True Combat Value of Wootz

[Emanuel]

Hi Chris,

Many thanks for your explanation. I had simply understood austenite to mean a high-grain crystal structure, as per Carlo's informative pictures. I understand my mistake now. I also found this good site http://www.metal-mart.com/Dictionary/dictlist.htm with quick definitions for metallurgical terms.

So temperature control is more or less the whole secret to good forging, correct? Now, would an European smith with comparable levels of knowledge and experience to a top Indian/Persian smith be able to create wootz/pulad ingots and forge a watered blade from European iron ore? Or is the precise mix of iron/carbon of Indian ore important? Gt.Obach, is your home-forged wootz chemically the same as the traditional Indian ingots?

Carlo, besides splitting kindling with an axe and cutting bread, it's true I've never cut anything Some training would indeed be recommended.

Regards,
Emanuel

[Chris Evans]

Hi Emanuel,

Originally Posted by Manolo

Hi Chris,
So temperature control is more or less the whole secret to good forging, correct?

You certainly identified correctly one of the most important factors. But there are many others such as the chemical composition of the steel, that of the fuel, atmosphere control, `soaking' time and temperature. Metallurgy involves the successful management of quite a number of variables.

Now, would an European smith with comparable levels of knowledge and experience to a top Indian/Persian smith be able to create wootz/pulad ingots and forge a watered blade from European iron ore? Or is the precise mix of iron/carbon of Indian ore important?

Forging Damascus Wootz with the tell-tale surface pattern was considered a lost art until very recently. Have a read of that paper that I gave the link to in my post early on, No8 in this thread. It will probably answer your questions. One of the big problems, as I see it, is that we do not even have a clear consensus as to what we are talking about, that is what exact type of steel, forging and heat treatment we are specifically interested in. For my part, I am happy to settle for any pre modern crucible steel, but others apply a much tighter definition. For example, in the above link, one of the swords was declared not to be true Wootz Damascus because it had a lower carbon content.

Cheers
Chris

[Gt Obach]

Hi

yes.. i believe the definition of wootz does wander all over the place for reasons....

ask yourself some questions...
- why does the definition wander
- why does the current definition follow the patent on wootz
- was wootz a lost secret prior to the patent ??
- was a proper survey done before making the above claim
- Do accurate recipes exist that are from ancient records and are accessible with university interlibrary loan..? ..... did they exist prior to the patent ? or did they magically appear after the patent?

I know i ask alot of questions... but I can't help my self... .. i have to stir the pot sometimes..



Manolo: the problem with comparing Euro smiths to Indian/Persian smiths is that they basing their smithing practices on much different materials... ... that is why the Euro smiths had a hard time with forging wootz... as the wootz material has to be forged at a much lower heat than what they safely use for their sword material....

now with the same technique... i believe it maybe possible with some of the european ores..... remember the carbide formers are micro alloys... very small amount is needed..
-- but the carbon level is critical to making the high carb wootz...


My homebrew wootz is made alot of the time with cast iron cut with mild iron.... but now a days... there is alot of tramp elements in the scrap iron... so you have to watch it... .. our metal standards are going down hill..
-- i've made all sorts of wootz from scrap... ..some with 52100 and cast iron.... with assorted springsteels and cast... 1018 iron and charcoal.... wrought and charcoal...

i know Jeff uses local ore
and Ric will use that high purity iron

I'd love to get some ore from the old areas... and try my hand at it... ... i thought awhile back that Achim did something like that.... i know he's worked some old ingots

so much wootz, so little time

Greg

[Jeff Pringle]

The steel I make typically runs a little higher in silicon and quite a bit lower in phosphorus compared to the analyses in the JOM article, but I recently got an ingot with comparable phosphorus that has great pattern, even though it's 0.73% Carbon...but I also get good patterns with low phosphorus, so I'm not sure what that means
Need...more...data

[Chris Evans]

Hi Greg,

I wasn't even aware that Wootz was patented. Who took out the patent and what exactly was patented? The composition or forging? Or both?


Jeff,

That blade's pattern is very beautiful. Given its hypoeutectoid composition, did you quench harden it? Are the patterns due to Ferrite or carbides?

Cheers
Chris

[Gt Obach]

Nice work, Jeff.... thats real sweet !


