How to Heat Treat AEB-L in the Home Shop

Thank you VERY much for the single oven information.

As far as grinding do you just profile the shape and not do any bevel development prior to heat treatment? What grit do you finish the blank at prior to heat treatment?

Thanks again for the information and help.
 
Dang! Now I have heard that AEB-L doesn't need to get quite as cold as some of the more complex steels, but that chart sure looks like a darn good argument in favor of scoring a dewar and some LN for pretty much ANY steel could benefit from cold treatment. :eek::thumbup:
DevinT said:
Read the paragraph at the bottom.

The chart shows that the longer you wait to sub zero quench the more RA you get. The colder you take it the less RA also. It does show that there is some benefit at a range of temps.

Stare some more and it should make sense.

Hoss
Click to expand...
 
jdm61 said:
Dang! Now I have heard that AEB-L doesn't need to get quite as cold as some of the more complex steels, but that chart sure looks like a darn good argument in favor of scoring a dewar and some LN for pretty much ANY steel could benefit from cold treatment. :eek::thumbup:
Click to expand...

Why? The chart shows that even on a steel that gets optimum RA transformation below -100. -100 is still going to get you almost all the benefit that a cryo would give. 8% RA is shown as best possible scenario. -100 still gets below 10% on the steel shown. AEB-L does not need cryo quench. Dry ice and your liquid medium of choice is plenty as I read it.
 
But the "magic" number on that chart seems to be -150F.
ricky_arthur said:
Why? The chart shows that even on a steel that gets optimum RA transformation below -100. -100 is still going to get you almost all the benefit that a cryo would give. 8% RA is shown as best possible scenario. -100 still gets below 10% on the steel shown. AEB-L does not need cryo quench. Dry ice and your liquid medium of choice is plenty as I read it.
Click to expand...
 
jdm61 said:
But the "magic" number on that chart seems to be -150F.
Click to expand...

True. But the chart is not for the steel we are discussing here, it was simply an example. Here is the data for 13c26/aeb-l.

sandvik_13c26_piece_hardening_70-95_zpstnjyffga.png



How the hardening parameters affect the product properties
Too high hardening temperature gives low hardness and bad wear resistance due to excessive content of retained austenite.
A low hardening temperature gives low hardness and reduced corrosion resistance.
Too long holding time at the optimal hardening temperature increases the amount of retained austenite and lowers the hardness.
Too short holding time at the optimal hardening temperature has the same effect as low austenitizing temperature.
The maximum hardness will be obtained at a retained austenite content of about 15%.
Deep freezing, i.e. cooling to below room temperature, increases the hardness by about 1–2 HRC.
With deep freezing, the highest possible hardness will be achieved by increasing the hardening temperature
 
But 15% RA is undesirable in knife blades, isn't it? My understanding is that the objective is to get to below 5%.
ricky_arthur said:
True. But the chart is not for the steel we are discussing here, it was simply an example. Here is the data for 13c26/aeb-l.

sandvik_13c26_piece_hardening_70-95_zpstnjyffga.png



How the hardening parameters affect the product properties
Too high hardening temperature gives low hardness and bad wear resistance due to excessive content of retained austenite.
A low hardening temperature gives low hardness and reduced corrosion resistance.
Too long holding time at the optimal hardening temperature increases the amount of retained austenite and lowers the hardness.
Too short holding time at the optimal hardening temperature has the same effect as low austenitizing temperature.
The maximum hardness will be obtained at a retained austenite content of about 15%.
Deep freezing, i.e. cooling to below room temperature, increases the hardness by about 1–2 HRC.
With deep freezing, the highest possible hardness will be achieved by increasing the hardening temperature
Click to expand...
 
Ricky, I am pretty sure that is a misprint. My son Larrin had dinner with the guys at Sandvik and they said RA levels were in the range of not being measurable or ~1.5 % when heat treated properly.

Hoss
 
Devin - I agree with you 15% is a misprint, looks like a decimal just got dropped. and again allow me to say THANK YOU for taking time to post info on HT'ing AEB-L steels. Since Sandvik seems to have lost interest in the custom knife market, AEB-L seems to be the steel of choice.

When you talked with Sandvik folk, how did they compare their 13C26 to AEB-L? I had a nice long phone chat (almost an hour) a yr or so ago about their steels. The applications engineer I talked with was pushing 14C28N over 13C26 for kitchen knives quite strongly..... Of course, it's hard to separate "marketing" vs "real world" sometimes when talking with company folk.

