CN102222547B

CN102222547B - Preparation method of bronze Nb3Sn folded yarns with small magnetic hysteresis loss

Info

Publication number: CN102222547B
Application number: CN2011100051461A
Authority: CN
Inventors: 郭建华; 贾晶晶; 张科; 王天成; 张丰收; 刘向宏; 冯勇; 张平祥
Original assignee: Western Superconducting Technologies Co Ltd
Current assignee: Western Superconducting Technologies Co Ltd
Priority date: 2011-01-06
Filing date: 2011-01-06
Publication date: 2012-07-25
Anticipated expiration: 2031-01-06
Also published as: CN102222547A

Abstract

The invention relates to a preparation method of bronze Nb3Sn folded yarns with small magnetic hysteresis loss. The method is technically characterized by the following steps of: adjusting the quantity of drill holes on a primary billet and pulling to obtain a sub-group component; performing secondary assembly to obtain a final billet; and stretching and annealing to obtain folded yarns with required performance parameters. In the folded yarns obtained with a process, the Ic performance is about 240A (12T, 4.2K), the loss is about 300 mJ/cm<3> (12T, 4.2K), and the magnetic hysteresis loss of a wire rod is effectively reduced.

Description

A kind of bronze method Nb3Sn strand preparation method of low magnetic hysteresis loss

Technical field

The present invention relates to a kind of bronze method Nb3Sn strand preparation method, belong to the manufacturing technology of the bronze method low-temperature superconducting wire that international thermonuclear fusion tissue (ITER) uses in its TF coil.

Background technology

The technology of preparing of bronze method strand is the key technology of ITER with the TF conductor, according to the specification requirement of ITER, and strand critical current I _c＞190A (12T, 4.2K), magnetic hysteresis loss Q _h＜500mJ/cm ³(12T, 4.2K), our strand I of making now _c, be employed in the method for designing of boring 19 holes on the high-tin bronze billet, (12T, 4.2K), magnetic hysteresis loss is 430mJ/cm can to reach 240A ³(12T, 4.2K), though satisfied the specification requirement of ITER, loss is nearer apart from requiring, and how changing arranging of core silk on the cross-sectional area of conductor, is not reducing I _cSituation under reduce magnetic hysteresis loss effectively, and obtain a kind of high I _c, the strand of low magnetic hysteresis loss to satisfy the ITER requirement higher to strand, is the problem that needs solution.

Summary of the invention

For fear of the weak point of prior art, the present invention proposes a kind of bronze method Nb3Sn strand preparation method of low magnetic hysteresis loss.

A kind of bronze method Nb3Sn strand preparation method of low magnetic hysteresis loss is characterized in that step is following:

Step 1: on the high-tin bronze billet of Φ 100 * 200mm～Φ 200 * 600mm, bore 37 holes; In Φ 10～Φ 30mm niobium alloy rod patchhole; EB electron beam soldering and sealing billet is adopted at the billet cap seal dress billet two ends of adopting oxygen-free copper to make again, obtains blank to be extruded;

Step 2: under 500～600 ℃ softening temperature, billet is carried out hot extrusion, with billet by Φ 100～Φ 200mm tube reducing to Φ 30～Φ 80mm; Then adopt 10%～30% pass reduction stretching blank; The each stretching finishes once to anneal in the drawing process of the pass reduction 10%～30%; Annealing temperature adopts 420 ℃～500 ℃; To Φ 8～Φ 5mm, adopt inferior constituent element moulding process to obtain the inferior constituent element of hexagon then the blank tube reducing of Φ 30～Φ 80mm;

Step 3: 0.5～2mm niobium sheet is rolled into the niobium pipe of tubulose through three roller rolling machines, adopt the machine work oxygen-free copper pipe, make the secondary billet jacket of Φ 100～Φ 200mm;

Step 4: the inferior constituent element of hexagon that step 3 is obtained combines to insert in the secondary billet jacket closely; Insert the niobium pipe in the space between inferior constituent element of hexagon and secondary billet jacket; The billet cap seal dress billet two ends of adopting oxygen-free copper to make; Adopt the soldering and sealing of EB electron beam again, obtain secondary billet to be extruded;

Step 5: under 500～600 ℃ softening temperature, billet is carried out hot extrusion, with the secondary billet by Φ 100～Φ 200mm tube reducing to Φ 30～Φ 80mm; Then adopt 10%～30% pass reduction stretching blank; The each stretching finishes once to anneal in the drawing process of the pass reduction 10%～30%; Annealing temperature adopts 420 ℃～500 ℃; The blank tube reducing of Φ 30～Φ 80mm to Φ 1.5～Φ 0.5mm, is and then carried out twisting, the strand line footpath that obtains requiring through the final draw line base of 10%～20% pass reduction at last; Chromium plating operation through 0.001～0.004 μ m thickness obtains the Φ 0.82mmNb that the TF toroidal field coil is used ₃The Sn line.

The bronze method Nb3Sn strand preparation method of a kind of low magnetic hysteresis loss of the present invention is under the situation that does not change final conductor cores filament diameter, to change the core silk to arrange to reduce the method for magnetic hysteresis loss.In the method, change arranging of core silk on the cross-sectional area of conductor, do not reducing I _cSituation under reduce magnetic hysteresis loss effectively, obtain a kind of high I _c, the strand of low magnetic hysteresis loss is to satisfy the ITER requirement higher to strand.

Description of drawings

Fig. 1: the process chart of this method;

Fig. 2: the Nb3Sn strand that 19 core methods for designing realize in the prior art;

Fig. 3: the Nb3Sn strand that 37 core methods for designing realize in this method.

