True Combat Value of Wootz

[RSWORD]

As this interesting discussion winds down, I only have one thing to add.

[Jeff D]

Originally Posted by RSWORD

As this interesting discussion winds down, I only have one thing to add.

Sweet Rick!
I will second that opinion

[Chris Evans]

Hi Folks,

I think that we gave this topic a pretty good airing, but by no means wrote the last word on the subject.

Someone brought this to my attention today:

http://groups-beta.google.com/group/...6bbef23a0311ac

Carbon nanotubes?

Help - We need to get hold of that paper.

Cheers
Chris

[Rivkin]

Well, my personal impression is somewhat mixed. The article in Nature starts bad - it talks a lot about crusaders, about mysterious blades their encountered, and then says oh, here we analyze such blade - from XVIIIth century. Then it continues to say that wootz (called damascus in the paper) have exhibited highly unusual super-qualities. As we discussed in this thread, this is somewhat questionable. There are some authors who liked it, some, like for example Tournie, whom Manoucher quotes on a different issue, believed that wootz weapons are simply very bad ones, and mechanical damascus is much better. Then it says that the secret of making wootz was "lost" in XVIIIth century, but yet somehow Kyrgyz and other smiths were able to work with Anosov in creating wootz blades in XIXth century. Geurk did make some wootz weaponry relatively late in XIXth century, albeit I think he did not make wootz.

Then we go into subject of carbon nanotubes. Ok, carbon nanotubes. It is obvious that carbon in wootz samples formed some sort of structure and it is obvious that this pattern would be formed on a nanoscale. I guess 50 year ago, before the word "nano" started to mean "grant money", no one would really care to specifically mention the nanoscale. What is new in this article is that it is formed a nanotube structure rather than diamond or graphite. This is what significant over here, and it is indeed an interesting discovery. Which again requires certain reiteration of the question "what is Wootz ?" For example Anosov, as fas as I remember, believed that wootz should consist chemically from carbon and iron, and all these stories about alloying are wrong. He is also quoted that every steel with a pattern would be called "bulat" (he did not use the word "wootz") by the people, even though some of it is mechanical, i.e. "artificial bulat", and some is "real bulat". So again we need to agree on what is wootz. For example Pendrey &Verhoeven & company believe that ".... The prior studies claiming to have either reproduced the genuine Damascus steel or explained the mechanism of pattern formation are reviewed. None of these studies have allowed modern blade smiths to reproduce the steel. The author and a blade smith, Alfred Pendray, has developed a process with which Pendray can produce blades that match the microstructures of the best museum quality genuine Damascus blades", meaning I guess that everyone else's wootz is fake. If they would mention which museums blades are "quality genuine Damascus blades", and which are definitely not, despite having visual pattern, this would make me more happy.

[Chris Evans]

Rivkin,

Where did you see the article? Do you have a link to it?

Cheers
Chris

[Rivkin]

Originally Posted by Chris Evans

Rivkin,

Where did you see the article? Do you have a link to it?

Cheers
Chris

I can send the pdf file of the article to everyone who emails me via the site(I don't have enough storage for private messages) his/her email.

Btw, have you seen Wadsworth's review article ?

[Ian]

Chris:

It's unclear to me what properties carbon nanotubes and nanowires might convey to steel. The authors suggest that such structures might explain the extaordinary cutting properties and strength of wootz versus other steels. Since we are having trouble here agreeing that wootz per se did have such special properties, I would put the discovery of these microstructures in wootz as interesting observations deserving further attention, but far from conclusive evidence that they convey special properties to wootz and not other steels. Do we know that these nanotubes and nanowires do not occur in other types of steel? Do we know that such strcutures convey greater strength and sharper cutting edge?

I suspect that wootz is not unique in regard to having these structures. Perhaps Dr Ann can help us here.

The article abstract is here: http://www.nature.com/nature/journal...s/444286a.html

You can purchase the full article online for $30 (I recommend the PDF version) here: http://www.nature.com/nature/journal...l/444286a.html. Or you can go to your local library, get the November 16, 2006 number of Nature, p. 286, and photocopy the article for pennies.

Ian.

[Chris Evans]

Hi Rivkin,

Originally Posted by Rivkin

I can send the pdf file of the article to everyone who emails me via the site(I don't have enough storage for private messages) his/her email.

