whoops

[gfish]

...I really need to stop talking to myself when other people are around.

Comments

[mdlbear]

Just wear a BT headset -- they'll think you're on the phone.

[gfish.livejournal.com]

That is an advantage to wearing my headset that hasn't gone unnoticed. :)

[catsittingstill.livejournal.com]

I have exactly the same problem. Maybe I should get a headset, as a disguise.

[jeffreycornish.livejournal.com]

I was telling that myself just the other day as folks were looking at me.

[sistawendy.livejournal.com]

So do I, o Finned One, so do I.

Damascus nanotubes

[memegarden.livejournal.com]

On a completely different topic, what do you think of this?

http://www.nature.com/news/2006/061113/full/061113-11.html

(and why do so many people think we don't know how to make Damascus steel, when I've met several people who do it?)

Re: Damascus nanotubes

[corivax.livejournal.com]

> and why do so many people think we don't know how to make Damascus steel, when I've met several people who do it?

Because "damascus steel" means two different things, one of which is a process lost a few centuries ago (wootz steel), and one of which was done much more extensively, and is still widely used today (pattern welding). For a very long time, we thought the 'damascus steel' was made by pattern welding (the process used to make katanas), and so the two words became synonymous, and still are, but metallurgical studies in the 90s established that the original "damascus swords" were probably not pattern-welded.

The original Damascus swords are currently believed to have been made from wootz steel, which stopped being produced in the 1700s, possibly because the mines containing exotic rare-earth impurities in the iron were exhausted. Experiments recreating wootz manufature and sword forging have been done, and plausible techniques have been discovered, but we don't know for sure how it was done.

(My favorite suggestion involves forges and crucibles built open to monsoon winds and only used during storms so that the wind turbulence stirs up the furnace and keeps it hot enough. I don't know if that's how it was done, but it's a cool idea. Storm-forged!)

Pattern welding and modern "damascene" are made by layering and pounding or folding steels of different compositions. If a metalsmith orders an ingot of damascene to make into a sword, it's pattern-welded.

It's easy to confuse them, as both techniques end up with very similar swirly patterns on the blade, but sophisticated metallurgical analysis has revealed very different interior microstructure.

Sorry to type your ear off - metallurgy is keen and I could go on all day. :)

Re: Damascus nanotubes

[gfish.livejournal.com]

To make it even more complicated there are several things called wootz steel. Most generally, wootz is a form of crucible steel. You put the iron, carbon, trace minerals and flux in a sealed crucible and heat it up. Getting it right is super-tricky, of course, particularly for getting output of a consistent carbon content. There are hundreds of different recipes, and it's possible that the traditional Indian wootz never got hot enough to be completely liquid. That would lead to a heterogenous steel, hence the pattern-welded looking steel. It's a pretty decent theory, but to the best of my knowledge has never been demonstrated.

In the end, I'm not nearly enough of a materials scientist to evaluate the nanotubes thing fairly. There are enough yahoos in the world who think they know more about metalurgy than they really do without me jumping on in.

Re: Damascus nanotubes

[memegarden.livejournal.com]

Thank you for the clarification--I appreciate it when someone can explain something that's bugging me.

Re: Damascus nanotubes

[vixyish.livejournal.com]

Hee. I first read the parenthetical as you just going "woot! steel!" but with a z to make it cuter, and was not until the second paragraph that I realized it was a real thing. :)

Wootz!

Re: Damascus nanotubes

[gfish.livejournal.com]

Oh, I've already planned that someday I am going to make some crucible steel, and that will be the subject line of the post.