Development of Extra‐Low Carbon Steel Sheets for Automotive Outer Panels via a Hybrid Blast Furnace + Electric Arc Furnace Process

This study investigates the development of extra‐low carbon steel sheets for automotive outer panels using a hybrid blast furnace (BF) and electric arc furnace (EAF) route, aimed at reducing the carbon footprint (CFP) of steel production. Two industrial‐scale test campaigns are performed with controlled variations in the scrap/hot briquetted iron (HBI) ratio in the EAF input while maintaining a fixed BF:EAF hot metal ratio of 75:25. Chemical composition, cleanliness, microstructure, mechanical properties, and formability are comprehensively evaluated. The test specimens exhibit properties equivalent to conventionally produced BF steel, including favorable {111} ferrite texture, absence of yield point elongation, and comparable values in hole expansion ratio, limiting drawing ratio, and forming limit diagram. Despite a slight increase in nitrogen levels with higher recycled input, effective Ti/Nb stabilization prevents aging phenomena. Furthermore, successful application to automotive side outer panels confirms suitability in industrial forming operations. To the best of the authors’ knowledge, this is the first comprehensive industrial‐scale demonstration of a hybrid BF + EAF route producing high‐quality extra‐low carbon steel sheets for automotive outer panels. The results suggest that the hybrid route provides a technically feasible approach to decarbonization for the automotive steel industry.