Has anyone tried a diff. temper on d2?

L

llecardu

Joined
May 31, 2008
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The title says it. Can't find any info about differential temper on d2. My prediction is its not recommended. What do you think?
 
Tough to do an and air hardening steel. I tried it once with A2 on a wakasashi, turned it into a horse shoe. You would have to do a full hard then try to draw the spine with a torch, not very effective.
 
Drawing the spine with a torch will work, but only to about about 800f and it has a secondary temper too.
 
I can't recall who it was, but someone claimed to have accomplished true diff. tempering on an air-hardening steel... I think it was D2 but I'm not sure about that either. Anyway I do remember it being reported as expensive and time-consuming.

Look up "Friction Forged" D2 blades... that's a little different, but does result in a very hard edge and soft spine/body. Looks like a costly process.

I don't really see the point, frankly. If you want the edge-holding of D2 with higher toughness and equal or better corrosion resistance, just use 3V or Elmax and temper them normally.
 
james terrio said:
I can't recall who it was, but someone claimed to have accomplished true diff. tempering on an air-hardening steel... I think it was D2 but I'm not sure about that either.
Click to expand...
It was Phil Hartsfield and he used A-2. He made some of the best "usable" swords you could buy.Toshishiro Obata heavily endorsed his swords. His knife size blades were small tanks that would slice.
I don't know what his procedure was, but he did claim he wasn't using a torch.
Now I want to clay up a piece of A-2 and see what happens :D
 
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JBS TOOLMAKER said:
It was Phil Hartsfield and he used A-2. He made some of the best "usable" swords you could buy.Toshishiro Obata heavily endorsed his swords. His knife size blades were small tanks that would slice.
I don't know what his procedure was, but he did claim he wasn't using a torch.
Now I want to clay up a piece of A-2 and see what happens :D
Click to expand...

Phils blades were made to be used and they have been. He was tight lipped on his heat treatment but in a video on the samurai sword IIRC he mentions using heat sinks in his process, but it is not clear what he did.

Here is an A2 sword with a nice hamon from Phill

L1000371.jpg
 
Oh yeah, I've done it in D2 as an experiment. A low temperature austenitization (1700, to avoid grain growth in the 2nd) which got the carbon out of the spheroidized condition and into solution followed by a ~ 900 deg spring temper followed by plasma arc austenization (sounds trick huh? okay, I actually just "heated it with a torch" using a large diffuse arc from a high powered TIG). The end result was really genuinely and truly terrible. This is the first I've ever mentioned it here.

From a heat perspective, I'm pretty sure this is all the "friction forging" is doing, but time and temp control with a "torch" ain't all that great.

I was aiming for an HRC67 edge, not so much a particularly tough spine. I failed. We shall not speak of this again... :D
 
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Short rule of thumb on any differential quench - If it air hardens, no. If it oil hardens - maybe. If it water hardens - yes.
 
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