Viking Swords and Wootz

Chris Evans · 14th January 2009, 12:33 AM

Hi Jeff (Pringle)

Nicely put. All valid observations.

Cheers
Chris

katana · 15th January 2009, 02:14 PM

Not being a metallurgist

but extremely interested in the forging of blades, could someone please help explain....
....am I correct in thinking that if a billet of wootz is forged, normalised, quenched and tempered the structure of the wootz is altered and the surface pattern lost...would that mean that crucible steel forged in the same way as sponge iron ( as perhaps viking smiths would have done) the resulting blade would also not have the same crystalline structure. (assuming wootz and crucible steel are not the same)

If so ...would the quality of the blade suffer, now that the structure of the crucible steel or wootz is much more homogenised after repeated hammering and folding ?

Would the carbon content of the crucible steel increase with the repeated heating in a charcoal forge ....if so wouldn't the higher carbon content make the blade increasingly brittle?

Thank you

Regards David

kisak · 15th January 2009, 03:39 PM

From my understanding, it would be entierly possible at least to obliterate the patterns seen in wootz and similar steels if you work the material "wrong". One of the things you want to achieve with the treatment you give to bloomery iron is to even out the chemical composition, while in patterned crucible steels those differences are what gives us the pattern. The "dangerous" part here is probably the extensive forging. The heat treatment (normalising, quench and temper) could leave the primary ferrite or carbides that form the pattern intact, in theory at least.

As for the properties, the impression I've gotten is that it's uncertain whether or not the grouped nature of the "pattern forming" parts in wootz and similar truly gives a benefit (it wouldn't surprise me if it was the other way around actually, fine scale and evenly distributed are often good ideas). Assuming that the austenitisation is done at the right temperature, it should be entierly possible to get the same amount of carbides out of the steel even after the pattern has been destroyed, they will just be more evenly distriburted in the blade.

Chris Evans · 15th January 2009, 10:17 PM

Hi David,

Your question covers a lot of territory defying short explanations that I may come up with and which could be readily understood - Keep in mind that sometimes it is said that those who understand the metallurgy of steel understand all of metallurgy because iron-carbon is so complex. Jeff Pringle can probably do beter, though in the meanwhile I suggest that you wrestle a bit with this paper: http://www.tms.org/pubs/journals/JOM...html#Verhoeven to better understand pattern yielding Wootz, which the authors call Wootz Damascus.

I should mention that swords made from bloomery iron (sponge iron) were forged at higher temperatures and I have read a number of accounts that later era European swordsmiths who managed to obtain Wootz cakes could not forge it successfully as they did not know that a lower temperature was a requisite.

Cheers
Chris

Gonzalo G · 17th January 2009, 02:33 AM

All depends on which europeans, and in which timeline. In Spain wootz was imported and forged to the mid 19th Century. You can see some references here:

http://forums.swordforum.com/showthread.php?t=80073

Sorry if I cannot follow in real time this discussion, but I don´t have many chances to get into internet.

In fact, there are many articles form Verhoeven online, and some of them are posted in forums, as you can´t find them on Verhoeven´s page anymore, but the last word on the antique wootz heat threatments and wootz blade quality (as the steel, it´s forging and the resulting sword cannot be separated completely), is yet to come from other sources and more extenisve studies of old blades. I believe there are more discoveries to make.

There are also other many sources about wootz, in english and in other languajes. Srinivasan and Ranganathan are some of them, but you can also find articles from the publications of the Indian National Science Academy, among others, here:

http://www.insa.ac.in/html/home.asp

The excellent work from Verhoeven "Matallurgy for Bladesmiths and Others...", is not very indispensable to the specific study of wootz, unless you want a deep comprehension of it´s chemical characteristics and structure, and it is a heavy reading for those not interested in learning metallurgy and forging and heat threating blades. But is a great treatise on this last subject, which I love and appreciate very much. It provides, neverthless, with the necessary understanding of general steel inner structures and how they are produced.
Regards

Gonzalo

14th January 2009, 12:33 AM	#1
Chris Evans Member Join Date: Mar 2005 Location: Australia Posts: 685	Hi Jeff (Pringle) Nicely put. All valid observations. Cheers Chris

