Timepiece component and method for manufacturing same, and blank for

Abstract

The invention provides a timepiece component, a method for manufacturing the timepiece component, a blank for the timepiece component and a method for manufacturing the blank for the timepiece component, and the quality of mirror finishing of the timepiece component can be improved. The method for manufacturing the timepiece component comprises the following steps: preparing a metal raw material; a forging step for forging and heat-treating the metal raw material to produce a timepiece component blank having a machining target portion to be cut; and a step in which the timepiece member is cut from the location to be processed of the timepiece member blank by cutting and ground, and the metal material is formed using a die designed so that the magnitude of strain at the location to be processed in the timepiece member blank falls within a prescribed range during forging. The heat treatment is performed under heat treatment conditions set in accordance with the magnitude of the strain of the portion to be processed in the blank for the timepiece component formed by forging, thereby homogenizing the grain size of the portion to be processed and isotropic the crystal orientation.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a timepiece component, a method for manufacturing a timepiece component blank, a timepiece component, and a timepiece component blank. Background Art

[0002] Patent document 1 discloses a method for manufacturing watch parts such as watch cases, in which an ingot containing Fe as a main component is forged into a roughly cylindrical metal composition, and after solution treatment, mechanical processing (rough processing) such as cutting, grinding, and lapping is performed to thereby process the ingot into a shape corresponding to the watch case. Then, after aging treatment, polishing, lapping, and texturing are performed to perform finishing processing in which the mirror portion, the pear-skin portion, and the texture portion are formed into a prescribed pattern, thereby manufacturing the watch case.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-70331

[0004] However, in the existing manufacturing method, there is a limit in improving the mirror finishing quality of watch parts. For example, as in Patent Document 1, when a watch part is manufactured from a cylindrical metal composition by cutting, when the ingot is processed into a cylindrical metal composition by rolling, forging, drawing, etc., the grain shape produces directionality and the crystal orientation has anisotropy. Therefore, in the watch part manufactured from a cylindrical metal composition by cutting, etc., the crystal orientation also produces anisotropy. In addition, there is also a method of plastically processing a metal composition into a shell shape by forging, but in this case, the processing rate varies locally, the grain size becomes uneven, and the crystal orientation also produces anisotropy.

[0005] Because the grinding process for mirror finishing is affected by the metal structure, even when the grain size is uneven or the crystal orientation is anisotropic, the surface of the watch component cannot be polished uniformly, resulting in a limit to the quality of the mirror finishing. Therefore, it is impossible to meet the demand for further improvement in the mirror finishing quality of watch components and the provision of watches with a higher sense of luxury. Summary of the Invention

[0006] The manufacturing method of watch components disclosed in the present invention is characterized in that the manufacturing method of watch components has the following steps: preparing a metal raw material; forging and heat treating the metal raw material to produce a watch component blank having a processing object portion that is an object of cutting processing; and cutting out the watch component from the processing object portion of the watch component blank by cutting and grinding it. During the forging, the metal raw material is formed using a mold designed so that the strain of the processing object portion in the watch component blank is within a specified range. The heat treatment is performed under heat treatment conditions set according to the strain of the processing object portion in the watch component blank formed by the forging, so that the grain size of the processing object portion is uniform and the crystal orientation is isotropic.

[0007] The manufacturing method of a watch component blank of the present invention is characterized in that the watch component blank is an object for cutting watch components, and the manufacturing method of the watch component blank has the following steps: a step of preparing a metal raw material; and forging and heat treating the metal raw material to manufacture a watch component blank having a processing object portion that is an object of cutting processing. During the forging, the metal raw material is formed using a mold designed so that the strain of the processing object portion in the watch component blank is within a specified range, and the heat treatment is performed under heat treatment conditions set according to the strain of the processing object portion in the watch component blank formed by the forging, so that the grain size of the processing object portion is uniform and the crystal orientation is isotropic.

[0008] The watch component of the present invention is characterized in that the watch component is manufactured by forging and heat treating a metal raw material to produce a watch component blank having a processing object portion that is an object of cutting processing, and then is cut out from the processing object portion by cutting and polished, thereby being manufactured, and the grain size of the watch component is uniformized and the crystal orientation is isotropic.