Btw, have you seen Wadsworth's review article ?

Sent you an e-mail to take up your very kind offer. Thank you.

No, I haven't seen Wadsworth's article. Where is it available?

Cheers
Chris

[Chris Evans]

Hi Ian,

Originally Posted by Ian

Chris:

It's unclear to me what properties carbon nanotubes and nanowires might convey to steel. .

I learned and practiced my metallurgy before the advent of so called nano-technology, so I confess absolute and total ignorance about the effects of sub microscopic structural components on the mechanical properties of steels, indeed any material. At this stage, all I can do is apply some basic logic to evaluate the evidence presented. But first I must read the full paper.

The authors suggest that such structures might explain the extaordinary cutting properties and strength of wootz versus other steels. Since we are having trouble here agreeing that wootz per se did have such special properties, I would put the discovery of these microstructures in wootz as interesting observations deserving further attention, but far from conclusive evidence that they convey special properties to wootz and not other steels. .

I thinks that we can safely accept that Wootz was, if properly forged and heat treated, at least potentially a notch above other contemporary steels. GT Obach's experience is agood example, and even 50yrs ago it was talked about (by metallurgists) as an outstanding early steel.

However, you raise the same points that I immediately thought of, namely that the same sub-microscopy structures may be found in other steels and may not be exclusive to Wootz.

Additionally, I have yet to see (it may have been published but I haven't seen it) comprehensive mechanical test results of Wootz vs more primitive steels, not to mention an exhaustive analysis of the mechanical loads that a sword edge is expected to cope with. Hardness I have seen, but not the other properties - We need this data before we can make valid comparisons. If it turns out that Wootz did indeed have superiors mechanical qualities over good quality primitive steel, then we can start exploring the contribution, if any, of its sub-microscopic structure.

Cheers
Chris

[Ann Feuerbach]

Hi all,
Just got back from a conference and will be reading the nature article soon. I have seen some work on nano structure in a 2004 article. History section in all these areas are bad. FYI wootz, only from 1795, not a real word, too bad it is used so much as it is so inaccurate and as no etymological roots.

[Andrew]

Originally Posted by Ann Feuerbach

Hi all,
Just got back from a conference and will be reading the nature article soon. I have seen some work on nano structure in a 2004 article. History section in all these areas are bad. FYI wootz, only from 1795, not a real word, too bad it is used so much as it is so inaccurate and as no etymological roots.

Hi Ann. Welcome back.

So, it sounds like the much more accurate term would simply be "crucible steel"? How about the term "balut"?

[Ian]

Originally Posted by Ann Feuerbach

Hi all,
Just got back from a conference and will be reading the nature article soon. I have seen some work on nano structure in a 2004 article. History section in all these areas are bad. FYI wootz, only from 1795, not a real word, too bad it is used so much as it is so inaccurate and as no etymological roots.

Thanks Ann.

Hope the conference was enjoyable, informative and productive. Like Andrew, I would welcome your suggestion for a better term than wootz. Look forward to hearing your views about the possible significance of these fine sub-micronic structures that have been described recently.

Regards,

Ian.

[Ann Feuerbach]

Hi all,
Bulat is good, but pulad (phulad) is better, because bulat comes from pulad or a related term and variations of the word pulad can be found in many languages. I did an etymological study of the words. The earliest use of the term pulad is a 6th century AD text. It may have originally came from Sanskrit or Avesten (which had a common root language). In sanskrit languages the prefix pu means pure or purify, while there are hundreds of words for iron in the languages of India including loha, lauha, etc. Pu loha (meaning pure or purified iron) or such was probably the origin for the word. I have checked this theory out with Sanskrit scholars and they agree with this.

I have no problem with the use of the term wootz when refering specifially to Indian steel, but the word assumes a geographic location, which can be inaccurate and assuming. I prefer the term crucible Damascus steel to prevent assumptions.

On a related note: If I read one more reference in the news, including the Nature article and National Geographic news (where the author even contacted me but took no notice to what I said) to the process being only from India, being lost, and references to crusaders and Damascus, Syria I am going to scream!

