True Combat Value of Wootz

Chris Evans · 30th November 2006, 01:24 AM

Greg,

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

Cheers
Chris

RSWORD · 30th November 2006, 02:00 AM

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 · 30th November 2006, 02:25 AM

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 · 30th November 2006, 03:22 PM

Quote:

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 · 30th November 2006, 11:05 PM

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 · 1st December 2006, 03:34 AM

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 · 1st December 2006, 03:53 AM

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 · 1st December 2006, 04:12 AM

Quote:

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!

1st December 2006, 03:34 AM	#6
FourBlades Member Join Date: Aug 2006 Location: Florida Posts: 13	Wootz sandwich anyone? 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

30th November 2006, 01:24 AM	#1
Chris Evans Member Join Date: Mar 2005 Location: Australia Posts: 685	Greg, Many thanks for that link - That patent explains a lot that I couldn't understand. Cheers Chris

30th November 2006, 02:00 AM	#2
RSWORD Member Join Date: Dec 2004 Location: Greensboro, NC Posts: 1,087	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!

30th November 2006, 02:25 AM	#3
Chris Evans Member Join Date: Mar 2005 Location: Australia Posts: 685	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

30th November 2006, 11:05 PM	#5
Chris Evans Member Join Date: Mar 2005 Location: Australia Posts: 685	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

1st December 2006, 03:53 AM	#7
RSWORD Member Join Date: Dec 2004 Location: Greensboro, NC Posts: 1,087	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.