 |
Before I started this page, I thought
I had a sufficiently clear idea of what "damascene technique" meant:
The forge-welding of steel and iron, or more
generally, two types of steel. I also believed that this produced superior
swords and mail, and - for obvious reasons - that this technique was pioneered
in Damascus in ancient times. |
 |
I also had a notion that this
damascene technique was also used in Toledo (Spain)
in ancient times, so when I visited Toledo in the spring of 2000, I
looked for some remnants of the famed Toledo sword smiths. |
|
 |
Indeed, there is a store selling
swords, knifes and other metal stuff at about every corner. However, their
merchandise are mostly "fantasy items" like the sword of Conan the
Barbar, probably mass produced somewhere in the far east - you can find that
everywhere in the world. |
|
 |
Then there was
"artistic" stuff (e.g. ornamental dishes and plates) and especially
jewelry done in what the Toledans called "damascene
technique". What this meant was that some darkish metal was
inlaid with silver or gold to obtain rich ornaments as shown
on the right. It certainly was not what I had in mind when I searched for
"damascene" technique |
|
|
 |
Accidentally, I run
across a shop connected to a real smithy - the last one left in Toledo, as the
owner said. |
|
 |
There they made swords the old
way; and with old he meant that they used to do this already for the Romans (so he said). At least, you could watch some
rather special forging techniques and try the swords produced: They could be
bent to a considerable degree without breaking or deformation - I actually
bought one. |
|
 |
However, there was no damascene
technique in this sword or in anything else in evidence; it was simply a solid
piece of (hopefully) very good steel. Obviously, I got it all wrong, so I
started to investigate a little. I chose the Internet rather than the science
library because this is a "on the side" activity for me. |
 |
Surfing the net for a
few evenings, first created a tremendous confusion, because the word
"damascene technique" seems to be used for many different things (see
below). Now, I'm a lot less confused, but there are still some questions. This
is no wonder, considering that steel was one of the main technical issues for
about 2000 years all over the world, that its historical development
would fill a small library, and that there ares still plenty of unresolved
issues. |
|
 |
So some questions seem still to be
open - there are no reliable answers or at least I couldn't find them.
Interestingly, a lot of people, including serious
"archeometallurgists" seem to share my interest - there appears to be
an increasing number of publications and investigations in the last 10 -
20 years. |
|
 |
Most interestingly, even nowadays,
steel technology seems to hold some mysteries and promises. And that brings us
right back to the properties and the manipulation of defects in crystals. |
 |
On this and some other
pages I will share my confusion and my findings with you; as time progresses,
this material may become clearer. I include
a lot of documents, mostly found in the Internet, for those who want to
investigate on their own. |
 |
The
material did become somewhat clearer, indeed. I include a few more remarks
based on my present (May 2001) understanding of damascene techniques:
always indicated by a yellow triangle or button |
|
 |
But beware! Everything below or in
the links thus represents my present knowledge and interpretations; it
may well be wrong - take care! |
|
|
|
 |
For me, the term
"damascene technique" until recently had the following detailed
meaning: |
|
 |
The manufacture of iron-based
artifacts, especially knifes and swords, from
two kinds of steel. You got it by hammering
together (at high temperatures of roughly 800 oC or so;
called "forge welding") a package of several sheets of the two kinds.
The sheets will fuse or weld as a result of solid state reaction and diffusion
- a solid "compound material" is formed. The layered package of two
kinds of steel is frequently folded over; the resulting structure is similar to
the cross-section through a folded and twisted cake made from two different
doughs (e.g. chocolate and vanilla).
Not wrong, but only covering a small part of what
is meant with "Damascene". |
|
 |
The two types of steels were
1. soft iron, relatively low in carbon
content, called
wrought iron; the basic product
of early iron production by solid state reactions at temperatures well below
the melting point of iron.
2. carbon-rich iron, often from an source
in India (that had a monopoly for many centuries) called "wootz steel". You may find some basic
information about the development of iron
and steel technology (including wrought iron and wootz steel) in the link.
Mostly wrong. |
|
 |
The resulting sword combined the positive
properties of the two constituents while avoiding the negative ones. It was
hard, but not brittle, could hold a sharp edge, did not deform easily, but
could be bent to a considerable degree.
Mostly wrong. |
|
 |
This "damascene technique" was
invented, or at least brought to perfection, in Damascus and Toledo in ancient
times.
Totally wrong |
|
 |
The old Celts, Germans, Vikings, Anglo-Saxons and
so on, imported their damscene swords from the south (in exchange, maybe, for
amber or blond women); or at
least some raw materials.
