Plate Quenching Air Hardening Steels

In my limited experience I have done all of my grinding after heat treatment, and gotten blades that were very straight, even with this pre-rolled AEB-L I use, which loves to warp back. Doing all grinding after heat treatment might not be such a good idea with S30V or other high wear resistance steels.
 
I ground some D2 over the week end and it was really hard compared to the CPM154 I usually use. I wouldn't want to grind it after it was hardened. I've ground a couple of daggers that were hardened first. I try to get my grinds as equal as possible before heat treating. If it is something that I think will warp I will heat treat first. Otherwise, with most simple grinds I have had good luck with no or minimal warpage. The way I check is to lay the blade down on a piece of granite and check both sides to see that I have the same clearance. If you can't get the warp out, heat it up again.
-John
 
What are you technically doing to a tool steel such as A2 if you harden it, wait till it cools to room temperature and then harden it again? Heck, lets even throw a temper in between hardenings. I've done this before and after the 2nd heat treat, it's still hard as a rock and the file will still not bite into it.
 
well just did my first plate quench with A2 with 1/2" plates I got from IMS Metals by where I live. I have to say it was awesome! I even re-heated a blade that was slightly warped on the first run and then re treated it, plate quenched it and it came out perfectly flat! Thanks guys!
 
bladsmth said:
Try 1" to 2" plates next time you make up a set.
Stacy
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Good lord! How much is that gonna cost me at um $3.29 a pound! I think the 8" x 12" plates at a 1/2" thick were already like $40 bucks!

Why so thick Stacy? Do I not need to stand on them when they are that thick because of all that excess weight?

Boy I must say those suckers quenched fast as I put the plates in the freezer for about 2 hours prior to quenching !
 
Pohan,
You would need 8" wide plates if you were quenching 5" wide knives.
Getting some that are 4X12 and 1" thick would be the same cost.
I just got a bar of 3X2X32 for $37.
Stacy
 
Stacy,

I was quenching 4 blades that were 3/4" wide + 1 that was 1" inch wide and all 1/8" thick! :D

Pohan

Does it really matter whether the plates are room temperature or if htey have been put in the freezer?
 
mete said:
C'mon RJ ,freezing the plates combines hardening and cryo !!
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lol mete :D


RJ: So you're saying that no matter the amount of force you use when grinding a blade with a 50 or 60 grit belt on a chisel grind, you get a warp?

I use 40 grit belts to grind blades and don't end up with warps. :D What is that people are doing to get the blade to warp? Grinding with an extremely fast belt speed and nearly smashing the blade with tremendous force when grinding? Good lord.
 
mete said:
C'mon RJ ,freezing the plates combines hardening and cryo !!
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I never said that but when you do 5-6 blades in a batch it does make a difference, and it keeps them out of my way:D. It still pretty warm here ( high 90 today ) so what ever it takes to get them below the curve.


Oh and here is what I said

"I also store my plates in the shop freezer....stuff quench'es fast"

Relax its just a thread:D Leu do whatever works for you

Spencer
 
I am relaxed :D Maybe it's the way I type that makes me appear like i've had too much espresso. :yawn: Which is probably the case tonight as there are Exams tomorrow and I need all the wakeup juice I can get!
 
My point is that, asymetric blades will generally come off the plates with about .005-.010" of warpage. The stresses set up in the steel during quench produce this warp, and you will see it when you flatten the unground side of the knife-Generally the center section of the knife is a little higher than the ends. Not much, but it's there.

I have frozen my plates, too. Doesn't seem to make a substantial difference in the final result, but, it is useful to cool warm plates down before re-use. Plus, your plates are on the thin side, so, what could it hurt?
Remember, the quench rate with plates is much faster than what is required, even when the plates are at RT.

I hope you aren't heat treating with a 40 grit finish. 220 grit is recommended to reduce the the effect of stress risers from coarse scratches.
 
On the 1/2 plates couldn't you just get some more 1/2 plates and drill and tap and bolt them together to get 1". I can get pieces of 1/2' aluminum plate from the drop at work on occasion and thats what I have done to get a set of 1" plates
 
Steel plates rather than aluminum?

As long as you are "over the nose" of the steel you're quenching, the rate of cooling has little effect. For an air quench steel, that rate of cooling is pretty darn slow.

Why does everybody use aluminum plates? It seems to me steel would work just as well and is quite a bit cheaper and more durable. Am I missing something?

I have read that stainless steels have slightly better corrosion resistance when oil quenched rather than air quenched due to more free chromium, but there are orders of magnitude difference between the heat transfer of oil and air. Steel and aluminum, not so much. Mete?
 
For thermal conductivity Ag is defined by 1, Cu .94, Al .53, Fe .18. For your question I think we spoke about this previously .Considering cost, availability ,conductivity seems to be the best choice .As far as 'will steel work' you'll have to do some experiments !!
 
I'd also like to say that if you used steel plates, there's a possibility of scorching the steel plates whereas aluminum will just get hot and the appearance will not change possibly like steel will. Maybe and maybe not! Guess you'll have to try it out!
 
rj martin said:
I hope you aren't heat treating with a 40 grit finish. 220 grit is recommended to reduce the the effect of stress risers from coarse scratches.
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I think I am! but then again by the time i've actually ground the entire blade out i think that 40 grit is no longer actually 40 grit? Maybe i'm wrong! (probably :D) To this date, I haven't seen any actual cracks visible to my eye...guess that doesn't mean they might not be there. Thanks for the advice on that RJ and thank you to the rest of you guys who chimed in!
 
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