[Rivkin]

I think what we have here is a cultural issue. I grew up in a commpunity (Asia/Eastern Europe) where "bulat" novadays simply means steel. Any steel. Even if you buy almost any translational of any old text, you will see that translator uses word "bulat" with no regard for the original text, i.e. assumes that it simply means steel. This is why you occasionally see russian works on bulat that pronounce that you know what (since we don't know how to call it ?), was used by Roland, prince Igor and virtually every other historic person, because the author did not check the manuscript's original for the exact _original_ wording.

Even in XIXth century, per Anosov, bulat meant any steel with a pattern, whether it is mechanical, you know what, or something even more simple.

The "wootz" word for me is a slang and I think we need such a word to clearly identify what we are talking about.

[Chris Evans]

Hi Folks,

Rivkin very kindly sent me a copy of that paper that was published in Nature. He is indeed a gentleman and a scholar and my sincerest thanks go to him

I hurriedly read it and the thing that immediately struck me is is the claim that Wootz had superior qualities, without telling us which exact attributes were being talked about. After all, in the context of swords, there are a number of mechanical properties that are considered desirable, most having to do with hardness and toughness. Hardness, is relatively simple, but toughness has many aspects.

The most often mentioned advantage of Wootz is its supposed combination of hardness and ductility resulting from the presence of carbides and nearly pure iron in its microstructure. The simplistic logic appears to be that the hard carbides do the cutting and the soft near pure iron provides the toughness. This paradigm is contrasted by that of conventional quenched & tempered Martensitic steels in which the same homogenous microstructure embodies both attributes.

Whilst true to some extent, I have a lot of trouble in accepting the above line of reasoning as a justification for declaring Wootz to be a superior steel. After all, it is well known that steel obtains its optimal hardness and toughness in the quenched and tempered Martensitic state, though I hasten to add, that work hardened Pearlitic steels, such as piano wire, can also be both surprisingly tough and hard. Whether Wotz swords were ever work hardened to to the same extent as modern piano wire, I have yet to find out.

A theoretical evaluation, from first principles, of Wootz is very difficult because the very large number of variables to be considered and all this has to be done in the context of various sword, the design of which introduces yet more variables.

Based on the papers that I read, most Wootz blades were not Martensic, rather work hardened Pearlitic with additional iron carbide embedded in it, though GT Obach did make the very important observation that partially quenched Martensitic blades, where the edge was expected to do the cutting, as well as fully quenched, were not uncommon. However, here we have to remember that once the carbon content of Martensitic steels exceeds 0.8%, the surplus carbon precipitates out as iron carbide, which can have detrimental effects on toughness, depending on its microstructure and localization. Whilst this effect can be minimized with very careful heat treatment, it is extremely unlikely that the ancients would have had the means or knowledge to achieve this.

So where does this leave us in relation to carbon nanotubes and which properties did these influence? I am at a loss.

Just looking at the evidence that so far I have managed to lay my hands on, it would appear that in centuries past Wootz acquired its formidable reputation more than anything else on account of the fact that it was melted during firing.

Unlike primitive steel, Wootz was free from insoluble inclusions, such as slag, which would float to the surface -The presence of coarse lumps of impurities in primitive steel could greatly weaken it and hence the need to remove these and disperse uniformly what remained - This was done by the process of extensive hammering and folding. But the presence of these impurities could only be minimized, never eliminated, and as such, primitive Martensitic steel always had a question mark against it. Also, during the process of hammering and folding, often the welds were incomplete due to poor technique or bad luck, introducing additional flaws.

To complete this rambling, I should reiterate that the great disadvantage of primitive Martensitic steel, in contrast to Wootz, was its variability due to the then poor understanding of metallurgy, as well as the presence of slag like impurities.

Of course, Wootz was good steel to start out with, but the forging process could very easily ruin it and the end product was not necessarily any better than that made from primitive steel. I think, that by sheer chance, it was possible to make a sword out of primitive Martensitic steel that was every bit as good as those made from Wootz, for in the end, all that was required was a correctly heat treated blade of about 0.8% carbon (optimal) and largely free from slag inclusions; But given the then extant incomplete knowledge of metallurgy and on the balance of probabilities, the odds lay with Wootz to deliver a superior blade.


