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Flexible as in it is easier to bend? Or bends further before breaking?
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Myths About Damascus - Edge Retention, Sharpness, and History
- Thread starter Larrin
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That’s a good point, the problem is bringing up all the potential questions and answers myself would take several pages and so I gave up and kicked the can down the road.
The carbon content is so similar between 15N20 and 1084 I’m not sure if it matters if any carbon migration occurs. Carbon diffusion is relatively fast, but there isn’t much equalization to happen. The main difference remains the nickel which can reduce the required austenitizing temp, but since both are near-eutectoid steels the optimum hardening temp isn’t that different anyway. And all of this language might be too technical for the original person who asked, now I have to define austenitizing and eutectoid, and why those concepts matter, and now I remember why I gave up on a lengthy response to begin with. Thanks for helping though, kuraki.
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Bends further before breaking.
I remember seeing a tv show where they were trying to recreate a particular Viking sword that was originally made from Damascus steel. And they were talking about how much further damascus steel could bend without breaking compared to the much more brittle European swords of the time.
I was wondering if there was any truth to that as they were trying to imply it was as good as modern automotive steel.
I remember seeing a tv show where they were trying to recreate a particular Viking sword that was originally made from Damascus steel. And they were talking about how much further damascus steel could bend without breaking compared to the much more brittle European swords of the time.
I was wondering if there was any truth to that as they were trying to imply it was as good as modern automotive steel.
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But again, "compatible," and "the same" are two every different things. Compatible is like saying "good enough for government work." I get that the HT is similar and compatible between those two steels, but I am asking about ideal HT, not "meh, close enough that they're both pretty good."
This question is a great way to illustrate my particular issue here.
Let's assume a hypothetical in which you are making two blades.
Blade #1 is in 15n20. Blade #2 is in 1084. You are doing an optimal HT for edge retention/abrasion resistance (just picking one at random to eliminate the greatest # of variables). Would the HT on both Blade #1 and Blade #2 be identical when each of those steels exists independent of the other in a blade?
If yes, then it answers my question in that you CAN get optimal HT for both of of the steels making up the composite of the blade. If the answer is no, then it answers my question in that Damascus steel blades will always be a compromise and never the ideal of both steels.
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Perhaps an idea for another article then. Just a thought.
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Sure it’s a good idea.
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It’s hard to answer questions about “optimal.” If the heat treatment was 99% optimal for steel and 100% optimal for the other, then is that close enough? And it is not as if there is one optimal heat treatment, there are a range of heat treatments that may be optimal for any given application. The idea of an ultimate, perfect heat treatment which is so much better than anything else is a bit overblown. If one steel is best with an austenitizing temperature that is 10 degrees lower than the other steel, I have a hard time believing that the same level of performance can’t be achieved.
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@WValtakis I’m pretty sure damasteel iis just a brand name for damascus from a certain producer.
Larrin
is there any truth to true historical damascus having improved edge retention vs european steels of the same historical era. I always thought this was the only instance where any claim was made to damascus (wootz, not pattern welded) having some superior properties. I had heard there was vanadium in the wootz steel which may be the source of this legend.
Larrin
is there any truth to true historical damascus having improved edge retention vs european steels of the same historical era. I always thought this was the only instance where any claim was made to damascus (wootz, not pattern welded) having some superior properties. I had heard there was vanadium in the wootz steel which may be the source of this legend.
kuraki
Fimbulvetr Knifeworks
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That's why I picked the combination I did to ask the questions I asked. I can't personally tell the difference between a 15n20 blade, a 1084 blade, and a pattern welded blade of them both when heat treated to the typical 1500F aus and 400F temper, with regard to edge retention. (So yes, to your specific question above)
If you were to say toughness, the 15n20 should outperform the composite as well as the 1084, though I have a feeling that the composite may beat the 1084 as well. I'd like to send Larrin some coupons for charpy testing to see if that's the case.
The reason it's so hard to give you a definitive answer to your question is the number of variables involved. Even if you define the optimal trait, and ignore all other traits, that almost makes it even harder because often in heat treating you can, with certain parameters, attain a particular trait at the extreme sacrifice to others, even to the point of making them unsuitable to be a knife.
