Thermodynamic Analysis and Process Control of Aluminum and Titanium Burning Loss in R-26 Alloy during Electroslag Remelting （ESR）

The aluminum increase and titanium loss during ESR of high Ti low Al R-26 alloy is a typical technical issue.Thermodynamic models of molten slag and slag-metal reaction were established to analyze the activities of slag components and their relationship with metal composition， and then slag optimization scheme were proposed and verified through process trial. The results indicated that， the model effectively calculated the variation of component activity in slag. The unstable oxides in slag， including 0.35%w［SiO2］ and 0.14%w［FeO］， cause the oxidation reaction of titanium. The reaction of Ti with Al2O3 at high temperature can proceed spontaneously， as the key that caused changes in the content of Al and Ti in ingot. With TiO2 added into the slag， the equilibrium Al content significantly decreased， thereby w［TiO2］ needs to be higher than 4% for w［Al］