The invention belongs to the technical field of
superconducting material processing engineering, and particularly relates to a continuous stepped
extrusion method for an NbTi / Cu single-core
ingot. According to the method, an assembled NbTi / Cu single-core
ingot is extruded by adopting a
ring type combined
extrusion rod and a continuous stepped
extrusion female die. The single-core
ingot structure comprises a Cu wrapping sleeve lower cover, a Cu wrapping sleeve cylinder, a Cu wrapping sleeve upper cover, an NbTi core rod and a Cu30Ni top cover, wherein specific oblique angles are machined at the top of the NbTi core rod and in the Cu wrapping sleeve upper cover. In the extrusion process, the three
ring type combined extrusion rods jointly advance by a first distance; then the outer rod stops, and the middle rod and the inner rod continue to be pushed by a second distance; finally, the middle rod stops, and only the inner rod is pushed by a third distance to complete extrusion. According to the method, by optimizing the end structure of a blank and introducing stepped deformation and composite ingot head design, the technical problems that in traditional extrusion, a
copper sheath is excessively thinned / damaged, an annular
tail is shrunk, and the head of an NbTi core rod deforms unevenly are solved.