The mechanism of spheroidizing of graphite during melting was studied by analyizing distribution of nodulizing elements. The nodule formation of the graphite may be due to the adsorption on the graphite surface, or to the nucleation of graphite by som...
The mechanism of spheroidizing of graphite during melting was studied by analyizing distribution of nodulizing elements. The nodule formation of the graphite may be due to the adsorption on the graphite surface, or to the nucleation of graphite by some compounds of nodulizing elements during melting. To eliminate the problems as many composition variables as possible, the samples used in these experiments consisted simply of pure iron and charcoal with pure nodulizing element. Nodular graphite was produced by the addition of Mg, Ca, Ce, Bi and Zr, in the critical concentration and analyzed retained nodulizing elements in graphite, interface between graphite and matrix and matrix by X-ray micro-analyzer.
The results were as follows.
(1) The spheroidizing of graphite in Mg-treated cast iron seemed to be due to the adsorption of nodulizing element on graphite surface and nucleation of graphite both.
(2) The spheroidizing of graphite in Ca, Ce-treated cast iron respectively seemed to be due to the adsorption of nodulizing element nn the graphite surface.
(3) The spheroidizing of graphite in Zr, Bi-treated cast iron respectively seemed to be due to the nucleation of graphite by some compounds of nodulizing elements.