[0009] The blank for watch components of the present invention is characterized in that the blank for watch components is an object for cutting into watch components, the blank for watch components is manufactured by forging and heat treating a metal raw material, and has a processing object portion that is the object of cutting processing, the grain size of the processing object portion is uniform, and the crystal orientation is isotropic. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a perspective view showing a timepiece component according to an embodiment.

[0011] Figure 2 This is a flowchart showing a manufacturing process of a timepiece component according to an embodiment.

[0012] Figure 3 This is a schematic diagram for explaining the manufacturing process of the timepiece component according to the embodiment.

[0013] Figure 4 It is a diagram illustrating a forging process according to the embodiment.

[0014] Figure 5 It is a diagram illustrating a cutting step in the embodiment.

[0015] Figure 6 It is a diagram illustrating a cutting step in the embodiment.

[0016] Figure 7 It is a diagram illustrating a cutting step in the embodiment.

[0017] Figure 8A is a graph showing the number of each crystal grain size in Examples.

[0018] Figure 8B Graph showing the number of each crystal grain size in Comparative Examples.

[0019] Figure 9A This is a graph showing the relationship between the diffraction angle and the diffracted X-ray intensity in Examples.

[0020] Figure 9B This is a graph showing the relationship between the diffraction angle and the diffracted X-ray intensity in a comparative example.

[0021] Figure 10 It is a graph showing the evaluation results of Examples and Comparative Examples.

[0022] Label Description

[0023] 2: Metal raw material; 3: Blank for watch parts; 10: Watch case; 10B: Watch case; 11: Watch body; 11B: Watch body; 15: Watch lugs; 15B: Watch lugs; 20: Die; 21: Upper die; 22: Lower die; 31: Part to be processed; 32: Part to be removed; S1: Process; S11: Process; S12: Forging process; S13: Heat treatment process; S2: Cutting process; S3: Finishing process. DETAILED DESCRIPTION

[0024] Figure 1This is a perspective view of a watch case 10, an example of a watch component. The watch case 10 includes a body 11 and lugs 15. The body 11 is a cylindrical metal component that houses a dial, movement, and other components (not shown). The lugs 15, for attaching a watch band, are located at the 6 o'clock and 12 o'clock positions on the body 11. A pair of lugs 15 protrude from the side of the body 11.

[0025] [Manufacturing of watch cases]

[0026] Figure 2 1 is a flowchart showing the manufacturing process of the watch case 10. Figure 3 This diagram schematically illustrates the manufacturing process. The manufacturing process for the watch case 10 includes a step S1 of manufacturing a watch component blank 3; a cutting step S2 of cutting out the watch case 10 from the processing target portion 31 of the manufactured watch component blank 3; and a finishing step S3 of performing finishing operations including grinding on the cut watch case 10.

[0027] The step S1 of manufacturing the blank 3 for a timepiece component includes a step S11 of preparing the metal raw material 2 , a forging step S12 of forging the metal raw material 2 , and a heat treatment step S13 of heat-treating the formed product formed by forging.

[0028] [Manufacturing of blanks for watch components]

[0029] In the step S1 of manufacturing the blank 3 for the watch component, first, a step S11 of preparing the metal raw material 2 made of a metal raw material such as stainless steel, titanium, platinum alloy, gold alloy, etc., which is the raw material of the watch case 10, is performed. Figure 3 As shown, a stainless steel cylindrical member is prepared as the metal raw material 2. Such a metal raw material 2 can be produced by melting, refining, continuous casting, various rolling processes, etc. of raw materials such as iron, chromium, and nickel, or it can be prepared by purchasing a commercially available round bar and cutting it into a predetermined length.

[0030] Next, refer to Figure 4 The forging step S12 for forging the metal raw material 2 will be described. In the present embodiment, hot forging is used as the forging, but cold forging may also be used.

[0031] In the forging step S12, the metal raw material 2 is heated for hot forging and placed in a die 20 consisting of an upper die 21 and a lower die 22. Next, a press is used to bring the upper die 21 closer to the lower die 22, flattening the metal raw material 2 and shaping it. Then, when the upper die 21 is separated from the lower die 22, plastic working is performed by forging to produce a watch component blank 3. The watch component blank 3 is a roughly disk-shaped component having a processing target portion 31 and a removal portion 32.

