Periodic electromagnetic stirring method of RH vacuum refining device

A periodic electromagnetic stirring method of an RH vacuum refining device comprises the following steps that 1, two dip pipes are inserted into molten steel of a steel ladle, a vacuumizing device is started, then argon is introduced, and the process that the molten steel circularly flows from an ascending pipe to a vacuum chamber to a descending pipe to the steel ladle to the ascending pipe is formed; 2, when argon blowing and stirring enable the circulating flow of the molten steel to tend to be stable and finally reach a stable state, opening an air cooling or water cooling device, introducing alternating current with periodically changed directions into an electromagnetic coil to generate an alternating magnetic field, and continuously performing periodic electromagnetic stirring on the molten steel in an ascending pipe in the RH refining device to promote argon bubbles to be broken in the ascending pipe so as to obtain the molten steel. The gas is dispersed towards the center of the ascending pipe to for