Superconducting wire U-shaped copper slot wire preparation method for electric arc additive manufacturing

Abstract

The invention discloses a preparation method of a U-shaped copper slot wire of a superconducting wire for electric arc additive manufacturing. The preparation method comprises the following steps: fixing a copper flat wire on a limiting tool of a processing production line; a welding gun is adjusted to the two sides of the copper flat wire on the limiting tool; a wire feeding pipe of a wire feeding device is adjusted to the position above the entering position of the copper flat wire; starting a welding gun to preheat the copper flat wire; starting a wire feeding device to feed the copper wire; and the copper flat wire and the copper wire are welded by a welding gun and then molded by a forming die to obtain the U-shaped copper slot wire. The manufacturing efficiency of manufacturing the superconducting wire U-shaped copper slot line in a small batch is improved through the electric arc additive manufacturing and forming module, and the manufacturing difficulty of the superconducting wire U-shaped copper slot line is reduced through the electric arc additive manufacturing and forming module.

Description

Technical Field

[0001] The invention relates to the technical field of superconducting wires, and in particular to a method for preparing a U-shaped copper groove wire of a superconducting wire manufactured by electric arc additive manufacturing. Background Art

[0002] NbTi / Cu superconducting wire (Wire In Channel, WIC) has the advantages of low cost and high stability of the prepared magnet. It is one of the main products of low-temperature superconducting wire and is widely used in superconducting magnets of magnetic resonance imaging (MRI) systems. WIC superconducting wire is prepared by inlaying and welding NbTi / Cu round wire and U-shaped copper groove wire with solder. The external U-shaped copper groove wire can provide sufficient stability for the superconducting wire to avoid "quenching" of the superconducting wire in extreme conditions.

[0003] Electric arc additive manufacturing (WAAM) is a technology that uses electric arc or plasma arc as a heat source to melt metal wire and directly manufactures a shape and size close to the finished product requirements by layer-by-layer cladding principle under program or software control. This technology has the advantages of high deposition efficiency, high material utilization rate, and low equipment cost. In the process of electric arc additive manufacturing, the shape, size and microstructure of the deposited layer can be precisely controlled by adjusting parameters such as arc scanning speed, wire feeding speed of wire feeding device, pulse frequency, peak current, peak time ratio, and base current ratio. At the same time, the rapid solidification conditions provided by electric arc additive manufacturing can refine the grain size and obtain good mechanical properties.

[0004] At present, U-shaped copper slot wires for superconducting wires are usually manufactured by processes such as round copper rod annealing, drawing, secondary annealing, flattening, over-molding, and two-pass rolling (grooving + forming). For the production of small batches of U-shaped copper slot wires outside conventional specifications, it is necessary to adjust the molds for multiple processes such as drawing and two-pass rolling, which is costly and inefficient. Summary of the invention

[0005] An embodiment of the present invention provides a method for preparing a U-shaped copper slot wire for superconducting wire by arc additive manufacturing, which is used to solve the problem in the prior art that the production of small batches of U-shaped copper slot wires for superconducting wires outside conventional specifications requires mold opening and adjustment of multiple processes such as drawing and two-pass rolling, which is costly and inefficient.

[0006] On the one hand, an embodiment of the present invention provides a method for preparing a U-shaped copper slot wire of a superconducting wire by arc additive manufacturing, comprising: Fix the copper flat wire on the limit fixture of the processing production line; Adjust the welding gun to the two sides of the copper flat wire on the limiting fixture; Adjusting the wire feeding tube of the wire feeding device to above the entry position of the copper flat wire on the limiting fixture; Starting the welding gun to preheat the copper flat wire; Starting the wire feeding device to feed the copper wire; The copper flat wire and the copper wire are welded by the welding gun and then shaped by a forming die to obtain a U-shaped copper groove wire.

[0007] In a possible implementation, the copper flat wire is moved on the processing line by a feeding device.

[0008] In a possible implementation, a plurality of pairs of welding guns are symmetrically arranged at equal distances on both sides of the copper flat wire, and all of the welding guns are provided with distance and angle fine-tuning devices.

