True Combat Value of Wootz

Chris Evans · 22nd November 2006, 05:48 AM

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 · 22nd November 2006, 01:35 PM

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.

tsubame1 · 22nd November 2006, 06:14 PM

Quote:

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 · 23rd November 2006, 01:52 PM

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 · 23rd November 2006, 03:22 PM

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 · 23rd November 2006, 05:04 PM

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 · 23rd November 2006, 05:35 PM

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.

tsubame1 · 23rd November 2006, 05:48 PM

Quote:

Originally Posted by 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.

Hi Dr. Feuerbach.

NihonTo (japanese blades) have martensite. A very high quality work my Dr. Tatsuo Inoue
was online but it is now available only downloading it by my site here under the title "Tatsuo Inoue Swordsmithing file":

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

I believe that "Control of inclusions in japanese ancient iron and steelmaking"
(available in the same link) can be of some interest to you too...

Gt Obach · 23rd November 2006, 07:50 PM

Hi

retained austenite is alway a problem with high alloys... especially with chromium.. .. I know Achim made a wootz with stainless levels of Cr ... and he did maintain it was tough... so i don't know .... if you reach the temp for martensite finish ... you should have good conversion... that why i like to undercool my blades abit... (just me being paranoid )

with the martensitic wootz.... you don't have an extended soak time as you would with other high alloy steel... I just treat it as a plain carbon steel with a very short 4 min soak at non-mag... ... basically, i don't want the large macro carbides to go into solution... just the steel matrix..... i know its abit bizarre.... just the opposite of modern heat treatments for high alloy steels... in the modern case you want the carbides to be dissolved
-- take for example A2 .... with 5% Cr needs 30 to 45 min at 1750 to 1800F for proper heat treat....

-- if you think about it..... part of the forging of the barstock is the growth of these macro carbides........ basically dissolving little ones and adding to the big.. .... through all those heat cycles......... from a black heat up to orange etc

also....... alot of the pattern of wootz has to do with how slow the cool time is from liquid charge to solid.... and.... combined with the roast time (anneal ) afterwards.......both time and temperature ...

just my opinion

Chris Evans · 24th November 2006, 12:27 AM

Hi Ann,

Quote:

Originally Posted by Ann Feuerbach

FYI, Personally, I have not come across any blades with Martensite.

Neither was I aware that they existed until that earlier post by GT Obach and also this paper by Verhoeven and Pendray, available here:

http://met.iisc.ernet.in/~rangu/text.pdf

Quote:

would be interested in any metallurgical studies of antique blades that do have Martensite, so references please.

So would I, but apart from the above, unfortunately I cannot help. I hasten to reiterate that as far as Wootz is concerned, I am a beginner on a steep learning curve.

I imagine that there must have been attempts to quench harden, as opposed to work harden, Wootz blades because of the superior hardness/strength attainable, but we do know the problems associated with quenching hypereutectoid steels. Perhaps quenching from the lowest possible temperature, established empirically would have minimized the problems to an acceptable level. Maybe, by sheer chance every now and then they managed to turn out a martensitic blade that wasn't badly flawed and performed superbly; I just cannot see the ancients regularly turning out superb Martensitic Wootz blades - Just my thoughts as an informed layman on the subject.

If I may impose on you a little: What is the highest measured hardness of a historical blade that you are aware of? And how was it tested (Brinell, Rockwell, Vickers)?.

I suspect that herein resides the original question of this thread. If Wootz swords were not quench hardened, merely work hardened, then I very much doubt that they could have ever been able to cut through armour, never mind wrought iron chains. And as such, whilst serviceable, their legendary reputations must have been based on gross exaggerations.

Cheers
Chris

Ann Feuerbach · 24th November 2006, 02:22 PM

Quote:

Originally Posted by Chris Evans

Neither was I aware that they existed until that earlier post by GT Obach and also this paper by Verhoeven and Pendray, available here:
http://met.iisc.ernet.in/~rangu/text.pdf

Sorry to be a pain, but where in the book do they mention a historical crucible steel blade with martensite? I have had a look and can not find it. Plus is GT Orbach's one from replication or an historical object? I remember doing a survey of all known published historical crucible steel objects, and I do not remember any with martensite, but I could have missed it.

Rivkin, As far as I recall, the information of Anasof's experiments, published by Bogachev, does suggest that his processes were comparable to traditional crucible steel ingredients and processes.

Gt Obach · 22nd November 2006, 02:16 PM

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 · 22nd November 2006, 03:07 PM

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 · 22nd November 2006, 04:52 PM

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.

22nd November 2006, 05:48 AM	#1
Chris Evans Member Join Date: Mar 2005 Location: Australia Posts: 685	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 Last edited by Chris Evans; 22nd November 2006 at 05:59 AM.

22nd November 2006, 01:35 PM	#2
Ann Feuerbach Member Join Date: Feb 2005 Posts: 133	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.

23rd November 2006, 01:52 PM	#4
Chris Evans Member Join Date: Mar 2005 Location: Australia Posts: 685	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

23rd November 2006, 03:22 PM	#5
Ann Feuerbach Member Join Date: Feb 2005 Posts: 133	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.

23rd November 2006, 05:04 PM	#6
Rivkin Member Join Date: Dec 2004 Posts: 655	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).

23rd November 2006, 05:35 PM	#7
Ann Feuerbach Member Join Date: Feb 2005 Posts: 133	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.

23rd November 2006, 07:50 PM	#9
Gt Obach Member Join Date: Mar 2005 Posts: 116	Hi retained austenite is alway a problem with high alloys... especially with chromium.. .. I know Achim made a wootz with stainless levels of Cr ... and he did maintain it was tough... so i don't know .... if you reach the temp for martensite finish ... you should have good conversion... that why i like to undercool my blades abit... (just me being paranoid ) with the martensitic wootz.... you don't have an extended soak time as you would with other high alloy steel... I just treat it as a plain carbon steel with a very short 4 min soak at non-mag... ... basically, i don't want the large macro carbides to go into solution... just the steel matrix..... i know its abit bizarre.... just the opposite of modern heat treatments for high alloy steels... in the modern case you want the carbides to be dissolved -- take for example A2 .... with 5% Cr needs 30 to 45 min at 1750 to 1800F for proper heat treat.... -- if you think about it..... part of the forging of the barstock is the growth of these macro carbides........ basically dissolving little ones and adding to the big.. .... through all those heat cycles......... from a black heat up to orange etc also....... alot of the pattern of wootz has to do with how slow the cool time is from liquid charge to solid.... and.... combined with the roast time (anneal ) afterwards.......both time and temperature ... just my opinion

22nd November 2006, 02:16 PM	#12
Gt Obach Member Join Date: Mar 2005 Posts: 116	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

22nd November 2006, 03:07 PM	#13
Ann Feuerbach Member Join Date: Feb 2005 Posts: 133	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!

22nd November 2006, 04:52 PM	#14
Rivkin Member Join Date: Dec 2004 Posts: 655	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.