-heat treating in cases of warpage
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