Wonder what this could be?

[kbaknife]

Gonna be pretty click, don'tcha think?

[Lin Rhea]

Oh My Karl! Or should I say, San Mai?

416 over high carbon?

[kbaknife]

Not 416.
Or stainless for that matter.

[magnus]

I don't know what it is but I like it!  Can I see more please???

Keeping the Faith!
Magnus

[kbaknife]

[bendbig]

Wow!! Now thats a looker for sure.

[magnus]

Thanks! That is awesome! Love that style blade.
Keeping the Faith!
Magnus

[Lin Rhea]

What's the story Karl? It sure is pretty. Lin

[kbaknife]

Believe it or not, it's a failure.
I discovered this really tee-tiny itty bitty faint black line along the spine and down the clip after I etched it and looked closer.
I'll try to explain what happened:
Carbon migration happens with the right mixture of time and temperature.
The outer San Mai layer, which is a type of low nickel alloy, sucked the carbon out of the inner core of 1095.
That's all good.
That's what I wanted it to do to show those Damascus-y lines in the etch.
But what I didn't prepare for was up on the spine.
I did a full blade austenize and quench.
The 1095 is exposed at the top and hardened.
That was bad.
Because, the San Mai laminate sucked carbon out of the outer portion of the inner 1095 core, making it a little carbon deficient as compared to the inner portion of the 1095 core - right?
So, when it hardened, the inner and outer portions of the 1095 core hardened at different rates and literally ripped the core down the middle on the spine.
Can't do that anymore.
So, I need to either clay up the spine, or not quench it.
Back to the drawing board.
Next one is already forged for tomorrow.

[Scott Roush]

very, very, very, very, very interesting Karl. I love this stuff.  So I've seen Burt Foster's carbon migration causing interesting activity in stainless.. but never thought that you could see such amazing patterning in... what? You say low nickel alloy... is it high carbon? Or some kind of mild steel?   Do you mind sharing how thick the outer layer is? Does the thickness affect the carbon migration patterning?

[Steve Nuckels]

A failure, but very interesting looking! What will you do with that blade now?

Also Karl, why did you cut the indent at the beginning of the tang?

Steve
--------
Potomac Forge

[kbaknife]

Why am I not surprised you would come up with these questions?
Scott, I got this idea from a maker I sit next to at the Ohio Classic.
This San Mai is 1095 and 203E.
203E is pressure vessel steel.
Ever see a propane tank rust out?
Nope.
The 203E has enough nickel in it to make it corrosion resistant, but not so much as to stop carbon migration.
It has been used in Damascus welding for years!
After about, I forget, 240 layers of equal thickness components, a high carbon/203E Damascus billet is homogeneous.
I forge up a billet of .300" 1095 and 1/4" 203E on the sides.
There are a TON of variables in this. A TON.
I haven't even begun on the second one that I forged up this afternoon, but I already think I screwed it up.
Just like this one.
This will take a long time to figure out, but I'm gonna get it.

[kbaknife]

Originally posted by Steve Nuckels:
A failure, but very interesting looking! What will you do with that blade now?

Also Karl, why did you cut the indent at the beginning of the tang?

Steve
--------
Potomac Forge

I might finish that blade and take it to Texas on a hog hunt!

That only looks like an indent, as that area is completely finished before I harden the blade in case I get some hardening there and can't file it later.
The rest of the tang will be tapered to this. I want where the guard will be to be fully shaped before hardening, with the edges slightly rounded.

[Scott Roush]

Thanks a bunch Karl.. so I'm assuming you might not get enough carbon migration if you keep your spine below austenization?

so why wouldn't this happen with any low carbon mild steel?

very cool stuff. Thanks for sharing.  I'm putting a lot of effort into learning to make steel that looks like that...  and you go ahead and do it right in your forge just by borrowing carbon from your core. dang.

[kbaknife]

I WANT! the carbon migration all throughout the steel. What I DON'T want is martensite!
The carbon migration occurs during the welding and drawing out stages, which are all ABOVE austenizing temps.

I need to be more careful when I harden.

I would imagine that any low carbon steel will rob carbon from the higher core.
It's the other alloys that give the different effects like we see here and all the chromium in 416 San Mai.

[4est trekker]

Mistake or not, it sure is pretty to LOOK at.  Thanks for sharing the details.

[Lin Rhea]

Karl,
would your solution be to clay the areas where the side steels cover the core? That way the edge that is exposed will assume all of the stress. ????

[kbaknife]

That was my thought, Lin.
I'll do that on the next one.
Or maybe even just do a 1/2 blade quench for the first 10 seconds or so.