I grew up in Pittsburgh when it was the Steel City. Scientists and engineers at US Steel worked hand in hand with the steelworkers in the mills. CORTEN steel is a fundamentally different material that gains strength as it rusts instead of deteriorating. It never requires paint or any care whatsover. You can't make something like that in a lab because the amount needed to test it is huge and the heat required is immense. The US Steel Tower and Barclays Center are made out of the stuff, and it is a favorite with sculptors.