Inclusion composition control in tyre cord steel by top slag refining

In order to improve the inclusion type and composition in tyre cord steel, ladle furnace refining has been simulated by laboratory experiments and thermodynamic calculation. It was found that slag metal reaction time and top slag composition have an important influence on the inclusion compositions in the final steel. To produce the desired low melting point ductile inclusions the optimum conditions were: reaction time 60 min, basicity (CaO/SiO 2 ) of top slag in the range of 1·0-1·2 and Al 2 O 3 content of slag in the range of 3-9 mass-%. These were then confirmed in industrial trials.