Effect of Temperature on the Oxidation Behavior of Al and Ti in Inconel(R) 718 Alloy by ESR Slag with Different Amounts of CaO

Abstract

It is necessary to reduce the amount of CaF2 in the electroslag remelting (ESR) slag because it causes a high specific energy consumption and several environmental problems. Laboratory-scale experiments were performed to study the effect of temperature on the oxidation behavior of Al and Ti in Inconel (R) 718 alloy by the CaF2-CaO-Al2O3-MgO-TiO2 slag containing different amounts of CaO. The oxidation loss of Al in the nickel-based alloy can be restrained by increasing the amount of CaO up to about 10 wt.% in the slag at 1873 K. However, an excessive amount of CaO in the slag will result in the oxidation of Ti when TiO2 content is less than 15 wt.%. The slag containing 35 wt.% CaO and 15 wt.% TiO2 can maintain a homogeneous distribution of Al and Ti in the remelted ingot in the ESR process. The corresponding usage amount of CaF2 was decreased, which was beneficial for decreasing specific energy consumption and fluoride pollution during the ESR process.