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Old 09-20-2018, 12:10 PM
Doug Lester Doug Lester is offline
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Location: Decatur, IL
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I think that what you are looking at was caused by using a shallow hardening steel, the 1095. There's a thing called film heat-transfer control (pg 88 Verhoeven, Steel Metallurgy for the Non-Metallurgist). What is boils down to is that steel under around 1/4"won't quench harden with a jacket of martensite around a pearlite core. It will only harden to a depth of about 1/16". So with the blade hardening from both sides it will harden to around 1/8" and thicker than that it will be pearlite. Now there is one other thing that will effect hardenability and that's grain size. The larger the grain size the more hardenable the steel will be but this will be at the expense of the strength of the blade. That may be why the auto-hamon didn't show up on the other blades or maybe those blades ended up a little thinner at the ricasso.

From the shape of the hamon I doubt that edge quenching was the culprit in this case. I think that if you follow the line of the hamon that it will follow the thickness of the grind.

Oh, by the way, those are real nice looking knives.

Doug


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Last edited by Doug Lester; 09-20-2018 at 12:13 PM.
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