Hi Chris... .. I spent a good bit of time... but i finally dug up the patent on the us patent site... so you can look for your self.. its alway better to see references first hand..

http://patft.uspto.gov/netacgi/nph-P...us&RS=damascus


I don't believe its been challenged

[Chris Evans]

Greg,

Many thanks for that link - That patent explains a lot that I couldn't understand.

Cheers
Chris

[RSWORD]

As a collector of wootz blades this has been an enlightening and quite enjoyable discussion. While I am not an experienced metalurgist to contribute to the discussion, I have made casual observations in the various wootz blades I have handled over the years or are in my collection. The first is that from a collectors point of view, the pattern of wootz is oftern associated with a particular region. For example, I would typically associate sham style wootz with Turkey or Syria. Low contrast wootz with a fine granular structure is most often associated with India. Very bold, high contrast wootz is often associated with Persia although you do find similar patterning in some Sosun Pata and Khanda that are almost certainly Indian. I even have an example of Russian forged wootz that has very little contrast but the pattern is tight and consistent throughout the blade. I have also noticed some other interesting features. One is heat treatment. I have a number of blades which exhibit a "hamon" of sorts, essentially a darkened zone along the edge due to the heat treatment. I have seen blades that seem only to be heat treated at the tip or in certain spots of the blade. One very interesting blade in my collection actually has a high carbon edge plate that has been inserted into wootz "cheeks". Now, imagine what potential cutting properties this sword might have. You have a high carbon edge plate which can be very hard and sharp with cheeks of wootz steel which can be quite pliable. I even have an "unknown" blade that is extremely thin, extremely pliable but is quite hard and tough throughout as an interesting variant.

You also see varying degrees of success in the overall controlling of heat of a blade. I have seen a few fine blades with really nice patterns that just melt away or disappear in areas where the heat was not controlled. I have an example of an Indian shamshir that broke in two in its life but was welded back together with practically no loss of the wootz pattern. In a day and time when controlling temperature must have been difficult, it seems the smiths had abilities to do some interesting things.

All this says is that wootz provides a fascinating variety of patterns, contrasts, colorations, heat treats, etc. that I think it is impossible to lump into one big broad category. It seems like one of those endeavors the more you learn about it, the more you realize is unknown. But isn't that the fun!

[Chris Evans]

Hi RSWORD,

Thank you for your most interesting post. You are confirming my worst fears, that we have reduced the term Wootz to a metallurgical cliche!

I think that there is much more to crucible steel than current interpretations of the term Wootz would suggest.

It would be very educational if you could photograph your collection, at least the more outstanding pieces and post them here. A bit of judicious file testing for hardness, standardized against steel specimens of known hardness would also throw a lot of light on the subject.

Cheers
Chris

[Jeff Pringle]

Given its hypoeutectoid composition, did you quench harden it? Are the patterns due to Ferrite or carbides?

Yes, its quenched in oil, from not too far above the critical temperature. There is a 'Hamon' effect due to the edge hardening but not the thicker part of the blade. Low alloy steels like wootz are very shallow hardening, so only the edge area cools fast enough to harden when you quench into oil.
The pattern is due to the natural alloy segragation that happens during ingot solidification; since it is not too far from the eutectiod, the pattern cannot be from excess carbides or excess ferrite. In higher carbon wootz, the carbides are just along for the ride, the pattern fundamentally comes from the difference in composition of the first and last parts of the melt to solidify.

[Chris Evans]

Hi Jeff,

Many thanks for that account.

I wonder if the ancients could consistently turn out hypoeutectoid Wootz, other than by accident. I imagine that controlling carbon absorption would be the main problem. It certainly would have made quenching and tempering easier.

Cheers
Chris

[FourBlades]

RSWORD,

I also have a (tulwar) blade that looks like it is made from two pieces of wootz with a non-wootz core. The wootz pattern stops as the blade gets thinner towards the sharp edge. It also has some areas where the wootz pattern disappears. There are some irregularities in this area and I wonder if it was also broken and welded together, perhaps not as expertly as yours. I am away from home now or I would post some pictures of it for comment.

Thanks,

John

[RSWORD]

I am always happy to share examples from the collection but I have found wootz to be difficult to photograph especially for the subtle details like we have been discussion such as coloration, temper lines, very subtle patterns, etc. Nonetheless, I will take a few shots over the weekend for comment and or discussion.

