Maraging steel 02N18K3M3T, which has essentially the same strength and reliability as commercial steel 02N18K9M5T, has been developed on the basis of laws revealed for the influence exerted by alloying elements, modifiers, and deoxidizers on the phase composition and production and mechanical properties of high-strength maraging steels, as well as a result of improvement of smelting, hot-deformation, and heat-treatment procedures. Use of steel 02N18K3M3T makes it possible to save scarce cobalt and molybdenum (∼60 and∼15 kg/ton, respectively) without lowering the set of high properties. This steel has good production plasticity adaptable to manufacture under hot deformation, is readily machined, is recommended for the fabrication of load-bearing aircraft components, as well as articles subject to repeated action, and is intended for operation in all climates at temperatures from −70 to +400°C.