[0009] In a possible implementation, the position limiting tooling, welding gun, wire feeding device and forming die are all arranged in an argon gas protection environment.

[0010] In a possible implementation, the wire feeding device is provided with a plurality of wire feeding tubes, and end heads of the plurality of wire feeding tubes are provided with distance and angle fine-tuning devices.

[0011] In a possible implementation, starting the welding gun to preheat the copper flat wire is starting two pairs of welding guns close to the feed port of the copper flat wire among the multiple pairs of welding guns.

[0012] In a possible implementation, starting the wire feeding device to feed the copper wire also includes: Start the material feeding device, the wire feeding device and all the welding guns.

[0013] The method for preparing a U-shaped copper slot wire of a superconducting wire by arc additive manufacturing in the present invention has the following advantages: (1) The arc additive manufacturing and forming module are used to improve the production efficiency of small batch production of superconducting wire U-shaped copper slot wire.

[0014] (2) The difficulty of manufacturing U-shaped copper slot wire of superconducting wire is reduced through arc additive manufacturing and forming modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A flow chart of a method for preparing a U-shaped copper slot wire of a superconducting wire manufactured by arc additive manufacturing provided in an embodiment of the present invention; Figure 2 A schematic diagram of a production line for a method for preparing a U-shaped copper slot wire of a superconducting wire manufactured by arc additive manufacturing provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Figure 1 A flowchart of a method for preparing a U-shaped copper slot wire of a superconducting wire manufactured by arc additive manufacturing is provided in an embodiment of the present invention; an embodiment of the present invention provides a method for preparing a U-shaped copper slot wire of a superconducting wire manufactured by arc additive manufacturing, comprising: Fix the copper flat wire on the limit fixture of the processing production line; Adjust the welding gun to the two sides of the copper flat wire on the limiting fixture; Adjusting the wire feeding tube of the wire feeding device to above the entry position of the copper flat wire on the limiting fixture; Starting the welding gun to preheat the copper flat wire; Starting the wire feeding device to feed the copper wire; The copper flat wire and the copper wire are welded by the welding gun and then shaped by a forming die to obtain a U-shaped copper groove wire; The copper flat wire is moved on the processing production line through a feeding device; The welding guns are arranged in pairs at equal distances and symmetrically on both sides of the copper flat wire, and all the welding guns are provided with distance and angle fine-tuning devices; The position limiting fixture, welding gun, wire feeding device and forming die are all arranged in an argon gas protection environment; The wire feeding device is provided with a plurality of wire feeding tubes, and the ends of the plurality of wire feeding tubes are provided with distance and angle fine-tuning devices; The starting of the welding gun to preheat the copper flat wire is to start two pairs of the welding guns close to the feed port of the copper flat wire; Starting the wire feeding device to feed the copper wire also includes: Start the material feeding device, the wire feeding device and all the welding guns.

[0019] For example, Figure 2As shown, the present application sets the arc additive manufacturing path according to the shape of the U-shaped copper groove line, and then sets the single-layer deposition height and copper flat strip preheating pass of the arc additive manufacturing. The processing program is written according to the processing path, deposition layer height and preheating pass and imported into the computer control system.

[0020] The copper flat strip is placed in the limiting fixture of the production line, and the positions of the wire feeding tubes in the welding gun and the wire feeding device are adjusted to facilitate the subsequent arc additive manufacturing steps; copper wire of a certain diameter is transported to the copper flat strip through the wire feeding device; the arc additive manufacturing is TIG additive manufacturing.

[0021] Set the parameters of TIG additive manufacturing: the copper flat belt moving speed is 300mm / min, the wire feeding speed of the wire feeding device is 300cm / min, the pulse frequency is 2.5HZ, the peak current is 250A~300A, the peak time accounts for 20%~30%, the base current accounts for 25%~30%, the shielding gas is argon, and the argon flow rate is generally 20L / min.

