Maraging steels are characterised by ultra-high strength due to the precipitate formed during ageing. Development of new maraging steels has drawn much attention from civil and military industry, targeting for specific applications. Maraging steels work well in electro-mechanical components where ultra-high strength is required, along with good dimensional stability during heat treatment. Several desirable properties of maraging steels are: ultra-high strength at room temperature; good weldability ; section size is an important factor in the hardening process; simple heat treatment, which results in minimum distortion;superior fracture toughness compared to quenched and tempered steel of similar strength level ;low carbon content, which precludes decarburization problems. These factors indicate that maraging steels could be used in applications such as shafts, and substitute for long, thin, carburized or nitrided parts, and components subject to impact fatigue, such as print hammers or clutches. The study has been conducted on samples which have been placed in solutions with different cooling speeds (water, air) and then subjected to the thermal treatments for precipitation until the apparition of the austenite.