Effects of Submerged Entry Nozzle Treated by Pulsed Positive Electric Field on Continuous Casting Process of Automotive Sheet Steel

This study investigates the effects of a pulsed positive electric field applied to the Submerged Entry Nozzle (SEN) on the continuous casting of automotive sheet steel. The results indicate that the pulsed positive electric field (average current of 75 A, pulsed current of 150 A, and frequency of 10 000 Hz) provides an electrostatic driving force for Al 2 O 3 inclusions to migrate away from the SEN wall, while disrupting their original force balance and inhibiting interinclusion contact and agglomeration. Consequently, the SEN inner cavity clogging thickness is reduced by 79.37% (from 12.65 to 2.61 mm), the average qualification rate of mold level fluctuations (QRM) (>±3 mm) is increased by 45.76%, the amount of the large‐sized inclusions (>5 μm) is decreased from 266 to 199, the morphology and composition of inclusions are regulated, the tensile strength of the slab increased by 3.85% (from 338 to 351 MPa), and the nonproportional elongation strength of the slab improves by 6.67% (from 210 to 224 MPa). This ultimately reduces the downgrade rate during slab rolling by 41.75% (from 1.03% to 0.60%).