Abstract: The size of bubbles directly influences the heat,mass,and momentum transfer processes between the bubbles and molten steel.The complexity of metallurgical processes and the high-temperature environment limit the application of conventional bubble refinement methods,resulting in generally large bubble sizes in molten steel,which severely restricts the production efficiency of metallurgical processes.This study proposes the periodically bidirectional rotating electromagnetic field to induce high-intensity turbulent flow in molten steel periodically,thereby achieving bubble refinement.Using numerical simulation methods,the turbulence intensity of molten steel under electromagnetic fields with different magnetic flux densities was investigated to determine the magnetic flux density suitable for bubble refinement.When the magnetic flux density increased to 240 mT,the turbulent flow of molten steel met the requirements for bubble breakup.The effect of the periodically bidirectional rotating electromagnetic field on the turbulent flow of molten steel was analyzed,and the bubble refinement effectiveness was examined.The proportion of large bubbles larger than 10 mm in the molten steel decreased to 3.09%,a reduction of 27.47%compared to conditions without the electromagnetic field.The number density proportion of bubbles in the 0.5-1 mm diameter range reached 40.03%,and the proportion of bubbles smaller than 5 mm was as high as 92.10%,an increase of 80.25%compared to conditions without the electromagnetic field.The turbulence intensity of molten steel under electromagnetic fields with different rotation periods and the corresponding bubble refinement effects were compared,with the optimal rotation period range identified as 3-5s.