Originally Posted by
AlexCyclistRoch
Problem with steels are that generally, as steels get harder, they get brittle. You COULD try heat-treating all the pieces of a chain, maybe even case-harden them, but then a chain would cost maybe $100. Coatings and regular lubrication are much more cost-effective.
You could alloy them to form carbides too, and numerous other things that would most likely increase cost and complicate things with dubious benefit. KMC, SRAM, and Shimano all advertise heat treating of some sort in the product description of at least some of their chains. Heat treatment may be standard on high end chains, or it might not. But I would imagine if it had some sort marketable advantage or was different, they'd advertise it.