Embodiment

Combine embodiment that the present invention is further described at present:

Instance 1:

Adopt the bronze billet of Φ 100 * 210mm, bores 37 through holes, afterwards the niobium rod of Φ 13mm is packed in the high-tin bronze boring billet, and the billet cap seal that adopts oxygen-free copper to make adorns the billet two ends,, obtain treating blank one time with electron beam soldering and sealing billet; Through hot extrusion the billet of Φ 100 is expressed to Φ 35mm and obtains the blank that stretches, adopt the annealing process combined that stretches, the working modulus between twice annealing is 10～50%, and the bar tube reducing that makes Φ 35mm is to Φ 5mm, and it is excellent that last moulding obtains the inferior constituent element of hexagonal.The inferior constituent element and the thick niobium barrier layer of 0.5mm of boundling are assembled in the Φ 130mm oxygen-free copper jacket; Soldering and sealing obtains the secondary billet; Hot extrusion secondary billet again; The secondary billet of Φ 130mm is expressed to Φ 52mm, adopts billet stretching annealing process that the stretching blank of Φ 52mm is worked into Φ 1mm, after twisting, finally stretch and plating obtains TF with Φ 0.82mm Nb ₃The Sn line.Through magnetic hysteresis loss test Q _h=305mJ/cm ³(12T, 4.2K).

Instance 2:

Adopt the bronze billet of Φ 160 * 400mm, bores 37 through holes, afterwards Φ 18mm niobium tantalum alloy rod is packed in the high-tin bronze boring billet, and the billet cap seal that adopts oxygen-free copper to make adorns the billet two ends, adopt electron beam soldering and sealing billet again, obtain treating blank one time; The process hot extrusion is expressed to Φ 55mm with the billet of Φ 160, adopts the annealing process combined that stretches, and the working modulus between twice annealing is 10～50%, and the bar tube reducing that makes Φ 55mm is to Φ 7mm, and last moulding obtains hexagonal Asia constituent element rod.The inferior constituent element and the thick niobium barrier layer of 1.0mm of boundling are assembled in the Φ 180mm oxygen-free copper jacket; Soldering and sealing obtains the secondary billet; The process hot extrusion is extruded onto Φ 60mm with the secondary billet of Φ 180mm again; Adopt billet stretching annealing process that the stretching blank of Φ 60mm is worked into Φ 1mm, after twisting, finally stretch and plating obtains TF with Φ 0.82mm Nb ₃The Sn line.Through magnetic hysteresis loss test Q _h=300mJ/cm ³(12T, 4.2K).

Instance 3:

Adopt the bronze billet of Φ 185 * 550mm, bores 37 through holes, afterwards Φ 25mm niobium tantalum alloy rod is packed in the high-tin bronze boring billet, and the billet cap seal that adopts oxygen-free copper to make adorns the billet two ends, adopt electron beam soldering and sealing billet again, obtain blank one time; The process hot extrusion is expressed to Φ 65mm with the billet of Φ 185mm, adopts the annealing process combined that stretches, and the working modulus between twice annealing is 10～50%, and the bar tube reducing that makes Φ 65mm is to Φ 8mm, and last moulding obtains hexagonal Asia constituent element rod.The inferior constituent element and the thick niobium barrier layer of 1.7mm of boundling are assembled in the Φ 185mm oxygen-free copper jacket; Soldering and sealing obtains the secondary billet; The process hot extrusion is extruded onto Φ 65mm with the secondary billet of Φ 185mm again; Adopt billet stretching annealing process that the stretching blank of Φ 65mm is worked into Φ 1mm, after twisting, finally stretch and plating obtains TF with Φ 0.82mm Nb ₃The Sn line.Through magnetic hysteresis loss test Q _h=308mJ/cm ³(12T, 4.2K).

Claims

1. the bronze method Nb of a low magnetic hysteresis loss ₃Sn strand preparation method is characterized in that step is following:

Step 1: on the high-tin bronze billet of Ф 100 * 200mm～Ф 200 * 600mm, bore 37 holes; In Ф 10～Ф 30mm niobium alloy rod patchhole; EB electron beam soldering and sealing billet is adopted at the billet cap seal dress billet two ends of adopting oxygen-free copper to make again, obtains blank to be extruded;

Step 2: under 500～600 ℃ softening temperature, billet is carried out hot extrusion, with billet by Ф 100～Ф 200mm tube reducing to Ф 30～Ф 80mm; Then adopt 10%～30% pass reduction stretching blank; The each stretching finishes once to anneal in the drawing process of the pass reduction 10%～30%; Annealing temperature adopts 420 ℃～500 ℃; To Ф 8～Ф 5mm, adopt inferior constituent element moulding process to obtain the inferior constituent element of hexagon then the blank tube reducing of Ф 30～Ф 80mm;

Step 3: 0.5～2mm niobium sheet is rolled into the niobium pipe of tubulose through three roller rolling machines, adopt the machine work oxygen-free copper pipe, make the secondary billet jacket of Ф 100～Ф 200mm;

Step 5: under 500～600 ℃ softening temperature, billet is carried out hot extrusion, with the secondary billet by Ф 100～Ф 200mm tube reducing to Ф 30～Ф 80mm; Then adopt 10%～30% pass reduction stretching blank; The each stretching finishes once to anneal in the drawing process of the pass reduction 10%～30%; Annealing temperature adopts 420 ℃～500 ℃; The blank tube reducing of Ф 30～Ф 80mm to Ф 1.5～Ф 0.5mm, is and then carried out twisting, the strand line footpath that obtains requiring through the final draw line base of 10%～20% pass reduction at last; Chromium plating operation through 0.001～0.004 μ m thickness obtains the Ф 0.82mmNb that the TF toroidal field coil is used ₃The Sn line.