John,

Sounds interesting. Look forward to seeing some pics of it.

[Jeff Pringle]

I wonder if the ancients could consistently turn out hypoeutectoid Wootz, other than by accident. I imagine that controlling carbon absorption would be the main problem. It certainly would have made quenching and tempering easier.

It is possible that they hit upon the 1.5%-ish range as the carbon level that most often gave well-melted ingots that were still forgeable; since carbon content is the big influence on melting temp. Too little carbon and it won't melt (at whatever the max temp of the charcoal-fired clay furnace they typically used was), too much and it's unforgeable. So they may have aimed for that content with the ingredients of the charge, and had a few outliers depending on how the crucibles sat in the heat of the furnace, or how carefully they measured the ingredients.

For photos, bright indirect light is a must, and then use black or white cardboard as the background reflected by the blade, one or the other will give you a good shot of the pattern. An overcast day outside, or lights with diffusers indoors work well.

Please do post photos of any unusual wootz effects!

[Chris Evans]

Hi Jeff,

From the Fe-C phase diagram, the MP difference for pure Iron and 2%C is not that great (224DegC), though substantial. It is only when we get to the 0.4% cast irons that the MP drops significantly . Whilst I recognize that Wootz with 2% is easier to melt than hypoeutectoid steel, I would have thought that the difference could have been overcome.

Where I envisage the real difficulty to have been is in ascertaining how much carbon would the steel absorb, with any accuracy. At this stage, my suspicion is that the hypoeutectoid Wootz produced was by decarburization, something not difficult to do once the steel was hot and fully Austenitized. I inadvertently managed to seriously decarburize steel by poor atmosphere control on a number of occasions.

Just my thoughts...

RSWORD

It will be great to see pics from your collection. I am also interested in the angle of the edge at the centre of percussion. It can tell us quite a lot.

Cheers
Chris

[Chris Evans]

Hi Jeff,

From the Fe-C phase diagram, the MP difference for pure Iron and 2%C is not that great (224DegC). It is only when we get to the 0.4% cast irons that the MP drops significantly . Whilst I recognize that Wootz with 2% is easier to melt than hypoeutectoid steel, I would have thought that the difference), though substantial, could have been overcome.

Where I envisage the real difficulty to have been is in ascertaining how much carbon would the steel absorb, with any accuracy. At this stage, my suspicion is that the hypoeutectoid Wootz produced was by decarburization, something not difficult to do once the steel was hot and fully Austenitized. I inadvertently managed to seriously decarburize steel by poor atmosphere control on a number of occasions. Just my thoughts...



RSWORD

It will be great to see pics from your collection. I am also interested in the angle of the edge at the centre of percussion. It can tell us quite a lot.

Cheers
Chris

[S.Al-Anizi]

Sorry for not contributing (for good or bad ) to this thread anymore, I really like the level of professional conversation and the sharing of facts and experiences around, by all those great people who have contributed to this thread. I have not lost interest in this topic, its just that I seemed to have lost it somewhere from the 5th page, I do not understand 75% of the metalurgical words tossed about Still, interesting and very informative though.

[RSWORD]

Ok. I have had fun this evening as I have had some pieces out and about and taking a lot of pictures. What I am going to do is do a separate thread for each example so we can discuss them individually. I will make comments from a collectors point of view and perhaps you guys can share any metalurgical comments and we will see how it goes. In any case, I enjoyed taking all the pictures but my photography skill is obiously lacking!

[Rivkin]

Fugh. I finished going through the original Anosov's report "On Bulats". It is a fantastic work. There are two comments that I would make:

a. I have to take back my statements about inconsistency in chemical composition etc. It is impossible to make such statements, since there are no less than four distinctive processes to make bulat per Anosov, and there are dozens of ways he combined ingridients, tempering and so on. For example, to enrich the blade with carbon he tried graphite, different kinds of wood and even diamonds, with different results.

b. Unfortunately here we have the same story as with later literature - as soon as we get to the performance of wootz blades, the "magic" replaces the science. In his introduction he talks a lot about how good bulat blades are. To give you an example, one of his strong points is that japanese blades (undoubtfully made from bulat) are very good - chop iron etc. This and other arguments are rather obvious misrepresentations of what bulat really is, and btw I know a strange guy who tests his chechen kindjals by attempting to cut hard steel _drills_, which is by far nothing like iron.

