Straightening AEBL, couple questions.

G

Grayzer86

Joined
Jan 15, 2012
Messages
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Hey guys, like many others, I am fighting warps with AEB-L. I don't mean heat treat issues, just the standard warps the bars have, plus bends occurring from profiling, drilling etc. No bevels are ground yet on any blades. What I am thinking of doing is straightening everything as good as I can, clamping between two steel plates, and doing a sub critical anneal I believe it's called. My reading says that a few hours at around 1350 should help de-stress the steel and remove some of the memory from when it was rolled. After that, I would partially grind my bevels on the .125 stock, and go straight to heat treat for the .093 and .070 stock, which would get bevels ground after heat treat.

Questions are:

Will this process help to correct any curvature I have right now, and help decrease warp during HT?

Do my temps and times for this stress relieve seem correct to you?

For a sub critical at 1300-1350, should I be foil wrapping? I have read it's low enough temp it won't hurt and I have heard that wrapping at that temp is still very important.

Lastly, if I do have to wrap, is the 1350 temp low enough that the foil packs would still be usable for the actual HT, or would I need to wrap them again. I never use packets twice at high temp, but am not sure if this would be ok or not.

Thanks in advance for anything you can assist with.
 
I am of no help but I wonder what the cause if these warps are. I was planning on ordering some AEBL for my first few knives but I might hold off on that now
 
I believe most of the curvature is a combination of stresses from rolling at the steel mill, and the fact that it is then coiled onto giant spools for storage or shipping. It seems like there is a lot of internal stress and any outside variables like grinding stress or uneven heat really has a negative effect. As a side note, in the annealed state as it arrives, the steel seems crazy soft and bendy to me. I don't know if it's the production method, the grain structure, or what, but to just grab a piece and bend it in your hands seems quite a bit easier than most other steels. The .070 stock I have seems to bend like aluminum, far easier than the 1095 and 15N20 I have in the same thickness.
 
Grayzer86 said:
I believe most of the curvature is a combination of stresses from rolling at the steel mill, and the fact that it is then coiled onto giant spools for storage or shipping. It seems like there is a lot of internal stress and any outside variables like grinding stress or uneven heat really has a negative effect. As a side note, in the annealed state as it arrives, the steel seems crazy soft and bendy to me. I don't know if it's the production method, the grain structure, or what, but to just grab a piece and bend it in your hands seems quite a bit easier than most other steels. The .070 stock I have seems to bend like aluminum, far easier than the 1095 and 15N20 I have in the same thickness.
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That's strange that it only seems to be a complaint of this particular steel. Maybe it is the grain structure. Jt was saying AEBL had some issues when he was trying to HT
 
Guess I will chime in. I personally think doing all that is a waste of time. I use to fight AEB-L like crazy to the point I was about to tell people not to send it to me. But through shear luck and proper time/temp and tools I came across a system that for me is perfect. The blades come out perfectly straight and even with a straight edge on them you can't see any gaps. But this joy was short lived once I went to sub zero treatment and thy came out warped. After some fiddling around with a few process I got that part solved. Then on the temper every once and a while a slight bow would pop up so I tryied a few things and solved that. I now am very happy with my process and actually look forward to heat treating this steel.

Every once and a while I get a rowdy blade that will not whip into shape. I do my best to counter bend during the temper and get it as close as I can. I find that if you don't correct the warp during the heat treat and it's really bad your left with few options for straightening. These include just trying to counter bend it in a vise or on a steel plate with rods. If it's so bad that your thinking about re heat treating I would recommend not doing it. I have tryied it and it will remove about half the warp and for some reasion you have about a 50% chance the blade will crack some time During the do over process.

I lost 2 blades out of 5 that I re heat treated and I'm almost positive thy cracked when thy went back in the oven to heat back up. So just a heads up, this steel does not like to be messed with after the fact so get it right the first time. Oh and don't grind your edge bevels befor heat treating you need all that surface area to keep them straight when you clamp them in the quench plates.
 
