1018/26c3 San-mai question

DevinT said:
What was the condition of the steel before hardening and tempering? Normalized, annealed, other? Are you using a forge or a furnace to heat treat?

Hoss
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Before hardening I had cycled it in my Evenheat. 1600F 10min cool to black, 1500F 10min cool to black, 1450F 10min cool to black.

Then I removed it from the stainless foil after it cooled down, gave it a thin wash of clay, dried out the wash in the oven at 170F for 1hr. Once the Evenheat was settled at 1475 I put the blade in, after the temp settled once again at 1475 I started timer for 10min. Quenched in room temp parks 50.


Stacy E. Apelt - Bladesmith said:
Too hot and too violent a quench.
Try quenching IN-1-2-3 ... OUT-1-2-3 ... back in the quench tank until cooled.

I have several of those split blades in the reject bin, so don't feel alone in the anguish. On ones that looked like yours, I have clamped the blade tight between metal plates in a vise and TIG welded the crack shut to salvage the bade for personal use or for friends. Sometimes it was unnoticeable.
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When I did quench the blade I didn’t hold in for 3 out for 3, then back in. The tang was out of the oil slightly and still glowing so I didn’t want to cause the parks 50 to flash. I held it in the parks 50 for about 6-7 sec.

On the next one should I make sure the whole blade is under the surface so that isn’t an issue and can do the 3in-3out-back in quench?

I use a tall mortar ammo can as a quench tank and I have about 5-6 gallons of parks 50 in it. Probably shouldn’t have worried about the oil flashing since I specifically use that ammo can for the air tight lid.
 
You did pretty much everything right that I can see.

Try 1445°F and use an interrupted quench and leave it in the quench until cooled (2-3 minutes) on the last IN. This may slow the conversion and allow a tad more auto-tempering.

Completely immersing the whole blade and tang in the initial quench should prevent any flashing.
 
Stacy E. Apelt - Bladesmith said:
You did pretty much everything right that I can see.

Try 1445°F and use an interrupted quench and leave it in the quench until cooled (2-3 minutes) on the last IN. This may slow the conversion and allow a tad more auto-tempering.

Completely immersing the whole blade and tang in the initial quench should prevent any flashing.
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Got it, thanks.

I have a list of a few things to do differently on the next one so it should definitely come out a lot better. Forging should go a lot smoother this time too, so it shouldn’t take me as many hours to get back to where this one failed.
 
Stacy E. Apelt - Bladesmith said:
I would still try and rescue this one for a shop knife. Run a TIG or even a MIG bead down the spine and finish it up.
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Worth a shot I guess. I’ll finish it up while I’m working on the second attempt.

Anything I should do when I weld it up to keep from overheating the tip? The crack ends a little under 1” from the tip
 
Clamp it in two metal plate and weld away. Some folks use pieces of wet cardboard between the clamp plates and the blade to assure minimum heat bleeding.
Start at the tip end of the crack and weld back down the spine.
 
I think copper may make it worse, as that layer is both soft and almost molten at the quench. I have had issues with Cu-mai blades. Mostly it was my fault for forging too hot and squirting out liquid copper.

I have seen no issue in blades with a nickel layer between the cladding and core.
 
reminds me of trying to make some mokume gane (well, i just wanted the layered step, before you do all the folding)
molten brass makes you glad you're wearing proper gear :P
 
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