Ceroxide Origins - A Tracer Program

Abstract

With the exception of Van Vlack, et aI,'" it has been conclusively shown by the writers 5'. in the technical literature on ceroxide defects that the composition of this defect is FeO-MnOSi0 2 -AI2 0 3 . There is agreement that the main sources of the ceroxide defect are ladle refractories, ladle slags, oxidation of the deoxidizers (Mn, Si, AI) and eroded sand grains. Direct and conclusive evidence on the degree each of these sources contributes to the formation of the ceroxide defect is sketchy. There is no quantitative method to rate ceroxide defective 798 64-53 castings which would enable an evaluation of the suggestions made in the past to eliminate and or reduce the defect. It has been shown 9 that organic halides (inhibitors), when incorporated in the mold cavity, reduce or eliminate the ceroxide by changing its viscosity, thus enabling it to penetrate into the sand. This method, although quite successful in the foundry laboratory, when tested in practice has shown anomalous results. The results on the effectiveness to reduce ceroxide ranged from better than laboratory to none at all. The aim of this paper is to present data that will trace the degree each of the four mentioned sources is responsible for the formation of the ceroxide defect. The defect was followed in the casting process by the use of tracers in 22 heats of steel. A quantitative method of evaluating the ceroxide defect will be presented. This paper will also show quantitatively the effectiveness of the organic halides (inhibitors) to reduce the ceroxide defe