Roughened wire, enameled wire, and method for manufacturing enameled wire

Abstract

The invention provides a rough rolled wire, an enameled wire and a method for manufacturing the enameled wire, which can form a high-quality enameled wire and inhibit surface oxidation. A roughing line having copper as the main component, in which the degree of oxidation obtained by measuring the surface of the roughing line is less than 25 by creating a histogram from the peak area of Raman spectrum peaks in each pixel of a mapped image obtained by a Raman spectrum mapping process, and measuring the degree of oxidation on the basis of the peak area of the Raman spectrum peaks in each pixel of the mapped image obtained by the Raman spectrum mapping process. The average value of the plurality of peak areas is determined from the histogram, and the average value is measured as the degree of oxidation, and the plurality of Raman spectrum peaks are peaks of lattice oscillation belonging to a vibration mode 2Eu of Cu2O. The histogram has, as a horizontal axis, a level obtained by dividing a range from a minimum value to a maximum value of the plurality of peak areas into 256, and, as a vertical axis, a degree, which is the number of pixels for each of the levels.

Description

Technical Field

[0001] The present invention relates to a rough rolling wire, an enameled wire, and a method for manufacturing an enameled wire. Background Art

[0002] Conventionally, a method for manufacturing an enameled wire in which an enamel coating film made of polyimide or polyamideimide is formed on the surface of a linear conductor has been widely known (for example, refer to Patent Document 1).

[0003] As the conductor of the enameled wire, a rough rolling wire in a state called a peeled material, from which the surface oxide coating film has been peeled off from a rough rolling wire called a wire rod, is usually used. The purpose of using the peeled material from which the oxide coating film has been peeled off as the material of the conductor is to improve the adhesion to the enamel coating and the appearance.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent No. 6730930 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] However, immediately after the oxide coating film is peeled off, oxidation of the surface of the peeled material still occurs. Therefore, if not managed under appropriate storage conditions (temperature, humidity, time), oxidation of the surface of the peeled material is promoted, resulting in discoloration.

[0009] Processing steps such as round drawing, rolling, and flat drawing, and an enamel coating process are performed on the peeled material. However, generally, the processing line for performing these processes does not include a device for peeling the oxide coating film, and there is no step for peeling the surface oxide coating film from the peeled material again. Therefore, in the case of discoloration of the peeled material, even after forming a semi-transparent enamel coating film, poor appearance due to discoloration of the conductor remains.

[0010] In addition, according to the research of the present inventors, it has been confirmed that in a rough rolling wire in which oxidation has occurred on the surface of a discolored peeled material or the like, due to embrittlement of the conductor surface caused by oxidation, the oxide coating film with a low elongation rate during drawing cracks, and the amount of copper powder (abrasion powder) generated increases. Moreover, the present inventors have found that copper powder adhering to the surface of a conductor formed by drawing a rough rolling wire is easily included in minute air bubbles, and when the solvent evaporates during firing after enamel coating, the minute air bubbles expand in volume (foam), resulting in poor appearance of the enameled wire.

[0011] In order to suppress such poor appearance of the enameled wire, in the manufacturing process of the enameled wire, it is required to use a peeled material or the like in which oxidation of the surface after peeling the oxide coating film is suppressed, a rough rolling wire in which oxidation of the surface is suppressed.

[0012] An object of the present invention is to provide a rough rolling wire that can form an enameled wire of high quality and suppresses surface oxidation, an enameled wire formed using the rough rolling wire, and a method for manufacturing the enameled wire.

[0013] Method for solving the problem

[0014] The present invention aims to solve the above problems and provides a rough rolling wire mainly composed of copper, wherein the oxidation degree obtained by measuring the surface of the rough rolling wire using Raman spectroscopic analysis is less than 25. The measurement of the oxidation degree is performed by performing mapping processing of Raman spectroscopy under the following conditions, making a histogram based on the peak areas of the Raman spectral peaks in each pixel of the obtained mapping image, calculating the average value of a plurality of the above peak areas from the histogram, and measuring the average value as the oxidation degree. The plurality of the above Raman spectral peaks belong to the vibration mode 2E of Cu 2 O and the peak of the lattice vibration of u The above histogram is a histogram with the level obtained by dividing the range from the minimum value to the maximum value of the plurality of the above peak areas into 256 as the horizontal axis and the number of the above pixels in each level, that is, the degree, as the vertical axis.

