18Ni-13Co-2.1Mo-2.2Ti Maraging Steel

18Ni-13Co-2.1Mo-2.2Ti is a high-strength maraging steel—an iron-nickel precipitation-hardened alloy that achieves exceptional strength through aging heat treatment rather than carbon hardening, resulting in very low carbon content (~0.05%) and excellent toughness-to-strength ratio. This grade is employed in aerospace and defense applications requiring damage-tolerant structures, including missile cases, aircraft landing gear, and pressure vessels, where the combination of ultra-high strength, low distortion during heat treatment, and superior fracture toughness outweighs the cost premium versus conventional alloy steels. Engineers select maraging steels when weight savings and reliability under extreme loads justify the investment, and when welding or precision machining are critical—properties where carbon-hardened steels exhibit brittleness or dimensional instability.