Am Montag, 16. Oktober 2017 23:46:54 UTC+2 schrieb Ed Huntress:

The most expensive *commercially available* steel I've even seen is
Cricible's CPM Rex 121, although it must have come down recently,
because it's even being sold for making knife blades. It's an extreme
high-speed steel.

As for steel used in structural applications, the maraging grades are
'way up there.

So how much do those steels cost?

Chris