Superconducting materials are usually filled with several NbTi/Cu single-core bars after bundling into an oxygen-free copper tube, then covered with welding, and through extrusion and stretching to obtain the finished superconducting wire. The traditional NbTi/Cu single-core material production process is to insert niobium sheet between NbTi rod and copper pipe, then cover and weld, and get NbTi/Cu single-core bar by extrusion and stretching. The main function of Nb sheet is to block the reaction of titanium element and Cu element in NbTi alloy, and generate uneven nodules. Copper excess ratio is the main technical index of NbTi/Cu single core bar, which refers to the volume content ratio of copper and non-copper parts, and the area of copper excess ratio will be removed before stretching after extrusion. During the whole process from the beginning to the end of extrusion, extrusion pressure changes greatly from large to small, the change of extrusion pressure makes the deformation of the mold large, the size of the head and tail of the extrusion product change greatly, and the copper ratio of the head and tail of the NbTi/Cu bar is larger than that of the uneven area, and due to the flow of metal during the extrusion process, The Nb sheet on the surface of NbTi rod obtained after extrusion can not completely wrap the surface of NbTi rod due to sliding, which also reduces the yield of NbTi/Cu single core bar.
The purpose is to provide a processing method to improve the yield of NbTi/Cu single core rod for superconducting, and to solve the problem that the surface of NbTi rod cannot be completely wrapped by the Nb sheet in the existing processing methods. The processing method to improve the yield of NbTi/Cu single core rod for superconductivity is to completely wrap the head of niobium-titanium rod with a length longer than niobium-titanium rod and prevent the sliding of Nb sheet. By using the hot isostatic pressing process, the combination of niobium-titanium bar, niobium layer and copper tube is more tight, so that the temperature of billet is more uniform during the preheating process before extrusion, so as to ensure the uniform deformation of the bar inside the billet during the extrusion process, so as to prepare a high uniform NbTi/Cu single core bar. In addition, the alloy bar inside the billet is uniform deformation during the extrusion process. The extrusion pressure is also reduced, the flow of metal is reduced, and the length of the copper stability region is increased, and the finished yield of NbTi/Cu single core bar produced by the processing method of the invention is 2% ~ 5% higher than that of the original processing method.
