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.Böhler M261 Extra is a precipitation hardening steel grade for plastic molds featuring excellent machinability in the solution annealed and aged condition.