METAL DUSTING PHENOMENON DURING CARBURIZATION OF FENICR-ALLOYS AT 850-1000-DEGREES-C

Three austenitic FeNiCr steels, G 4848, G 4852 and 36 XM, have been co rroded in CH4 + H-2 mixtures, at 850, 900 and 1000 degrees C. Under th eses conditions a new metal dusting phenomenon has been observed where closed cavities near the exposed surfaces of the alloys are filled wi th a powdery mixture of graphite, iron metal, chromium carbide and als o in cases SiO2. It is tentatively concluded that the powder is formed through the decomposition of (Cr, Fe)(7)C-3.