Efeitos de carbono, cromo e molibdenio na solidificação de ferros fundidos brancos com alto teor de cromo




The ternary Fe-Cr-C diagrams, as applied to the of high Cr white Cast Iron, were reviewed. Solidification A model was proposed for the solidification sequence .and for the main microconstituints characteristics of these alloys containing or not molybdenun.Solidification experiments were performed on 30 mm diameter samples. The austenite and eutectic arrest temperatures, the number of eutectic carbide particles on the total and eutectic volume, the fraction of primary austenite and the numberof secondary aendrite arms were measured. These measurements were performed on alloys containing 15 and 20% chromium, whith 2,3; 3,0 and 3,6% carbon. For each carbon content 1,5 or 2,5% molybdenum were added. It was observed that the increase of the carbon content resu1ted in a lower austenitic and eutectic formation temperatures, in a reduced number of carbide partic1es eutectic volume as well as in a lower vo1umetric fraction primary austenite and dendrite arm spacing. The molibdenum addition 1ed to a lower austenite and eutectic formation arrest temperatures, a lower number of the carbide particles in total and in eutectic volume,and a higher primary austenite volumetric fraction. When alloys containing 15 and 20% chromiun were compared, was observed the elevation of the eutectic arrest temperatures as well as the elevation of the number of particles in the total volume and in the eutectic co1ume and the lowering of the primary austenite volumetric fraction in the 20% Cr alloy


ferro fundido solidificação

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