View Sample Alloy Digest Data Sheet (PDF)Since 1952, Alloy Digest has been the leading reference for materials property data on metals and alloys used throughout the world. Featuring graphs, charts and tables, these sheets give facts and figures on composition or characterization, physical and mechanical properties, heat treatment, and machinability.SAE 4427 is a 0.5% molybdenum steel designed for carburizing applications and it is also useful for general purposes. It is recommended for case-hardened gears, pinions, shafts and similar components.