On 27 Mar 2006 17:46:12 -0800, "oneota" wrote:

The man uses the product (which he called in English
"pig iron") to repeatedly hammer and heat into steel which he finally
makes into steel sword blades,

I havent a clue about Korean techniques, but this is a typical process
for any sword-making tradition from the medieval period to the 18th
century.

You begun with a billet of crude pig iron. Surface carburisation turns
this to a blister steel and repeated cut-weld-draw down cycles make this
into a high quality steel. The final result varies from surface hard
through laminated pseudo-damascus to pattern-welded steels.

There's a good description in Leon Kapp's excellent Japanese sword book.