How far should I take thin AEB-L before heat treatment?

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WillSwift

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Jul 1, 2012
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I am inexperienced with this steel and need a little advice.

I've been working on a set of steak knives recently, they are made of cold rolled AEB-L that is about .072in thick. They have a blade length of 5in and I am doing a right hand chisel grind on them. I have been noticing concerning warpage in the blade as I approach approximately .035in - .040in behind the edge, pressumably due to the stresses in the cold rolled metal.


I'm wondering If I would be better off defining my plunge and edge thickness at a 30-45 degree angle and sending them off to HT, to do the majority of the grinding after treatment. Or if I should stick with my typical method of grinding to about 75% and finishing after HT?

If anyone has experience with AEB-L please chime in, is it easy to work with post HT? Is it prone to warping when a Chisel grind is used?

Cheers,
-Will
 
AEB-L is basically 1070 with chrome. Because there is no excess carbon, the chrome stays free. It works easily post-HT. I would take the bevel to an .020" edge and have Peter's do the HT unless you have a good oven, quench plates, cryo, and experience.
 
Just profiling, then HT in plates, then cryo and temper, then do all the grinding is a good way. AEB-L grinds pretty easy at a high hardness, with sharp belts.
 
I've had zero problem grinding thin AEB-L/CPM-154/Elmax kitchen blades right down to final dimension before sending them to Peter's for HT. No warpage, no distortion. They come back ready to clean up and sharpen.

I have had a fair amount of problems with the same very thin, very acute designs made of simpler steels like O1 and 1095... they often waffle/wobble/wander along the edge a LOT, if ground that thin before HT. Sometimes that's barely noticeable; sometimes to the extent that I had to completely re-grind them anyway and ended up with a blade 1/4" less wide than I designed originally. :thumbdn:

I suspect that's because higher-alloy steels are simply more stable during the whole HT process, and don't require as severe a quench. The upshot is, I now grind stainless right down to almost nothing, and leave carbon a whole lot thicker before HT.

BUT... all those blades I've done thus far have been symmetrical grinds. It's possible that a chisel grind might present more problems. Ask your heat-treater.

When in doubt... profile, drill, HT and grind cool.
 
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Even though I have spent the money to be able to HT Stainless steel and enjoy it, I send my thin AEB-L to Peters because they do a better job keeping things straight. I grind the bevels post HT alternating sides and keeping things cool so the steel doesn't have a reason to develop any bends. This process may be overkill but I now get consistant results even with long fillet knives (something I used to dread). I have never tried a chisel grind on thin AEB-l.
 
Just a comments:

Why would you want a chisel grind on such thin stock...especially for a steak knife? A symmetrical grind would be a better choice.

Personally, I do all bevel grinding post HT on thin blades. With a symmetrical grind on .072 stock, that is just a pass or two per side. AEBL grinds easily post HT and polishes well.
 
Like James, I have sent AEB-L to Peters' with final dimensions. Edge thickness less than .010". I do NOT recommend you go that thin, and I bet Brad at Peter's hope you don't either! Peter's asks .015" minimum edge thickness for stainless steel. I've done a few AEB-L in .065". Never had a warping issue...all come back dead straight.
 
After heat treat your blade is straight and you can focus on final edge thickness/ plunge lines and distal taper. It is easier to make mistakes and screw all those things up if you do them before heat treat. Compared to other steels, AeB-L is easy enough to grind and sand once hardened.
 
If the blade height is tall give a little extra thickness at the edge before HT. IMO AEB-L wants to warp back to the roll it came from at the mill. plate quench. Also an even Sub zero quench tip down.
 
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