Q:

Flash has 1500 to 2100 MPa ultimate strength at 0.20 to 0.40%wt carbon. Why don't other AHS Steels just add carbon to match the strength of Flash?

A:

Other AHSS becomes brittle as their strength increases so Steel Mills add expensive alloying instead of carbon. Flash possesses a unique microstructure that enables more carbon to increase strength without becoming brittle.