[0015] Raman measurement device: RAMANforce Standard VIS-NIR-HS manufactured by Nanophoton

[0016] Laser wavelength: 532.06 nm

[0017] Width of the entrance slit of the spectroscope: 50 μm

[0018] Ratio of the light quantity after attenuation by the ND filter to the maximum light quantity of the laser (attenuation ratio): 215 / 255 Number of rulings of the diffraction grating: 600 gr / mm

[0019] Magnification of the objective lens: 100 times

[0020] Numerical aperture (NA): 0.9

[0021] Mapping range: 88×60 μm

[0022] Pixel size: 2×2 μm

[0023] In addition, the present invention aims to solve the above problems and provides an enameled wire including a conductor formed by drawing the above rough rolling wire and an insulating coating provided around the conductor.

[0024] In addition, the present invention aims to solve the above-mentioned problems and provides a method for manufacturing an enameled wire, which includes a mapping process, an evaluation process, a wire drawing process and a coating film forming process; in the mapping process, a laser is irradiated on the surface of a rough rolled wire whose main component is copper, and a Raman spectrum mapping process is performed; in the evaluation process, a mapping image obtained by the above-mentioned mapping process is obtained, and the Raman spectrum attributable to Cu contained in each pixel is generated. 2 O vibration mode 2E u A histogram of the peak areas of the peaks of the lattice vibration of the rough rolled wire is prepared, and the degree of oxidation on the surface of the rough rolled wire is evaluated using the average value of the peak areas obtained based on the histogram; in the wire drawing process, the rough rolled wire is drawn after the evaluation process; in the film forming process, after the wire drawing process, an enamel coating is applied to the surface of the conductor formed by drawing the rough rolled wire, and the enamel coating is fired to form an insulating film around the conductor; and the wire drawing process and the film forming process are carried out when a specified result is obtained in the evaluation process.

[0025] Effects of the Invention

[0026] According to the present invention, it is possible to provide a rough rolled wire with suppressed surface oxidation, an enameled wire formed using the rough rolled wire, and a method for producing the enameled wire, which can form a high-quality enameled wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Among them, (a) and (b) are examples of photographs showing the appearance of peeled materials.

[0028] Figure 2 It is a radial cross-sectional view of the enameled wire according to the embodiment of the present invention.

[0029] Figure 3 In the figure, (a) is an optical microscope image of the surface of the peeled material, and (b) shows the Figure 3 (a) is a mapping image obtained by Raman scattering measurement within the measurement range shown.

[0030] Figure 4 is an example of a Raman spectrum obtained by Raman scattering measurement of the surface of a peeled material, showing Figure 3 (a) shows two Raman spectra measured at the measurement points indicated by “1” and “2” (the center point of the cross) included in the optical microscope image.

[0031] Figure 5 Indicates that it contains Figure 4 Histogram of the Raman spectrum mapping image.

[0032] Figure 6It is a graph in which the horizontal axis represents the storage time (h) of the skived material and the vertical axis represents the degree of oxidation, plotting the data in Table 1.

[0033] Description of Reference Numerals

[0034] 100: enameled wire, 10: conductor, 11: insulating coating film. Detailed Description of the Invention

[0035] (Characteristics of the rough rolling wire)

[0036] The rough rolling wire of the present invention is a rough rolling wire with suppressed surface oxidation and a main component of copper as a whole, typically a skived material. The skived material refers to a rough rolling wire in a state where the surface oxidation coating film has been peeled off from the rough rolling wire called a wire rod. Hereinafter, as an embodiment of the present invention, the skived material will be described. The skived material of the embodiment of the present invention is referred to as skived material 1. It should be noted that the main component being copper means that, for example, the copper concentration is 99.9% or more.