Cheers
Chris

[tsubame1]

Originally Posted by Chris Evans

Of course, Wootz was good steel to start out with, but the forging process could very easily ruin it and the end product was not necessarily any better than that made from primitive steel. I think, that by sheer chance, it was possible to make a sword out of primitive Martensitic steel that was every bit as good as those made from Wootz, for in the end, all that was required was a correctly heat treated blade of about 0.8% carbon (optimal) and largely free from slag inclusions; But given the then extant incomplete knowledge of metallurgy and on the balance of probabilities, the odds lay with Wootz to deliver a superior blade.

This gives me the possibility to highlight again that in order to evaluate
the "true combat value of wootz" as this thread is named, we should consider
the SMITH too.

Assuming (and i'm only saying ASSUMING) that the wootz is no better then
other western steels, we get only half of the equation's result. Might be the
great performances that the wootz is assumed to have are due to the
abilities the smiths achieved in working this material.
May be both were only slightly superior in front of western ones but adding
such slight superiorities we get a not-so-slight superiority.
The smith factor is overlooked in this thread making it a debate about
sheer composition of the steel, not the qualities he can achieve with
proper and skillfull smithing. "Nanostructures" of rough material can be
useless to a crappy smith.

[Gt Obach]

I'd completely agree with that.. ... very good points..

i will add... something here..

if you look at one factor in steel such as grain size... if you have a large grain size, the steel won't be as tough and can crack easier..... Now... the same steel with a very small grain size will be much tougher and resist cracking

now... if you look at the 2 processes... when you forge weld steel, the temperature is very very high (yellow to white heat) and tends to grow the size of grain in the steel...... if you do not take steps to Normalize the steel.... you will have a steel that is weakened due to large grain... ... an experienced smith should know how to make the grain small again..!

The wootz forging process must be done at a lower heat.... from red to orange.... because any heat higher than that and you are very close to melting some of the components of the ingot... .. it is strange... but some components of the ingot matrix start to fall apart and the whole cake will become mushy/crumbly....
-- so by the very nature of wootz... it will force you to keep the grain structure small......

its something i'm familiar with having forged a few blades.... but i never seen it written about in the old historical accounts..


don't worry though..........if you have a patternwelded blade.... with a small grain structure .... it will be very tough steel aswell......

So it does boil down to....... a well made patternwelded or wootz blade, involves many people... if all these people do their job very well...... you'll have a very tough and beautiful sword...

Greg

[tsubame1]

Exactly Greg.
Michael "Tinker" Pierce is of the same advise as per the attachment
hereunder. I add a table about the temperatures at which you should get the
several structures (showed at microscope) too :

[Chris Evans]

Hi Folks,



1. What Carlo and GT Obach say about the input of the smith is absolutely correct and cannot be emphasized sufficiently. These days we concentrate a little too much on the potential of the basic steel and tend to disregard the process of forging and heat treatment, which in the old days was of equal or greater importance. We have to keep in mind that the ancients had no accurate means of measuring temperature and worse still, had little or no idea as to why things turned out (metallurgically) the way they did. Theirs was an entirely empirical process.

2. GT Obach: Did you ever do a metallographic examination of your quenched Wootz blades? If so, what was the carbide distribution like?

3. Carlo: Thank you for those illustrations of grain sizes and microstructures. For those who would like to read a little more, here is a good article, albeit a little heavy at times.

http://www.osti.gov/bridge/servlets/...pb9/861397.PDF


Cheers
Chris

[Chris Evans]

Hi,

Here is something that I picked up, written by Dr. John Verhoeven:

There is a general myth in some of the popular literature that genuine Damascus steel blades possess outstanding mechanical properties, often thought superior to modern steels. This idea was shown to be incorrect as long ago as 1924. A famous Swiss collector, Henri Moser, donated 4 genuine Damascus steel swords, one with a non typical carbon content and microstructure, to B. Zschokke, who performed extensive careful experiments including metallographic and chemical analysis in addition to mechanical testing [15]. A series of bending tests compared samples from the swords to a pattern welded blade and a cast blade from the famous German knife center in Solingen. The 3 good Damascus blades showed significantly inferior bending deflection prior to breakage than the 2 Solingen blades in spite of the fact that the Brinell hardness of the 3 ranged from only 193 to 248, compared to 347 and 463 for the pattern welded and cast Solingen blade, respectively. This is not too surprising in view of the now well known fact that toughness of high carbon steels is inherently low; the Solingen blades had carbon levels of 0.5 to 0.6% compared to 1.3 to 1.9% for the 3 Damascus blades. The reputation of Damascus steel blades being superior to European blades was probably established prior to the 17th century when European blades were still being made by forge welding of carburized iron. It is hard to avoid embrittlement of such blades due to imperfect welding during the forging process as well as difficulty with the carburizing process.

