Large-specification enamelled copper flat wire for vertical winding and preparation method of large-specification enamelled copper flat wire

Abstract

The invention belongs to the technical field of enameled copper flat wires, and particularly relates to a large-specification enameled copper flat wire for vertical winding and a preparation method thereof.The preparation method comprises the steps that S1, a low-oxygen copper rod is rolled into a flat blank on a double-roller rolling mill, and then the flat blank is stretched into a needed flat wire blank through a multi-pass flat drawing die; s2, ultrasonic cleaning is conducted on the flat wire blank in the step S1 to remove impurities, then double-section annealing treatment is conducted, and an annealed flat wire blank is obtained; s3, performing multi-pass mold method painting and repeated baking on the annealed flat wire blank in the step S2, and then fully cooling to obtain an enameled flat wire blank; and S4, firstly lubricating the enameled flat wire blank in the step S3, and then taking up to obtain the enameled copper flat wire. By effectively regulating and controlling the annealing temperature, the annealing wire speed, the temperature of each stage in the baking process and paint layer structure components, the problem that a paint film is prone to cracking in the winding process of the large-specification enameled copper flat wire is solved, operation is easy, and the method is suitable for large-scale industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of enameled copper flat wires, and in particular relates to a large-size enameled copper flat wire for vertical winding and a preparation method thereof. Background Art

[0002] Affected by the increasing depletion of natural resources, photovoltaic power generation new energy technology has gradually attracted global attention and importance. As the core component of power conversion in photovoltaic power generation technology, the demand for inverters is increasing day by day, and the technical requirements for enameled wires used in inductor coils in inverters are also increasing accordingly. Compared with enameled round wires, enameled copper flat wires have the advantages of small space occupancy, good heat dissipation performance, low high-frequency current loss and high motor power density. However, enameled flat wires have poor bending performance, poor paint film adhesion, and easy cracking of the paint film during vertical winding. This phenomenon is more common in large-size (width-to-thickness ratio greater than 4) enameled flat wires, so the product is difficult to meet the needs of downstream customers.

[0003] Therefore, providing a method for preparing large-size enameled rectangular copper wire for vertical winding that is simple to operate and has safe and reliable performance is one of the current research focuses of those skilled in the art. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the existing technology of large-sized enameled flat wires and provide a method for preparing large-sized enameled flat copper wires for vertical winding, so that the paint film of the prepared enameled flat copper wires will not crack during the winding process.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: A method for preparing a large-size enameled rectangular copper wire for vertical winding comprises the following steps: Step S1, rolling the low-oxygen copper rod into a flat billet on a double-roll rolling mill, and then stretching it into a desired flat wire billet through a multi-pass flat drawing die; Step S2, firstly ultrasonically clean the flat wire blank obtained in step S1 to remove impurities such as copper powder, and then perform a double-stage annealing treatment to obtain an annealed flat wire blank; Step S3, performing multiple passes of die-based painting and repeated baking on the annealed flat wire blank of step S2, and obtaining an enameled flat wire blank after sufficient cooling; Step S4, first lubricate the enameled flat wire blank of step S3, and then take up the wire to obtain the enameled flat copper wire.

[0006] In a preferred example, in step S1, the diameter of the low-oxygen copper rod is 4.5-10 mm; the number of passes of the flat drawing die is 2-5 times, and the deformation amount of each flat drawing pass is 10-30%.

[0007] In a preferred example, in step S2, the frequency of ultrasonic cleaning is 20 to 50 KHZ.

[0008] In a preferred example, step S2, double-stage annealing treatment: the annealing temperature range of the flat wire billet inlet end is 400-620°C, the annealing temperature range of the flat wire billet outlet end is 380-600°C, and the annealing line speed is 6-14 m / min.

[0009] In a preferred example, in step S3, the number of paint coats is 12 to 17 times, wherein the distribution ratio of the paint coats of the primer, the mid-coat and the top-coat is 2 to 4: 10 to 14: 1 to 2, the paint film thickness on the narrow side is 80 to 130 μm, and the paint film thickness on the wide side is 80 to 130 μm.

[0010] In a preferred example, in step S3, the temperature range of the baking inlet zone is 70-120°C, the temperature range of the lower layer one is 180-240°C, the temperature range of the lower layer two is 280-340°C, and the temperature range of the curing zone is 380-420°C.

[0011] In a preferred example, in step S3, the cooling fan speed is 1000-2600 r / min.

