new guy - A2 tool steel

blade_user

blade_user

Joined
Feb 26, 2008
Messages
65
Hello all,

I've been lurking here for the past few months and have learned an immense amount. So, I'd like to thank all who post here as it has helped my learning curve a lot.

I have been making small knives out of A2 for the last few months using a backyard forge (using the color-temp method) for reaching austenite and the home oven for tempering. I've been following the HT recipe on the Crucible website for A2: 1775F (bright orange) for 30 min, quench, 400F x 2 for 1 hour each. I've recently acquired an Evenheat kf kiln; so, the huge uncertainty in the temperatures had been squashed.

But, I have a couple of questions regarding the quench for A2. I've used oil, blown air, and compressed air - all with acceptable results.

I realize that it's an air quench steel and it's not an oil or water cooled steel (like O1, W1, or 10xx), but can A2 be cooled too quickly? (cracks, etc.)
Does anyone have a good quench method for A2?
..Or is just letting it cool in room temperature air sufficient?

Again, thanks to all who post here. I'll post pics of what I do from now on to mark progress.

-Mike
 
A lot of us use 1" or equivalent aluminum plates to quench air hardening steels. The plates act as heat sinks to draw the heat out more rapidly, and by sandwiching the blades between thick plates, you decrease the chance of a blade warping by uneven cooling.

And yes, you can quench any steel too quickly. By oil quenching air hardening steels, you can induce grand scale failure with obvious cracks or even snapped blades, and you can also induce micro failure with very small stress fractures that may not show up until a force or impact is imparted to the blade. Some traditionally air hardening steels can survive being quenched in a slower oil, but I couldn't tell you which ones.

--nathan
 
Thanks for the response. I have some 1" plate, and I'll start using it.

I'm using ss foil to maintain the finish during the heating. Do I need to strip it off before using the plates, clamp the plates with it on or does it matter? Does the fact that it is air hardening allow me the extra time required to strip the foil off of it?

Again, thanks for the response.
 
You can take the time to strip the foil off, but there really is no need. Myself and most makers just plate quench in the foil. I usually leave the bottom edge of the foil packet exposed from the plates so after the blade has cooled a bit with no color in it, I can snip it off with the blade still in the plates, quickly pull the blade out of the packet to check for warps, and then re-plate. If you are going to correct warps, you need to do this before the blade has cooled too much.

--nathan
 
No problem. A2 is a great steel from all I hear. I need to go ahead and make some blades using it.

--nathan
 
I have used quite a bit of A2, the most important part is the soak, it really does take 20 or minutes to get a good soak. I always do a plate quench, it really helps you see if your blade is bent and do some corrections.
 
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