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.UNS No. H51321 is a medium-hardenability, through-hardening steel of low (0.75-1.00%) chromium content. It is recommended for uses where moderate strength and toughness are satisfactory. It may be used in the unhardened condition or after quenching in water or oil followed by tempering to the desired strength level.