Ricky, the graph you posted above seems to have came from the Sandvik site for 13C26, NOT AEB-L.... or am I mistaken? The two steels do have very similar chemical composition, but not the same even though the razor blade market is the same for both steels. I just clicked on your link and boy has Sandvik changed their website.... and NOT for the better. Less info is given than before.... MUCH less. The detailed hardening guide that was available before showing more detailed info is now a broken link.

Ken H>

edit: I "finally" found a link that worked to get to the hardening guide: http://smt.sandvik.com/en/products/...ife-steel/hardening-guide/hardening-programs/

The above link will take you to this page which might be better: http://smt.sandvik.com/en/products/...-13c26-piece-hardening-deep-freezing-70c-95f/
 
Last edited:
You are missing the point. :( I'm not talking about the specific end RA levels. the data says that you are going to convert all the RA that is possible to convert by -95 with those 2 steels. Look I'm sure it doesn't hurt a thing by spending extra money to buy use and maintain a LN set up. All I'm saying is you are mistaken if you think there will be a measurable difference in the performance of a blade done at -95 vs -150 when we are specifically talking about 13c26/AEB-L. Yes. There will be a miniscule improvement if you are talking about say s35vn. But that isn't what this thread was talking about. Let me be clear. It doesn't bother me what someone else does, I want to make sure I'm not missing something. And I don't think I am.
 
Ricky, we were not saying YOU had the mis-print, but that Sandvik has the mis-print on their webpage. You took your info direct from Sandvik which says: "The maximum hardness will be obtained at a retained austenite content of about 15%".

My understanding is the max hardness you get from the steel is going to be after a -95ºF dry ice treatment. The Sandvik application engineer I talked with says their tests have shown there is NO advantage to using LN vs dry ice slurry for knife blades. He felt they had tested it sufficiently to determine if LN was advantageous. For AEB-L (which is a different steel, different manuf) LN might well have an advantage vs dry ice.

Allow me to add, my talk about AEB-L is from reading - I have NOT been very successful in getting an "as quenched" much over 62 Rc with dry ice, not the 64Rc other folks are getting. With Sandvik steels I could hit their Rc hardness with my HT'ing nicely.

Ken H>
 
Ken H> said:
My understanding is the max hardness you get from the steel is going to be after a -95ºF dry ice treatment. The Sandvik application engineer I talked with says their tests have shown there is NO advantage to using LN vs dry ice slurry for knife blades. He felt they had tested it sufficiently to determine if LN was advantageous. For AEB-L (which is a different steel, different manuf) LN might well have an advantage vs dry ice.

Ken H>
Click to expand...

Thank you Ken. ^^^. That what I was trying to verify. I wanted to make sure I was reading the data correctly that nothing magical was going to happen at -150 for aeb-l.
 
There is another facet in that data that is interesting. It says you need to get below 600 within 2 minutes. It also says in a couple places that an oil quench is ideal. There is a big difference in a 2 minute forced air cooling and an oil quench. I wonder if 63-64 would be attainable with an oil quench? My testing with 154cm showed I could get full hardness with plate quench and an oil quench wasn't necessary. But I haven't tried an oil quench with AEB-L. Have you?
 
Look at the 12C27 graphs below, what Sandvik stated "The maximum hardness will be obtained at a retained austenite content of about 15%" is probably for room temperature quench. Alloy elements fraction of aebl are at similar level of 12C27. So deal with your RA well or endure wimpy/low-toughness (and possibly weak too) :D

freezing-1.jpg

freezing-2.jpg
 
Well, from those graphs it does look like Sandvik is saying 15% and not a typo. Also, it looks like quenching from 2050ºF, then into dry ice slurry gives most hardness and less RA at 15%. I was thinking a lower number for RA was the norm for properly HT'd blades? I sure wish AEB-L gave as much HT'ing info as Sandvik does for their steels.

Bluntcut: are those "as quenched" Rc numbers in the top graph give about 61 Rc as max hardness (<2 000ºF) for 12C27 even with dry ice?

Ricky, your "600", isn't that 600ºC? Which is 1112ºF.

Remember folks - taking HT info from one manuf and using for a different manuf is not the same. While both AEB-L and Sandvik are both Swedish manuf - they are still not "necessarily" the same HT requirement. In the real world, they should be VERY close.

Ken H>
 
Thank you for the valuable informations!
The gold is:
1. The correct temperature is that the blade get in your oven....not necessarily the temp read by the tc, so testing the coupons is time very well spent.
2. The preheat, when you get your blade even up in temp without anything bad happening within the steel, then you quickly get to aust.temp in the shorter time possible without distortion or grain growt, nor carbides lumping together.
3. The prequench at lower temperature is a neat idea i'm going to test myself
 
You must log in or register to reply here.
Back
Top