JPH03230422A - Manufacture of aluminium stabilized superconducting wire - Google Patents

Abstract

PURPOSE:To easily obtain an Al stabilized superconducting wire of high quality by extrusively coating aluminium on a superconducting core material, rolling it, binding some wires into several groups, coating aluminium thereon, and by applying rolling processes in turn. CONSTITUTION:After a Nb-Ti billet 1 is forged and face-cut, it is hot-extruded into a Nb-Ti pin material 2. Al is extrusively coated on the pin material 2 by a conform extrusion method, into a superconducting primary element material 3. The element material 3 is rolled by forced lubrication rolling, into an Al coated superconducting wire 4. The wire 4 is stranded into a strand 5, which is processed into a molding strand 6 of circular cross section through die- drawing. Al is extrusively coated on the strand 6 by conform extrusion, into a superconducting secondary element material 7, which is rolled by forced lubrication rolling, into an Al stabilized superconducting wire 8. The deformation in the cross sectional direction is made even thereby, and a long-size cable can easily be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing an Aj2 stabilized superconducting wire with excellent quality and performance.

[Conventional technology and its issues]

Superconducting wire consists of a superconducting core material coated with Cu as a stabilizing material, which acts as a bypass for heat and electricity during quenching.As a stabilizing material, AlO is more effective at resisting electricity at extremely low temperatures than Cu. It is considered a preferred material because of its low resistance and low magnetoresistive effect.

By the way, in the conventional manufacturing of superconducting wires, a superconducting core material is charged into a Cu pipe, this is stretched to form a superconducting wire, and then a plurality of these superconducting wires are inserted into a Cu pipe. Alternatively, the formed stranded wire may be coated with Cu after processing, and then stretched.

In the above method for manufacturing a superconducting wire, when stretching is performed by replacing the Cu pipe with an Af pipe, the superconducting core material and the outer layer of AI! Because the deformability is significantly different from that of wire rods, it is said that the superconducting core material may break, or the /l coating layer may undergo bulge deformation, making it impossible to produce a sound wire rod, especially during drawing or wire drawing. There was a problem.

[Means to solve problems]

The present invention was developed as a result of intensive research in view of the above situation.
It was discovered that a superconducting wire using No. 2 as a stabilizing material can be drawn with high quality by forced lubrication wire drawing method, and after further research, the present invention was completed.

That is, the present invention uses AI! in the superconducting core material! , is extruded and coated to form a superconducting primary material, and the primary material is drawn using a forced lubrication wire drawing method to create an AI! , the step of forming a coated superconducting wire, bundling or twisting a plurality of the Aj2 coated superconducting wires to form a superconducting wire aggregate of a predetermined shape, and then extruding and coating the aggregate with Al to form a superconducting secondary material. This is a method for producing an Al-stabilized superconducting wire, which is characterized by sequentially performing a step of drawing the secondary material into a predetermined shape by a forced lubrication wire drawing method.

The method of the present invention will be specifically explained below with reference to the drawings.

FIG. 1 is a process explanatory diagram showing one embodiment of the method of the present invention. That is, the Nb-Ti billet 1 is forged and then hot-extruded to form the Nb-Ti bar 2 (Figure A), and the Nb-Ti bar 2 is extruded and coated with Al2 by the conform extrusion method. and forming a superconducting primary material 3 (1 piece), drawing this primary material 3 by forced lubrication wire drawing method to form an AN coated superconducting wire 4. ! : The process of making (Figure C), this superconducting wire 4 is made into a stranded wire 5 by the normal wire stranding method, and then this! P: Processing the wire 5 into a formed stranded wire 6 with a circular cross section by die drawing method (Fig. 1), Aff is applied to this formed stranded wire 6.
i is extruded and coated using the conform extrusion method to form a superconducting secondary material 7 (Figure E), and this superconducting secondary material 7 is drawn using a forced lubrication wire drawing method to form an AI! , stabilized superconductor v
It consists of the process of making A8 (see the figure).

In the method of the present invention, any superconducting material including Nb-Ti alloy can be used for the superconducting core material. In addition, the Al material covering the superconducting core material is usually high-purity Al with low electrical resistance.
is used.

In the method of the present invention, the conform extrusion method is suitable for extruding and coating the superconducting core material with Al. In the conform extrusion method, as illustrated in FIG. 2, a coating material 12 is introduced using a rotary wheel 10 having a groove 9 on its periphery and a fixed block 11 that slides in contact with a portion of the outer peripheral surface of the wheel 10. A sub-extrusion chamber 1 that forms a main extrusion chamber 13 and communicates with the main extrusion chamber 13 within the fixed block 11
4, attach a die to one end of the sub-extrusion chamber 14 and a nipple 16 to the other end, introduce the core material 17 through the nipple 16, and press fit the covering material 12 from the main extrusion chamber 13 to form the sub-extrusion chamber 8. In step 14, both are combined and the coating material 12 is extruded and coated around the core material 17 through a die j. This conform extrusion method is a method suitable for manufacturing small-sized and long composite materials. be.

