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.CENTRI-CAST GRAY IRON 30 is a centrifugally cast gray iron with a nominal tensile strength of 30,000 psi. It is produced in the form of tubing which has a wide range of uses for applications where freedom from pattern cost is an important consideration and where size and shape are of paramount importance.