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JT, I can’t for the life of me figure out what the hell you're talking about in that last post. You’ve got a solution to the issue through temp control, etc, but then you speak of losing blades and also the need for straightening them after cryo...?

Huh?

;)

AEBL is the most consistently warping steel I work with. I’ve heard a variety of theories posited about why it does, but the bottom line is it does, and you need to deal with it. Rather than chase the reason, which I’m entirely certain I’m not qualified to do, I’ve made a tool to help me straighten them...

Behold The Weapon:


37922754816_c51183397a_c.jpg



24124945948_0d29db5fab_c.jpg



26200518799_278f15a66b_c.jpg
 
This arrangement absolutely does not require as many screws as I used. I elected to do this for other reasons. Clamp the blade between three of the screws, or more if you have to, overbend it just slightly, and chuck the entire assembly into the tempering oven.


The bottom line though, is that all you need is something solid with three points of contact. It could be as simple as this piece of square tubing and two screws on one side with a single screw on the other between the other two. Part of knife making is dealing with warp. AEBL moves on me 90% of the time - sometimes in quench, sometimes in temper, sometimes after cryo. The only thing we can do is find a means to deal with it.
 
I've found if aeb-L doesn't leave the plates from quenching to cryo to tempering, it will generally come out dead flat. I'd you do any step without plates it will warp every time.

I always struggled with it until this most recent batch of fillet knives when I finally found something that works for me.
Edit to clarify, the only time it leaves the plates is between quench and cryo, and just long enough to take the foil off.
 
JTknives said:
Guess I will chime in. I personally think doing all that is a waste of time. I use to fight AEB-L like crazy to the point I was about to tell people not to send it to me. But through shear luck and proper time/temp and tools I came across a system that for me is perfect. The blades come out perfectly straight and even with a straight edge on them you can't see any gaps. But this joy was short lived once I went to sub zero treatment and thy came out warped. After some fiddling around with a few process I got that part solved. Then on the temper every once and a while a slight bow would pop up so I tryied a few things and solved that. I now am very happy with my process and actually look forward to heat treating this steel.

Every once and a while I get a rowdy blade that will not whip into shape. I do my best to counter bend during the temper and get it as close as I can. I find that if you don't correct the warp during the heat treat and it's really bad your left with few options for straightening. These include just trying to counter bend it in a vise or on a steel plate with rods. If it's so bad that your thinking about re heat treating I would recommend not doing it. I have tryied it and it will remove about half the warp and for some reasion you have about a 50% chance the blade will crack some time During the do over process.

I lost 2 blades out of 5 that I re heat treated and I'm almost positive thy cracked when thy went back in the oven to heat back up. So just a heads up, this steel does not like to be messed with after the fact so get it right the first time. Oh and don't grind your edge bevels befor heat treating you need all that surface area to keep them straight when you clamp them in the quench plates.
Click to expand...
Soooo...what’s the process? I have a stack of aebl and am curious. Care to share?
 
Sorry if my last post was not making any sence. I had just got home from a long day at work and my brain was kinda out of it. All I was saying is AEB-L will take any chance it can to bow, even if its straight coming out of the quench plates. The cracking happened on blades that I had to re heat treat. Thy where fine going into the oven but when I pulled then from the quench plates there was a crack. Also if your blade warps so bad that your considering re heat treating to straighten it be forewarned that the steel seams to come out of the plates with about half the bow it started with. Geoff hit the nail on the head, same way I do things, I also had to discover this for my self.
 
I haven't any warping issues with AEB-L since I followed some advice (maybe from JT?) posted here:

Using a couple of inexpensive bar clamps, I clamp it between quenching plates as soon as it comes out of the oven, and leave it clamped for at least a few minutes; five minutes seems about right, although I often get impatient and unclamp it after a couple minutes. You want the steel to be cool-ish when it comes out of the plates.

I do the same clamping after normalizing and after each tempering cycle. The cryo treatment hasn't introduced problems. I mainly use .07 and .100-.110 thickness, doing all griding post-HT. Haven't had a warped blade since.

matthew
 
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