Another wootz question

[ariel]

Re-reading Figiel's book.
All high-class wootz blades seem to be "built" of 2 sections: the body is covered with intricate " whorly" design, but the edge consists of long, relatively straight lines, resembling the Sham pattern. Of course, these are not made of a different ingot, but are simply the result of a more extensive hammering.
My question: what do we know about the effect of the extent of forging on the structure of wootz? Is it possible, that the so-called "pedestrian" Sham pattern is simply the result of over-hammering?

[Jeff Pringle]

It is dangerous to assume anything written on the technical aspects of wootz is correct, at least before Verhoeven & Pendray’s Scientific American article in 2000. I suspect Figiel is wrong in his reasoning - the lines show up more at the edge due to more extensive grinding there, not hammering. The same effect happens in pattern welded material. If we assume the ingots were all roughly the same size, then they would all need the same amount of hammering to be transformed from ingot to blade material.

[ALEX]

An outstanding analytical question, Ariel!
You are correct - these lines are result of extensive forging, BUT they develop on edges only! If it would be just result of overhammering/multiple forging cycles we'd see these lines throughout the entire width. I think it has to do with cooling as well = the edges cool faster than the core because they are thinner, and it allows the contrast to develop more "gracefully"... granting it has been properly hammered and from a top quality wootz ingot!
I do not think sham is a result of overhammering alone, I think it's more a result of low-contrast ingot to begin with, and perhaps under-hammering:-)
Also, the presense of these lines on the edge indicate the better (and perhaps earlier made) quality of the blade to me - I often see them on better patterned, such as Kirk laddered, blades. Not sure if grinding alone can create such an effect.

[ariel]

Cooling is a good one!
Not being a metalworker, I would still assume that more hammering is needed to achieve a thinner edge than a thicker body.
No matter what: the edges of the highest-quality wootz blades look like Sham.
Thus, the question remains: is Sham an "overworked" Kara Khorasan?

[Jeff D]

I am of the belief that sham is quite different than kara khorasan. The edges of a khorsan blade has thin stripes in the same manner that the ladder pattern has thinner stripes. Most likely during the forging the original pearlite and cementite crystals are elongated and thinned. When the blade is 'beveled' for the edge or a ladder you see the thinner cross section of the bands. My understanding that if the blade has a lot of hammering, it breaks up these crystals to give the 'jumble of matches' appearance seen on many fine Indian pieces.
The etching of sham is also quite different than the etch of khorsan. Philip Tom has explained it to me more as a slow controlled rust. This indicates to me that it has a different chemistry.

Here are a couple of my own blades to illustrate. First picture is kara khorsan with its edge, the second is a Turkish sham kilij, and the third is a ladder rung.


All the best Jeff

[ariel]

If that's the case, the ingot must have been the determining factor. Then, how did the smiths know which one will produce a Khorasan and which one a Sham? They would have to finish the blade and etch it to reveal the final result. Lower quality(Sham) would have not been discarded ( too expensive), but just sold for a lower price. The highest quality would have been signed "Assadollah". Then, where is the multitude of Sham blades from Iran? Why would ingots from the same source ( mostly India) produce Khorasan blades in Iran and Sham in Turkey? Did the Ottoman bladesmiths consciously select ingots with Sham pattern?

[Jeff D]

Originally Posted by ariel

The highest quality would have been signed "Assadollah".

Only if it was made by the family line

Originally Posted by ariel

Then, where is the multitude of Sham blades from Iran? Why would ingots from the same source ( mostly India) produce Khorasan blades in Iran and Sham in Turkey? Did the Ottoman bladesmiths consciously select ingots with Sham pattern?

Here I don't know the answer, but, I have always assumed that the ingots came from a different source. Even if they came from the same source but a different batch, I believe the ingots had an surface appearance which could be differentiated by an experienced eye.

Jeff

[ariel]

And the Turks were so dumb that they purposefully took only the "bad" ones?

