The composition of a slag system has been shown to be particularly important and influential for the new technology of

electroslag remelting withdrawal process. The oxidation of the GH984G alloy elements, in contact with different contents

of CaF2–CaO–Al2O3–MgO–TiO2–SiO2 in various slag systems, has been investigated in the present study by performing

slag–metal equilibrium experiments and ion and molecule coexistence theory analysis. The results show that CaF2 and

MgO have only a minor effect on the oxidation rates of Al and Ti in the GH984G superalloys. However, it was found that

SiO2 would intensify the oxidation degree of Al and Ti, and Al was found to become easier oxidized than Ti. Moreover,

CaO was found to reduce the activity of SiO2 and, thereby, also the oxidation degree of Al and Ti. Also, TiO2 was found to

reduce the oxidation rate of Ti and instead increase the oxidation rate of Al. Finally, the effect of Al2O3 on the oxidation of

Al and Ti was observed to be opposite to that of TiO2. The calculated results were found to be in good agreement with

experimental measurements. Moreover, viscosity experiments showed that CaO would rapidly increase the viscosity of the

slag at low temperatures, and that the viscosity of the slag would increase with an increase in SiO2 content.