The forced lubrication wire drawing method includes a method in which a plurality of dies 18 are fixed in a box 19 and a lubricant 20 is supplied under pressure between the dies 18 by a pump as shown in FIG. As shown in the figure, 0.05 to 0.5 on one side between the wire drawing material and the wire drawing material.
An in-left tube (lubricant introduction tube) 21 with a clearance of 1 is placed in close contact with the front surface of the die 18, and the lubricant 20 supplied from the tube 21 is drawn into the wire drawing material to provide high-pressure lubrication on the die 18 surface. There are methods such as the inleft tube method that generate this condition. These forced lubrication wire drawing methods allow plastic deformation to be made uniform in the cross-sectional direction because a sufficient amount of lubricant is supplied into the die, and are therefore particularly suitable for processing difficult-to-work metals, composite materials, and the like.

Said A! The general method for forming a superconducting wire assembly made by bundling or twisting multiple coated superconducting wires into a desired shape such as a circle or rectangle is to draw it through a die, but it is also possible to use a method such as die forging. is also possible. In the superconducting wire assembly after forming, the superconducting wires are in close contact with each other on the inside, reducing gaps, and the outer surface is smooth with less unevenness.

The formed stranded wire thus obtained is again coated with 11 and subjected to the stretching process, but A! Coating and conform extrusion methods are preferred, and wire drawing is performed by forced lubrication wire drawing.

[Effect]

In the method of the present invention, the Af-coated superconducting wire is drawn by a forced lubrication wire drawing method, so lubricant is sufficiently supplied to the inner surface of the die, and deformation in the cross-sectional direction is made uniform.
A high quality /1 stabilized superconducting wire is produced.

In addition, if the superconducting core material or superconducting wire assembly is coated with Al by the conform extrusion method, a long A! Stabilized superconducting wires can be easily manufactured without the need for welding or the like.

〔Example] The present invention will be explained in detail below using examples.

Example 1 A Nb-Ti alloy consisting of 50% Ti and the balance Nb was melted in a consumable electrode type arc melting furnace and cast into a billet of 100 mmφ. Next, this billet was forged to 801TIIIφ, and the forged material was subjected to Eznm face milling, and then this forged material was hot extruded to form a Nb-Ti bar material of 10nuaφ.
-Ti rod material was extrusion coated with 99.9993% purity Af by conform extrusion method to obtain a 15 mmφ superconducting primary material. Next, this primary material is drawn using a forced lubrication wire drawing method to form an A2 coated superconducting wire of 5 mm + φ.Then, this superconducting wire is twisted into a 7-strand stranded wire, and then this stranded wire is It was drawn through a die to form a shaped stranded wire with a circular cross section of 10a+mφ. Next, this formed stranded wire is extrusion coated with Af of the same purity as described above using the conform extrusion method to form a 15 mmφ superconducting secondary material, and then this secondary material is drawn using a forced lubrication wire drawing method. 2.
It was made into an A2 stabilized superconducting wire with a diameter of 25 mm.

Example 2 An A42 stabilized superconducting wire was produced in the same manner as in Example I, except that in Example 1, 10 A2 coated superconducting wires of 5ffIIIlφ were bundled, drawn through a die, and processed into a molded assembly with a circular cross section of 101φ. was manufactured.

To each and every one of you who have thus obtained! We investigated the quality and performance of stabilized superconducting wires.

As a result, in terms of quality, both the superconducting core material and the 142 stabilizing material layer were uniformly processed, and the adhesion between the superconducting core material and the AP stabilizing material layer was also extremely good. In terms of performance, Jc (critical current density) under 4.2K and 6 Tesla is 1910 A/o+m' for both Examples 1 and 2.
showed a high value. This value is equivalent to the value of the Cu-stabilized superconducting wire manufactured by the same method as in Example 1, except that the conventionally used 99.9998% oxygen-free Cu was used for the extrusion coating material. there were.

〔effect〕

As described above, according to the method of the present invention, an Al-stabilized superconducting wire with excellent quality and performance can be easily produced, and it has a significant industrial effect.

[Brief explanation of drawings]

FIG. 1 is a process explanatory diagram showing one embodiment of the method of the present invention;
FIG. 4 is an explanatory view of the main parts of the conform extrusion method or the forced lubrication wire drawing method used in the present invention.

Claims (1)

[Claims] A step of extruding and coating a superconducting core material with aluminum to form a superconducting primary material, a step of drawing the primary material using a forced lubrication wire drawing method to form an aluminum-coated superconducting wire, or bundling a plurality of the aluminum-coated superconducting wires, Alternatively, a process of twisting together to form a superconducting wire aggregate in a predetermined shape, then extrusion coating the aggregate with aluminum to form a superconducting secondary material, and drawing the secondary material into a predetermined shape using a forced lubrication wire drawing method. 1. A method for producing an aluminum stabilized superconducting wire, the method comprising sequentially performing the following steps.