Metal dusting: what determines the degradation rate?

摘要

We have identified a compositional relationship between several commerciallyrnavailable wrought alloys, focussing only on the iron, nickel, chromium and aluminiumrncontent. The degradation rate due to metal dusting varies with the surface conditionrnof each alloy: a ground surface condition corresponds to smaller mass losses than arnpickled surface condition. We have derived a relation between the maximumrnobserved degradation rate due to metal dusting and the chromium plus aluminiumrncontent of each alloy. This relation has been verified by comparing data from severalrnexposures using different gas compositions and pressures. The results indicate thatrnfor the gas used in this exposure, the degradation rate strongly decreases up to arnchromium plus aluminium content of 33 wt%. Above this value, the mass loss rate isrnnegligible. The current relation is also found valid for coatings.