"It didn't even have to have a sharp blade, although that helped. But the main impact of the sword was when you slashed at someone and bashed through his skull, or his arm or his leg. It was for a hard hit."
Yeah, I remember that part and I found it questionable as well. In my own mind I could remember people talking about doing test cutting (including I think here on the ARMA site) where they said that even the dull bladed weapons cut quite surprisingly well. I guess I assumed that is what the guy meant.
On the other hand the best sources I can find seems to indicate that the Viking weapons and metalurgy in general, was like their shipbuilding and some other technologies, if any thing superior to most of their contemporaries.
The pattern welded swords in particular were supposed to be extremely sharp. If the hyperbolic descriptions in the sagas can be believed at even one tenth, I think one has to assume that at the very least, the Norse smiths were making them as sharp as they possibly could without making the blades too brittle.
There is one anecdote which Kevin Cashen mentioned once, which I think is from one of the sagas, about placing a newly crafted sword in a stream and floating a hair down to it: if it cut the hair then it was a "good sword".
Some modern smiths say that the pattern welded weapons while being more flexible were not as hard and therefore sharp as homogeneous high carbon steel swords, but others like Cashen (who seems to be very well regarded in the swordsmithing community) claim that with increasingly perfected tempering techniques and the introduction of some trace elements (such as vanadium and phosphorous) which were believed to exist in VIking swords, they have been able to make swords harder and sharper than the best weapons made from modern steel with a higher carbon content.
There was also an interesting article in Popular Science magazine about how tiny amounts of Vanadium found in Indian Wootz ("damascus") steel helped to harden it by fitting into the troughs of tiny cementite 'waves' or ripples which were formed in the steel during the tempering process.
It's all a little over my head, I can't even make a clay pot in a kiln!
JR
JR