[0037] Processing such as round drawing, flat drawing, and rolling is performed on the skived material 1 used as the conductor of the enameled wire, and an insulating coating film is formed on its surface. That is, the degree of oxidation of the surface of the skived material 1 before performing processing such as drawing and rolling is preferably less than 25. Here, the degree of oxidation is a parameter representing the degree of oxidation obtained by Raman scattering measurement. Details of the degree of oxidation will be described later. It should be noted that the measurement of the degree of oxidation of the skived material 1 and the like described later can also be similarly performed on the rough rolling wire without skiving. Therefore, the rough rolling wire of the present invention also includes the rough rolling wire without skiving, and the degree of oxidation of the surface before performing processing can be made less than 25.

[0038] Figure 1 (a) and (b) are examples of photos showing the appearance of the skived material. Figure 1 The degree of oxidation of the surface of the skived material shown in (a) is 21.84, corresponding to the skived material 1 of the embodiment of the present invention. In Figure 1 In the skived material shown in (a), almost no discoloration of the surface is seen, which indicates that the surface oxidation is suppressed.

[0039] On the other hand, Figure 1 The degree of oxidation of the surface of the skived material shown in (b) is 102.6, which does not belong to the skived material 1 of the embodiment of the present invention. In Figure 1 In the skived material shown in (b), some discolored and blackened parts are seen, which indicates that a certain degree of oxidation has occurred on the surface.

[0040] The stripping material 1 can be used as a material for the conductor of an enameled wire. For example, after drawing the stripping material 1, a coating of polyimide or polyamideimide is applied to the surface of the stripping material 1 and fired, whereby an enameled wire having an enamel coating film formed around the stripping material 1 can be manufactured. That is, according to an embodiment of the present invention, an enameled wire including a conductor made of the stripping material 1 and an insulating coating film provided around the conductor can be provided.

[0041] Figure 2 It is a cross-sectional view in the radial direction of the enameled wire 100 according to an embodiment of the present invention. Figure 2 The enameled wire 100 shown has a rectangular cross-sectional shape and includes a flat wire-shaped conductor 10 formed by flat drawing a rough rolling wire such as the stripping material 1 and an insulating coating film 11 formed around the conductor 10. It should be noted that the enameled wire 100 may also be an enameled wire having a circular cross-sectional shape. In this case, the conductor 10 is formed by circular drawing a rough rolling wire such as the stripping material 1.

[0042] Figure 1 The stripping materials shown in (a) and (b) are stripping materials with a diameter of 6.3 mm used as raw materials for flat enameled wire conductors. They are obtained by peeling (stripping) the oxide film on the surface of a wire rod with a diameter of 8 mm and applying a lubricant. The wire material as the raw material is oxygen-free copper (OFC) manufactured by the dipping molding system of Showa Wire & Cable Co., Ltd.

[0043] (Measurement of oxidation degree)

[0044] The oxidation degree means that laser is irradiated on the surface of the stripping material, Raman spectroscopy is mapped, and based on the peak of the lattice vibration of the vibration mode 2E of Cu 2 O (hereinafter referred to as the Cu u O peak) in each pixel of the obtained mapping image, when a histogram is made with the range from the minimum value to the maximum value of the peak area divided into 256 levels as the horizontal axis and the number of pixels in each level, that is, the degree, as the vertical axis, the average value of the peak area of the Cu 2 O peak obtained from this histogram. 2 O peak area.

[0045] The mapping process in the above definition of the degree of oxidation was carried out using a Raman measurement device (RAMANforceStandard VIS-NIR-HS manufactured by Nanophoton) under the following conditions: the laser wavelength was 532.06 nm, the width of the incident slit of the spectroscope was 50 μm, the ratio of the reduced light quantity of the ND filter to the maximum laser light quantity (attenuation ratio) was 215 / 255, the number of rulings of the diffraction grating was 600 gr / mm, the magnification and numerical aperture (NA) of the objective lens were 100 times and 0.9 respectively, and the mapping range and pixel size were 88×60 μm and 2×2 μm respectively (i.e., the number of pixels in the mapping image was 1320).

[0046] As described above, the degree of oxidation of the surface of the peeled material is measured by Raman spectroscopic analysis of Raman scattered light, so that the degree of oxidation of the surface can be evaluated in a non-contact manner without damaging the peeled material. In addition, in the measurement of the degree of oxidation, the peak area of the Cu 2 O peak in the Raman spectrum is used, so that the degree of oxidation of the surface of the peeled material can be evaluated with high precision. For example, in the case of analyzing the composition of the surface of the peeled material by elemental analysis, it is difficult to evaluate the degree of oxidation with high precision because information on oxygen other than the oxygen contained in the copper oxide is mixed.

