Join Date: Mar 2006
Location: Sturgeon Bay, Wisconsin
This will be rough, but its from memory.
I can not speak for Dr. Williams, but I was in India when he first presented this paper in 2007 (later published in Gladius I think). It is my recollection, as I do not have the paper in front of me, that Dr. Williams tested 13? Ulfberht blades of the 30-60? known and four or so (all with "Ulfberht" spelled the same by the way) turned out to be slag free in the body of the blade and it is this lack of slag and the carbon content which led to the idea that it was forged from a crucible steel product. I can see no flaw in that argument.
The only other way to obtain slag free steel is to be lucky enough to have some form as a liquid in the bottom of an open reduction process and use this to forge a sword, but I have not ever seen a large enough single piece to make a sword (a small knife perhaps, but not a sword). There was no evidence of a weld line in the slag free blades tested...this does not mean that there was no weld, but id does mean that none was seen. I would think that this could be proven one way or another by sectioning the entire blade in many directions, but I doubt this would ever be allowed to occur.
Where the crucible steel came from is up for debate as it is almost impossible to trace the origin of such things.
The article referenced above is more sensational then the original as one would expect such in a popular newspaper.
Do keep in mind that Dr. Williams also gave us the "Knight and the Blast-furnace" some years ago...which was no small task either.
What this slag free finding shows me is that the old smiths were far more clever then we think and perhaps trade was far more widespread then what was previously assumed. This also illustrates the matter of discovering craftsmen's work and viewing it with tools which allow us to appreciate their accomplishments.