DRÁPALA Jaromír VSB - Technical University of Ostrava

Spoluautoři BROŽOVÁ Silvie, MADAJ Michal, VU THE HA, MACHOVČÁK Pavel

In the paper the results of the theoretical and experimental study of behaviour of mischmetal and non-ferrous metals in steels will be presented. The samples of three special steels were prepared with micro-alloying of mischmetal in using of plasma metallurgy. Microstructure (light optical microscope), chemical microanalysis (SEM and X-ray EDX analysis), mass spectroscopy and REM & SEM analyses (device LYRA 3 XMU, firm TECSAN Brno) and Instrumental Neutron Activation Analysis (Research Centre Řež) were provided. Ce addition resulted in the formation of micrometer size inclusions which can be utilized for controlling grain size structure of steel castings. The majority of the particles have settled at the bottom part of the sample, indicating that the convection flow during solidification was very weak. The REM addition slightly diminished hardness of the steel. It was found a segregation phenomena in the distribution of cerium in the volume of special steels after relatively quick crystallization process. This work was solved in the frame of the project TA CR No. TA03010161 „Experimental development of non-ferrous metals utilization for microstructure refinement in the production of steel ingots for forgings in the specific work”.

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