2019 Volume 105 Issue 3 Pages 363-368
In recycling a lot of low grade ferrous scraps, we cannot remove tramp elements, such as copper and tin, which are inevitably dissolved in molten iron. Accordingly, the thermodynamic data between such tramp elements and alloying elements in molten iron are necessary to know the influence of them on the property of steel. In this work, the interaction between tin and M(M: Mo, B, Ni, Ti or Nb) in iron has been investigated by using immiscibility between Fe and Ag phases at 1873 K. The distribution ratio of Sn between Fe and Ag, LSn = xSn(in Ag)/xSn(in Fe), increases with increasing Mo, B, Ti or Nb content and decreases with an increase of Ni content. That is to say, it is found that the interaction coefficients of Mo, B, Ti or Nb on Sn are positive and that of Ni on Sn has a negative value. The interaction coefficients of M on Sn are estimated from the activity coefficients of M in Fe and Sn, and those values are compared with the experimental ones. It is found that the experimentally measured interaction coefficients of Pb and Nb are much different from the estimated values. It is important to measure the interaction coefficient of M on Sn experimentally to know the effect of M on Sn activity accurately.