Totally and inexcusably wrong |
 |
As indicated, this view has a few
correct points, but it is often totally wrong; it needs to be modified and
enlarged. In what follows I give a brief outline of my present (May
2001) understanding (which includes a lot of open questions and most
likely some misunderstandings, too). |
|
 |
On two other pages are (commented)
lists of articles which I found
interesting and a cross-linked glossary
of some issues I was looking for in the Net. Use with
care. |
|
|
|
 |
As it turned out, "damascene
technique" means quite different things to different people; but even
within the defintion given above, there are
many variants. |
|
 |
The "steel" part could consist of iron which is rich
in Phosphorous and not necessarily Carbon (especially, maybe, in northern
Europe?). |
|
 |
The forge welding could be
done by folding over the same basic material which, however, may have been
quite inhomogeneous. Lots of folding and forge welding created a homogeneous
looking material - this is the Japanese way (horribly
abbreviated). |
|
 |
The welding technique was not only continued (and somewhat
irregular) folding and hammering, but a more complicated technique, called
"pattern welding". The result
could look like this: |
|
|
|
|
|
|
|
 |
It also could look like this. This is a photograph of a real
piece of damascene steel recently made by the German master smith
Manfred Sachse (whom
we will encounter again) and taken from his
Home page |
|
|
|
|
|
|
|
|
|
|
 |
In the "Württembergisches
Landesmuseeum" in Stuttgart I saw a very impressive sword from the
Merowinger time (around 500 A.C.) that was made by pattern welding (and
found in Ingersheim - direct neighbor of the town of Geisingen where I grew
up). This sword from Ingersheim was
reproduced by a modern smith - Manfred Sachse - as follows: |
|
|
|
|
|
|
|
|
|
|
 |
The loose stack of steel plates is banged into a rod with a
cross section of about 1cm2 - some work! Several of those
rods, about 1 m long are produced. The labelling "High carbon"
in the drawing could, perhaps, also mean "high Phosphorous". |
|
 |
Next, these rods are twisted and ground flat on two sides. The
twisting is hard to draw, but you get the idea. |
|
|
|
|
|
|
|
 |
What it looks like on the surface if you now grind the twisted
rod to increasing depth is this:
(From the Internet
article of Lee A. Jones: The Serpent in the Sword: Pattern-welding in Early
Medieval Swords) |
|
|
|
|
|
 |
Original Fig. Captions:
Patterns disclosed by successively grinding a facet
along the length of a twisted rod demonstrated in a clay model of a rod
composed of sixteen alternating layers prepared by bladesmith Dan Maragni. The
rod has been mildly squared and joined along side another rod, shown only
focally at the edge. The rod was progressively ground and photographed at each
interval, reduced in overall thickness by the percentage shown in the scale
below. Further leveling of the rod will reverse this trend, as a mirror image
of the patterns first disclosed. |
|
|
|
|
|
 |
Several of those rods were than forged welded; with possibly a
pure steel rod on the outside. Banged into shape, and ground to a sharp edge,
we have a fine sword, it represented about the value of a car in todays
currencies. |
|
|
|
|
|
|
|
|
|
|
 |
only it was even more complicated: Two independent layers were
used for the center part, so that the front and backside od the sword looked
different; and the twisted regions were alternated with non-twisted regions to
form specific pattern down the lenght of the sword. Well,
look at it yourself. |
|
 |
This is probably as close as you can get to a
magical or simply famous sword like Notung (Wagner's sword for Siegmund and Siegfried),
Excalibur (King Artus), Balmung (What Siegfried made from the Notung pieces
in the Nibelungen saga,
Tourendal (Roland saga), Mimung
("Wieland der
Schmied" made it for his son Wittich), Eckesachs and Nagelring (Dietrich von Bern), Colada and Tizona (El
Cid) - and so on. |
|
 |
More about "magical swords" can be found in
this
(German) link. |
 |
Alltogether, in a model showing all
process stages and also on display in the "Landesmuseeum" mentioned
above, it looks like this: |
|
|
|
|
|
|
|
|
 |
It seems that pattern welding and
P-rich steels were especially popular in northern Europe; but some kind
of "damascening" or pattern welding can be found all over the
world. |
|
 |
It would be totally wrong, however, to credit ancient smith
with the invention of something very sophisticated. The truth is: They had no
choice but to come up with some kind of pattern welding! |
|
 |
The reason is that nobody could melt wrought iron or mild
steel with a melting point of 1550 oC during the first
2000 years of iron technology. Only cast
iron (eutectic melting point at about 4% C is 1130
oC) could be molten (and was used in large quantities in ancient
China) |
|
 |
Everybody had to work with small lumps of iron out of a
"bloom" obtained by a solid state reaction.