Conclusion, which is also about the quality, this time of Anosov's bulats is also highly disappointing. Short text with no reproducable experiments (i.e. such blade is compared to such blade) that cites for example that Anosov was not able to make from english steel the blades that cut as fine cloth as the one made from his bulat (properly prepared). It can be interpreted as something that shows the superiority of bulat. However one also has to note that Anosov's experiments were quite complex to reproduce and required collosal work to determine the right tempering, ingridients and so on, resulting in a very expensive and very capritious with respect to the conditions of making (i.e. improper making would not produce such good results) end product. On one side it is possible that top wootz smiths produced steel far superior to ordinary pre XXth century steels; on the other hand comparison was made with mass produced english steel - who can vouch that some top quality steelmakers would not make something much better ?

[Chris Evans]

Hi Al-Anizi,

Originally Posted by S.Al-Anizi

Sorry for not contributing (for good or bad ) to this thread anymore, I really like the level of professional conversation and the sharing of facts and experiences around, by all those great people who have contributed to this thread. I have not lost interest in this topic, its just that I seemed to have lost it somewhere from the 5th page, I do not understand 75% of the metallurgical words tossed about Still, interesting and very informative though.

I was really worried that this might happen - I apologize - We turned this thread into an insider's discussion. I don't know hat we can do to remedy the situation - Perhaps, the underlisted glossary may render the technical terms used a little more understandable.

Austenite: A crystal structure of iron and its alloys that is known for its softness and malleability. It only can be found once the steel is heated to red heat. If it is rapidly cooled (quenched) it transforms into Marteniste. If, on the other hand, it is cooled slowly, it will transform into Ferrite and Cementite.

Austenite - Retained: Austenite that fails to transform into Martensite upon quenching and is retained as such at room temperature. Retained Austenite is much more likely to form with steels with a carbon content greater than 0.8%, that is , hypereutectoid. It is generally considered highly undesirable as it is a source of weakness. Usually, the quenched steel is a mixture of Martensite and Austenite in varying proportions - Depending where it is located, a small amount of Retained Austenite can usually be tolerated.

Carburization: Iron is heated in the presence of carbon so that it may absorb this element. This is obtained by heating above red heat, when the crystal structure changes to Austenite, which readily absorbs carbon.

Cementite: An intermetallic compound of iron and carbon. It is both extremely hard and brittle. It is usually, though not always, found as tiny globules, in which case it is called sperodized Cementaite or as very thin plates (lamellae) in the structure known as Pearlite.

De-Carburization: The removal of carbon from steel by heating to above red heat so that the crystal structure changes to Austenite and in an oxygen rich atmosphere. The carbon leaves the steel to combine with the oxygen.

Eutectoid Steel: A steel of 0.8% carbon content - Optimal composition for hardness and toughness.

Hypo-eutectoid Steel: A steel with a carbon content of less than 0.8% carbon, but usually more than 0.4% carbon

Hyper-eutectoid Steel: A steel with a carbon content in excess of 0.8% but less than 2%. These steels are considered very difficult to harden by transforming Austentie to Martensite (by quenching from red heat) because of the tendency of the high carbon Austenite to remain as such down to room temperature.

Ferrite: The crystal structure of unhardened near pure iron that prevails at room temperature. It is fairly soft and malleable, though not to the same extent as Austenite. As the carbon content of steel approaches 0.8%, Ferrite is increasingly complemented by the presence of Pearlite.

Hardening: A process by which steel is rendered both hard and tough. This is usually attained by the transformation of Austenite to Martensite by fisrt heating to red heat and then rapidly cooling, usually by quenching into water or oil. Afterwards the had and brittle Martensitic steel is toughened through tempering, by reheating to a lower temperature (than red heat). And alternative to hardening by heating and quenching is to cold work (work hardening) the steel - This is the same effect as when we bend coat-hanger wire backwards and forwards; Whilst this can increase both the hardness and toughness of steel, it is not as effective as heating and quenching.

Martensite: The crystal structure of steel hardened by quenching from red heat. Since in the as quenched state it is very brittle, it is normally softened and made less so by tempering. The maximum carbon content of Austenite that can be converted to Martensite is around 1% - Any more than this value will result in the retention of Austentite down to room temperature.

