Heat Treating experiment for Hamon

theWeatherman

theWeatherman

Well-Known Member
Well I conducted my HT experiment trying to obtain an active hamon from a torch. What I did was use 1095 and placed clay on the blade and then did an interrupted water quench for 4 secs and then into vegetable oil. I then etched with Ferric Chloride.

I expected 1 of 2 things to happen. 1) To get the active hamon along the clay coating or 2) just get the strait line that I usually get when using a torch.

What really happened was I got both!!!! You can see the wave from the clay and then the strait line from the torch.

What I did find out though is that I did not use a thick enough clay coating I am thinking. I have done some research looking at the amount of clay and found that others are using way way thicker than what I used. I just used a small small (~1/64") of clay maybe less. I am guessing that a thicker amount of clay will hopefully not show the torch line.

What do you guys think?

IMG_0424.jpg
 
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I'm trying to understand what you did here. Did you heat the blade with a torch from the edge? Also where was the clay coating in relationship to the quench line? It seems totally weird that you would have what I would take as a line of martensetic steel through the pearletic steel. Even if the torch did not heat the area between the spine and the bright line on the blade enough to austinize it, I still can't think of anything that would cause that line other than forge gremlins. Maybe wiser heads will prevail.

Doug
 
Doug Lester said:
I'm trying to understand what you did here. Did you heat the blade with a torch from the edge? Also where was the clay coating in relationship to the quench line? It seems totally weird that you would have what I would take as a line of martensetic steel through the pearletic steel. Even if the torch did not heat the area between the spine and the bright line on the blade enough to austinize it, I still can't think of anything that would cause that line other than forge gremlins. Maybe wiser heads will prevail.

Doug
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Ah! I am glad you said something. This was all done stock removal no forging.

When I HT with a torch I try to keep the torch about 1/3 the way from the edge allowing for everything below it to get to temp. However when I was doing this the only different thing was that the blade had clay on it. The Clay ended where you see the waves closest to the edge. So the path of the torch flame was through the clay.

Now what I am guessing happened was that the clay didn't insulate the blade totally from the torch flame, which is why you see the line from the path of the torch flame on the blade. If you look closely at the ricasso area you don't really see the line from the flame but further away you do. Because of that I am also making the guess that I didn't have enough clay on the blade to "protect"/insulate the blade?
 
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I have never tried this type of HT at all so I am not sure I totally understand the process at all. However if I understand it the spine is kept cool by the clay, while the blade edge is heated to give the blade a differential tempering. It looks like to me the clay did do its job, however the torch heat was hot enough that it passed on through it and the second line is that point where the spine contacted the quench medium. So in essence you ended up with two quench lines/hamons.

In short the heat was a little too high and the clay did not totally stop the transfer to the spine, giving you two lines one at the top edge of the clay and the other at quench line. My understanding that if the clay is too little you don't get the line at the top of the clay. Which lends credence to the thought maybe the heat just overpowered it!

But then like I said this is kind of a guess on my part! I hope this makes sense, it did before I typed it and now that I read it back I am not so sure I am really getting my point across, or just sounding like I am rambling! :what!::biggrin:

Well I have reread my own post a couple of times and it is beginning to sound like rambling! If I can figure out how to better say what I am trying to say I will come back again and re-edit if not excuse my ramblings. I know what I am trying to say but when I look at in print it comes out all wrong!

Let me try to explain what I am saying like this. I think the heat was too high and that is why you got the two quench lines.

Quote:What I did was use 1095 and placed clay on the blade and then did an interrupted water quench for 4 secs and then into vegetable oil. I then etched with Ferric Chloride.

In other words the one quench line is the first quench in the water and the second is the interrupted quench in the veggie oil!

Dang I need another cup of Joe after that. I feel like I was just tripping all over my tongue!:biggrin:
 
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The problem that I see with that theory, though I have to admit that I can't think of anything better, is that after 4 seconds in water the 1095 will have converted to either pearlite or martensite and the quench in oil will do nothing more than cool the blade at a slower rate than water did, reducing temperature shock. I think that you're onto something when you said that you think that the steel was austinized under the clay coating and it may well have terminated at the point of the bright line on the blade. I just don't see what would cause the formation of martensite under the clay at that point when there is pearlite formation under the clay below it.

An idea just percolated up as I was typing; here's the hypothesis. The cooler steel under the spine that was not austinized acted as a heat sink and allowed the austinite at it's border to cool quickly enough, even though it was under the clay, to form a band of martensetic steel. The steel under the clay that was more distant from the boarder still could not cool quickly enough to avoid pearlite formation. When you go past the clay coating the heat was removed fast enough to form martensite again.

Doug
 
Believe it or not by my ramblings that is more or less what I was trying to say. I think it was sooooooooooooo hot that the piece was in essence quenched twice. If it was moved from one medium to the other quick enough that the first didn't have time too to fully cool the entire blade.



I know someone who is a moderator that has immensely more knowledge than myself on this subject of quenches and martensite. Perhaps Kevin will chime in too what we are seeing!


Like I said I am not familiar enough with this process to state that is what happened, I am not sure that it is even possible, to get two quench lines like that! I would think that if what I am assuming happened, really happened the excessive heat would not be good for the blade. However that is my theory and I sticking too it! :what!::biggrin:

I just went back and looked at the pic one more time and the two quench lines come close to intersecting at the riccaso!:les: I have to say this one has really got me baffled, cause too me my theory defies my logic!:31: but, I never said I was too smart!:3:
 
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I do appreciate you guys chiming in.

Doug - So are you saying that I didn't leave it in the water long enough? I didn't want the blade to crack so I didn't just use water, should I just use water or should I leave it in the water for longer than 4 secs?

After thinking about it, my theory is that the torch flame was to hot.

I am going to keep messing around with this idea and see what I can produce and come out with. I am going to reduce the flame and try a smaller blade so that I can heat the entire blade not just the edge and then let you guys know the results from that.
 
In my experience a water quench the tink usually happens upon entering the quench or nano seconds there after about the time you here the hiss, then you here the tink and that all she wrote.

It almost defies logic that is what caused the two lines but I have too say I don't know how else to explain it. All I can say is you were quick and the heat was extreme!:what!::31::biggrin:

EDIT:

Doug or some of the others can tell you more about whether oil or water is best for a torch/differential quench like that but, I gave up on the water after about the fifth blade I cracked!

I finally bit the big one and bought 5 gallons of Parks50. (Due to some circumstances beyond my control in my life at this point in time) I have only used once so far but, I am loving the results, of using it that one time!
 
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looks like you got lucky..

1095 and a torch is asking for problems, especialy in water. You'll get much better results with less chance of crack/warp with some type of forge where you can let the blade soak at heat for about 10-15min.
I've also noticed that when quenching, it's around the 3-5 second mark that you feel the "tink", if it happens sooner it's usually because I over heated it.
 
No, 4 seconds in water will produce whatever changes that are going to be made. It would take only slightly longer for complete conversion to pearlite to occur cooling 1095 in air. If you ever saw the video of a Japanese sword maker water quenching a blade in a large fish tank you would be surprised that any blade survives water quenching. The blade, which was clay coated was straight when it went into the tank. The blade immediately took a pronounced curve towards the edge then reversed to leave the concave curve in the spine. I would say that the process was maybe about 2 seconds. Blade preparation to reduce stress raisers is critical for water quenching. I wouldn't recommend it unless I tried oil and found that it wouldn't harden the steel enough. Warm oil is safer.

Doug
 
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