Best Air Quenching Method for D2 Steel

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hppyevraftr

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I need some advice. I hope someone can please help me. I recently got some bars of D2 steel, and I've read pretty much everything I think I need to get started w/ a good heat treatment.

Now before everyone gives me advice on where I can mail it to, I'm doing this thing myself. My question is a simple one.

What is "Air Quenching"? Whenever I read it, it just says that. Do I simply take it out of the kiln @ 1800-1875 degrees and let it sit until it cools down (I know, temper before it cools down completely)....

Or do I use some kind of air compressor air hose, and blow the crap out of it to quench? I saw a guy on YouTube do differential quenching using this method. He pulled it out of his oven and blew on it with an air compressor hose until it was warm.

What is AIR QUENCHING for D2? PLEASE HELP ME with this one simple question, I am lost. Anything else is much appreciated also, but I really need help w/ Air quenching for D2.

Thanks in advance fellas!
 
First you need to let it soak at 1850 for 30 minutes. Don't know if you knew that part. You also need to have the blade wrapped and sealed in a stainless steel foil envelope to protect it while it is that hot that long. Many clamp it between a couple pieces of thick aluminum, steel or brass to quench it, but, blowing on it gently with cool air will work. I would keep it even on both sides to help keep it from warping. Even a fan should work. D2 will harden if you get it below 1300f in less than 4 1/2 minutes and keep cooling it to room temperature. Leave the foil on until cool enough to handle.
 
I think makers would rather use plate quench .Quench between two aluminum plates about 1" thick while still in the foil. this is a fast quench and normally prevents warping.
 
hppyevraftr said:
(I know, temper before it cools down completely)....
Click to expand...

Actually, this is not totally correct for D2 or most stainless. Really more for simple steels.

Get it as cold as you can before the first temper to minimize retained austenite. I take my D2 to -100F before temper, but even a trip to the freezer will be better than nothing. You certainly don't want to temper while it is still warm to the touch unless you're talking about a big complex thick stamping die or something. Otherwise, RA is where D2 develops its fine edge stability problems.

I have found 450 to a good tempering temp for D2 to get me in the low 60s.
 
I pretty much agree with everything said about D2 quench, and especially what Nathann said about freezing it. One of the steels that seems to perform better in blades with either dry ice and alcohol -110 F. or LN. This is after quenching between frozen plates of aluminum first.
Ken.
 
You guys absolutely rock. I couldn't really figure that part out, now it all totally clicks.
I can't thank you enough, seriously. For taking the time to help me, you're true gentlemen. Thanks :)
 
If air quenching I remove it from the foil hot. I'd much rather use a plate quench, however and then just leave it in the packet.
 
I also sub zero my D2 before tempering. Get a couple pounds of dry ice and a couple gallons of kerosene. Many grocery stores have dry ice. You can get kerosene at the hardware store that they stock for heaters. Put, the ice in a pan large enough to hold enough kerosene to cover the blade well, then add kerosene slowly as it will foam over if you are not careful. Stick in your blade and let it set a while then temper.
 
Do any of you folks use anti-scale compound on air-hardening steels, instead of SS foil? Will it hold up at those temps?
 
Never tried, can't see where it would be worth the hassle. Foil is very easy and will run you less than a dollar per blade.
 
james terrio said:
Do any of you folks use anti-scale compound on air-hardening steels, instead of SS foil? Will it hold up at those temps?
Click to expand...
If you plan to use anti-scale compound, make sure that you buy the high temp variety. The regular stuff is only good to about 1600. When anything goes wrong with it, particularly the dry anti-scale, you can end up with pits.
 
Yeah, that's part of why I asked, D2 and other high-alloy steels require up to/around 1950F... cost was the other reason.
 
Honestly, I think the only reason to use anti-scale is if you can't do it in foil,like with carbon steels that need a pretty fast quench. I think that with very shallow hardening steels like W2, even the thin coat of anti-scale may slow things down a bit.
 
So what's the deal with plates vs. air? The reason I ask is, as well as the blade being beveled, I grind a lot of tapered tangs. I hear people talking about getting warping with plates because there's poor/uneven contact. In that case wouldn't air-quenching reduce the likelihood of warpage? Is there a big difference in hardness attained using air vs. plates? (I'm thinking specifically about D2)
 
for taper tangs many taper after ht

foil costs me almost 10$ per blade, but I make big blades (15" by 3" average) or I am getting ripped off on foil!

if someone is getting good results with anti scale please post the brand!

thanks
 
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