Development of Nb3Sn superconducting wires for high field magnets at Kobe Steel and JASTEC

Research and development activities and some recent results related to Nb3Sn superconducting wires in Kobe Steel, Ltd. (KSL) and Japan Superconductor Technology Inc. (JASTEC) are introduced. First, an outline of the activities is described briefly from a historical point of view. Following that, improvements in the characteristics (i.e., critical current density (Jc), n-value and mechanical properties) of bronze-processed Nb3Sn wires are reviewed. Finally, the status of development for the Ta–Sn powder-in-tube (TS-PIT) process is briefly discussed.