[0012] In a preferred example, in step S4, the lubrication method is narrow edge lubrication.

[0013] In a preferred example, the method further includes step S5: performing sample inspection on the enameled copper flat wire obtained in step S4. During the bending performance test of the sample inspection, the narrow side is bent 180° on a round rod with a diameter of 15 mm.

[0014] Based on a general inventive concept, another object of the present invention is to provide an enameled rectangular copper wire prepared by the above preparation method.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are as follows: By effectively regulating the annealing temperature, annealing line speed, the temperature at each stage of the baking process, and the paint layer structure components, the flexibility and adhesion of the paint film of the enameled copper flat wire are ensured, and the problem of easy cracking of the paint film during the winding process of large-sized enameled copper flat wire is solved; in addition, the method of the present invention is simple to operate and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a process flow chart for preparing the enameled rectangular copper wire of the present invention; Figure 2 A schematic diagram of the painting structure of the annealed flat wire blank prepared in the present invention; Figure 1-2 The meanings of the markings are as follows: 1-annealed flat wire billet, 2-primary coating, 3-middle coating, 4-top coating. DETAILED DESCRIPTION

[0017] In the description of the present invention, it is necessary to understand that the indicated orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and the purpose is only to facilitate the description of the present invention and simplify the description. It does not indicate or imply that the indicated components must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0018] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in conjunction with specific embodiments, but the present invention is not limited to these embodiments. It should be noted that, under the premise of not conflicting, the embodiments described below or the technical features can be arbitrarily combined to form new embodiments. In the present invention, unless otherwise specified, all parts and percentages are mass units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments, if not otherwise specified, are conventional methods in the art.

[0019] As used herein, the terms "comprises," "including," "contains," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0020] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range limited by a series of upper preferred values ​​and lower preferred values, this should be understood to specifically disclose all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including a range of "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise specified, this range is intended to include its end values ​​and all integers and fractions within this range.

[0021] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0022] Example 1

[0023] A method for preparing a large-size enameled copper flat wire for vertical winding, see Figure 1 , including the following steps: Step S1, rolling a low-oxygen copper rod with a diameter of 8 mm into a flat billet on a double-roll rolling mill, and then stretching it into a 1.2×9 mm flat wire billet through a flat drawing die for 5 passes; Among them, the deformation of the flat drawing pass is 20-25%, and the width-to-thickness ratio of the flat wire is 7.5; Step S2, firstly performing ultrasonic cleaning on the 1.2×9 mm flat wire blank of step S1 at a frequency of 25 kHz, and then performing a double-stage annealing treatment to obtain an annealed flat wire blank 1; Double-stage annealing treatment: the annealing temperature at the inlet end of the flat wire billet is 600°C, the annealing temperature at the outlet end is 580°C, and the annealing line speed is 12m / min; Step S3, performing multiple passes of die-based painting and repeated baking on the annealed flat wire blank 1 of step S2, and obtaining an enameled flat wire blank after sufficient cooling under the condition that the speed of the cooling fan is 2000 r / min; The number of painting passes is 16, wherein the distribution ratio of the painting passes of the base coat 2, the middle coat 3 and the top coat 4 is 3:12:1. The painting structure is as follows: Figure 2 As shown; the paint used is polyamide-imide paint, the paint film thickness on the narrow side is 99μm, and the paint film thickness on the wide side is 103μm; The temperature range of the baking inlet zone is 85°C, the temperature range of the lower layer one is 220°C, the temperature range of the lower layer two is 330°C, and the temperature range of the curing zone is 410°C; Step S4, first lubricate the narrow side of the enameled flat wire blank obtained in step S3, and then wind up the wire to obtain the enameled flat copper wire; Step S5, performing sample inspection on the enameled copper flat wire in step S4, wherein no paint film cracking occurs when the narrow side of the flat wire is bent 180° on a round rod with a diameter of 15 mm.

