Yeah, metallurgy is not my strong suit, and I’m sorry but we never got the rest of your response. Also, apologies for the delay, we’ve got a few left over in our backlog from during the trip, and I’m going to try to knock those out over the next couple days.
The short version is that the katana was forged out of pig iron. The Japanese gave it a fancy name, but it was still the same low quality stuff Europe and China were using to make plows and cookware. It was forged using the same techniques Europe had used in the 800s, and abandoned before Japan was ever founded.
My understanding is that you beat the blade out and fold it, in an effort to remove excess carbon, making the blade less brittle, but also softer.
I’ve heard (and read) that Katanas should be refereed to as either iron or cold steel, and, as with a lot of the Katana, there’s a lot of parsing of myth from reality, because of the blade’s cultural history and status. I erred with cold steel, which, given everything else, might be technically wrong.
Anyway, if you want to dig in more, I’d be glad to post it together into a coherent post. The easiest format would be if you’d actually register an account, and write the whole thing up in one shot, but I can use the quote system in here to stitch it together.