Iron-based alloy composition containing special proportions of nickel, chromium, aluminum, copper and carbon provides good corrosion-resistance characteristics for service in caustic media, e.g., sodium hydroxide, chloride media, e.g., magnesium chloride, caustic-chloride media, e.g., sodium hydroxide-sodium chloride mixtures, and also when exposed to some acid media, e.g., nitric acid. Special utility particularly includes resistance to stress-corrosion-cracking in hot caustic and chloride media. Alloy has good workability for production of wrought products such as plate, bar and sheet and is also suitable for making corrosion-resistant castings and welded structures, e.g., chemical plant equipment.