Fabrication of (6 + 1)-Structure Superconducting Cable Based on 30-Core MgB2 Superconducting Wire

30-core MgB
₂
superconducting wire with a diameter of 1.0 mm has been prepared by the conventional in-situ powder-in-tube (PIT) method. The metallographic analysis results show that the 30-core MgB
₂
wire has good uniformity in both transverse and longitudinal directions, and the critical current (Ic) and critical current density (Jc) at 4.2 K and 4 T reach 82.6 A and 7.3 × 10
⁴
A/cm
²
, respectively. Furthermore, (6 + 1)-structure MgB
₂
superconducting cables have also been successfully fabricated with different twist pitches (Tp) by the twisted and reacted (T&R) route, comprising six 30-core MgB
₂
wires around one copper wire in the center. The Ic of the (6 + 1)-structure MgB
₂
superconducting cable with 50 mm Tp reaches 467 A at 4.2 K and 4 T, suggesting no degradation of the MgB
₂
wire when self-field effects are taken into account.