"Good Lord, this technology has been around for over 1600 years? To think how much rust proof steel could have saved in money, time, and labor. Staggering."
I just thought the same thing - rust proof! All these years, the technology was lost. How many other secrets have been lost to us, and are just waiting to be rediscovered?
My Granddad passed away last year at age 98. He was at turns a foundry worker, machinist, master patternmaker and coremaker. He claimed that the "old timers" (folks who were 50 or so in the 1920s) told him that there had once been a process to harden copper so as to use it for tools, etc.
One wonders if the ancient Egyptians (who used copper tools to cut the stone used in the Pyramids) knew of this process.
There was probably a scroll or three on this in the Great Library of Alexandira before it was destroyed.