I hate to be a nudnik, but I feel this question can tell us something important.

[Jeff D]

Originally Posted by ariel

And the Turks were so dumb that they purposefully took only the "bad" ones?

I hate to be a nudnik, but I feel this question can tell us something important.

Well I suppose that may be one explanation. I think it unlikely. More reasonable explanations are, forging secrets, trade limitations, or a whole host of other reasons.


All the best
Jeff

[kisak]

Originally Posted by ariel

If that's the case, the ingot must have been the determining factor. Then, how did the smiths know which one will produce a Khorasan and which one a Sham?

Manouchehr's book mentions smiths determining the quality of wootz ingots by polishing (and etching?) a small part of the surface.

[ariel]

Citation from Figiel's book ( pp.20-21):
"...as a result of repeated forging, there was realignment of the crystalline structure. If the cake was forged longitudinally, parallel rows of crystals would result. If the cake was forged in different directions the crystals would form wavy lines of complex motley patterns including circular and ladderlike distortions."
Sure, Figiel was not a bladesmith, but he consulted with Pendray who knew a thing or two about wootz :-)

If that's the case, the difference between Persian, Indian and even Turkish wootz blades might have been mostly, if not exclusively, due to technical aspects of handling ingots. Temperature, duration of forging, force of pounding, orientation of the ingot, altered directions of forging, speed of cooling etc. were responsible for different patterns.
With tens of thousands of wootz ingots coming from India on an yearly basis, the smith needed just to verify that a particular ingot was indeed " wootzy", did not have a lot of slag trapped inside and ... that's it. From there on, the ultimate result depended strictly on the master's skills.
This, likely, explains why the contemporary masters have such hard time to reproduce the beauty of old Indian and Persian blades. Contemporary metallurgy knows precisely the nature of wootz, the percentage of carbon and the microelements facilitating formation of dendrites, the temperature/time optimization of the process etc. This is purely science, and we are very good at it.
What is missing, is the hands-on collection of idiosyncratic manipulations peculiar to old artists: how hard to pound, at what metal color, when to turn, when to grind and how much , how to cool etc, etc, etc.

Here is an example of a bulat (wootz) dagger by Anosov
http://talks.guns.ru/forums/icons/fo...81/1681918.jpg
http://talks.guns.ru/forums/icons/fo...81/1681922.jpg
http://talks.guns.ru/forums/icons/fo...81/1681920.jpg
He got the secret.

[Jeff D]

Originally Posted by ariel

If that's the case, the difference between Persian, Indian and even Turkish wootz blades might have been mostly, if not exclusively, due to technical aspects of handling ingots. Temperature, duration of forging, force of pounding, orientation of the ingot, altered directions of forging, speed of cooling etc. were responsible for different patterns.
With tens of thousands of wootz ingots coming from India on an yearly basis, the smith needed just to verify that a particular ingot was indeed " wootzy", did not have a lot of slag trapped inside and ... that's it. From there on, the ultimate result depended strictly on the master's skills.
This, likely, explains why the contemporary masters have such hard time to reproduce the beauty of old Indian and Persian blades. Contemporary metallurgy knows precisely the nature of wootz, the percentage of carbon and the microelements facilitating formation of dendrites, the temperature/time optimization of the process etc. This is purely science, and we are very good at it.
What is missing, is the hands-on collection of idiosyncratic manipulations peculiar to old artists: how hard to pound, at what metal color, when to turn, when to grind and how much , how to cool etc, etc, etc.

Here is an example of a bulat (wootz) dagger by Anosov
http://talks.guns.ru/forums/icons/fo...81/1681918.jpg
http://talks.guns.ru/forums/icons/fo...81/1681922.jpg
http://talks.guns.ru/forums/icons/fo...81/1681920.jpg
He got the secret.