[0047] Hereinafter, the specific steps for measuring the degree of oxidation will be described. The method for measuring the degree of oxidation of the surface of the peeled material according to the embodiment of the present invention includes a step of irradiating the surface of the peeled material with laser light to perform mapping processing on the Raman spectrum and a step of deriving the degree of oxidation of the surface of the peeled material based on the peak area of the Cu 2 O peak in a plurality of Raman spectra obtained by this mapping processing.

[0048] Here, the mapping process refers to a process of repeatedly performing measurement while scanning measurement points (laser irradiation points) in a specified measurement area on the surface of the measurement object. The two-dimensional measurement data obtained by the mapping process, that is, the mapping image, has data on the peak area of the Cu 2 O peak included in the Raman spectrum obtained by one Raman scattering measurement for each pixel. In the Raman scattering measurement of the present embodiment, the spot diameter of the laser light irradiated on the surface of the peeled material is, for example, 0.4 to 2.2 μm.

[0049] The peak area of the Cu 2 O peak included in the Raman spectrum changes according to the amount of the oxide on the surface of the peeled material. Therefore, the peak area of the Cu 2 O peak becomes an evaluation material for the degree of oxidation of the surface of the peeled material.

[0050] Figure 3(a) is an optical microscope image of the surface of the peeled material. The rectangular frame included in this optical microscope image indicates the measurement range of Raman scattering measurement. Figure 3 (b) shows Figure 3 the mapping image obtained by Raman scattering measurement within the measurement range shown in Figure 3 (a). Figure 3 The size of the measurement range shown in (a) and the mapping image shown in (b) is 88×60 μm, and the size of one pixel of the mapping image is 2 μm×2 μm. Each pixel of the mapping image contains data on the intensity of the peak (Cu 2 O vibration mode 2E u ) of the lattice vibration belonging to Cu 2 O peak.

[0051] Figure 4 is an example of the Raman spectrum obtained by Raman scattering measurement of the surface of the peeled material performed under the above conditions, and shows two Raman spectra measured at the measurement points (the points at the center of the crosses) indicated by "1" and "2" included in the optical microscope image shown in Figure 3 (a). The Cu 2 O peak is included in this Raman spectrum. Figure 3 Each pixel of the mapping image shown in (b) has a color density corresponding to the intensity of the Cu 2 O peak measured in that pixel.

[0052] The Cu 2 O peak takes the maximum intensity in the range of 190 cm -1 or more and 250 cm -1 or less near 220 cm -1 in the Raman spectrum. The wave numbers at which each peak included in the Raman spectrum takes the maximum intensity may shift due to the environmental temperature during measurement, etc., but the magnitude relationship of the wave numbers at which these peaks take the maximum intensity remains unchanged, so there will be no misidentification.

[0053] The peak area of the Cu 2 O peak in this embodiment is calculated using the Covell method. Regarding the wave number range for measuring the peak area of the Cu 2 O peak, the valley values around the peak are set manually. In this embodiment, the position where the Cu 2 O peak takes the maximum intensity is set to ±11.9 cm -1 . It should be noted that the wave number range for measuring the peak area of the Cu 2 O peak is set once initially in the measurement within the 88×60 μm measurement range as shown in Figure 3 (a). In addition, as for the wave number range for measuring the peak area of the Cu 2Analysis software for measuring the peak area of the O peak, using RAMAN Viewer Nanophoton corp Ver.4.5.54.29507.

[0054] For example, Figure 4 In the exemplified Raman spectrum, Cu 2 The peak areas of the O peak are 96.3 (upper Raman spectrum) and 49.4 (lower Raman spectrum).

