Thermodynamic Analysis of the Oxidation Behavior of Cerium in High‐Speed Steel during Electroslag Remelting

Cerium loss is difficult to be avoided during the electroslag remelting (ESR) process. To reduce the cerium loss in high‐speed steel during the ESR process, the present study investigates the thermodynamics of cerium oxidation in cerium‐containing high‐speed steel based on the thermodynamic calculation and laboratory‐scale steel–slag reaction experiments. The results show that the reactions between [Ce] and (Al 2 O 3 ), as well as [Ce] and (MgO) contribute to the cerium loss in the steel. Increasing the contents of CaF 2 and MgO in the slag, the activities of Al 2 O 3 and Ce 2 O 3 show a slightly decreasing trend. The addition of CaO and Ce 2 O 3 significantly reduces the Al 2 O 3 activity but enhances the Ce 2 O 3 activity. MgO activity shows an insignificant change with the contents of CaO and Ce 2 O 3 , while it decreases with adding Al 2 O 3 and CaF 2 . Reducing Al 2 O 3 content and enhancing Ce 2 O 3 content in the slag are feasible to increase the cerium yield in the steel. With increasing Al 2 O 3 content from 16.93 to 26.92 wt%, the cerium yield decreases from 8.4% to 6.0%. Increasing Ce 2 O 3 content from 3.98 to 11.01 wt% enhances the cerium yield from 6.0% to 16.9%. The actual soluble Ce content in equilibrium with slag is almost less than 0.001 wt%.