Heat Treating and Metallurgy Discussion of heat treatment and metallurgy in knife making. |
12-25-2021, 01:43 PM
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Steel Addict
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Join Date: Dec 2012
Location: South Baldwin Co across the bay from Mobile, AL
Posts: 129
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@Kevin: Thank you for posting - Your knowledge is always greatly appreciated. Please review my Post #2 and call out anything that needs correcting. While I do like to have some idea of how the chemistry works in HT'ing, but important thing for me is a "cookbook recipe" to follow. Sometimes I tend to get confused with all the "big words"
I've been doing SS (AEB-L and 14C28N) mostly for the last few years and just last few months after getting a press I've started working with carbon steel, Damascus, San Mai, Go-Mai, etc using 1075 or 1085 with 15N20. After final forging of billet I'll hold forge around 1700°F or so and soak the billet and a big chunk of steel in forge for 10 to 15 minutes, then bury in vermiculite together overnight. This usually put the billet in a condition to saw, drill, etc.
The billet is then shaped into blade ready for HT. I'll then go thru 3 cycles of heat 'n air cook around 1500°F, and call it ready to HT.
Kevin, considering my procedures, could you comment on best steps and temperatures at each step? I know that's asking a lot, but it sure would help me, and I suspect many other folks also.
Ken H>
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12-26-2021, 11:50 AM
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Skilled
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Join Date: Feb 2003
Location: Hubbardston, MI
Posts: 324
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Quote:
Originally Posted by KenH
@Kevin: Thank you for posting - Your knowledge is always greatly appreciated. Please review my Post #2 and call out anything that needs correcting. While I do like to have some idea of how the chemistry works in HT'ing, but important thing for me is a "cookbook recipe" to follow. Sometimes I tend to get confused with all the "big words"
I've been doing SS (AEB-L and 14C28N) mostly for the last few years and just last few months after getting a press I've started working with carbon steel, Damascus, San Mai, Go-Mai, etc using 1075 or 1085 with 15N20. After final forging of billet I'll hold forge around 1700°F or so and soak the billet and a big chunk of steel in forge for 10 to 15 minutes, then bury in vermiculite together overnight. This usually put the billet in a condition to saw, drill, etc.
The billet is then shaped into blade ready for HT. I'll then go thru 3 cycles of heat 'n air cook around 1500°F, and call it ready to HT.
Kevin, considering my procedures, could you comment on best steps and temperatures at each step? I know that's asking a lot, but it sure would help me, and I suspect many other folks also.
Ken H>
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Hello Ken,
I personally would not go for the vermiculite from 1700°F, but if the billet cuts easily, it cuts easily. I would air cool from 1700°F and follow it up with a seperate annealing cycle at a lower temperature, if you wish to go lamellar (vermiculite cool from above non-magnetic). I would go more around 1400°F for your pre hardening refining heats.
On the topic of those who use descending heats- this probably was born from those who tried higher heats for grain refinement and found a point of diminishing returns sticking with the same heat but found further refinement by dropping subsequent temperatures. This would be due to the fact that with decreasing grain size you will also get lower grain coarsening temperatures in simple steels. The descending heats may very well have been keeping ahead the grain enlargement point as things got very fine. But going with lower temps to begin with will keep things ahead of the curve anyhow. Also rate of heating and rate of cooling will have very powerful effects on grain size as well, extended soaking is not a good idea for grain refining heats.
Last edited by Kevin R. Cashen; 12-26-2021 at 11:52 AM.
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12-26-2021, 03:39 PM
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Steel Addict
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Join Date: Dec 2012
Location: South Baldwin Co across the bay from Mobile, AL
Posts: 129
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@Kevin: Thank you for your comments. I will use your first paragraph steps for my process. As mentioned about the only thing I'm really looking for as the first step from forging the billet is to get it soft for ease of cutting, drilling, etc.
After the blade is profiled and perhaps some of the bevel ground in, then I wish to get the blade in good condition for HT'ing, grain all same size, SMALL grain. It sounds like I'm on track for that now with your guidance. THANK YOU!
Ken H>
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Tags
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1084, 15n20, advice, bee, black, blade, blades, bullet, ca, edge, forging, grinding, heat, heat treat, heat treatment, hot, knife, knifemaking, quenched, question, relief, simple, steel, stock removal, supply |
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