This report resulted from a survey of users and manufacturers of maraging steels, Government agencies, research institutions, and published literature. It presents the technical status of the 18-percent nickel maraging steels in detail and brings together a large body of knowledge with regard to the metallurgical and engineering aspects of maraging steels. Since such steels were first announced in 1959, they have become highly important in aerospace, defense, and industrial work. The requirements of the National Aeronautics and Space Administration have given impetus to their development, and research now underway is expected to result in further improvements and applicability. The NASA Office of Technology Utilization sponsored this report as part of its program to disseminate information on technological developments which appear to be useful for general industrial applications.

Various aspects of the physical metallurgy of the 18 % nickel maraging steels are discussed in this report in the light of the knowledge which has thus far been accumulated on these steels. The 18 % nickel type of maraging steel was singled out for discussion because of its especially attractive combination of strength and fracture toughness, the comparative simplicity with which it can be hardened, and the relative ease with which it can be formed and joined. The highnickel maraging steels are considered to be outstanding members of a loose-knit family of agehardenable or precipitation-hardenable martensitic steels. Some comparisons and analogies are drawn among various members of this family with particular reference to the 18% nickel steels. (Author).

The monograph has been written keeping in mind the researchers and practicing technologists designing and working with 18 % Ni maraging steels. These steels have been the subject of several publications over the years and the focus of the book has been to review and document the progress made over the last three decades with reference to their metallurgy, production and application. Analysis and prevention of failures encountered in critical production processes - melting, hot working and heat treatment - forms an important part of the book. The monograph also addresses fusion welding of maraging steels, the dominating method of joining these steels. Environment-induced degradation is a major issue when it comes to working with maraging steels and the book dwells on this aspect. Successful attempts have been made by the author and his coworkers to optimize melting, hot working, heat treatment and welding procedures to realize the best combination of strength and fracture toughness in both base metal and weld joints. If this book inspires further research and development on this group of steels and increased exploitation of their potential, the purpose can be said to be achieved.

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