Letters to the Editor
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It's already here !
The $2,500 Tata car ! But not much wootz in it I'll wager ...
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System of the world
Andrew,
If you have not yet read Neal Stephenson's three book series The Baroque Cycle (http://en.wikipedia.org/wiki/The_Baroque_Cycle), you should give it a try. I mention this here, because the second book, The Confusion, has along section dealing with one of the protagonists dealing with wootz production in India in . The series as a whole deals with beginning of our modern economic system, as well as a lot of the technological advances of the 1600 and 1700's. And of course the title of this blog evokes the title of the last book, The System of the World.
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cool, so how'd they do it?
If I'm not mistaken, at least some processes for producing sword steel are based on folding and hammering the metal (did I hear this about Samurai swords somewhere?). This suggests a mechanism for obtaining effects on a molecular scale because you double the number of layers every time you fold and hammer. Do it twenty times and each layer could be one millionth the total thickness. Do it thirty times and you are down to one billionth. At some point, the discrete layers cannot really exist because the projected thickness is less than intermolecular distances.
If you don't have a forge and an electron microscope handy, you can try this with two colors of silly putty: flatten them into equal strips and place one atop the other. Now fold, reflatten, repeat a few times (it doesn't take much). Observe all the layering. Don't do it too many times or you will merely mix the colors evenly.
I cannot begin to guess how such a process would give you carbon nanotubes (and it may have nothing to do with it--aren't Bucky balls at least formed spontaneously in soot?). But I imagine that many thin layers of iron could give a kind of substrate with very different chemical properties than a pure crystal.
Based on that, there is some plausibility to the idea the some kind of nanoscale engineering is possible with relatively simple technology. Please do get the word out before the vondanikenheads claim this as proof that Damascus steel was invented by space aliens (as if they haven't already).
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Yes Japanese steel is folded over
At least 10 times. This gives it 2^10 alternating layers of harder and softer steel bonded by a thin layer of carbon between each. What you get is a hard steel sheet like a tempered spring. Extremely hard on the surface but flexible with memory without any of the softness. Which means you can grind the edge to a razor's edge and, the sword being flexible won't crack. In addition the 1000+ layers with carbon physically placed interstitially means that the steel is somewhat less susceptible to corrosion. Which if you don't know, steel is a LOT more sensitive to rust than iron. Iron is soft and rusts but then the rust coats the outer layer and blocks further corrosion. Steel will rust straight through from one side of a sheet or plate to the other.
You would probably find as well that Damascus steel contains alloys of other materials commonly used today to harden steel like Chromium, Vanadium and Manganese. If they found any Tungsten or Nickel they probably discarded it since they couldn't forge it at high enough temperatures.
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Neal Stephenson
Embarassing.
Not only am I familiar with The Baroque cycle (I reviewed each of the three volumes for Salon)...
http://dir.salon.com/story/tech/books/2003/09/24/quicksilver/
http://dir.salon.com/story/books/review/2004/04/21/confusion/
http://dir.salon.com/story/tech/books/2004/09/22/system/
...but as I was researching this topic I kept thinking to myself, this seems like it could be a chapter right out of Stephenson's epic, and I _even_ recalled the section that takes place at an Indian mine but I didn't connect the dots and realize that the steel being smelted in Stephenson was wootz.
Ah well.
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Samurai Swords
I'm not an expert, but I watched a recent Nova special on just this topic with some fascination. They way they told it, the folding part was not so key -- it was merely a way to remove impurities. They did not describe any nanoscale features; simply a two-part construction: a core of low-carbon steel (softer but less brittle) wrapped by an outer layer of high-carbon steel (brittle, but very hard). In cross-section, the outer layer wraps in a sort of V shape around the core, with the cutting edge at the tip of the V. The core functions to keep the sword from shattering when striking an object, therefore allowing the cutting edge to be made extremely hard -- and therefore very sharp.
This construction also gives the Samurai sword gets its distinctive curve: the sword is perfectly straight when the swordsmith finishes pounding it out, but when he quenches it by dunking it in water, the low-carbon steel contracts quite a bit more than the high-carbon steel does. Therefore, the sword bends away from the high-carbon cutting edge.
Like the Indian steel, the steel made for the Samurai swords, called "Tamahagane," is smelted with carbon added directly -- here, in the form of charcoal that helps also to fuel the fire. The resulting product, when done right, has a range of different carbon levels; the swordsmith must carefuly choose the right nuggets to make each part of the sword out of.
By the way, given that carbon fullerenes and nanotubes form readily from e.g. a candle's flame, I would expect most any steel containing enough carbon to contain nanotubes.
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fullerenes and carbon
thanks for the info dcmserver -- in one of the articles I link to, a critic of the Paufler thesis, Verhoeven, makes the same case as you do about the likelihood that carbon nanotubes would be in most steel swords.
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That's not right
"Damascene" can refer to any of three different things:
1. Wootz, or true Damascene
2. Pattern-Welded Steel, or false Damascene
3. Certain styles of inlay
Late Roman swords were often pattern-welded but were not made of wootz. However, because early studies called both pattern-welded steel and wootz "Damascene," we get this kind of mix-up. Sorry.