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.FERRALIUM alloy SD40 is a recent modification of FERRALIUM alloy 255 (Alloy Digest SS-481) with higher nominal molybdenum and nitrogen. It meets the empirical PREN formula to a minimum 40.