Hybrid Temperature Modeling for the Ruhrstahl–Heraeus Process: Coupling a Data‐Driven Approach With a Physics‐Based Process Model

The Ruhrstahl–Heraeus (RH) vacuum degassing process is a key technology in modern steelmaking for producing high‐performance steel grades, performing degassing, decarburization, inclusion separation and modification, and high‐yield alloying in a single unit. Since RH treatment is often the final step before continuous casting, robust process control and reliable temperature monitoring are essential. This work presents a hybrid temperature model for continuous temperature prediction during the RH process. Enthalpy contributions from alloying additions, including the sensible heat required to reach melting temperature (), the enthalpy of fusion () where applicable, and the integral enthalpy of mixing or dissolution (), as well as reaction enthalpies (), are derived from thermodynamic calculations using FactSage databases. These values represent the exothermic and endothermic heat changes arising from physicochemical interactions among elements within the system. Heat losses by radiation and convection are included, together with an unsteady‐state term representing heat‐up of the cold vacuum vessel, parameterized by multiple linear regression based on a recent study by the authors. The model shows excellent agreement, with an RMSE of 2.79 °C, an MAE of 2.16 °C, and an R 2 of 0.98.