The Properties of Industrial Superconducting Composite Wires for the UNK Magnets

The present note describes the properties of superconducting composite wires consisting of 6·10-6 m Nb — 50% Ti filaments for the UNK magnets. The properties have been studied from the data on commercial batches of wires, 3000 km long and proceeding from the technology of twofold billets (55 × 162). A strand is 0.85·10-3 m in diameter and the copper-to-noncopper area ratio is 1.385/1. The current density in the filaments is (2550 ± 250)·106 A/m2 (B=5 T, T=4.23 K). The Residual Resistivity Ratio (RRR) for the initial copper is ≥ 160 and for the wire of the final size it is ≥ 70. The manufacturing technology for the wire with 6·10-6 m filaments from 0.25–0.3 m billets has been developed. The current density obtained in the strands from large billets is 2800±290 A/mm2. The current rise parameter is I0 ≃ 11 (n ≃ 50). Production of the wire for standard UNK magnets has begun.