Method of preparing Nb.sub.3 Al superconducting wire

A method of preparing an Nb.sub.3 Al superconducting stranded wire, comprising the steps in the following order:

• passing an Nb/Al composite stranded wire, being formed by stranding up a plurality of Nb/Al composite wires each consisting of an Nb metal or an Nb alloy and an Al metal or an Al alloy, through a furnace for heating the same from the room temperature to a prescribed temperature;
• passing said heated Nb/Al composite stranded wire through said furnace for holding the same at said prescribed temperature, wherein said steps of heating and holding the Nb/Al composite is to form Nb.sub.3 Al superconductivity;
• and
• passing said Nb/Al composite stranded wire, being held at said prescribed temperature, further through a cooling part for cooling the same from said prescribed temperature to the room temperature in a short time to maintain the Nb.sub.3 Al superconductivity,
• said step of heating said Nb/Al composite stranded wire, said step of holding the same at said prescribed temperature and said step of passing the same through said cooling part being continuously carried out by continuously moving said Nb/Al composite stranded wire.

A method of preparing an Nb.sub.3 Al superconducting stranded wire, comprising the steps in the following order:

• passing an Nb/Al composite wire consisting of an Nb metal or an Nb alloy and an Al metal or an Al alloy through a furnace for heating the same from the room temperature to a prescribed temperature;
• passing said heated Nb/Al composite wire through said furnace for holding the same at said prescribed temperature, wherein said steps of heating and holding said Nb/Al composite wire is to form Nb.sub.3 Al superconductivity;
• passing said Nb/Al composite wire, being held at said prescribed temperature, further through a cooling part for cooling the same from said prescribed temperature to the room temperature in a short time to maintain the Nb.sub.3 Al superconductivity;
• and
• collecting and stranding up a plurality of said Nb/Al composite wires being passed through said cooling part,
• said step of heating said Nb/Al composite wire, said step of holding the same at said prescribed temperature and said step of passing the same through said cooling part being continuously carried out by continuously moving said Nb/Al composite wire.