EQUILIBRIUM PARTITION RATIO OF C, Mn, AND Si IN A HIGH CARBON STEEL

As part of a continuing program to study solid-liquid equilibria in continuously cast steels, the equilibrium partition ratio, k, of C, Mn, and Si between solid (austenite) and liquid Fe has been experimentally determined as a function of solidification path for the Fe-C-Mn-Si quaternary system. The experimental results show that k for Mn and Si depends on which solidification path is taken. For Si, k decreases with temperature and increases as composition of carbon in the liquid increases: as wt% C in the liquid changes from 1.37 to 2.72 wt% C, k for Si increased from less than unity to greater than unity (i.e., from 0.827 to 1.079 wt% Si). On the other hand, k for Mn increases with temperature but decreases with the carbon content in the liquid. The equilibrium partition ratio for C, however, showed little variation with temperature and composition of carbon in the liquid.