hamon from interrupted quench?

J

Jason Fry

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Jun 5, 2008
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I've messed around with forming a quench line from an edge quench. This last batch I watched the vapor jacket and pulled the blade from the oil as the edge cooled, kept it out for 15-20 seconds, then put it back in. The interrupted quench resulted in a pretty decent wavy hamon, at least compared to my previous straight quench lines. It seemed like the hamon was a bit below (toward the edge) of where the vapor jacket line was when I pulled the blade from the oil. The blade was a nicholson file, bare, no clay. Anyone with more experience on interrupted quench hamons care to comment?
 
Yeah, I've gotten pretty cool hamon from interrupted quench and no clay, but have only done it a couple times. I quench the full blade, not just the edge, in for 3 seconds, then out for 3 and back in. Sometimes I get two lines. Your line was low probably because of the 15-20 seconds out. Interesting stuff!
 
This experiment was the whole blade in, not just the edge. Two things to try on the next set. One, let the vapor jacket line get a little higher. Two, take the blade out for less time. IF (that's a big if) the files are 1095/w1, it shouldn't take more than 3 or 4 seconds of interruption to get pearlite. What if I'm using 1080, which I happen to have plenty of?
 
15 to 20 seconds is too long out of the oil for 1095 and similar steels and files. 1080 has the same cooling curve.
I go:
In 1-2-3...Out 1-2-3...Back in too cool ( slow count). With a clay coated blade The hamon should fall a little below the clay line this way. For heavier blades you may have to adjust the times by experimentation ( maybe a five count?).

Stacy
 
watch out when doing this i onces HTed 5 blades all edge quenced in oil and then out a bit and then i hot water

and yes i got a nice temper lines on the blades but soon found out that the back was harder then the edge..

BTW we need pics!!! :)

DC
 
If the blade is held out of the quench too long when doing an interrupted quench, the heat in the thicker part of the blade will soften (temper) or slow/stop the transformation of martensite at the edge. I have found an interrupted quench is not necessary with an oil quench, as it is with water but can produce interesting hamon.
 
Pics not coming. These knives are a matched set for a customer. I spoke with him last night about the hamons (which he didn't specify in his order) and he said he'd prefer the blades with a regular hand sanded matte finish, not etched to show the hamon, so that the two knives will be more identical.
 
Hamons are tons of fun to experment with!! :thumbup::thumbup:

EVERYTHING can be a factor............
 
That is cool stuff. Making me want to get into high carbon...
 
Different question, but same batch of blades. I did an interrupted quench on a trap spring and got a hamon. I've not had great luck getting these to harden well, I think because of low carbon content. They'll take a razor edge, but not hold it very well. They will skate a file. They work better tempered at 350, compared to the files etc. that chip below about 450. How low can the carbon content go and still get a hamon?
 
Many sword makers use 1050.
As long as there is enough carbon for some martensite to form on the edge ( harden), the clay covered area will become pearlite and ferrite.That will make the line of distinction show. I think 1050 is a practical lower limit for blades, but the hamon might show at a much lower carbon content.

The killer of getting a hamon is any alloy ingredients in the steel that deepen the hardening, and thus slow the hardening rate.

Stacy
 
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