Contribution to the influence of chemical composition and cooling conditions on the eutectic solidification range of Fe–C–X-melts

The eutectic solidification range (ESR) is the difference between the eutectic temperature of the stable Fe–C-system (iron–carbon, iron–graphite) and the eutectic temperature of the metastable Fe–Fe3C-system (iron–ironcarbide, iron–cementite). This range is a key to graphitization. The size and the location of the range are important to determine the solidification system: grey or mottled or white. Quantitative investigations by thermal analysis (TA) with croning-sand and steel crucibles at the Technical University Clausthal in Germany gave the following results: Si and Al expand the range, the stable system is promoted. Cu and Ni have no significant influence. P, Mn, Cr, Mo and S contract the range, the metastable system is promoted. Increasing cooling rate normally decreases the transformation temperatures. Concerning these results a combination of thermal analysis and the spectrometric analysis could be very useful. Variations in chemical composition can be taken into account to evaluate temperature–time curves and graphitization tendency more accurately.