[0055] After obtaining the peak area of the Cu 2 O peak in each pixel of the mapped image, with the range from the minimum to the maximum of the peak area of the Cu 2 O peak in each pixel of the mapped image divided into 256 levels as the horizontal axis and the number of pixels in each level, i.e., the degree, as the vertical axis, a histogram is made. Then, the average value of the peak area of the peak is obtained from the made histogram and taken as the oxidation degree. Figure 5 Showing, as an example of the histogram, the histogram of the mapped image of the Raman spectrum containing Figure 4 .

[0056] (Evaluation of Stripping Material)

[0057] The following shows the results of the evaluation of the oxidation degree of the stripping material based on experiments.

[0058] First, as the first evaluation, the relationship between the oxidation degree of the surface of the stripping material and the oxidation state judged by the discoloration of the surface is evaluated. In this evaluation, for the stripping material mainly composed of copper stored under various storage conditions (temperature from 10°C to 45°C, humidity from 50%RH to 95%RH, time from 4 hours to 48 hours), the oxidation degree is measured by the above method, and the presence or absence of discoloration is judged by visual observation. In this evaluation, a stripping material with a diameter of 6.3 mm and a length of about 5 cm is used and stored in a thermo-hygrostat.

[0059] The following Table 1 shows the numerical values of the oxidation degree (average peak area of the Cu 2 O peak) of the stripping material obtained through experiments for each storage condition. In addition, for the case where surface discoloration is visually confirmed, "(discoloration)" is noted under the numerical value of the oxidation degree.

[0060] [Table 1]

[0061]

[0062] Figure 6 is a graph obtained by plotting the data in Table 1 with the horizontal axis being the storage time (h) of the stripping material and the vertical axis being the oxidation degree. According to Table 1, Figure 6As can be seen from the results shown, oxidation of the surface of the peeled material is suppressed when the degree of oxidation is less than about 25, and oxidation of the surface of the peeled material is suppressed when it is stored under conditions of a temperature of 40°C or lower, a humidity of 95% RH or lower, and a time of 48 hours or less.

[0063] It should be noted that Figure 1 the peeled material shown in (a) is the peeled material stored under the conditions of a temperature of 40°C, a humidity of 95% RH, and a time of 12 hours contained in Table 1. Additionally, Figure 1 the peeled material shown in (b) is the peeled material contained in Table 1 stored under the conditions of a temperature of 45°C, a humidity of 95% RH, and a time of 24 hours.

[0064] Next, as the second evaluation, the relationship between the degree of oxidation of the surface of the peeled material, the oxidation state judged by the discoloration of the surface, and the wear quality during wire drawing of the peeled material was evaluated. In this evaluation, for peeled materials mainly composed of copper stored under various storage conditions (temperature of 50°C, humidity of 10 - 22% RH, time of 48 hours - 3 weeks), the degree of oxidation was measured based on the above method, the presence or absence of discoloration was judged by visual observation of the appearance, and the mass of the wear powder after wire drawing was measured.

[0065] In this evaluation, a peeled material with a diameter of 6.3 mm and a length of about 9 m was used and stored in a thermostatic bath in a wound state with a winding diameter of 1.09 m. In the measurement of the degree of oxidation, the peeled material was cut into lengths of about 5 cm and subjected to Raman scattering mapping. In wire drawing, a peeled material with a length of about 9 m was installed on a single-head wire drawing machine and wire drawn using a wire drawing die with a die aperture of 5.33 mm in diameter. After wire drawing the peeled material, the wear powder of the peeled material attached to the die was removed using ethanol and tweezers, and after drying at 45°C for 24 hours to evaporate the ethanol, the mass of this wear powder was measured using an electronic balance. This mass measurement was carried out 3 times, and the average value of the obtained measurement values was used as the wear quality (mg / 9 m) during wire drawing of the peeled material.

[0066] The following Table 2 shows the storage conditions, the numerical values of the degree of oxidation (average peak area of the Cu 2 O peak), the presence or absence of surface discoloration judged visually, and the wear quality during wire drawing for 4 peeled materials (designated as Specimens A - D) for which this evaluation was carried out. It should be noted that "not stored" as the storage condition for Specimen A means that Specimen A is the peeled material just after peeling the oxidation coating and has not been stored in a thermostatic bath. Additionally, the storage humidity of Specimens B - D varies within the range of 10 - 22% RH due to the humidity deviation at each position in the large thermostatic bath.

