A Transformer–LSTM Hybrid Model for End Point Molten Steel Temperature Prediction in Vacuum Degassing Refining
摘要
Accurate prediction of end point molten steel temperature during the Vacuum Degassing (VD) refining process is critical for improving product quality and energy efficiency. This study proposed a hybrid Transformer–Long Short-Term Memory (LSTM) model integrating global feature representation (via self-attention) and local temporal dynamics, with hyperparameter optimization via Optuna. Industrial data from a domestic steel plant encompassing 12 key process parameters were preprocessed by 3σ criteria and Min–Max normalization. The proposed model achieved a remarkable prediction accuracy of 91.5% within a ± 3 °C error margin, with R2 = 0.99, RMSE = 1.82 and MAE = 1.25. This performance significantly surpasses that of baseline LSTM (83%, R2 = 0.97, RMSE = 2.52, MAE = 2.04) and Transformer (75%, R2 = 0.97, RMSE = 2.61, MAE = 2.53) models. Furthermore, the model demonstrated robustness in tracking temperature inflection points amidst process disturbances. By enabling more precise end point temperature control, this approach reduces the overheating margin by over 4.0 °C compared with conventional methods, which typically operate within a ± 5–10 °C tolerance band. This enhanced precision provides an effective AI-driven solution for low-carbon intelligent control in VD refining, with potential applications in other secondary metallurgy processes and electric arc furnaces, thereby contributing directly to industrial decarbonization and energy optimization goals.
Graphical Abstract