The full article is here: http://bronksknifeworks.com/historical.htm

I don't know how representative the samples studied were, but the above observations further support the view that Wootz was only outstanding when compared to the primitive steels of olden days. However, here is another article that puts things into a somewhat different perspective:

http://www.llnl.gov/tid/lof/documents/pdf/237566.pdf

Cheers
Chris

[Ann Feuerbach]

Here is my two cents, extract from my PhD...
"The ductility of Damascus blades was one feature that distinguished it from other types of steels. Damascus steel blades typically contain spheroidal/globular cementite in a ferrite/pearlite matrix. Metallurgical experiments conducted by Ebner and Maurer (1982) on steel concluded that toughness and ductility coincide with a spheroidization of carbides. They also noted that additional tempering decreases the strength whereas toughness and ductility vary only slightly (Ebner and Maurer, 1982). Thus, the microstructure of hypereutectoid Damascus steel is optimum for ductility."

I think trying to determine which is the "best quality" sword is like trying to determine what the "Best" car is...American made? Japanese? German? Italian? British? depends on your needs, even the most expensive ones can produce a "lemon", while a cheaper car may perform very well for a long time, plus personal experience, preference, and how much you can afford.

[Gt Obach]

Hi

oddly... i do have abit that is suppose to be looked at.. and hopefully i'll get some good pic's from it...

but that is the problem right there... my steel is a modern crucible steel... and there is no way to make a connection a solid connection to the past.. .. i try to use the old recipes that are out there... .... ..it's like baking a cake with a list of ingredients and process... made by a person who is a casual observer..... ..... so there are alot of pieces missing to the puzzle..

i've read about the Zschokke swords and have real difficulty with some of the study..... such a narrow sample generalized to a whole sword population should be taken with a grain of salt.... it totally overlooks low carbon wootz... and other types of wootz...its not all made the same way..
-- also ... there are many ways wootz can be hardened... i'd like to hear about martensite... seemingly overlooked for some bizarre reason ?

actually what we really need is a series of studies.... from blades in crucible steel producing areas... and other regions... ... also the studies must be done by people who arent' going to benefit financially from the study..
( i know i'm asking alot... but i can dream )

onto my homebrew
I've said this in the past... that my steel functions much like a 1080 carbon steel... so i've never seen magic properties, just a very decent knife steel.....

oh by the way... if you want to read more about uhcs, det, detwad... theres tonnes of patents on the stuff... back in university i used to love to read it...

http://patft.uspto.gov/netacgi/nph-P...S=PN/5,445,685

check the references..... and click on the blue links for more.... also look at the studies...
-- enough superplasticity to boggle the mind

oh and by the way... i just did a little tutorial on SFI about my forging process... . but be warned... I went picture crazy and the download might bore you to tears..

http://forums.swordforum.com/showthread.php?t=74040

take care
Greg

[Ann Feuerbach]

From Greg: "actually what we really need is a series of studies.... from blades in crucible steel producing areas... and other regions... ... also the studies must be done by people who arent' going to benefit financially from the study..
( i know i'm asking alot... but i can dream )"

No dream, I have put in a grant for such a study (and have been gathering data on this for years) cross you fingers I get the grant! I do hope to gain financially from the study (in the form of a book) but have no hidden agenda's of what the outcome of the study should be. Just need: time, money, and samples!

[Rivkin]

Chris Evans: thank you very, I appreciate your words, however wootz is not my specialty so here I am not a scholar.

Because of this topic I have consulted my library extensively in the past two months, with just a single conclusion - hell knows.

First of all there were collosal number of experiments performed on wootz blades starting with XIXth century (Moser collection, russian cavalry experiment, the most recent experiments by Tavadze and so on), with exactly opposite conclusions. In order to keep it "in bay" I would just address the russian part. all said below is my personal opinion.