Pearlite: The microstructure of unhardened eutectoid steel, that is, with a carbon content of 0.8%. When viewed under the microscope it consists of very thin layers of Cementite alternating with Ferrite and has the appearance of mother-of-pearl, hence its name. Under 0.8%C Pearlite is accompanied by Ferrite and above that composition by Cementite.

Sorbite: A name given to Martensite which has been tempered.

Sponge/Bloom/Bloomery Iron: Is and extremely low carbon steel that is obtained by heating the iron ore (Iron Oxide) with carbon to red heat, without any melting taking place. The oxygen in the ore combines with the carbon, in a process known as `reduction', to leave behind the very low carbon steel in a sponge like state. The pores of the iron sponge, the Bloom, are full of slag (coarse glass) from the ore. This slag has to be removed by extensive hammering in the red hot state, by squeezing it out of the many pores. To render it into hardenable steel it has to be Carburized. This method was used extensively in antiquity to prodce iron and steel.

Steel: An alloy of iron and carbon. The stuff from which swords and dagger are made (after the bronze age). Ideally, it is both hard and tough.

Tempering: The re-heating of as quenched steel to render it less brittle, at the expense of some loss of hardness. Tempering is carried out at temperatures at which shiny steel changes its colour to that of straw or even blue.

Wootz/Puald/Bulat/Crucible Steel: Steel made in ancient India by heating iron ore with carbon in a crucible. Wootz differs from `sponge/Bloom' iron in as much that it it melts in the crucible and thus the slag and other impurities float to the surface.

Cheers
Chris

[Chris Evans]

RSWORD,

Look forward to the pics.

Rivkin,

I reluctantly concluded that at this point we simply do not know enough about Wootz and the requirements of ancient swordsmen to assess its combat worthiness.

To make headway, we need to examine a larger number of swords and daggers made from this steel and most importantly ascertain if the better ones, in the functional sense and not just eye candy, were hardened by quenching or merely work hardened. Also, we have to ascertain if the practice of adding a special steel edge, in the Japanese manner, was used by the Damscus and other regional sword smiths.

As I see the problem now, with the advantage of modern metallurgical knowledge we can, as Greg and other amply demonstrated, make extremely good cutting implements from high carbon crucible steel. However, we do not know if the ancients knew all the tricks required to arrive at comparable results.

Cheers
Chris

[Chris Evans]

RSWORD

I would like to express my thanks and appreciation for your efforts in posting the photos of your Wootz blades. They certainly present food for thought. As I mentioned elsewhere, it would help us enormously if somehow the edge hardness of those blades could be ascertained. A bit of very careful file testing against samples of known hardness would go a long way.....

With regards to the one that seems to have a hardened steel edge inserted, it brings to my mind a story that I was told in my student days, long ago, about clever forgeries involving a common (?) steel blade somehow overlaid with thin veneers of Wootz. I hasten to add that this never made much sense to me as the work involved would have been huge, requiring great skill - Much more likely is that here we have a composite type of sword construction that was misunderstood by Europeans.

Again, may thanks
Chris

[tsubame1]

Is the use of wootz for gun barrels enough to be considered "true combat value"?

If yes, i've already mentioned it but Philip gave a good hint in another thread :

"I suspect that the barrel on your gun is much older, with the breech altered to accept a percussion bolster and nipple. The configuration of your barrel could well indicate Persian manufacture. Without inscriptions it can be difficult to date these, but good quality ones remained in service for a long, long time.

Many of these old Persian (and Indian) barrels are of twist damascus steel. HAVE YOU TAKEN YOUR GUN APART? Often, the portion of the barrel covered by wood is less corroded and a damascus pattern might be visible."

Post n.10 here :

http://www.vikingsword.com/vb/showthread.php?t=3636

[S.Al-Anizi]

Many, many thanks Chris, for that list. Ive always wanted to know, very basically, what those terms meant. I already knew simple stuff like...steel (DUH ), hardening, tempering, quenching, but not the rest. I have even printed your text for future reference.

Thanks a bunch!

[Andrew]

Originally Posted by tsubame1

Is the use of wootz for gun barrels enough to be considered "true combat value"?

