HEAT TREATED? WOOTZ BLADE

[ALEX]

Recently I came across this interesting shamshir. It was found in a dismembered condition, i.e. all parts were separated. The blade was heavily chromed over. Yet the chrome was bleeding enough to yield two stamps, which read:" Shah Abbas. Work of Assad Allah ISFAHANI". The stamps are genuine, and after chrome was carefully removed by electrolytic process, the portion of the blade was polished and etched. It revealed a wonderful wootz with clear ladder formations. But what surprised me is the temper/heat treated? line, or several lines, which run at the edge of the blade. They are of darker color, and the sword appears two-colored. First I thought of two types of metal (soft/hard) were used, BUT the wootz pattern runs via the whole surface of the blade. It appears equally developed on white body and dark edge portions. I know it is very difficult to control wootz when it comes to heat treating, and I wonder if someone knows or have seen anything similar????
I'll post more pictures after restoration.

[RSWORD]

Alex,

I have a number of examples in my collection where there is evidence of heat treating, most evidently in the differing coloration in these zones. I imagine if we had more blades in new polish you would find a larger number of wootz blades with this feature. They were intended, after all, for use and a heat treated edge provided a harder edge.

[ward]

Nice blade.
Seen this mostly on Turkish blades, Persian seem to be full quench but find the temperline on them too soemtimes

ward

[Gt Obach]

but weren't all wootz blades air quenched...?

actually you can differentially harden a blade when you quench it... if you have a shallow hardening steel ( like wootz ) .. it has to be cooled quickly enough to produce martensite... if not, then it only can go to other structures.....

so if you quench in oil.. the thin edge section will cool quick enough to harden but the spine will retain to much heat to harden... ( very similar to the japanese clay coat without clay )

with a hot,thinner ...quicker oil, you can fully harden the blade......

Greg

[Richard Furrer]

Hello All,
There have been no reports which I am aware of which state that any wootz blade was martensitic.
On a recent trip through north India I saw many blade which showed this darker edge, many were Persian, but a few Indian.....as I understand the differences.
This will be the subject of some study in the near future.

I have several samples to test, but should anyone have any blades which exhibit this and are of no use for anything else I would like to take a sample of the blade for testing...and yes, this is a destructive test and yes it will occur in a lab both in the UK and in the US.

My gut reaction was that they were heat treated in some fashion, but quenching to martensite is but one possibility.

Ric

[Gt Obach]

Hi

Journal of the history of Arabic science vol 1, 1978 pg 3-30
" Metallographic examination of Two Damascene steel blades
by Jerzy Piaskowski

two swords had strips of carbides in a sorbitic matrix ( sorbite being highly tempered martensite.. )

and theres two more

one study by H. Maryon on a dagger... and another by C. Panseri on 2 swords.
-- both conclude cementite strips in a sorbite matrix


just some reading
Greg

[ALEX]

Thanks to all!!!
I have not seen too many heat-treated/two-colored wootz blades yet. I am still a beginner:-) But this blade looks more like 3-dimensional now after polishing/etching. i.e. the pattern and color change depending on an angle you look at it, just like a fine Persian carpet:-) Here it is after restoration: