True Combat Value of Wootz

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!

Chris Evans · 1st December 2006, 04:43 AM

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 · 1st December 2006, 04:44 AM

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 · 2nd December 2006, 07:49 PM

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.

1st December 2006, 03:34 AM	#4
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, 02:25 AM	#1
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	#3
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	#5
RSWORD Member Join Date: Dec 2004 Location: Greensboro, NC Posts: 1,086	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.

1st December 2006, 04:43 AM	#7
Chris Evans Member Join Date: Mar 2005 Location: Australia Posts: 685	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

1st December 2006, 04:44 AM	#8
Chris Evans Member Join Date: Mar 2005 Location: Australia Posts: 685	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

2nd December 2006, 07:49 PM	#9
S.Al-Anizi Member Join Date: Jun 2006 Location: Arabia Posts: 278	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.