aeb-l needing advice!

M

Max Albert

Joined
Mar 7, 2019
Messages
7
Hey everyone
first off thank you to all who may assist me on this.
Im having some issues with AEB-l warpage and i may have figured it out but wanted to get anyone chiming in
So here are my simple steps to cross cancel
i use .082 thickness profile the blad but i grind after its tempered so that cancels that out
(FULL DISCLOSURE i did not wrap in foil as i was trying to get a kuroichi finish on stainless... i feel like decarburization may be a factor to warpage)
heat up to what AKS suggests with my evenheat
clamp in aluminum plates(attached to vice) and wait to cool.
NOW HERE is where once i unwind the vice and pull out the blade..and i got weird warpage on all three blades.
I temper at 350 with c clamps to a file...the warpage is the same..
is it because i didnt wrap in foil?
Thanks to all who can help me!
 
I would profile a new blade and wrap it in foil this time. That blade is probably fried.
 
for sure! thats what i plan on doing but i feel like my question, besides it being decarburized, is that does the foil prevent warpage because it prevents decarb?
I just profiled 12 aebl and im just debating to send it off because im not sure how to handle aebl as i do high carbon
 
The foil will not prevent warpage.
Plate-quenching in vertical plates may help reduce warpage due to droop, but you will probably have to straighten anyway.
 
AEB-L is a little more prone to warping than other steels I've worked with. I find that if I make sure to plate quench with adequate time and pressure this helps to minimize warp. I made a tempering jig based on one by Matthew Gregory. It's a 2" X 2" X 18" steel tube with a slot cut in the top and the sides are drilled and tapped to fit screws along the sides. It allows the blade to be held by the screws and the warped part bent past straight. I have found that just clamping it straight during tempering doesn't always work.
 
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Aebl is a tricky steel. It is very sensitive to just about anything. We have solved the warping issue and our blades come out nice and straight. Every once in a while we get one that try’s to take off on us but that’s very rare. And yeah as you have learned clamping it straight during the temper does nothing to aebl. Thinner aebl is even more picky then the thicker stuff. Our process has been developed and refined over hundreds of aebl blades. So as much as I would love to lay it all out it’s our bread and butter so to speak. If your still having issues we would be happy to heat treat your blades for you. Also we do not use a torch to straighten blades.
 
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JTknives said:
Aebl is a tricky steel. It is very sensitive to just about anything. We have solved the warping issue and our blades come out nice and straight. Every once in a while we get one that try’s to take off on us but that’s very rare. And yeah as you have learned clamping it straight during the temper does nothing to aebl. Thinner aebl is even more picky then the thicker stuff. Our process has been developed and refined over hundreds of aebl blades. So as much as I would love to lay it all out it’s our bread and butter so to speak. If your still having issues we would be happy to heat treat your blades for you. Also we do not use a torch to straighten blades.
Click to expand...
I’ve seen you respond to a lot of people on Aebl and you’re very knowledgeable on it but would you care to explain your steps because you are mentioning that they are straight through your process but maybe letting me know step by step might help a friendly neighbor
 
Max Albert said:
I’ve seen you respond to a lot of people on Aebl and you’re very knowledgeable on it but would you care to explain your steps because you are mentioning that they are straight through your process but maybe letting me know step by step might help a friendly neighbor
Click to expand...
I would like to say this so JT does not need to. I feel JT has every right to protect the details he has invested a lot of energy, thought, time, equipment, and cost into. We should recognize and respect that investment on his part. Hopefully my comment is not considered out of line...
 
nope
Cushing H. said:
I would like to say this so JT does not need to. I feel JT has every right to protect the details he has invested a lot of energy, thought, time, equipment, and cost into. We should recognize and respect that investment on his part. Hopefully my comment is not considered out of line...
Click to expand...
nope not out of line! I totally get it!
admire what ya said and his craft :)
 
OK, I'll chime in on the warping AEB-L since I used to have the same problem. The thing that works so well for me is same as mentioned in the linked thread in post #6.

Clamp in quench plates until cool, remove from quench plates, remove SS foil, then clamp again (I use 1/2"X2" bar stock for this clamp) for cold treatment (either -5F or -95F), and LEAVE clamped until removing from cold treatment. Any concern, leave clamped for first temper at least. By following those steps I've not had any problem with warps in AEB-L, even fairly thin blades .040". Of course the ONLY grinding pre-HT is for profiling with all bevel grinding post HT.
 
I have found the foil bags besides providing a neutral atmosphere for the heat treat, it also provides assistance in establishing an even temperature, reducing hot spots and uneven heating. Anyone had any luck trying a normalizing cycle prior to heat treating?
 
Edit to add: The following is from a very good thread where Hoss comments on HT'ing AEB-L. I took several posts and put together the following - any errors are my own fault.

DevinT (Hoss) recommends a very good HT procedure that I follow. For the "normalizing" cycle you would Soak blade at 1725ºF for 10 minutes, plate quench – Hoss calls this the “Pre-Quench” which helps with smaller grain size and perhaps helps prevent warp.

