THE CORROSION OF MONEL AND 70-30 CUPRONICKEL IN HYDROFLUORIC ACID

Monel is shown to be suitable for the handling of 1O to 70% HF at 14O deg F and for handling 38 and 48% acid at boiling; cupronickel also is useful over part of this range. Elimination of O/sub 2/ is necessary to achieve maximum corrosion resistance. Some accelerated interface attack was noted for 70-30 cupronickel. Welding of Monel is the preferable joining method. Silver solder joints are subject to embrittlement. Work hardening, annealing, and external stress do not significantly influence the corrosion of Monel. Galvanic coupling of Monel with silver or silver solder is to be avoided. (auth