Cold synthesizing method for obtaining bar-like semifinished product frow which to produce high-performance super conducting cables

Abstract

To improve the performance of superconducting cables, a composition method for obtaining a bar-like semifinished product by exclusively cold plastic deformation operations has been devised, and which includes the steps of: forming round-section, mono- or multifilament, superconducting copper bars of relatively long length; assembling the bars about a cylindrical copper core of substantially the same length, using assembly templates which open book-fashion and are fitted to and slide along an assembly bench, the templates having through holes arranged in a circle to support the bars, and a central through seat for supporting the core; tying the bars onto an outer lateral surface of the core; sliding onto one end of the assembly so formed a number of metal supporting rings resting on the assembly bench, while sliding the templates off the opposite end of the assembly; sliding a copper tube onto the assembly so formed, while at the same time cutting the ties in axial sequence and sliding off the supporting rings; and performing a number of drawing operations on the finished assembly to gradually reduce the cross section and increase the length of the assembly to obtain a bar-like semifinished product of the required dimensions, from which, after salt bath heat treatment, a superconducting cable is obtained by cold drawing.

Description

technical field [0001] The present invention relates to a cold synthesis method for obtaining rod-shaped semi-finished products that can be used for the manufacture of superconducting cables, in particular niobium-titanium (hereinafter referred to as "NbTi") superconducting cables. [0002] The invention also relates to a superconducting cable produced from this rod-shaped semi-finished product. Background technique [0003] Currently, superconductors, especially NbTi cables, are manufactured from an assembly consisting of: a cup-shaped copper ingot into which is sequentially inserted a rod with a core of superconducting material made of one or more NbTi metal Wire bound, and a copper (and / or other precious metal) sheath. The rods are short (up to about 800 mm) and have a hexagonal cross-section to facilitate mounting on the copper ingot. The free end of the copper ingot is then sealed by welding a copper cap, a vacuum is formed in the body of the assembly thus formed, and...

AI Technical Summary

Problems solved by technology

[0004] The main disadvantage of superconductors and especially NbTi cables as mentioned above is their very low critical current (Jc) compared to the capabilities of the alloy

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