Strange patterns in AEB-L after etching

H

Honest Knife Co

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Jan 15, 2024
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Hello. Hoping someone can shed some light on this issue. I have some AEB-L knives that are showing a strange pattern after etching.

The blanks were cut on a waterjet. Preheat treat, I ground bevels into the knives and left about 45 to 50 thousand at the edge. The knives were heat treated professionally with cryo treatment and tempered to 61 HRC.

After heat treat, I ground in the final bevels. Then hand sanded to 600 grit followed by ferric acid quench three times at 8 minutes each.

When I saw the pattern, I assumed that my ferric was contaminated. I disposed of that batch and mixed up a new one with distilled water at a 3 to 1 ratio. I got the same pattern.

This has happened on three knives now out of the batch.

See pictures here:




Any insight would be great!
 
I'll let someone who works a lot of AEB-L answer better, but I don't think AEB-L is a good etch choice.

Additionally, long etches need to be removed, rinsed, and wiped down every few minutes or you get "trails". You also have to have the blade very clean before any etch. Best procedure is washing and drying followed by an alcohol wipe down.
 
That looks like carbide segregation/banding to me, especially since you said it's the same pattern after trying again. And BIG TIME banding. I have never etched AEBL, but would never guess that much banding be visible in a steel with such small carbides and low volume of them. I've seen banding in AEBL during grinding/polishing, but it is very small and almost not noticeable (just after polish.....I've never etched AEBL). Any lengthwise scratch pattern hides any small banding I've seen (again...no etch).

That reminds me more of the banding you would get with something like D2 or 440C, ingot steels that aren't very homogenous to begin with, and then questionable heats, etc.

If you repolish the blade with your 600 grit polish, and then re-etch, and the pattern is EXACTLY the same, then it's carbide segregation, and I would question if it's AEBL.

Like Stacy said, AEBL is a razor blade steel that takes a great polish, and no need to etch it. If those knives are really AEBL, I would be a bit surprised. But, hey, it's 25°F in San Antonio right now! Anything's possible.
 
Thanks for the feedback Stuart Davenport Knives Stuart Davenport Knives

I've reached out to the supplier and sent them pics. I'll hold off on saying who it is for now, there is no need to throw them under the bus as I'm unsure of the reason. I did reach out to them and they are looking into it.

I have repolished and got the same pattern, so it's in the steel. Maybe I got 440 or something else in error?
 
Any pictures of non weird etched knives you make? Interested to see the difference.
Looks good. If I were to make this on purpose I would try point heating with high current. Something like a spot welder. High current would austenitize a spot and the magnetic fields would cyclone around and move the carbides in circles. A theory. Well, I do have several microwave transformers laying around... :D
Ask your heat treater did he straighten the blade.
 
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JoeBusic said:
Any pictures of non weird etched knives you make? Interested to see the difference.
Looks good. If I were to make this on purpose I would try point heating with high current. Something like a spot welder. High current would austenitize a spot and the magnetic fields would cyclone around and move the carbides in circles. A theory. Well, I do have several microwave transformers laying around... :D
Ask your heat treater did he straighten the blade.
Click to expand...

Hi Joe,

More knives on my instagram account here: https://www.instagram.com/honestknifeco/

Yes, I'm sure straightening was required. The AEB-L (if that's what it was!) was really warped coming off the waterjet. I straightened by hand as much as I could before sending it off.
 
JoeBusic said:
Any pictures of non weird etched knives you make? Interested to see the difference.
Looks good. If I were to make this on purpose I would try point heating with high current. Something like a spot welder. High current would austenitize a spot and the magnetic fields would cyclone around and move the carbides in circles. A theory. Well, I do have several microwave transformers laying around... :D
Ask your heat treater did he straighten the blade.
Click to expand...
 
it looks like both some alloy banding and/or the manufacturer might have started with a vanadium rich ore maybe.
some of the pattern looks similar to some wootz not sure if that should be possible though

best guess would be alloy banding or mixup with steel ordered/sent?
 
Found this thread out of a curiosity search, not surprised to see this is super visible with an etch, I just finished hand sanding an AEBL kitchen knife to 1200 Grit and I can see the same visible banding in the steel with no etch at all, thought it was odd for a monosteel, this is my first time working with AEB-L. I will try to capture a picture or video. This particular AEB-L stock I'm using was sourced from NJ steel baron in June of 2024
 
Here's a short showing it (you may need to set to 1080p to see clearly)
 
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I’ve made bout as many knives as anyone from AEB-L (15 on the bench right now and another 150ish in a box under the bench). I’ve never seen anything like that. I’ve even etched a few (got them mixed up and was checking to see what steel was what), and still didn’t see anything like that. That being said I do them with a scothbrite belt finish, so I haven’t super polished them although I’ve mirror polished a couple too. Still, haven't seen anything like that. I’d problably fall into that ain’t AEB-L camp but don’t know for sure just my experience.
 
I haven't done nearly the number of knives as Dave has, but I've done quite a few. I take them to a hand rubbed 800 grit finish. Under certain light, I can just make out the carbide structure, blessed with very good eyesight. I think the vast majority of makers wouldn't even notice it. But I have never seen AEBL have carbide banding like what was posted in that video. Curious as to which supplier that came from.
 
My guess is that it's actually X65cr13 and not AEB-L. I do over 100 AEB-L blades a year and have never seen that.
 
I get those on 14C28N when sanded above 800 grit. It took me some time to figure out it's not me, it's the steel.
 
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