The invention relates to the technical field of superconducting cables, and aims to provide a
magnesium boride superconducting cable for a
magnet device and a preparation method of the
magnesium boride superconducting cable for the
magnet device. Two
magnesium boride superconducting single wires and an annealed
copper wire are twisted together to form a first-stage cable, a second-stage cable is formed by compositely twisting four first-stage cables, and a third-stage cable is formed by compositely twisting four second-stage cables; and after the three-stage cable is twisted, a layer of 316L stainless steel strip is overlapped and lapped to reinforce protection so as to enhance the electromagnetic force resistance and stable operation capability of the cable, and a layer of high-temperature-resistant glass tape is overlapped and lapped on the outermost layer to serve as an insulating layer. The
magnesium boride superconducting cable produced by adopting the structure and the method is used for winding a
magnet coil, the cable is straight and free of undesirable phenomena such as bending and snakelike in the winding process, the wound coil is poured with
epoxy resin, the
voltage endurance capacity of the coil after pouring and curing reaches 15 kv or above, the coil is in a superconducting state at the temperature of 39 K, the high
critical current density is achieved, and the coil can be used for manufacturing the
magnet coil. And a relatively
high magnetic field is generated, and the application prospect is wide.