Hey steel nerds... subcritical anneal vs. slow cool anneal?

DevinT said:
Grains of steel look like soap bubbles in a jar. During grain growth, grains eat each other becoming larger. Carbides occur within the grain and at the grain boundaries.

Within similar carbide volumes, the smaller the carbides, the more of them you have and the more evenly distributed they are. The more carbides you have, grains will have a hard time growing because they are bumping up against the carbides, or pinning the grain boundaries.

Pearlite occurs mostly in simple or low alloy steels. Under a microscope, pearlite looks like very fine lamellar carbides in between ferrite, they are much finer than normal carbides. The finer the pearlite, the finer the grain when heat treated.

The finer the spheroidite or the finer the pearlite, the finer the grain in the final heat treated piece.

Hoss
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Out of curiosity, would you recommend hardening from fine spheroidite or pearlite if going for controlled hamon formation with clay? I've had good experience with both methods on 1095 and have not yet tried spheroidite with my W2 (just forge, normalize and down cycle, grind/clay/quench).
Thanks for all your previous posts, informative as always.
Also aware of the insane amount of variables in hamon formation, just curious about your preferred state to harden from when shooting for one.
-Trey
 
comet_sharp said:
Out of curiosity, would you recommend hardening from fine spheroidite or pearlite if going for controlled hamon formation with clay? I've had good experience with both methods on 1095 and have not yet tried spheroidite with my W2 (just forge, normalize and down cycle, grind/clay/quench).
Thanks for all your previous posts, informative as always.
Also aware of the insane amount of variables in hamon formation, just curious about your preferred state to harden from when shooting for one.
-Trey
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Good question, which means I don’t know the answer. I’ve never made a knife with a hamon. I’ve tried doing a hamon a couple of times and never finished a single one.

I would guess that fine pearlite would be perfectly fine. Fine pearlite is a very good condition to austenitize and then quench from for simple and very low alloy steels.

I work with more high alloy steels in general.

Don Hanson III and others hopefully will chime in here.

Hoss
 
I'm more interested in Jamon than Hamon ! :rolleyes:
The most beautiful hamon structures are those made by traditional polished by hand types !

'Refining grain' - the only way you'll be refining grain size is to create new grains ! However heat and time can grow existing grains.
This is corrected after Samurai 's post
 
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Fine pearlite or fine spheroidized condition is what I use when going for a hamon. If doing a longer soak, martensite is fine too. You just want the get hot enough long enough that the martensite under the clay converts to austenite when heating.
 
Willie71 said:
Fine pearlite or fine spheroidized condition is what I use when going for a hamon. If doing a longer soak, martensite is fine too. You just want the get hot enough long enough that the martensite under the clay converts to austenite when heating.
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I was unable to do a hamon on W2 without it touching the edge until I switched to a drum forge from kiln.
I think you're right where soak time is a bigger factor than previous steel state as long as it is in a good hard enable state (fine pearlite/spheroidite)
Thanks for the insight everyone
-Trey
 
mete said:
I'm more interested in Jamon than Hamon ! :rolleyes:
The most beautiful hamon structures are those made by traditional polished by hand types !

'Refining grain' - the only way you'll be refining grain size is to create new grains ! However heat and time can grow existing grains. That's why I said work on grains first , carbides later,
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Just for clarification, I think Mete accidentally got it backwards on this post, but correct on his original post. Carbides, first. Aus grain second. (Normalize first, thermal cycle second)
 
Samurai - Sorry , you're right ,thanks for the correction.. The reason is that some of the carbide things happen at higher temperatures than what we can do with grains.
 
comet_sharp said:
I was unable to do a hamon on W2 without it touching the edge until I switched to a drum forge from kiln.
I think you're right where soak time is a bigger factor than previous steel state as long as it is in a good hard enable state (fine pearlite/spheroidite)
Thanks for the insight everyone
-Trey
Click to expand...

I have no trouble with the kiln. It took a lot of trial and error to get the clay thickness, steel geometry, soak times, and quenches “right”, as if there is a “right.” If I went to a forge, I’d have to figure out the process again. I do go for an optimum performing blade, rather than heat treating for the best hamon, which can be at odds each other.
 
Willie71 said:
I have no trouble with the kiln. It took a lot of trial and error to get the clay thickness, steel geometry, soak times, and quenches “right”, as if there is a “right.” If I went to a forge, I’d have to figure out the process again. I do go for an optimum performing blade, rather than heat treating for the best hamon, which can be at odds each other.
Click to expand...
I was unable to fully harden it in my kiln without going over because my kiln had an uneven heat spread. My drum holds a more consistent and even heat so all my heat treat in general is much better now. My kiln had a heat trap in the end that cause a large temperature gap between front and back of oven.
Aldos W2 responds best for me in the 1475 (+/- 10°F) range with a short soak.
-Trey
 
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