[0022] Then, without starting the wire feeding device, start the two pairs of welding guns near the feeding port to preheat the copper flat strip, and then start the remaining welding guns and wire feeding devices in turn, and perform arc additive manufacturing according to the parameters of TIG additive manufacturing. After the deposition is stable, adjust some parameters of arc additive manufacturing: the peak current is 220A~255A, the peak time accounts for 14%~20%, and the base current accounts for 10%~15%.

[0023] After the arc additive manufacturing is completed, the U-shaped copper trough wire semi-finished product passes through the final forming mold to complete the manufacturing of the U-shaped copper trough wire.

[0024] The single-layer deposition height is set to 0.5~1.0mm, the copper flat strip preheating pass is 2 times, and the tungsten tip of the welding gun is adjusted to be 3mm~8mm above the copper flat strip. This distance is also called the arc length. The position of the wire feeding tube in the wire feeding device is adjusted so that the angle between the wire feeding tube and the welding gun is 30°~50°, and the two are located in the same vertical plane.

[0025] In a possible embodiment, in embodiment 1, a 4.2×2.5 / 1.6 mm specification U-shaped copper slot wire is prepared; (1) The arc additive manufacturing path is set according to the shape of the U-shaped copper groove line, and then the single-layer deposition height and copper flat strip preheating pass of arc additive manufacturing are set. The single-layer deposition height is set to 1.0 mm, and the preheating pass is set to 2.

[0026] (2) Placing the copper flat strip in a limiting fixture of a processing machine tool, adjusting the position of a wire feeding tube in a welding gun and a wire feeding device to facilitate subsequent arc additive manufacturing steps; delivering a copper wire with a diameter of 1.6 mm to the copper flat strip through the wire feeding device; the arc additive manufacturing is TIG additive manufacturing.

[0027] (3) Set the parameters of TIG additive manufacturing: the copper flat strip moving speed is 300 mm / min, the wire feeding speed of the wire feeding device is 300 cm / min, the pulse frequency is 2.5 Hz, the peak current is 300 A, the peak time accounts for 30%, the base current accounts for 30%, the shielding gas is argon, and the argon flow rate is 20 L / min.

[0028] (4) Without starting the wire feeding device, start the two welding guns near the feeding port to preheat the copper flat strip under the other parameters except the wire feeding speed in step (3), start the remaining welding guns and wire feeding devices in turn, and perform arc additive manufacturing according to the parameters in step (3). After the deposition is stable, adjust some parameters of arc additive manufacturing: the peak current is 255 A, the peak time accounts for 20%, and the base current accounts for 15%.

[0029] (5) After the arc additive manufacturing is completed, the U-shaped copper trough wire semi-finished product passes through the final forming mold to complete the manufacturing of the U-shaped copper trough wire.

[0030] In a possible embodiment, in Example 2, a 3.2×2.0 / 1.6 mm specification U-shaped copper slot wire is prepared; (1) Set the arc additive manufacturing path according to the shape of the U-shaped copper groove line, and then set the single-layer deposition height of the arc additive manufacturing and the preheating pass of the copper flat strip. The single-layer deposition height is set to 0.6 mm, and the preheating pass is set to 2 passes; (2) placing the copper flat strip in a limited fixture of a processing machine tool, adjusting the position of a welding gun and a wire feeding tube in a wire feeding device to facilitate subsequent arc additive manufacturing steps; delivering a copper wire with a diameter of 1.6 mm to the copper flat strip through the wire feeding device; the arc additive manufacturing is TIG additive manufacturing; (3) Set the parameters of TIG additive manufacturing: the copper flat belt moving speed is 300 mm / min, the wire feeding speed of the wire feeding device is 300 cm / min, the pulse frequency is 2.5 Hz, the peak current is 280 A, the peak time accounts for 25%, the base current accounts for 30%, the shielding gas is argon, and the argon flow rate is 20 L / min; (4) Without starting the wire feeding device, under the other parameters except the wire feeding speed in step (3), start the two sets of welding guns near the feeding port to preheat the copper flat strip, and then start the remaining welding guns and wire feeding devices in turn, and perform arc additive manufacturing according to the parameters of step (3). After the deposition is stable, adjust some parameters of arc additive manufacturing: the peak current is 230A, the peak time accounts for 18%, and the base current accounts for 13%; (5) After the arc additive manufacturing is completed, the U-shaped copper trough wire semi-finished product passes through the final forming mold to complete the manufacturing of the U-shaped copper trough wire.