[0067] [Table 2]

[0068]

[0069] According to the results shown in Table 2, in Sample D, which should have been oxidized more than Sample C based on the storage conditions, oxidation was suppressed compared to Sample C. This is considered to be because Samples B to C were stored in a large constant temperature chamber with large humidity deviations at each position, so the humidity around the portion where the degree of oxidation was actually measured and the discoloration was observed varied between Samples B to C. Therefore, in the results included in Table 2, the relationship between the storage conditions and the evaluation results (degree of oxidation, presence or absence of discoloration, and wear quality during wire drawing) of Samples B to D was judged to be of low reliability and could not be used as evaluation materials.

[0070] On the other hand, the relationship between the degree of oxidation, the presence or absence of discoloration, and the wear quality during wire drawing of samples A to D shows that in samples A, B, and D having a degree of oxidation of less than 25, surface oxidation is suppressed, and further, wear during wire drawing is reduced, and the amount of wear powder generated is reduced. If the amount of wear powder generated is reduced, it is possible to suppress the appearance defect of the enameled wire caused by the foaming of fine bubbles contained in the wear powder attached to the surface of the peeling material during firing after enameling.

[0071] (Manufacture of enameled wire)

[0072] According to the present embodiment, the enameled wire can be manufactured using a rough rolled wire such as a peeled material whose oxidation degree is evaluated by the above-mentioned evaluation method.

[0073] That is, according to the present embodiment, a method for manufacturing an enameled wire can be provided, which includes a mapping process, an evaluation process, a wire drawing process, and a coating film forming process. In the mapping process, a laser is irradiated on the surface of a rough rolled wire whose main component is copper, and a Raman spectrum mapping process is performed. In the evaluation process, a mapping image obtained by the mapping process is generated, and the Raman spectrum attributable to Cu contained in each pixel is generated. 2 O vibration mode 2E u A histogram of the peak area of ​​the peak of the lattice vibration is obtained, and the degree of oxidation on the surface of the rough rolled wire is evaluated using the average value of the peak area of ​​the peak obtained from the histogram. In the wire drawing step, the rough rolled wire is drawn after the evaluation step, and in the coating forming step, after the wire drawing step, an enamel coating is applied to the surface of the conductor formed by drawing the rough rolled wire and fired to form an insulating coating around the conductor.

[0074] In the manufacturing method of the enameled wire, the wire drawing step and the coating forming step are performed when a predetermined result is obtained in the evaluation step. For example, as described above, it is preferred that the degree of oxidation of the surface of the rough rolled wire is less than 25, so when the result that the degree of oxidation of the surface of the rough rolled wire is less than 25 is obtained in the evaluation step, the wire drawing step and the coating forming step are performed.

[0075] That is, for example, in the mapping process in the mapping treatment step, a Raman measurement device (Nanophoton's RAMANforce Standard VIS-NIR-HS) is used. The mapping treatment is carried out under the conditions that the laser wavelength is 532.06 nm, the width of the incident slit of the spectroscope is 50 μm, the ratio of the light quantity after attenuation by the ND filter to the maximum light quantity of the laser (attenuation ratio) is 215 / 255, the number of rulings of the diffraction grating is 600 gr / mm, the magnification and numerical aperture (NA) of the objective lens are 100 times and 0.9 respectively, and the mapping range and pixel size are 88×60 μm and 2×2 μm respectively. When the histogram produced in the evaluation process has the range from the minimum to the maximum of the peak area of the peak divided into 256 levels as the horizontal axis and the number of pixels in each level as the vertical axis, in the evaluation process, when the average value of the peak area of the peak obtained from the histogram is less than 25, the wire drawing process and the film forming process are carried out.

[0076] It should be noted that for the rough rolling line in the wire drawing process and the formation of the insulating film in the film forming process, the techniques used in the manufacturing methods of conventional general enameled wires can be used. In addition, besides the wire drawing process, a rolling process can also be carried out, and this rolling process is carried out for processing the round rough rolling line into a flat wire.

