Radiometric tracing of dross and aluminium oxide in rimmed steel ingots

The reduction of mechanical properties of rimmed steels may be caused by the local increase in the content of non-metallic impurities generated in the process of casting accompanied by forced interruption of the cast-iron mould boil. The contamination of rimmed steel with dross was studied by radioactive labelling of the dross with 141Ce in form of oxide and 46Sc as the Al-Sc alloy. The radioactive tracers were added to the steel surface and the ingots were mechanically covered. The results of operating trials proved unambiguously that dross penetrated from the surface to the ingot body, the highest impurity levels were found in the neighbourhood of the head and heal of the ingot and along the longitudinal axis of the rolled sections. (author). 2 figs., 2 tabs., 3 refs