Stage I - during russian-caucasian and russian-ottoman conflicts of early XIXthe century general Patto writes that the enemy's yataghans and shashkas are better than russian weapons. Assumption is made by the ministry of finance that this superiority is due to crucible damascus (wanted to say wootz) nature of the swords. Massive expeditions are mounted in all directions (central asia, caucasus, west) to find the secret.

Stage II - the expidition send to Caucasus collects various techniques and comes to a conclusion that neither shashkas nor yataghans are made of crucible damascus (too long, "crud" from now on), but rather - from mechanical one. Report is presented to the minister of Finance, supervising the effort. In the same time in Zlatoust georgian Revaz makes wootz weapons repeating indian patterns, but no one can reproduce his results by using his technique, so he is declared to be a crook.

Stage III Anosov publishes his techniques of "bulatization". Interesting notes:
1. He claims historical attribution of super-powers to bulat based on the literature (prince Igor) which never contained "bulat" in the original, the term was used in later translations.
2. He makes a few blades, repeating the "best" pattern of indian and khorasani swords, with very good cutting properties. The problem - the blades do not nearly match the chemical decomposition of indian blades they are compared with.
3. No one is able to reproduce any of his processes after Anosov's death (Chernov and others).

Stage IV - persian bulat blades completely fail the russian army test on bending. As a results all persian blades are given special standards, 3-4 times "lighter" than for other blades (i.e. 1/13th of a "line" rather than 1/4th of a "line" bending angle to be used in testing).

Stage V. Russian government nearly completely abandons the research.

[tsubame1]

Originally Posted by Chris Evans

3. Carlo: Thank you for those illustrations of grain sizes and microstructures. For those who would like to read a little more, here is a good article, albeit a little heavy at times.

http://www.osti.gov/bridge/servlets/...pb9/861397.PDF

Chris, thanks for the link. This is another one that, even if referred to
japanese swords only, is of high interest to the ones that are interested in
metallurgy. Many information of general interest :

http://xoomer.alice.it/tsubame/ZZZZZZ_DOWNLOADS.htm

Click on Tatsuo Inoue Swordsmithing file.

You've to download it.
Sadly it is no more on line and I've stored it into my website to preserve
the info from oblivion.

[tsubame1]

Originally Posted by Ann Feuerbach

I think trying to determine which is the "best quality" sword is like trying to determine what the "Best" car is...American made? Japanese? German? Italian? British? depends on your needs, even the most expensive ones can produce a "lemon", while a cheaper car may perform very well for a long time, plus personal experience, preference, and how much you can afford.

You're right Dr. Ann.
This thread switched from "True combat value of the wootz" to "in order to produce swords is crucible damascus better then european steels in later times ?".
Whether, after the info provided, we can answer at the original topic
"wootz had good and true combat value", at the second question which the
thread has switched to, due to the almost exclusively western info provided
we can only reply the way you made : "depends on...".

[Chris Evans]

GT Obach and Ann,

I have been wondering about Martensitic (quench hardened) Wootz. I imagine that the practical difficulty would have been the avoidance of re-dissolving the iron carbides whilst Austenitizing and then upon quenching ending up with retained Austenite, as well as Martensite, which is a trait of high carbon steels and potentially disastrous to toughness.

I suppose that this could have been minimized by keeping the Asutenitizing temperature as low as possible, but in the absence of modern temperature measurement apparatus and knowing how to deal with the problem, I just cannot see how the ancients managed to get over it. Any thoughts?

Cheers
Chris

[Ann Feuerbach]

FYI, Personally, I have not come across any blades with Martensite. I would be interested in any metallurgical studies of antique blades that do have Martensite, so references please.

[Rivkin]

1. I could not agree more with the importance of smith's qualifications.
2. So do we move from wootz to "crucible damascus" or we stay with "wootz" ? I like wootz more - it is shorter.
3. The problem is also "what is wootz ?". For example, a lot of people do not believe that what Anosov made was anything similar (besides patterns) to traditional wootz.
4. While the subject is heavily obscured by myths and so on, it seems that comparison wootz vs. others were repeatedly made with different results (i.e. Anosov's bulat seemed to be of really high quality).

[Ann Feuerbach]

FYI, I have held the blade that Anosov made for Faraday. It had a light sham-like pattern, however, the blade was overcleaned and that may be why the pattern was faint and only visable near the handle.