Equilibrium partition ratios of C, Mn, and Si in a high carbon steel

As part of a program to study solid-liquid equilibria in continuously cast steels, the equilibrium partition ratios of C, Mn and Si between solid (austenite) and liquid Fe have been experimentally determined as a function of the solidification path in Fe-C-Mn-Si alloy (AISI 91125). The experimental results show that the partition ratios of Si and Mn depend on the solidification path. The partition ratio of Si decreases with temperature and increases as composition of carbon in the liquid increases. Specifically, as the concentration of carbon in the liquid changes from 1.37 to 2.72 wt.% C, the partition ratio of Si increases from 0.83 to 1.08. On the other hand, the partition of 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 the liquid.