damascus hamon photos

J

jiminy

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160 layer twist pattern damascus billet of 1084 and 15n20.

This blade went thru the normal process i.e. heat treat the entire blade only portion of the knife, quench in oil, followed by double temper in the oven, (the knife exhibited the proper color on the blade upon removal from the first tempering cycle) ...nothing out of the ordinary.
The entire knife was immersed in the etchant (fc), and when it was removed and scrubbed clean, there was a visible hamon line on the blade. No matter how hard I scrubbed with a soapy cloth and steel wool, the hamon line stayed and the blade portion remained darker than the rest of the knife. There is no difference in the depth of the etch, so I'm at a loss to explain how the hamon manifested itself, and what caused it ...as I've never seen it before. What it looks like is if the blade were dipped and etched in two stages, but of course that didn't occur, and in any case the hamon line wanders somewhat and the etch is smooth.

Anyways, I'm at a loss to explain it ...anyone have the answer as to what exactly occurred?

Thanks

hamon1.jpg

hamon2.jpg

hamon3.jpg

hamon4.jpg
 
fairly simple really, almost any damascus will etch differently when it's heat treated, not just depth, but color as well can be effected by the HT. The harder part of the blade got darker, the un-hardened portion remained the same as it would have prior to HT.

Tony
 
I understand what apparently occurred, what I don't understand is why it doesn't occur all the time. This is the first time I've noticed it, and on my previous damascus blades I've done the same exact process with no noticeable hamon appearing. (There are always minor variances in the etch, but nothing like this ...being so distinct.)
 
I can only guess and say that you didn't get the whole blade to critical temp. The lighter portion near the tang didn't harden as much as the rest of it. Maybe you've just been lucky in the past and always gotten the whole thing up to critical temp before quenching, and this time you didn't for whatever reason?
 
I've had the same thing happen to me. A slight variance in temp will bring this effect out. I just learned that either I fully harden the blade to the tang or just edge quench the blade. we remove the blade every minute or so and scrub with 0000 steel wool. This seems to blend in the temper line. You can always remove hardness from tang area with a torch.
 
You got a thick chunk of steel behind that blade and Chiro was probably right about it not being up to full critical, at least not up past the ricasso. I'm not sure if you'e doing this or not, but it helps equalize the heat-treat. Make sure you put the blade in handle-first to heat that large area up, then switch it around and heat the blade up. The crappy part is that even if you do find a way to blend it in, you still have a part of your blade that isn't hardened. Back to the forge! :D
 
Thanks for the answers.

I don't see why it would have to be rehardened exactly, as more of the blade is 'hard' than in a knife that only has the edge hardened ..displaying a hamon line only along the 1/2" or so of the knife's edge. After all, who cuts anything that far back close to the handle :) The other 'good' thing about where the hardness now begins is that it moves the stress point forward from where the blade narrows to the tang ...theoretically making the blade/tang junction less likely of a failure point. Anyways, that's my story and I'm sticking to it :)
 
I don't have a clue as to what is going on there, other than the suggestion of not getting to critical makes sense to me. That aside, I think that's a beautiful pattern!
 
Doesn't look like a hamon line to me. Did you by chance not get the blade down in the fc deep enough on the first etch. I have done this by mistake just to check the pattern and this would happen, Sand the blade back down and clean it up. Then etch it again and see if it goes away.


Sorry, I should have read the complete post. Oh well!
 
Are you sure you got the whole blade in the oil and did not stop at that point? It is a pretty crisp/straight hamon and I would think it would not be straight if the problem was getting the blade up to critical. The hamon should not be straight because the edges should be at/above critical. It looks quench related to me.

Unfortunately the same thing you see there is what makes me heat treat the bolstes and back spacer on my folders. Just because I want even contrast between all the pieces, so everything gets HT'd. And it is a pain in the a$$ to HT those little parts. :rolleyes:

I would do the HT over again, but that is just me. People will ask what that line is and then you have to explain that you don't really know. If you re-do the HT and it comes out good, nobody is the wiser. :)
 
Just as stated above, I heat treated a damascus blade (Thunderforged) for a fellow and eventually the only way he could get the damascus bolsters to etch like the blade was have me heat treat the bolsters. All was well after that.

RL
 
Two things here...
If that's chefs knife that last inch gets used as much as the rest of the blade. If you're de-boning a chicken and use that section to crack a leg bone it will probable chip out big time.
#2 if that is a hamon from not getting the handle and the thick part of the blade why doses it go straight across...travelling from the thin edge to the thick spine. wouldn't it go more from the thick area under the handle to the spine...at an angle?
remember I'm a newbie, and I 'm probably wrong.

by the way that damascus looks really nice. I'd like to see a pic of the entire blade.
 
If it's not a hamon of some type, then I'm at a loss to explain it, as the blade was easily heated above critical the entire length of the blade, extending well into the tang (as evidenced by the pale straw color extending well down the tang after tempering). It's possible, I suppose, that it occurred during the quench, but I was positive that I sunk the entire blade well down into the oil ...but maybe I didn't. Maybe I didn't get it completely down into the oil fast enough ...shying away in anticipation of the flare up of burning oil ...I don't know. I'll have to pay closer attention next time to what exactly is occurring during the quench, I suppose.

(Oh, and it wasn't the etchant, as the knife was completely submerged in the fc.)

In any case, the hamon line stays. The knife is going to be a 'compact Persian', so I don't see a problem with the back edge of the blade being in the low 50's hardness-wise. (after all, good swords are around 52 or so :)) And with this design it's probably a blessing in disguise, as it moves the stress point away from the sharp angle at the blade/tang junction.
If it was a custom order, however (which it's not), that would be an entirely different matter.

Again, thanks for the comments, and I'll post a photo when it's done.
 
Personally I'd recommend you just send that poor blade to me for proper "disposal." ;) Or like Sean suggested, re HT. I'd put my money on the quench, not getting it wholly submerged.
 
For your perusal: Compact Damascus Persian

(160 layer 1084 & 15n20)
OAL = just shy of 9"
blade length = 4 5/8"
blade width = just shy of 1 1/4"
blade thickness = 1/4"
handle = bubinga w/ 3/16" brass pins

This thing ended up being razor sharp and pointy ...I've already stuck myself once while applying the finish to the handle. It balances right at the blade/handle junction, even with the very thick blade.

compact_persian1.jpg

compact_persian2.jpg

compact_persian3.jpg
 
I have had this happen from time to time.It seems to trace back to the quench.I usually can resand the blade by hand and blend the line in better.It often still shows,so I have generally requenched the blade.
BTW the "pale straw color" after the temper is not an indicator of whether the steel is properly hardened or not.It indicates the temperature the steel reached during temper.
 
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