[0024] Example 2

[0025] A method for preparing a large-size enameled copper flat wire for vertical winding, see Figure 1 , including the following steps: Step S1, rolling a low-oxygen copper rod with a diameter of 4.5 mm into a flat billet on a double-roll rolling mill, and then stretching it into a 1×7 mm flat wire billet through a two-pass flat drawing die; Among them, the deformation of the flat drawing pass is 20-25%, and the width-to-thickness ratio of the flat wire is 7; Step S2, firstly performing ultrasonic cleaning on the 1×7 mm flat wire blank of step S1 at a frequency of 25 kHz, and then performing a double-stage annealing treatment to obtain an annealed flat wire blank 1; Double-stage annealing treatment: the annealing temperature at the inlet end of the flat wire billet is 480°C, the annealing temperature at the outlet end is 460°C, and the annealing line speed is 12.4m / min; Step S3, performing multiple passes of die-based painting and repeated baking on the annealed flat wire blank 1 of step S2, and obtaining an enameled flat wire blank after sufficient cooling under the condition that the speed of the cooling fan is 1500 r / min; The number of painting passes is 15, wherein the distribution ratio of the primer 2, the middle coating 3 and the top coating 4 is 2:12:1. The paint structure is as follows: Figure 2 As shown; the paint used is polyamide-imide paint, the paint film thickness on the narrow side is 106μm, and the paint film thickness on the wide side is 102μm; The temperature range of the baking inlet zone is 96°C, the temperature range of the lower layer one is 190°C, the temperature range of the lower layer two is 310°C, and the temperature range of the curing zone is 390°C; Step S4, first lubricate the narrow side of the enameled flat wire blank obtained in step S3, and then wind up the wire to obtain the enameled flat copper wire; Step S5, performing sample inspection on the enameled copper flat wire in step S4, wherein no paint film cracking occurs when the narrow side of the flat wire is bent 180° on a round rod with a diameter of 15 mm.

[0026] The above embodiments are merely preferred implementations of the present invention. Any simple modification, amendment and substitution of the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a large-size enameled rectangular copper wire for vertical winding, characterized in that: The following steps are involved: Step S1, rolling the low-oxygen copper rod into a flat billet on a double-roll rolling mill, and then stretching it into a desired flat wire billet through a multi-pass flat drawing die; Step S2, ultrasonically cleaning the flat wire blank obtained in step S1 to remove impurities, and then performing a double-stage annealing treatment to obtain an annealed flat wire blank (1); Step S3, performing multiple passes of die-based painting and repeated baking on the annealed flat wire blank (1) of step S2, and obtaining an enameled flat wire blank after sufficient cooling; Step S4, first lubricate the enameled flat wire blank of step S3, and then take up the wire to obtain the enameled flat copper wire.

2. The method for preparing a large-size enameled rectangular copper wire for vertical winding according to claim 1, characterized in that: Step S1, the diameter of the low-oxygen copper rod is 4.5-10 mm; the number of passes of the flat drawing die is 2-5 times, and the deformation amount of each flat drawing pass is 10-30%.

3. The method for preparing a large-size enameled rectangular copper wire for vertical winding according to claim 1, characterized in that: Step S2, the frequency of ultrasonic cleaning is 20-50KHZ.

4. The method for preparing a large-size enameled rectangular copper wire for vertical winding according to claim 1, characterized in that: Step S2, double-stage annealing treatment: the annealing temperature range of the flat wire billet inlet end is 400-620°C, the annealing temperature range of the flat wire billet outlet end is 380-600°C, and the annealing line speed is 6-14 m / min.

5. The method for preparing a large-size enameled rectangular copper wire for vertical winding according to claim 1, characterized in that: Step S3, the number of painting passes is 12 to 17 times, wherein the distribution ratio of the paint passes of the primer (2), the middle coating (3) and the top coating (4) is 2 to 4:10 to 14:1 to 2, the paint film thickness of the narrow side is 80 to 130 μm, and the paint film thickness of the wide side is 80 to 130 μm.

6. The method for preparing a large-size enameled rectangular copper wire for vertical winding according to claim 1, characterized in that: Step S3, the temperature range of the baking inlet zone is 70-120°C, the temperature range of the lower layer 1 is 180-240°C, the temperature range of the lower layer 2 is 280-340°C, and the temperature range of the curing zone is 380-420°C.

7. The method for preparing a large-size enameled rectangular copper wire for vertical winding according to claim 1, characterized in that: Step S3, the cooling fan speed is 1000-2600 r / min.

8. The method for preparing a large-size enameled rectangular copper wire for vertical winding according to claim 1, characterized in that: Step S4: the lubrication method is narrow edge lubrication.

9. The method for preparing a large-size enameled rectangular copper wire for vertical winding according to claim 1, characterized in that: The method further comprises step S5: performing sample inspection on the enameled copper flat wire obtained in step S4. During the bending performance test of the sample inspection, the narrow side is bent 180° on a round rod with a diameter of 15 mm.

10. The enameled rectangular copper wire prepared by the preparation method according to any one of claims 1 to 9.

Images