This small lumps needed to be forge-welded, i.e. banged together at high
temperatures, to obtain large pieces. Invariably, the little lumps had on
occasion different C or P content; the forge welded blades showed
some structure. Iron blooms obtained in different regions from different ore
deposits also would be different; with a little trading it could not escape
notice that forge welded parts showed structures, and that some parts were hard
and others soft. |
|
 |
It is then a small step to first forge-weld some kind of iron
to relatively homogeneous stuff, then some other kind (easily distinguished by
color or hardness, produced in some special way, or traded from some other
smiths) - and having two kinds of iron plus knowing about forge welding,
pattern welding is something that does not need a big innovation. |
 |
Even so, it took almost 1000
years of forge welding and simple pattern welding before welding reached its
zenith around 700 - 800 AD, producing extremely complicated and
certainly very beautiful and valuable works of art (the performance in real
fights was probably no better than that of simpler swords, however). |
|
 |
And, to be clear, the whole process was not simple at all! It
took a lot of knowledge, experience and practice, to produce a "good"
pattern-welded sword! Those ancient and medieval smiths were not barbarian
brutes but highly educated and skillful man! |
 |
First questions come to mind; some
answers are contained in the commented
list of articles |
|
 |
Who did it when (and how)? Which cultures just copied, and
which ones invented or improved? |
|
 |
Were those pattern-welded swords really much better than
"regular" ones? Or was the whole thing more for show, a status thing?
Was damascening or pattern welding a major innovation or something you couldn't
avoid discovering?
Crude Answer: The better pattern-welded
swords were superior to swords from plain iron (or soft, inhomogeneous steel),
but inferior to swords from good homogeneous steel. See the table below for
data on "true" damascene swords. |
|
 |
What were the ingredients? How where they obtained? How did
different types of starting materials influence or determine the forging
process and the final result? |
|
 |
What exactly was the role of Damascus or Toledo? |
|
 |
What exactly were the famous Damascus blades? How were they
made, and how good were they really? |
|
|
|
 |
The last question seems to have an
answer: |
|
 |
"True" Damascene blades were made from wootz
steel only. The Damascene (or water) pattern comes from a striated
precipitation of Fe3C particles and not from folding and
welding two kinds of material. |
|
 |
The "secret" art was how the high carbon wootz steel
(coming close to cast iron) was treated to yield a highly flexible and
extremely sharp blade - check in the commented list of articles. |
|
 |
It now appears that it was cricial to have traces of Vanadium
(or somethimg similar) to enable proper nucleation of the
Fe3C particles - see the
latest article to this subject |
 |
What seems less clear, however, is
how good these blades really were. Obviously, the crusaders, wielding quite
respectable swords themselves, were mightily impressed. |
|
 |
Trying to forge similar blades lead European sword smiths
astray, however. They believed that these blades were composed of two types of
steel and re-invented the "old" pattern welding technology in new
variants - seemingly without much success. The explanation given above seems to
be a pretty recent discovery! |
|
 |
How good "true" damascene blades were was something
an early metallurgist actually did find out to some extent. Prof. Zschokke
(from Switzerland) was lucky enough to get a few true damascene blades for
(destructive) investigations (this is quite unusual because these blades ar
valuable and museums and collectors do not easily agree to have some
destroyed). |
|
 |
Some of this results (taken frorm the
book of M. Sachse) were |
|
|
|
|
|
General composition |
Sample |
[C] |
[Si] |
[Mn] |
[S] |
[P] |
1. Knife |
1,677 |
0,015 |
0,056 |
0,006 |
0,086 |
2. Knife |
1,575 |
0,011 |
0,03 |
0,018 |
0,104 |
3. Saber |
1.874 |
0,049 |
0,005 |
0,013 |
0,127 |
4. Saber |
0,569 |
0,119 |
0,159 |
0,032 |
0,252 |
5. Saber |
1,324 |
0,062 |
0,019 |
0,008 |
0,108 |
6. Saber |
1,726 |
0,062 |
0,028 |
0,020 |
0,172 |
7. Modern welded steel (Solingen) |
0,606 |
0,059 |
0,069 |
0,007 |
0,024 |
8. Modern cast steel (Solingen) |
0,499 |
0,518 |
0,413 |
0,038 |
0,045 |
|
|
|
|
|
|
Properties |
Sample |
3 |
4 |
5 |
6 |
7 |
8 |
Bending toughness |
13,4 |
15,2 |
11,5 |
14,5 |
21,6 |
30,0 |
Work to bend |
94 |
221 |
55 |
63 |
361 |
622 |
Angle of bending |
27 |
59 |
19 |
17 |
69 |
78 |
Hardness |
216 |
233 |
193 |
248 |
347 |
463 |
|
|
|
|
|
 |
What ever the numbers mean (no units were given), the modern
blades always "win". Otherwise blade No. 4 is best. In any
case - the properties of what was (and is) traded as "true" damascene
vary widely, there are very good and very lousy specimen. |
|
|
|
 |
The expression "Damascene
Technique" thus has a lot of different meanings. In the listing below I
include some techniques that are not "officially" listed as
