The utility model relates to a NbTi superconducting switch wire with high nickel content and a preparation method thereof, which comprises the following steps: S1: NbTi bar is loaded into a Nb cylinder, then into a drilled CuNi ingot, and NbTi/CuNi composite bar is prepared by degassing, vacuum electron beam welding, hot isostatic pressing and extrusion; S2: skinning, cold drawing and annealing the NbTi/CuNi composite bar blank; S3: Cold tandem rolling is carried out, and the aging heat treatment is alternately carried out, and the NbTi/CuNi composite line is obtained. S4: The NbTi/CuNi composite wire is twisted, drawn and painted to obtain the NbTi superconducting switch wire. The invention solves the problems that the NbTi superconducting switch wire with high Ni content has high hardness, serious work hardening, frequent wire break, broken core and low performance in the drawing process. In the process of magnetic excitation, there is no loss of excess.
The raw materials of NbTi bar and drilled CuNi ingot are annealed, and the specifications of NbTi bar, drilled CuNi ingot and Nb cylinder are further defined, and the specific extrusion temperature and hot isostatic pressure temperature are used to optimize the deformation of the core wire. In step S3 of the invention, once the aging heat treatment is started, the annealing cannot be carried out, in order that the ω precipitated during the high temperature annealing process has a great influence on the performance of the superconducting wire; Cold tandem rolling is chosen because the process of reducing the size of the material, the material is subjected to large compressive stress, small tensile stress, in the process of reducing the neck will not occur and lead to broken wire; Because of the irregular shape of the material after cold continuous rolling, it is necessary to use the roll die to draw and round the material after cold continuous rolling. In the steps S2~4 of the invention, the problems of material work hardening, wire breaking and neck shrinkage are solved; The purpose of the pitch limit of the twist is to ensure that all the core wires are fully transposed and reduce the eddy current loss of the superconducting wire.
