See reference below about the composition of damascus and other specialty
ancient swords. They cite actual chemical analyses. Apparently it
isn't very hard to add carbon to iron to get steel; practically any smelter had
to do it because they used charcoal to roast the ore. I don't agree with
the original article you cited about accidental carburization, it didn't have
any actual analyses to back up that opinion. This guy actually cut up and
analyzed old swords.
*cringes*
Some who wander are lost.