damascene, but follow the general idea. The adjectives used in differentiating
the diverse techniques are mostly my invention |
 |
Folding
Damascene; two kinds of steel: |
|
 |
Folding over a stack of different steels several times; gives
many layers with beautiful, but irregular patterns. The kind of damascene that
many modern smiths do
today. |
|
 |
This technique was to some extent re-invented in the West
after encountering "true" Damascus swords in an attempt to emulate
these famous weapons |
|
 |
Many myths abound. In truth, the finished product has a rather
homogenized C content (i.e. is not a real "compound" material
from two different steels and no better that a homogeneous blade from good
steel). But the damascene pattern obtained after suitable treatment (etching)
gives this Damascus steel a special beauty and appeal. It does not so much
reflect the different C concentration of the layers, but probably (I'm not so
sure about this) the different amount of other impurities, especially P (which,
supposedly, does not diffuse as fast as C). |
 |
Folding
(Damascene); one kind of steel |
|
 |
What the Japanese did to get sword material. Not usually
called Damascene, but not so different, because the small lumps of iron or
steel selected from a bloom were, after all, rather different in composition
and contained slag inclusions and other inhomogeneities. The speciality of the
Japanese was a lot of folding and hammering; the finished product therefore
does not show evidence of folding to the naked eye - it is now quite (but not
totally) homogeneous on the outside. |
 |
"Simple" pattern welding or laminating |
|
 |
This could be, e.g. just some mild steel in the middle and
hard steel at the edges; or a core of soft iron surrounded by harder stuff.
What (maybe) the Romans had and the early Celts. There is no particular pattern
besides the simple geometry of the design. |
|
 |
The Japanese also used this technique; their swords consisted
of up to three different kinds of steel (each one obtained through multiple
folding as described above) welded together or laminated in
quite complicated
arrangements. |
 |
"Decorative" pattern welding - like the technique
shown above. |
|
 |
While the twisting had also technical advantages compared to
forge welded untwisted rods, its main purpose - at least in later - times, was
the decorative effects possible with this technique. Designs much more
complicated than the one shown above were in use. |
|
 |
In later times - lets say around 1000 BC - when smiths
had learned how to make swords form homogeneous steel (especially in Toledo, it
seems); the blade may still have been adorned with a thin layer of pattern
welded foil only for the look of it! |
 |
"True"
Damascus |
|
 |
Swords and other implements made from one kind of steel - the
famous wootz steel - obtained from Indian sources from sometime before
300 BC up to the 7th century AD. After that, the people in
Damascus, in Toledo and probably other places also, could produce this
high-carbon steel themselves. |
|
 |
Treated the right way, Fe3C (cementite)
forms in striations, producing the special "damascene" pattern (often
referred to as "water pattern", too). These were the swords of
tall tales that emerged
when the crusaders met the arab owners of these beauties. |
|
 |
One
recent scientific
paper reproduced the ancient technique successfully and claims it needs
three thing to produce "true" Damascus sword:
- The right combination of time/temperature firing during ingot making
- the proper thermomechanical sequencing during the forging process.
- and the right chemical composition (especially minor element additions,
e.g. V in sufficient concentrations
|
|
|
|
|
|
We are right back to point defects in crystals! |
|
|
|
|
|
 |
At least one more modern smith works on "true"
damascene made from wootz steel (he send me an e-mail). You may jump to an
article about him and
his art by activating the link. (if the link does not work any more, here is
the
stored
version) |
 |
"Mysterious" Damascus |
|
 |
There are some people out there, who honestly believe (more or
less based on a scientific background) that everything was either
quite
different or that the technology is truly lost. |
|
 |
But then there are also those, who cook up some pseudo-scientific bullshit
including some magic - usually in the attempt to sell their "magic"
product. |
 |
"Inlay" Damascus (what they sell in
Toledo) |
|
 |
While this is certainly a technique to intimately combine two
metals (not necessarily by forging, but e.g. by soldering); it is not a
technique usually associated with the making of swords, knifes, armor or other
"functional" products. It may have been used in Toledo for adornments
of the sword hilts, though. |
 |
"Microelectronic"
Damascene technique. |
|
 |
"Damascene technique" (even "double
damascene") has become a common name in microelectronic technology;
everybody in this business knows what it means. |
|
 |
It has, however, nothing to do with all the variants given
above that could produce a sword, but is a kind of "inlay" damascene
technique, albeit on a <1mm scale. |
|
|
|