http://www.tms.org/pubs/journals/JOM/9809/Verhoeven-9809.html

I just found this article whilst I was browsing the internet, and thought that it might be of interest. One of the better articles on the subject that I've come across.

If you have not seen it already or anyone interested in the topic check out this site as well. Great info.

Craig

Molten Muse

Greetings,

This is an extremely interesting paper any way you look at it, however since reading it, one piece of data has been bumping around in my mind:

The paper cites the Rockwell C hardness along a transverse section of 3 historic, museum quality blades. The highest Rockwell hardness being 37.

In my mind, RC 37 is very very soft.

The blades that this data was taken from represent examples of blades made with a material that was, at the time, the pinacle of metallurgical technology. Supposedly, this material, known in the west as Wootz steel, was highly sought after and reknowned as a very tough steel.

This brings me to several questions:

1) Perhaps wootz blades weren't sought after so much for their practical qualities, but more for their aesthetic qualities. Is there any evidence for this in the literature?

Supporting evidence:

The paper states that these blades were all air-hardened, as that process best brings out the damascene pattern. As far as I know (and please ,please correct me if I'm wrong), air-hardening, by nature does not harden high-carbon steels to their full potential (oil or water quenching leads to much harder steel). I know there are caveats to this, such that harder = more built in stress, which must be released by proper tempering.

2) What is the measured Rockwell C hardness of other high quality swords at the same time period (16th - 17th century)?

Please cite references if you are able, I am very very interested in this question.

3) If the hardnesses of other blades contemporary to the blades in this paper are more or less equivalent (high 30's, low 40's), perhaps our modern day ideas of how tough (therefore how much damage a sword could sustain) swords were is flawed.

This question is conditional on the answer to the previous question, of course, but what do you think?

Very interesting stuff!

Dustin

The theory on these blades is that the cutting properties are due to the excess of fine cementite they have by virtue of their high carbon content, cementite is much harder than hardened steel, but would be too fine to show up on a rockwell tester. The unhardened matrix makes for a very tough support.
However, there are period descriptions of hardening sword blades, al-Kindi and al-Tarsusi are mentioned in "Persian Steel" by Allen & Gilmour, and there are others - so it's not like they were all soft metal.
We need more data!
:D

I am working on an article dealing with that stuff right now. I will try to finish it up soon and it will give you some info to explore.

Best
Craig