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 4135 is a medium-carbon chromium-molybdenum alloy steel for heavy-duty service. Although nominally an oil-hardening grade, it may be water hardened if proper precautions are exercised. It is used for a wide variety of engineering applications.