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Cable Damascus HT problems


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IMG_0155.JPGI forged my first real cable damascus blade today, with mystery cable, most likely improved plow steel. It is a triple core blade, but I didn't get the defined herringbone pattern I wanted :unsure:

I normalized by bringing it to non-magnetic 3 times and air cooling to ambient temp, then brought to non-magnetic and did a full quench in preheated automatic transmission fluid. The problem is that the edge of the blade didn't harden to my liking. The spine and first .75 inches of the tip are hard, but the rest is fairly easy to cut with a file. Any ideas why this happened and/or how to fix it?

 

Dimensions:

7" OAL

Distal: .125 to .0625 over 3.25"

thickness of cutting edge: .046 (3/64")

 

Pictures: (not sure what the max is, so I'll go conservative)

IMG_0162.JPG

IMG_0163.JPG

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Is it possible that the edge might have cooled down just enough between the forge and the quench to prevent hardening? I can't think of any other reason why the spine would be hard but not the edge, although I have never made damascus so there might be something there that I don't know. I would try quenching again and see what happens. Nice looking blade, by the way. I want to try some cable damascus soon.

Edited by Dan Rice
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I had the same problem, only on reverse places, edge hardened nicely but for the tip :) I started to leave the edge and point a bit more thicker, and I go to a slightly higher temperature in the forge, so it cools to the quenching temperature as I move it from the forge to the oil tank.

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attachicon.gifIMG_0155.JPGI forged my first real cable damascus blade today, with mystery cable, most likely improved plow steel. It is a triple core blade, but I didn't get the defined herringbone pattern I wanted :unsure:

I normalized by bringing it to non-magnetic 3 times and air cooling to ambient temp, then brought to non-magnetic and did a full quench in preheated automatic transmission fluid. The problem is that the edge of the blade didn't harden to my liking. The spine and first .75 inches of the tip are hard, but the rest is fairly easy to cut with a file. Any ideas why this happened and/or how to fix it?

 

Dimensions:

7" OAL

Distal: .125 to .0625 over 3.25"

thickness of cutting edge: .046 (3/64")

 

Pictures: (not sure what the max is, so I'll go conservative)

Congrats on the forging. I don't want to rain on your parade but I always say the camera will catch any flaw you didn't see.

 

In the pic above, approx. 1`" from where the blades edge stops at back of the blades edge and the hidden tang begins there appears to be a line/flaw in the steel. In the picture there appears to be a slight indentation and line the runs upward towards the point of the knife.

 

If that is what I am seeing it will make for a weak at that line and possible future breakage! I hope it is something else because I had to give someone that kind of news!!

Edited by C Craft
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Why were you expecting a herringbone with cable? Just curious, the pattern you got is pretty much what cable does unless you add something else to it or make a many, many layered billet with it.

 

As for the hardening, since it's mystery cable you may need to go to a brine quench. If one part is hardening and another is not, you are missing the cooling curve for that steel. The two solutions are either more heat in the steel before quenching (a bad thing in simple steels like this due to grain growth) or a faster quenchant. Since the spine hardened we know you got enough heat, but like Ondrej said you lost just enough from the thinner edge to miss the curve. This can be a matter of a degree or two, so it may also be that you just need to get it from the forge into the quench tank faster. If it is XX improved cable, it is basically 1095, which means if you've normalized it enough to get really fine grain you have less than one second to drop the temperature from 1425 F to below 950 F or it will not harden. That is not less than one second to get from the forge to the quench, that's less than one second in the quench itself. If the oil is not cooling the steel fast enough it won't harden. Since the spine did harden, that means the edge cooled off just enough not to.

 

 

Yet another possibility is decarburization during the welding. If you lost too much carbon it won't harden as much, if at all.

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quench in brine or hot water, heat a tad more, and always make a couple of small test wedges to harden before working with mystery stuff (harden and temper, actually).

 

looks good. I hope the flaw mentioned above is not a big one (cable is so full of junk, it is hard to get everything out).

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Sorry it took me so long to get back to this, I currently only have internet access on the weekends. <_<

 

Dan; That was my initial speculation also, but I haven't had a chance to re-HT it.

 

C Craft; you are correct. After buffing the blade I noticed it. It appears to be a section where the strands didn't completely weld. I will try to sand it out (hopefully). Personally, I am amazed that it actually welded since it is a piece that I got out of the ground in Frankfort, MI, from mooring the old car ferry (I assume).

 

Alan; After welding the cable into a solid billet, I hot cut about 90% of the way through and folded the bar into an three layer accordion and re-welded. On paper I had a herringbone pattern, but it looks like the shop trolls had other plans.

 

It sounds like water is my best option for this; any advice on temperature and/or tempering? If the weather holds off, I plan to get out this weekend and play with the forge some more. Fingers crossed for good results. :D

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Success! I tried a brine, heated to about 120-150 degrees F, set on the edge of my forge pot (brake drum) to cut down time to the quench, and now the entire blade will skate a file. I did get some weird spatter patterns on the blade though. I had read on a different forum that these are a result of overheating the blade. Is this correct? If so, do I need to do anything such as re-normalize and HT?

That flaw mentioned above sanded out nicely btw :)

 

I also forged a small neck knife out of the end of an old Nicholson Magicut file while I had the forge hot. Any advice for the HT on this one?

Edited by Chase W
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If the "spatter" looks like little blister thingies it is indeed overheating. Your choice if you want to normalize, grind it out, and reharden. Some people like the look.

 

Nicholson uses (or did before they moved to Mexico and gave up on any quality whatsoever) a proprietary grade of 1095, so treat it accordingly.

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