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.SAE 4042 is an alloy steel containing nominally 0.25% molybdenum. It combines moderate strength with good toughness in the quenched-and-tempered condition because it is relatively free from temper embrittlement when tempered in the range 850-1100 F.