Based on numerical simulation of fluid-thermal coupling field of a one-strand slab tundish

the average residence time of liquid steel was analyzed at different slab casting speeds

and under static magnetic fields with different intensity

the liquid steel flow was also investigated according to the electromagnetic hydrodynamics（MHD）.The results show that both reasonable lower casting speed and the stronger magnetic field can postpone the average staying time of the liquid steel.With the action of the electromagnetic force which is in contrast to the velocity of the liquid steel

the distribution of the flow field is changed

thus reducing the impaction to the tundish wall

so the upper surface of the molten steel can be flown more smoothly

however

the decrease of temperature of the steel is slight.The average temperature at the outlet is decreased by 0.46 K when the magnetic intensity is 0.10 T.Through changing magnetic field intensity

it is found that the combined effect exhibits desirable in the range of0.10

0

.15 T.