post quench Rc for AEB-L??

K

Ken H>

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Dec 31, 2011
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Hello all, there's a nice thread going about HT'ing AEB-L and didn't wish to clutter up a good thread with my question. When using quench plates, what is considered a "decent" Rc reading direct from Quench plates? The chart on Alphaknife's website gives about 64 Rc as from quench, but not sure if that's quench plates, oil quench or what.

So, what do most folks here using quench plates get direct from quench plates for AEB-L? What is considered too low Rc from quench plates to be usable for a decent paring or steak knife?

Thanks to all for info,

Ken H>
 
I just went through this the other day, I preheated to 1550, then put the blades in, went to 1940 and plate quenched and used compressed air with the blade still in foil. It tested at 62.5. Then I did a sub zero with dry ice and denatured alcohol. It went up to 64 average. Then I tempered at 300 for 2 hours twice. It checked out at 62, 61.5, and 62.5 near the edge. This was all done on a flat blade with no grinds. Rockwell tested where the bevels are going to be. I checked it throughout the process as I'm new to stainless and was also doing a few 440c blades.
 
Hey Kevin, I pretty much do the same but add a sub-zero between tempers.How long do you soak at 1550 before ramping to 1940.Thanks,Lu
 
Thank you Kevin - That's exactly the type of info I was looking for. I was not aware that sub-zero soak would increase the Rc hardness (edit: YES!! I did know sub-zero soak would increase Rc - I've tested this myself and seen an increase in Rc results. Can't imagine why I wrote "didn't know"). I have seen fresh out of plate quench the Rc is less than after it sits a few hours. Yep, on my thin stuff I profile the blade, HT/temper before grinding bevel.

Your Rc is what I'm wishing for on my AEB-L steel. I did some test coupons yesterday and had a hard time getting over 60Rc(no dry ice for coupons). I tried temps up to 2,000ºF, plate quench (clamped with C-clamp), run water over plates for faster cooling. Realized these small coupons were cooled to touch before I could get water over plates.

Ken H>
 
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If your not going to use freeze/cold treatment, try lower austenizing temperatures to reduce retained austenite. Also consider that at th we temperatures, small changes can make a fair difference. If your temperature readout is off by even 2%, that means you're up to 2050 or down to 1950 with a 2000 target.
 
I was at 1550 for 10 minutes. And forgot to say soaked at 1940 for 30 minutes. I will say that it was my first time doing 440c and did the AEBL the exact same and got similar Rockwell numbers. (2 440c and 1 AEBL folder blades) I read here on the board that you can treat them the same. Could've been beginners luck. In the recent thread by Devin he explains to do test coupons and I plan to do this very thing.
I also quench with the blade still in the package, between 2 aluminum plates, just pressing down by hand, the other hand blowing compressed air between the plates. The sub-zero I checked with my thermocouple and it got down to -110
 
I know this seems silly to ask, but is there any chance you mixed up the 440C and AEB-L? Wouldn't be the first time it happened to someone.
 
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