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.Copper Alloy No. 844 is a free-cutting copper-tin-lead-zinc alloy for castings; it was formerly identified as 81-3-7-9 alloy. It is characterized by good casting properties, moderate strength and ductility, good machinability and good resistance to corrosion. It is used widely for fittings, plumbing goods and valves.