PDA

View Full Version : Aeb-L user experiences?



WillC
07-07-2012, 04:56 PM
Hello all. I'm doing some Ht testing with the batch of 14c28n I have. I'm trying to get an idea of what I can expect from the steel when everything is done right. It feels a little alien to me at the moment compared to the relative simplicity of a carbon steel.
So far on my test pieces I got maximum hardness possible from them, 62/63hrc with LN, and tempered back a touch to 61/62hrc. On a very thin egde pushed to destruction I am finding the edge distorts rather than chips, which I find odd. It makes me think stainless behaves in different way at a given hardness. I'm finding it a little sticky to grind too but i'm sure i'll get used to it:D
Apart from giving me the feeling its a touch soft even though its testing over 61hrc it takes a lovely fine edge and responds very well to the stones and strop, very much like a carbon steel, which is what I was after.
So what are your user experience with well heat treated Aeb-l, not exactly the same steel but very similar. Do you get edge folds or ripples hammering or slicing against cooked bone say, or would it chip out?
For those who may have experience in heat treating the steel following annealing i'm quenching at 1065 degrees c in oil then a dunk in LN and tempering at 175 dgerees c for an hour.
In the mean time I'll destroy some more samples and let you know what happens:D
Many thanks
Will

Larrin
07-07-2012, 05:34 PM
Rolling over is a product of either too thin an edge or just from superior toughness. Unless of course you have massive soft spots, but I'll assume you don't have those. The steel has to either chip or rollover, though it can roll over some and then chip. I wouldn't attribute it to "acting softer." Brittle materials break and ductile materials undergo deformation before breaking.

tk59
07-07-2012, 05:36 PM
I've experienced rolling over before cracking or chipping using ~20-25 deg included angle using AEB-L. I haven't used AEB-L for bone chopping though.

WillC
07-07-2012, 05:46 PM
Cheers Larrin. Yep fairly sure there are no soft spots it tested evenly down the edge before grinding. One thing which concerns me is the critical soak times on a tapered blade I will try some uniform width sample pieces see if there is any difference.
It does take a good amount of flex before deforming. I ground it very thin behind the edge towards tip, It folded at this point hacking into a knot of wood but that was asking allot from a very thin edge. Its much harder to deform nearer the heel where its a touch thicker behind the edge.
My first though on stropping and testing on some hair tops is I would like to make a razor from it.:D

WillC
07-07-2012, 06:07 PM
Thanks Tk, thats very helpful. Yep well first testing seems very positive. I ground the edge to 0.1mm behind the edge and about the same 10-12 degrees per side. I would say it behaves in a very similar way to 1080/15n20 @ 61ish hrc it will deform on a thin edge before chipping. With blue paper 2 on a similar edge, it is much harder to distort and eventually chips, showing a little distortion on the edge of the chip. The edge it takes is slicker than both those though.
I'll do a bit more testing to put my mind at ease. I don't suppose you did any edge flex tests on the Nilox?:D

TB_London
07-07-2012, 07:09 PM
I haven't noticed any edge deformation on my DT ITK, though haven't hacked it into bone or anything harder than a squash
Have you done a fracture test with it yet?

WillC
07-07-2012, 07:22 PM
No i was so keen to try it on food i made a couple of petty. I will break a piece on the next test batch.

ajhuff
07-07-2012, 08:22 PM
I KNOW it's not AEB-L but I dropped my Geshin Ginga on the floor at work. I thought my foot broke the fall but no, the edge has 3-4 dents in it instead of chips. My point is that hardness across a range of steels is not an indicator of brittleness. Yes absolutely two steels can have the exact same hardness and one be brittle and the other not. Likewise you can have two metals one brittle with low hardness and one ductile at high hardness.

-AJ

WillC
07-07-2012, 08:49 PM
Yep I got you AJ, This could well be an ideal Ht for this steel for kitchen duties ,hard but not chippy, but somehow i'm not going to be satisfied until I've tried some variations. I'll start again at full hardness and work back from there, let you know what happens.:biggrin:
looking at Sandvik's micrographs it seems over soaking or under soaking at temperature can cause brittleness. Due to the blades being tapered i'm estimating soak time from an average thickness. One thing I need to establish is that i'm not effectively over soaking the thinner tip and under soaking the thicker parts.

SpikeC
07-07-2012, 08:50 PM
Just don't over think it!

WillC
07-07-2012, 09:05 PM
Ha ha, probably no danger of that:laugh: But I wont be happy until i've worked out the parameters a bit more.
This is a datasheet with some micrographs under different HT conditions.
http://www.kmts.co.za/stores/afri-thipa/articleimages/14C28N%20Draft%20data%20sheet.pdf
Over soaking or under soaking at temperature would cause a loss of potential hardness, so I can test for that in more detail on a tapered piece.
I'm pretty sure these tested the same near the tip as to the heel.

tk59
07-08-2012, 06:49 PM
I KNOW it's not AEB-L but I dropped my Geshin Ginga...How do you know?

@Will: If you mean a brass rod test, no. However, Niolox at 62 hrc "seems" more brittle to me. It's been a while but I believe I've lost a tip or two on Niolox. The AEB-L blades I have tend to deform when they get tipped. I don't know if that is a characteristic of the steel or that particular HT.

ajhuff
07-08-2012, 09:16 PM
I don't know what it is made of. Moot point.

-AJ