|Overview Luristan Project||Part 2||Pommel and hilt|
|Part 3||Animals and blade|
|Part 4||Discussion of the results|
The Luristan Project - Results from Cut Sword; Part 1
|Sword No. 5 (2744) had been
cut in two parts and will be
referred to in what follows as "cut sword".
It could easily provide enough material for a complete Ph.D. thesis. Unfortunately, not only were our project finances
and time budgets limited, we also did not have the proper analytical tools (or sufficient experience) at our disposal to
do an in-depth investigation. Nevertheless, in what follows you will find a lot of pictures and some comments.
|The huge size of the "specimen" does
not allow to use standard equipment like most microscopes, electron
microscopes or various spectrometers. One either has to go for specialized equipment (that does exist but is
not easily accessible without sufficient funds) or needs to cut the sample to size.
We did what we could and then donated the cut sword (like the others) to the Royal Museum of History and Art in
Brussels, Belgium, where Prof. Bruno Overlaet eventually can instigate a thorough investigation.
|This module (and its successors) uses more and
larger pictures than usual, so you might want to enlarge the
browser window. An extra module linked to this one shows humongous-size pictures. Why is that-? Simple::
|The normal way to
publish project results is to send a paper to a suitable scientific journal. I
have done that a
few hundred times so I know how it works. Why not here? Simple once more:
|What we 1) did was:|
|Taking some pictures of the "as
cut" and "as etched in Bochum" halves. Some examples of that are
already shown in the results overview.
|While the "Bochum" half
was left untouched, the other ("Kiel half") was polished to a mirror
finish. This needed to
be done by hand and took a lot of time and effort. Of course that wasn't done by me but by
Ingo Petri, an archaeologist with an extensive training in metallurgy.
|The polished Kiel half-sword was
then etched with
Nital. Microscope pictures were taking along defined
lines in several areas (see below). Nital etch delineates the basic structure showing grains and in
particular cementite inclusions.
|Subsequently the sword was
repolished and etched with
Pictures then were
taken along the same lines as before.
|This was a lot of work. The results
(see below) are remarkable but typically raise questions that can only be
answered by an in-depth analysis employing more advanced methods.
At this point it is necessary to recall that chemical etching, while a powerful and simple tool, always needs
interpretation by an "expert". But even experts do not always know what they see. An expert does know what
a Nital etch reveals in an iron-carbon steel as long as not much else is contained in the iron. With experience,
one might be able to interpret what a Nital etch shows in common steels, containing some Mn, Si, etc. besides
carbon. What you get if sizeable quantities of the rest of the periodic table are contained in the sample, is
not always clear, however. For the Oberhoffer etch these uncertainties are even worse.
|While we do have some experience
with etching Fe / steel and interpreting the results, we cannot claim
expert status. The interpretations given below thus must be taken with a grain of salt. To make it plain:
The "Bochum Striations" and First Conclusions
|As pointed out in the
results overview, the half-sword
etched by the team of
in Bochum, Germany, showed well-developed striations on a macroscopic (0.1 mm - 1 mm) scale. Looking at this
surface with a microscope does not produce additional information since the roughness of the as-cut surface
overwhelms all finer features. It is thus of interest to see if this structure could also be found in the polished
and etched half of the sword.
|The answer is: yes - but! While the Oberhoffer
etch essentially produced a rather similar
striation pattern (see below), the Nital etch only showed it faint striations in particular in
the two heads as demonstrated by the pictures below.
|In producing these pictures a problem is
encountered that needs to be mentioned here. Before etching the surface has
been polished to a mirror-like appearance. After the etching we still have a mirror-like surface. Now imagine you want to
take a picture of the surface of your bathroom mirror. Just pointing a camera and shooting will produce a (mirror-image)
picture of you and your camera. Same thing here. Some features in the images are due to reflections and that obscures
to some extent the structures we want to see.
|Anyway, we may draw
some first (tentative) conclusions:
|It remains to be seen if the detailed analysis of the etched areas support the above conclusions|
Definition of Investigated Areas
|The following picture defines the
areas investigated in some detail by optical microscopy. Along the red lines a
of pictures were taken and then (electronically) glued together, producing a kind of scan. The numbers denote
the first and the last picture ID number for the Nital and the Oberhoffer etch.
|Let's start with the Nital scan
through the left head; number 1 - 14 for
the Nital etch; No. 210 - 233
for the Oberhoffer etch.. Below are small (!) scale pictures of the total scans after Nital and Oberhoffer etching.
Some full scale pictures of scans can be accessed via links to the large picture files given in the margins.
|A first few obvious observations are:
|A first conclusion is possible:|
|In other words: The
first tentative conclusions based on the
macroscopic appearance of the cut,
are fully supported by the microscopic study of one of the "heads". It remains to be seen if the other
scans bear out this finding.
|Here are the two
"Nital" scans from the second head (right-hand side). I omit the
Oberhoffer scan since
it does not lent itself to easy interpretation once more.
|It is hard to conceive how these
structures could have been produced without fire-welding some layers together.
But shouldn't one expect in this case that the elongated slag inclusion should sit right in the weld boundary?
The answer is two-pronged
|Yes - you would expect elongated (slag) inclusion if
you stretch your material after fire-welding (e.g while
faggoting; shown here).
Fold over, introducing some (oxide) particles into the welding plane. Stretch and thus elongate the particles,
then fold over (introducing new particles), then stretch again (elongating some more), etc. In the finished stacked
you find elongated inclusions right in the boundary.
|No - you would not expect elongated (slag)
inclusions in the weld boundary if you first
draw out sheets from pieces of the bloom, thereby elongating the slag inclusions contained in the bloom, and then
fire-weld a stack of those sheets. You would then find elongated lag inclusions somewhere in the welded structure
and weld seams containing at best small particles that are not elongated. If the smith cleaned the sheets
before welding and knew what he was doing, you might find rather perfect welding planes in a material
otherwise full of (elongated) large slag inclusions.
Something like this:
|All things considered, we might
safely assume that the old Luristan smiths worked with rather imperfect blooms,
quantities of slag and other non-iron objects. They forged thin plates out of the stuff and fire-welded them to the best of their ability.
They may not yet have discovered the art of purifying the bloom parts and thus could not rid the material of the larger slag inclusions.
Alternatively, maybe they didn't care because some "dirty" sheets didn't matter much if you payed attention to what
you were doing otherwise. I'll get to that.
|In order not to overload this module, I will continue in two separate modules. Here are the links|
|Part 2 Pommel and hilt
Part 3 Animals and blade
Part 4 Discussion of the results
|1)||As is customary for
scientific papers, the "we" actually refers to the one person (grad
student to post-doc) who actually did the real work. Grinding and polishing the
specimen by hand for many, many, hours, taking hundreds of pictures with some
microscope, editing the pictures, and so on. These
their work, we assume, basking in the reflected glory of their professors.
Here the unsung hero was Ingo Petri who did the skilled and extensive metallurgical work in this project.
Discussion of the "Cut Sword" Findings
Part 1 Basics about Scythians and Their Akinakai
Scythian Special Large Pictures
The Luristan Project - Results from Cut Swords Part 2
The Luristan Project - Large Pictures of Cut Sword
The Luristan Project - Literature Review
The Luristan Project - Results from Cut Swords
Literature to "Scythian Special"
The Luristan Project - Results
© H. Föll (Iron, Steel and Swords script)