[0077] (Effect of the Embodiment)

[0078] According to the above-described embodiment of the present invention, through the mapping treatment using Raman scattering, it is possible to clarify the storage conditions of the rough rolling line such as the peeling material that can suppress surface oxidation, set appropriate storage conditions, or measure the surface oxidation degree and select the rough rolling line with suppressed oxidation. Thus, it is possible to provide a rough rolling line with suppressed surface oxidation and an enameled wire formed using the rough rolling line, which can form a high-quality enameled wire.

[0079] (Summary of the Embodiment)

[0080] Next, reference numerals in the embodiment are used to record the technical idea grasped from the above-described embodiment. However, the reference numerals and the like in the following description do not limit the components in the claims to the components specifically shown in the embodiment.

[0081] [1] A rough rolling line (1) mainly composed of copper, the oxidation degree obtained by measuring the surface of the rough rolling line using Raman spectroscopic analysis is less than 25. The measurement of the oxidation degree is carried out by performing mapping processing of Raman spectra under the following conditions, making a histogram based on the peak areas of the Raman spectral peaks in each pixel of the obtained mapping image, calculating the average value of a plurality of the above peak areas from the histogram, and using this average value as the oxidation degree for measurement. A plurality of the above Raman spectral peaks belong to Cu2 Vibrational mode 2E of O u For the peaks of the lattice vibration, the above histogram has the horizontal axis representing the levels obtained by dividing the range from the minimum to the maximum of the areas of multiple above-mentioned peaks into 256 levels, and the vertical axis representing the number of the above-mentioned pixels, i.e., the degree, for each of the above levels.

[0082] Raman measurement device: RAMANforce Standard VIS-NIR-HS manufactured by Nanophoton

[0083] Laser wavelength: 532.06 nm

[0084] Width of the entrance slit of the spectroscope: 50 μm

[0085] Ratio of the light quantity after attenuation by the ND filter to the maximum laser light quantity (attenuation ratio): 215 / 255 Number of rulings of the diffraction grating: 600 gr / mm

[0086] Magnification of the objective lens: 100×

[0087] Numerical aperture (NA): 0.9

[0088] Mapping range: 88×60 μm

[0089] Pixel size: 2×2 μm

[0090] [2] An enameled wire (100) comprising a conductor (10) obtained by drawing the rough rolling wire (1) described in the above [1] and an insulating coating film (11) provided around the conductor (10).

[0091] [3] A method for manufacturing an enameled wire (100), which includes a drawing process of drawing the rough rolling wire (1) described in the above [1] and a coating film forming process of coating an enamel coating material on the surface of the conductor (10) formed by drawing the rough rolling wire (1) and firing to form an insulating coating film (11) around the conductor (10) after the drawing process.

[0092] [4] A method for manufacturing an enameled wire (100), which includes: a mapping process of irradiating a laser on the surface of a rough rolling wire (1) mainly composed of copper and performing mapping processing on the Raman spectrum; an evaluation process of creating, for each pixel of the mapping image obtained by the above mapping process, the Cu 2 Vibrational mode 2E of O uA histogram of the peak areas of the lattice vibration peaks is used to evaluate the degree of oxidation of the surface of the rough rolling line (1) using the average value of the peak areas obtained from the above histogram; a wire drawing process, after the above evaluation process, the rough rolling line (1) is wire drawn; and a film forming process, after the above wire drawing process, an enamel coating is applied to the surface of the conductor (10) formed by wire drawing the rough rolling line (1) and fired, thereby forming an insulating film (11) around the conductor (10); the above wire drawing process and the above film forming process are carried out when a specified result is obtained in the above evaluation process.

[0093] [5] According to the method for manufacturing an enameled wire (100) described in the above [4], wherein the mapping process in the above mapping process uses a Raman measurement device (RAMANforce Standard VIS-NIR-HS manufactured by Nanophoton), and is carried out under the conditions that the laser wavelength is 532.06 nm, the width of the incident slit of the spectroscope is 50 μm, the ratio of the reduced light quantity of the ND filter to the maximum laser light quantity (attenuation ratio) is 215 / 255, the number of rulings of the diffraction grating is 600 gr / mm, the magnification and numerical aperture (NA) of the objective lens are 100 times and 0.9 respectively, the mapping range and pixel size are 88×60 μm and 2×2 μm respectively. The above histogram made in the above evaluation process is a histogram with the grades obtained by dividing the range from the minimum value to the maximum value of the above peak area into 256 as the horizontal axis and the number of the above pixels in each grade, that is, the degree, as the vertical axis. In the above evaluation process, when the average value of the above peak area obtained from the above histogram is less than 25, the above wire drawing process and the above film forming process are carried out.

