Successful commercialization of superconducting cables that are distortion resistant, and that can be wound after heat treatment

June 12, 2014

Furukawa Electric Co., Ltd. has delivered the new cables used for superconducting magnets that are being constructed under the High Magnetic Field Collaboratory Plan In collaboration with Tohoku University (Sendai, Miyagi Prefecture), Furukawa Electric Co., Ltd. has developed the world's first Nb-rod-processed Copper-Niobium (hereinafter CuNb) reinforced niobium-tin (hereinafter, Nb3Sn) superconducting cable that can be wound after heat treatment for Nb3Sn generation(react and wind method).

This superconducting cable is going to be used as a main component in the Non-Refrigerated 25T (Tesla) Superconducting Magnet(notes 1) that is under construction at Tohoku University based on the High Magnetic Field Collaboratory Plan(notes 2), a Ministry of Education, Culture, Sports, Science and Technology project.


Nb3Sn superconducting cables with a high critical magnetic field are currently being used for superconducting magnets that generate a strong magnetic field. These Nb3Sn superconducting cables are extremely fragile, and an addition of about 1% distortion would break the Nb3Sn and impede the flow of electric current.

In order to prevent a decline in performance, generally, heat treatment is performed in a large furnace (from several dozen hours to several hundred hours at 600 – 700°C) for Nb3Sn generation after winding for use as superconducting magnets, to ensure that no distortion is added to the Nb3Sn generated. In this manufacturing method, a large heat-treatment furnace is needed to apply heat treatment uniformly to the entire magnet, and there were a number of constraints in the production process, including heat resistance required for parts such as bobbins and the like.

Technology developed

In collaboration with Tohoku University, Furukawa Electric has successfully developed the world’s first CuNb reinforced Nb3Sn superconducting cable that is distortion resistant, and that can be wound after heat treatment for Nb3Sn generation, and we delivered mass produced products with a gross length of 7.8 kilometers to TOSHIBA CORPORATION in March of this year. Because the newly developed superconducting cable does not require heat treatment in the form of a magnet, the superconducting magnet manufacturing process is simplified, providing for cost reductions.

It is expected that the newly developed cable will be used for the 30T magnet and 50T hybrid magnet, which aim at generating stronger magnetic fields, in the High Magnetic Field Collaboratory Plan, and the cable also has great potential such as applying it to the existing consumer NMR(notes 3) to replace Nb3Sn cables using the conventional method.

Due to the record snowfall in February this year, there was damage at our Nikko offices, including part of the roof collapsing in the factory. The manufacturing equipment used to make CuNb reinforced Nb3Sn superconducting cables was damaged, but we are continuing with manufacturing by contracting out part of the manufacturing process, and we are striving toward a full recovery. We will continue to develop superconducting technologies with excellent performance to contribute to the development of state-of-the-art technologies.


  • The electric current does not degrade even with ±0.8% distortion added in heat treatment generated with Nb3Sn.
  • By applying repeated distortion (± 0.5%) in the heat treatment generated with Nb3Sn to the cable and element wire, the electric current in the magnetic field is increased up to 1.5 (prior distortion effect).

About Furukawa Electric Group

Furukawa Electric (TSE; 5801, ISIN; JP3827200001) Group started business in 1884, when its copper-smelting facility and wire manufacturing factory was established. Since then Furukawa Electric has become pioneers in the latest technologies by addressing diverse technological issues.
Furukawa Electric has released products in a number of areas, including telecommunications, electronics, automobiles, and construction, with the three types of materials it works with at their core, namely, optics, plastics, and metals. Many of these products have attained the top global market share, and all of its products have contributed to society in numerous business areas. Furukawa Electric reported consolidated revenues of JPY 931.8 billion (approximately USD 9.3B) for the fiscal year ended March 31, 2014.

(note 1)Non-Refrigerated 25T Superconducting Magnet;
High magnetic field magnet using metal superconducting conductors (NbTi conductor, Nb3Sn conductor) and high-temperature superconductors (Gd tape cable). It has a characteristic that liquid helium is not used in refrigeration and provides a long-term, stable, high magnetic field.

(note 2)High Magnetic Field Collaboratory Plan;
A theme of the Ministry of Education, Culture, Sports, Science, and Technology (MEXT)’s Large Research Projects. The plan is intended to build a domestic high magnetic field facilities research base and enhance high magnetic field facilities. Developments are expected in material science and life science development, including a new material phase in the high magnetic field. Construction costs of \14.4 billion yen and a construction time of 2015 to 2019 are planned.

(note 3)NMR;
Nuclear magnetic resonance spectrometer. It can be used for the three-dimensional chemical structure analysis of 5T-class low-molecular-weight material, 10T-class protein, and Super-20T inorganic material. The device contributes to the creation of new drug analysis as a rapid analytical tool for structural analysis of the molecular weight of large proteins and drug compounds that is widely used in the field of analytical chemistry. NMRs use superconducting magnets to generate magnetic fields.