[0031] In a possible embodiment, in Example 3, a U-shaped copper slot wire with a specification of 2.6×1.6 / 1.3 mm is prepared; (1) Set the arc additive manufacturing path according to the shape of the U-shaped copper groove line, and then set the single-layer deposition height of the arc additive manufacturing and the preheating pass of the copper flat strip. The single-layer deposition height is set to 0.5 mm, and the preheating pass is set to 2 passes; (2) placing the copper flat strip in a limited fixture of a processing machine tool, adjusting the position of a welding gun and a wire feeding tube in a wire feeding device to facilitate subsequent arc additive manufacturing steps; delivering a copper wire with a diameter of 1.6 mm to the copper flat strip through the wire feeding device; the arc additive manufacturing is TIG additive manufacturing; (3) Set the parameters of TIG additive manufacturing: the copper flat belt moving speed is 300 mm / min, the wire feeding speed of the wire feeding device is 300 cm / min, the pulse frequency is 2.5 Hz, the peak current is 250 A, the peak time accounts for 20%, the base current accounts for 25%, the shielding gas is argon, and the argon flow rate is 20 L / min; (4) Without starting the wire feeding device, under the other parameters except the wire feeding speed in step (3), start the two sets of welding guns near the feeding port to preheat the copper flat strip, and then start the remaining welding guns and wire feeding devices in turn, and perform arc additive manufacturing according to the parameters of step (3). After the deposition is stable, adjust some parameters of arc additive manufacturing: the peak current is 220A, the peak time accounts for 14%, and the base current accounts for 10%; (5) After the arc additive manufacturing is completed, the U-shaped copper trough wire semi-finished product passes through the final forming mold to complete the manufacturing of the U-shaped copper trough wire.

[0032] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0033] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a U-shaped copper slot wire of a superconducting wire by arc additive manufacturing, characterized in that: include: Fix the copper flat wire on the limit fixture of the processing production line; Adjust the welding gun to the two sides of the copper flat wire on the limiting fixture; Adjusting the wire feeding tube of the wire feeding device to above the entry position of the copper flat wire on the limiting fixture; Starting the welding gun to preheat the copper flat wire; Starting the wire feeding device to feed the copper wire; The copper flat wire and the copper wire are welded by the welding gun and then shaped by a forming die to obtain a U-shaped copper groove wire.

2. The method for preparing a U-shaped copper slot wire of a superconducting wire manufactured by arc additive manufacturing according to claim 1, characterized in that: The copper flat wire is moved on the processing line by a feeding device.

3. The method for preparing a U-shaped copper slot wire of a superconducting wire manufactured by arc additive manufacturing according to claim 2, characterized in that: A plurality of pairs of welding guns are symmetrically arranged at equal distances on both sides of the copper flat wire, and all the welding guns are provided with angle and distance fine-tuning devices.

4. The method for preparing a U-shaped copper slot wire of a superconducting wire manufactured by arc additive manufacturing according to claim 1, characterized in that: The position limiting fixture, welding gun, wire feeding device and forming die are all arranged in an argon gas protection environment.

5. The method for preparing a U-shaped copper slot wire of a superconducting wire manufactured by arc additive manufacturing according to claim 1, characterized in that: The wire feeding device is provided with a plurality of wire feeding tubes, and angle and distance fine-tuning devices are arranged on the ends of the plurality of wire feeding tubes.

6. The method for preparing a U-shaped copper slot wire of a superconducting wire manufactured by arc additive manufacturing according to claim 3, characterized in that: The starting of the welding gun to preheat the copper flat wire is to start two pairs of the welding guns close to the feed opening of the copper flat wire.

7. The method for preparing a U-shaped copper slot wire of a superconducting wire manufactured by arc additive manufacturing according to claim 6, characterized in that: Starting the wire feeding device to feed the copper wire also includes: Start the material feeding device, the wire feeding device and all the welding guns.

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