15th January 2009, 02:14 PM	#2
katana Member Join Date: Jan 2006 Location: Kent Posts: 2,658	Not being a metallurgist but extremely interested in the forging of blades, could someone please help explain.... ....am I correct in thinking that if a billet of wootz is forged, normalised, quenched and tempered the structure of the wootz is altered and the surface pattern lost...would that mean that crucible steel forged in the same way as sponge iron ( as perhaps viking smiths would have done) the resulting blade would also not have the same crystalline structure. (assuming wootz and crucible steel are not the same) If so ...would the quality of the blade suffer, now that the structure of the crucible steel or wootz is much more homogenised after repeated hammering and folding ? Would the carbon content of the crucible steel increase with the repeated heating in a charcoal forge ....if so wouldn't the higher carbon content make the blade increasingly brittle? Thank you Regards David

15th January 2009, 03:39 PM	#3
kisak Member Join Date: Jul 2008 Location: Stockholm Posts: 182	From my understanding, it would be entierly possible at least to obliterate the patterns seen in wootz and similar steels if you work the material "wrong". One of the things you want to achieve with the treatment you give to bloomery iron is to even out the chemical composition, while in patterned crucible steels those differences are what gives us the pattern. The "dangerous" part here is probably the extensive forging. The heat treatment (normalising, quench and temper) could leave the primary ferrite or carbides that form the pattern intact, in theory at least. As for the properties, the impression I've gotten is that it's uncertain whether or not the grouped nature of the "pattern forming" parts in wootz and similar truly gives a benefit (it wouldn't surprise me if it was the other way around actually, fine scale and evenly distributed are often good ideas). Assuming that the austenitisation is done at the right temperature, it should be entierly possible to get the same amount of carbides out of the steel even after the pattern has been destroyed, they will just be more evenly distriburted in the blade.

15th January 2009, 10:17 PM	#4
Chris Evans Member Join Date: Mar 2005 Location: Australia Posts: 685	Hi David, Your question covers a lot of territory defying short explanations that I may come up with and which could be readily understood - Keep in mind that sometimes it is said that those who understand the metallurgy of steel understand all of metallurgy because iron-carbon is so complex. Jeff Pringle can probably do beter, though in the meanwhile I suggest that you wrestle a bit with this paper: http://www.tms.org/pubs/journals/JOM...html#Verhoeven to better understand pattern yielding Wootz, which the authors call Wootz Damascus. I should mention that swords made from bloomery iron (sponge iron) were forged at higher temperatures and I have read a number of accounts that later era European swordsmiths who managed to obtain Wootz cakes could not forge it successfully as they did not know that a lower temperature was a requisite. Cheers Chris

17th January 2009, 02:33 AM	#5
Gonzalo G Member Join Date: Apr 2007 Location: Nothern Mexico Posts: 458	All depends on which europeans, and in which timeline. In Spain wootz was imported and forged to the mid 19th Century. You can see some references here: http://forums.swordforum.com/showthread.php?t=80073 Sorry if I cannot follow in real time this discussion, but I don´t have many chances to get into internet. In fact, there are many articles form Verhoeven online, and some of them are posted in forums, as you can´t find them on Verhoeven´s page anymore, but the last word on the antique wootz heat threatments and wootz blade quality (as the steel, it´s forging and the resulting sword cannot be separated completely), is yet to come from other sources and more extenisve studies of old blades. I believe there are more discoveries to make. There are also other many sources about wootz, in english and in other languajes. Srinivasan and Ranganathan are some of them, but you can also find articles from the publications of the Indian National Science Academy, among others, here: http://www.insa.ac.in/html/home.asp The excellent work from Verhoeven "Matallurgy for Bladesmiths and Others...", is not very indispensable to the specific study of wootz, unless you want a deep comprehension of it´s chemical characteristics and structure, and it is a heavy reading for those not interested in learning metallurgy and forging and heat threating blades. But is a great treatise on this last subject, which I love and appreciate very much. It provides, neverthless, with the necessary understanding of general steel inner structures and how they are produced. Regards Gonzalo