Monel 400 shows high strength and excellent corrosion resistance in a range of acidic and alkaline environments and is especially suitable for reducing conditions.^[22] It also has good ductility and thermal conductivity. Monel 400 typically finds application in marine engineering, chemical and hydrocarbon processing, heat exchangers, valves, and pumps. It is covered by the following standards: BS 3075, 3076 NA 13, DTD 204B and ASTM B164.^[23]

Large use of Monel 400 is made in alkylation units, namely in the reacting section in contact with concentrated hydrofluoric acid.