I don't think this is true. The Ingot was also critical. Kindi even stated it;
'Swords made in Yemeni workshops from Yemeni crucible steel were regarded as the highest quality swords, whereas those made by Yemeni swordsmiths using imported crucible steel were classified only as medium quality. This classification was absolute; the best Yemeni sword-smith could only achieve a medium quality blade even if the best quality imported Indian crucible steel was used.' Pg 59, Hoyland and Gilmore
Medieval Islamic swords and Swordmaking

Jeff

[ariel]

Are there any surviving examples of Yemeni wootz swords? Tough to judge with only hearsay for evidence...

[Jeff D]

Originally Posted by ariel

Tough to judge with only hearsay for evidence...

True, but hearsay is a higher power then speculation.

More hearsay; ' Biruni may have been getting his information from another source as well for he goes on to say (in so many words) that, while he is willing to believe that a sword of one type could not be changed into another, the ingredients of the steel could be changed (in the crucible) so as to produce different watered effects, revealed by final polishing.' Pg 173 of Hoyland and Gilmore.

Jeff

[Gonzalo G]

Jeff, how important could it be the presence on enough manganese in the crucible to produce different banded effects, as it seems to have incidence over the carbon segregation? Could it be a factor to explain some of this differences?
Regards

Gonzalo

[Jeff D]

Originally Posted by Gonzalo G

Jeff, how important could it be the presence on enough manganese in the crucible to produce different banded effects, as it seems to have incidence over the carbon segregation? Could it be a factor to explain some of this differences?
Regards

Gonzalo

Hi Gonzalo,

I am not a metallurgist, But, I thought the Manganese dioxide was added to neutralize the Sulfur in the iron, which makes the blade too brittle to work with when heated. Verhoeven does state that very small traces of Manganese will promote banding (less effect then Vanadium). I think trace amounts are usually present anyway, so I don't think that is the reason it was added to the crucible.
I personally feel that it is more likely the original source of the iron, with its inherent properties that made the biggest difference. The other ingredients and etchants may have helped or hindered somewhat but Like Verhoven did, a smith would keep hitting a wall until the right iron was found. I agree with ariel that a poor smith even with the correct iron could loose the effect.

All the Best
Jeff

[Gonzalo G]

I agree, Jeff. But manganese also has been mentioned by some metallurgists as an ingredient affecting the dendritic structure and appearance of the wootz, and not only as a mean to neutralize the sulphur. Nevermind, I was only trying to check this point. With respect to the vanadium, the same can be said. I understand indian ores were characterized by the presence of vanadium. I don´t know if somebody had conducted experiments in this way, changing the additional ingredients, or their amount, and using the same forging technique, to see the possible changes on the appearance of the dendritic structure. Of course, forging techniques had great inicidence to this respect, but I was only intending to see the differences originated on the making of the ingots. Thank you.
Regards

Gonzalo

[Jeff D]

Hi Gonzalo,

Vanadium, Molybdenum, chromium, niobium and manganese all produce the effect. The elements can be found naturally in different quantities in different ores depending on their source. These are the one mentioned by Verhoeven in his 2001 Scientific America article. I am sure there are others as well. I suppose these elements could have been added to the crucible, but, I am sure the ingredients would be a highly guarded secret. I suspect the additions were not entirely known or the smiths imported into Spain would have been able to reproduce the watered pattern from the local ores. Apparently they were not.

All the Best
Jeff

[Jeff Pringle]

I’m sure the Turkish, Persian and Indian smiths were primarily working with metal from different production centers, which used somewhat different ores and processes. But perhaps the Turks were buying up all the ingots that were less prone to material loss and fracture while forging…
To recapture the old metal requires orchestrating the alloy, the ingot, the forging method, heat treatment, and even the polishing and etching - all have significant effects on the finished appearance.
To illustrate the importance of the ingot alloy to the pattern, here is metal from two modern ingots that were forged in a similar way. One of these is not going to ever look Persian!