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.UNISEAL 29-17 is a controlled expansion iron-base alloy containing nickel and cobalt. It is widely used for glass-to-metal seals with borosilicate glasses commonly employed in electronic power tube envelopes.