I don't personally believe, or have any data, or any experience telling me it's possible to make a pattern welded blade that exceeds the performance of it's individual parts (today, with modern steel, in antiquity it perhaps was possible, as the side effect of driving out impurity increased performance). I shoot for performing as well as. It's certainly possible to do that, with a number of mixtures. Whether pattern welding can improve toughness or not, I want to see testing on. Because as we move away from 15n20/1080, to something like Cru Forge V and A203E, I'm curious how much carbon diffuses from the CFV, as it has a lot to spare and A203E has very little (but would the nickel content of A203E inhibit some of that diffusion?) Can you end up with a blade that has the wear resistance of CFV and the toughness of A203E? How about something close to the wear resistance of CFV and close to the toughness of A203E?
Would something close meet your definition of optimal? Close to the toughness of an alloy that won't even harden enough to be a knife on it's own, close to the wear resistance of a CFV knife that isn't half as tough as A203E? Or would they mingle so much as to create something that is just middling and adequate?
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That's why I picked the combination I did to ask the questions I asked. I can't personally tell the difference between a 15n20 blade, a 1084 blade, and a pattern welded blade of them both when heat treated to the typical 1500F aus and 400F temper, with regard to edge retention. (So yes, to your specific question above)
If you were to say toughness, the 15n20 should outperform the composite as well as the 1084, though I have a feeling that the composite may beat the 1084 as well. I'd like to send Larrin some coupons for charpy testing to see if that's the case.
The reason it's so hard to give you a definitive answer to your question is the number of variables involved. Even if you define the optimal trait, and ignore all other traits, that almost makes it even harder because often in heat treating you can, with certain parameters, attain a particular trait at the extreme sacrifice to others, even to the point of making them unsuitable to be a knife.
I don't personally believe, or have any data, or any experience telling me it's possible to make a pattern welded blade that exceeds the performance of it's individual parts (today, with modern steel, in antiquity it perhaps was possible, as the side effect of driving out impurity increased performance). I shoot for performing as well as. It's certainly possible to do that, with a number of mixtures. Whether pattern welding can improve toughness or not, I want to see testing on. Because as we move away from 15n20/1080, to something like Cru Forge V and A203E, I'm curious how much carbon diffuses from the CFV, as it has a lot to spare and A203E has very little (but would the nickel content of A203E inhibit some of that diffusion?) Can you end up with a blade that has the wear resistance of CFV and the toughness of A203E? How about something close to the wear resistance of CFV and close to the toughness of A203E?
Would something close meet your definition of optimal? Close to the toughness of an alloy that won't even harden enough to be a knife on it's own, close to the wear resistance of a CFV knife that isn't half as tough as A203E? Or would they mingle so much as to create something that is just middling and adequate?
Excellent information. Thanks guys. Yes I do really that "optimal" is a moving target, but like in any field of work there are certain established "best practice" methods of doing things. I always was under the impression that each steel had its own HT protocols (within a fairly narrow range) to get the most of the steel. Different temps, cryo, etc etc... So my question and always been whether the Solomonic approach of picking steels that HT fairly similarly and just going with something that would "do the job" was really going to be good enough. Based on the info here, it sounds like the answer is yes, at least with the classic combo of 15n20 and 1084 because even its close enough that any difference is purely academic anyway.
Are there other examples of steels that have such close HT protocols that they'd work well as a Damascus?
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Lets forget the Europeans and speak about the Japanese who have been making some version of Damascus swords for centuries which I always thought were excellent, and better than one steel swords. Any Japanese knife makers or aficionados out there willing to make a comment?
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What do you think about damascus made from two different steel with a bit bigger difference in wear rate ? If one steel wear faster then other it should make edge "toothy" and probably will have better cutting performance ?
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We reported on our CATRA testing of AEB-L/154CM damascus where we didn't see that effect.
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The folding process was done to homogenize the steel, and historically was done to a much greater degree than it is on modern factory-produced swords that use modern steels. Like, to the point where seeing the layers is often difficult. And that was the point. The carbon content of the base billet was inconsistent and the folding was like mixing cookie batter to make sure all your chocolate chips didn't end up in one cookie. Then different grades of that steel that had been sorted based on their approximate carbon content would be used to put together a laminated blade. European pattern welding was done mostly when smiths were working with bits of bog iron, which were small, and had to be forge welded together to make large objects. Once methods or sourcing and processing the raw material improved the method was mostly abandoned simply because it was no longer a necessary step to make a good blade. If the Japanese had access to better quality iron deposits and smelting/refining tech they probably would have made the same switch.