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Browsing by Subject "argonowanie"

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  • thumbnail.journal.alt
    Item type:Doctoral Dissertation, Access status: Open Access ,
    Wpływ warunków prowadzenia wytopów odzyskowo-tlenowych i argonowania na zawartość gazów w staliwie Hadfielda
    (Data obrony: 2007) Sobula, Sebastian
    Wydział Odlewnictwa
    The Hadfield cast steel is very popular material in nowadays because of its good wear resistance at dynamic stresses and price. At high manganesse content this steel has tendency to dissolve a lot of nitrogen in duration of melt. The higher nitrogen solubility in liquid state and very low solubility i solid state causes the formation of bubles during solidification. Nitrogen is introduced to the melt with a return scrap and some ferroalloys ($Fe-Si, Fe-Mn$). The nitrogen content decreases in the electric are furnace by oxygen blowing into the molten steel. Double killing in the ladle ($Al+Fe-Ti$) and the argon stirring with synthetic slag was used for improve cleannes of the steel. That treatment permmited to produce cast steel with $317,2 \pm 40ppm$ N and castings with $283,9 \pm 36,7$ ppm of nitrogen. This nitrogen concentration protects against gas bubles in castings (bubles are created over 400 ppm of nitrogen). It has been shown that nitrides and oxides formed during double-killing are eliminate during argon stirring.