(Hoss and Larrin say it’s ok to wait until next day for 2nd step)

When using only one oven, set oven set at 1950-2000⁰F (depending on results of test above). AFTER oven stabilizes at 1975F, then place blade in oven and soak (austenitze) for 15 minutes. It’s not good for blade to be in oven the long period of time required for ramping up.

Dry ice quench right after plate quench, continuous cool down. At this point expect 62 to 63 Rc. With an extended cryo (LN) there will be some nano sized carbides that precipitate to provide slightly better wear resistance with a slight decrease in toughness.

Temper twice, first temper for 1 hour at 350F, 2nd temper for 2 hours – choose temperature based on Rc test prior to temper. Tempering at 350F doesn’t change Rc much at all. Each 25F increase in temper temp seems to drop 1 Rc point. Tempering at 375F seems to drop from 62-63 Rc range to 61-62 Rc range, and moving to 400F would expect to drop another point.

Final Rc post temper should be 60 to 61 Rc for best kitchen use. (some folks are reporting a Rc of 62 works good for a kitchen slicer)

DevinT says: For HT'ing without dry ice (freezer only at -5F), Lower the quench temp to 1925⁰F, (per tests 1950⁰F in my oven) keep the soak time at temp to 15 minutes, 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.

Keep blade clamped in quench plates thru all the above steps, OR, remove from quench plates and clamp between bar to prevent warp during cold quench and tempering.

To anneal AEB-L wrap blades in foil, soak at 1350⁰F for 12 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. Once the sub-critical anneal is complete, ramp oven to 1725F, then place blade in oven for 20 minute soak. Remove blade, clamp in quench plates to cool, ramp oven to 1975F for final HT.
 
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I will point out that JT is now offering a service where he will cut your blanks out of AEB-L, heat treat them and send them to you for a VERY reasonable cost. He is currently doing 6 blanks for me, a couple of thin kitchen knives and 4 hunters that are a little thicker.
 
Ken H> said:
Edit to add: The following is from a very good thread where Hoss comments on HT'ing AEB-L. I took several posts and put together the following - any errors are my own fault.

DevinT (Hoss) recommends a very good HT procedure that I follow. For the "normalizing" cycle you would Soak blade at 1725ºF for 20 minutes, plate quench – Hoss calls this the “Pre-Quench” which helps with smaller grain size and perhaps helps prevent warp.

(Hoss and Larrin say it’s ok to wait until next day for 2nd step)

When using only one oven, set oven set at 1950-2000⁰F (depending on results of test above). AFTER oven stabilizes at 1975F, then place blade in oven and soak (austenitze) for 8 minutes. It’s not good for blade to be in oven the long period of time required for ramping up.

Dry ice quench right after plate quench, continuous cool down. At this point expect 62 to 63 Rc. With an extended cryo (LN) there will be some nano sized carbides that precipitate to provide slightly better wear resistance with a slight decrease in toughness.

Temper twice, first temper for 1 hour at 350F, 2nd temper for 2 hours – choose temperature based on Rc test prior to temper. Tempering at 350F doesn’t change Rc much at all. Each 25F increase in temper temp seems to drop 1 Rc point. Tempering at 375F seems to drop from 62-63 Rc range to 61-62 Rc range, and moving to 400F would expect to drop another point.

Final Rc post temper should be 60 to 61 Rc for best kitchen use. (some folks are reporting a Rc of 62 works good for a kitchen slicer)

DevinT says: For HT'ing without dry ice (freezer only at -5F), Lower the quench temp to 1925⁰F, (per tests 1950⁰F in my oven) keep the soak time at temp to 8 minutes, 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.

Keep blade clamped in quench plates thru all the above steps, OR, remove from quench plates and clamp between bar to prevent warp during cold quench and tempering.

To anneal AEB-L wrap blades in foil, soak at 1350⁰F for 12 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. Once the sub-critical anneal is complete, ramp oven to 1725F, then place blade in oven for 20 minute soak. Remove blade, clamp in quench plates to cool, ramp oven to 1975F for final HT.
Click to expand...

I would be very careful reheat treating. The manufacture specifically states this steel should not be re heat treated.
 
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@JT, I remember reading that Sandvick does not recommend re-HT'ing blades. BUT - when DevinT and Larrin suggest it's possible to re-HT by the quoted method I'll take their word. I wouldn't be surprised but what DevinT has done more specialized testing of AEB-L than the engineering folks.

I don't know, but I don't think they suggest that is preferred, but perhaps it's a way to reasonably salvage a blade by re-HT'ing. I would be interested in hearing one of them chime in on the discussion. As stated in original post, any mistakes made in the procedure are my mistakes. I collected the info from DevinT's thread on using two ovens for HT'ing AEB-L, with suggestions how to "get by" with only one oven.

Ken H>
 
The 1750 prequench gives an extra point of hardness after the full austenitize quench.

I do not recommend re-heat treating after full austenitize and quench to correct a warp, you’ll need to do a sub-critical anneal first.

AEB-L is a simple steel and requires a simple heat treat.

Do not over soak. Move from step to step reasonably quickly. Easy-peasy.

Hoss
 
Larrin wrote about aeb-l on knifesteelnerds.com. Look up “All about AEB-L” march 4th, 2019.

Maybe somebody could link to that article, I don’t know how, too old.

Hoss
 
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