 It was developed in collaboration between the US Air Force and the Ellwood National Forge Company.The development of Eglin steel was commissioned to find a low-cost replacement for strong and tough but expensive superalloy steels such as AF-1410, Aermet-100, HY-180, and HP9-4-20/30.A high-performance casing material is required so the weapon survives the high impact speeds required for deep penetration.