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.NITRALLOY 135 MODIFIED is a special alloy steel which can be nitrided, that is, surface hardened without final quenching by the action of ammonia gas at relatively low temperatures. (Also known as Nitralloy Type G Modified).