Optimization of Inclusion Control Technology for Hollow Stabilizer Bar Steel of Automobile

This study systematically investigates and optimizes refining process parameters to enhance molten steel cleanliness for automotive hollow stabilizer bars. Through thermodynamic calculations and industrial trials on a 110 ton converter–Ladle furnace(LF)–Ruhrstahl Heraeus (RH)–continuous casting production line, key process improvements are identified. Thermodynamic analysis reveals that increasing the CaO/Al 2 O 3 ratio from 1.03 to 1.39 enhances slag inclusion absorption capacity ( K 0 ) from 12.9 to 30.25. Industrial trials demonstrate that an 8 min RH circulation reduces total oxygen content to 11 ppm, while 7 min of static blowing at 5 Nm 3 h −1 minimizes inclusion size and density. Microstructural characterization indicates that the steel primarily contains finely dispersed Al 2 O 3 inclusions , with trace sulfides and TiN. Optimization of the secondary cooling system reduces TiN inclusion density from 53 to 36 mm − 2 , area fraction from 123.64 to 98.77 ppm, and average diameter from 3.52 to 3.29 μm, confirming effective refinement. Furthermore, this study elucidates TiN formation mechanisms during secondary cooling. Process optimization reduces banded structures to grade 2.0–2.5 and limits decarburization depth to ≤0.03 mm, increasing the product qualification rate from 75.6% to over 92.5%. These findings provide a systematic framework for clean steel production, yielding significant industrial and economic benefits.