Well, last summer I was riding my bike home from the strawberry farm where I worked, and what should I find but a piece of Thomas Powers' "infamous carry-iron", to quote another thread. It was a 6 inch piece of 1/4 in. walled 2 1/2 square tube with two elongated holes (on opposite sides) that promptly went in my backpack. I don't have any pictures or know what it was from, but a spark test seemed to indicate low to medium carbon steel.