[0094] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the invention. In addition, the above-described embodiments do not limit the invention related to the claims. In addition, it should be noted that not all combinations of the features described in the embodiments are necessarily required for the method of solving the problems of the invention.

Claims

1. A rough rolled wire, which contains copper as a main component, and the degree of oxidation obtained by measuring the surface of the rough rolled wire using Raman spectrometry is less than 25, In the measurement of the oxidation degree, Raman spectrum mapping processing is performed under the following conditions, a histogram is prepared based on the peak area of ​​the Raman spectrum peak in each pixel of the obtained mapping image, an average value of a plurality of the peak areas is obtained based on the histogram, and the average value is used as the oxidation degree, The Raman spectrum peaks are attributed to the vibration mode 2E of Cu2O. u The peak of the lattice vibration, The histogram is a histogram with the range from the minimum value to the maximum value of the plurality of peak areas divided into 256 levels as the horizontal axis and the number of pixels, i.e., the degree, of each level as the vertical axis. Raman measurement device: RAMANforce Standard VIS-NIR-HS manufactured by Nanophoton, Laser wavelength: 532.06nm, The width of the incident slit of the beam splitter: 50 μm, The ratio of the light intensity attenuated by the ND filter to the maximum light intensity of the laser is the attenuation ratio: 215 / 255. The number of lines of the diffraction grating: 600gr / mm, Objective lens magnification: 100 times, Numerical aperture, NA: 0.9, Mapping range: 88×60μm, Pixel size: 2×2μm. 2 . An enameled wire comprising a conductor obtained by drawing the rough rolled wire according to claim 1 , and an insulating film provided around the conductor.

3. A method for manufacturing an enameled wire, comprising: A wire drawing step of drawing the rough rolled wire according to claim 1, and The coating forming step is a step of applying enamel to the surface of the conductor formed by drawing the rough rolled wire and firing the enamel to form an insulating coating around the conductor after the wire drawing step.

4. A method for manufacturing an enameled wire, comprising: In the mapping process, the surface of the rough rolled wire whose main component is copper is irradiated with laser light to map the Raman spectrum. Evaluation step: preparing the vibration mode 2E attributed to Cu2O contained in each pixel of the mapping image obtained by the mapping process u A histogram of the peak areas of the peaks of the lattice vibration of the rough rolled wire is obtained, and the degree of oxidation of the surface of the rough rolled wire is evaluated using the average value of the peak areas obtained from the histogram. a wire drawing step of drawing the rough rolled wire after the evaluation step, and a coating forming step of applying an enamel coating on the surface of the conductor formed by drawing the rough rolled wire and firing the enamel coating after the wire drawing step, thereby forming an insulating coating around the conductor; The wire drawing step and the coating film forming step are performed when a predetermined result is obtained in the evaluation step.

5. The method for manufacturing an enameled wire according to claim 4, wherein: The mapping process in the mapping process step is performed using a Raman measurement device, namely, RAMANforceStandard VIS-NIR-HS manufactured by Nanophoton, under the following conditions: a laser wavelength of 532.06 nm, a width of an incident slit of a spectrometer of 50 μm, a ratio of the amount of light attenuated by an ND filter to the maximum amount of light from the laser, namely, an attenuation ratio of 215 / 255, a number of lines of a diffraction grating of 600 gr / mm, a magnification of an objective lens and a numerical aperture, namely, NA, of 100 times and 0.9, respectively, a mapping range and a pixel size of 88×60 μm and 2×2 μm, respectively. The histogram prepared in the evaluation step is a histogram with the range from the minimum value to the maximum value of the peak area divided into 256 levels as the horizontal axis and the number of pixels, i.e., the degree, of each level as the vertical axis. In the evaluation step, when the average value of the peak areas obtained from the histogram is less than 25, the wire drawing step and the film forming step are performed.

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