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.A.C.I. TYPE HC* is a heat resistant 28% chromium alloy steel containing up to 4% nickel. It is recommended for oxidation resistance in high sulphur atmospheres.