Abstrait

Influence of the silicon content on the high temperature oxidation of a spheroidal graphite cast iron. part 2: Oxidation behaviour of the SG cast iron samples versus their SI content

Mamadou Saidou Diallo, Lionel Aranda, Pascal Villeger, Patrice Berthod, Elodie Conrath

In this second part of the work the re-melted then re-solidified spheroidal graphite (SG) cast iron samples, without or with enrichment in silicon, were exposed to high temperature (rather fast heating, 10 minutes at 957°C, very slowcooling) in air.Concerning the surface state all the sampleswere oxidized, with the exclusive formation of Fe2O3. The oxide scaleswere about 20-25 µm thick and a graphite-free zone developed from the external surface over an about 60-70µm depth. The silicon had a lowering influence on these two parameters, clearly for the first one but not so clear for the second one. Concerning the bulk the thermal cycle appliedwas largely sufficient to correct the matrix microstructure since all primary cementite and pearlite have disappeared. The influence of these silicon contents and these heattreatment parameters remains to be tested for much coarser microstructures of SG cast irons.