If yes, i've already mentioned it but Philip gave a good hint in another thread :

"I suspect that the barrel on your gun is much older, with the breech altered to accept a percussion bolster and nipple. The configuration of your barrel could well indicate Persian manufacture. Without inscriptions it can be difficult to date these, but good quality ones remained in service for a long, long time.

Many of these old Persian (and Indian) barrels are of twist damascus steel. HAVE YOU TAKEN YOUR GUN APART? Often, the portion of the barrel covered by wood is less corroded and a damascus pattern might be visible."

Post n.10 here :

http://www.vikingsword.com/vb/showthread.php?t=3636

Hi Carlo. I think Philip was talking about pattern welded "damascus", not wootz.

[ariel]

Originally Posted by Rivkin

Fugh. I finished going through the original Anosov's report "On Bulats". It is a fantastic work. There are two comments that I would make:

a. I have to take back my statements about inconsistency in chemical composition etc. It is impossible to make such statements, since there are no less than four distinctive processes to make bulat per Anosov, and there are dozens of ways he combined ingridients, tempering and so on. For example, to enrich the blade with carbon he tried graphite, different kinds of wood and even diamonds, with different results.

b. Unfortunately here we have the same story as with later literature - as soon as we get to the performance of wootz blades, the "magic" replaces the science. In his introduction he talks a lot about how good bulat blades are. To give you an example, one of his strong points is that japanese blades (undoubtfully made from bulat) are very good - chop iron etc. This and other arguments are rather obvious misrepresentations of what bulat really is, and btw I know a strange guy who tests his chechen kindjals by attempting to cut hard steel _drills_, which is by far nothing like iron.

Conclusion, which is also about the quality, this time of Anosov's bulats is also highly disappointing. Short text with no reproducable experiments (i.e. such blade is compared to such blade) that cites for example that Anosov was not able to make from english steel the blades that cut as fine cloth as the one made from his bulat (properly prepared). It can be interpreted as something that shows the superiority of bulat. However one also has to note that Anosov's experiments were quite complex to reproduce and required collosal work to determine the right tempering, ingridients and so on, resulting in a very expensive and very capritious with respect to the conditions of making (i.e. improper making would not produce such good results) end product. On one side it is possible that top wootz smiths produced steel far superior to ordinary pre XXth century steels; on the other hand comparison was made with mass produced english steel - who can vouch that some top quality steelmakers would not make something much better ?

RSWORD just posted this:
http://www.vikingsword.com/vb/showthread.php?t=3680
No matter how many uncertainties are there in the Anosov's book, the final result was terrific

[Chris Evans]

Hi S.Al-Anizi,

Originally Posted by S.Al-Anizi

Many, many thanks Chris, for that list. Ive always wanted to know, very basically, what those terms meant. I already knew simple stuff like...steel (DUH ), hardening, tempering, quenching, but not the rest. I have even printed your text for future reference.

Thanks a bunch!

Glad tp have been of some help. I wrote those definitions on the run and left out much. I suggest that if you wish to use them for future reference that you complete the picture, so to speak, by looking up more comprehensive sources

Cheers
Chris

[Chris Evans]

Hi Folks,

Just a couple of thoughts:

Something else that we do not know, in relation to Wootz, is how common was the regional concurrent usage of steel made from sponge/bloom iron. Perhaps, Wootz was a specialized steel suitable for some applications and not others.

Another question is whether the hardened steel insert edges found on some swords, as evidenced by RSWORD's beautiful example, were made from Wootz or sponge iron steel.

Cheers
Chris

[Emanuel]

Chris,
Your definitions are extremely helpful, many thanks.

As a quick aside - since wootz/patterned crucible steel was so desirable in weapons for its aesthetic properties as well as mechanical, was wootz ever used for jewellery? Are there purely decorative objects made of crucible steel and etched?

Regards,
Emanuel

[Chris Evans]

Hi Emanuel,

Originally Posted by Manolo

Chris,
Your definitions are extremely helpful, many thanks.

Thank you.

As a quick aside - since wootz/patterned crucible steel was so desirable in weapons for its aesthetic properties as well as mechanical, was wootz ever used for jewellery? Are there purely decorative objects made of crucible steel and etched?

Very good question - We need to know more about Wootz usage.

Cheers
Chris