[0032] The die 20 used in forging forms the metal material 2 by using a die designed to keep the strain of the workpiece 31 of the watch component blank 3 within a specified range. Specifically, the die 20 is designed to maintain the same strain in the workpiece 31 of the watch component blank 3, i.e., within a specified range, taking into account the deformation of the metal material 2 during hot forging. The specified range for the strain of the workpiece 31 of the watch component blank 3 is sufficient as long as the strain is eliminated, the grain size is uniform, and the crystal orientation is isotropic, through the heat treatment step S13 described later. For example, the strain of the workpiece 31 can be within ±20% of its average value. Therefore, if the average strain of the workpiece 31 is 0.03, the strain of each part of the workpiece 31 will be within a range of 0.024 to 0.036.

[0033] Furthermore, the removed portion 32 is removed during the cutting process described later, so there is no need to consider the size or variation of the strain. Therefore, the removed portion 32 of the forming die 20 is designed to reduce forging resistance and prevent forging defects, thereby improving the plastic workability during forging.

[0034] Furthermore, the die 20, consisting of the upper die 21 and the lower die 22, is designed so that excess material protrudes laterally from the outer periphery of the workpiece 31 as burrs 33. Furthermore, the die 20 is designed so that the magnitude of the strain on the workpiece 31 remains constant. Therefore, the die 20 is a semi-enclosed die.

[0035] like Figure 3 as well as Figure 4 As shown, the removed portion 32 is a disc-shaped portion with a small thickness, and the processing target portion 31 is a circular ring-shaped portion along the outer circumference of the removed portion 32. Therefore, the deformation of the processing target portion 31 is small, and the strain is also small, while the removed portion 32 is more deformed than the processing target portion 31, and the strain is also large.

[0036] In the heat treatment step S13, the watch component blank 3 formed in the forging step S12 is heat treated under specified heat treatment conditions to remove strain in the processing object portion 31, causing recrystallization, thereby achieving uniform grain size and isotropy of crystal orientation in the metal structure of the processing object portion 31.

[0037] Homogenization of grain size means that the standard deviation of grain size is below a specified value. For example, in the case where the majority (for example, more than 95%) of the grain sizes of the metal structure of the processing object portion 31 are in the range of 10 μm to 500 μm, if the standard deviation of the grain size is less than 50 μm, then it becomes a single peak in the histogram representing the degree of each grain size, and it can be said that the grain size is homogenized. Furthermore, if the standard deviation is less than 30 μm, it can be said that the grain size is further homogenized. On the other hand, in the case where the grain size is divided into relatively small sizes and large sizes and is not homogenized, the histogram representing the degree of each grain size also becomes a split peak divided into two peaks, and the standard deviation is also greater than 50 μm. Therefore, by measuring the grain size and calculating its standard deviation, it is possible to determine whether the grain size is homogenized.

[0038] Isotropy of the crystal orientation refers to an orientation state in which the mirror properties of the crystal orientation are not affected by polishing, and refers to a relative intensity of diffraction lines by X-ray diffraction being within a range of ±30% or less relative to a theoretical value.

[0039] Therefore, the heat treatment conditions only need to be conditions that can achieve the above-mentioned uniformity of grain size and isotropy of crystal orientation. Specifically, they are the temperature and time of heating during heat treatment, the change rate conditions, the holding temperature and time, the temperature and time of cooling, the change rate conditions, the atmosphere in each process (vacuum degree, gas type, pressure, gas flow rate), etc.

[0040] Therefore, the heat treatment conditions are set according to the material of the watch component blank 3, etc. For example, when the watch component blank 3 is made of austenitic stainless steel, the heating temperature during the heat treatment is set to a range of 1000 to 1300 degrees Celsius, and the heating time is set to a range of 1 minute to 180 minutes. Other conditions are also set according to the material of the watch component blank 3, etc.

[0041] The design of the mold 20 and the heat treatment conditions may be adjusted by initially setting them through simulation or the like, experimentally forming the timepiece component blank 3 and evaluating the timepiece component blank 3 .

[0042] The timepiece component blank 3 is manufactured through the above step S1 including the step S11 of preparing the metal raw material 2 , the forging step S12 , and the heat treatment step S13 .

[0043] Next, if Figure 2 As shown, a cutting step S2 is executed for cutting out the timepiece case 10 as a timepiece component from the processing target portion 31 of the timepiece component blank 3 by cutting.

[0044] That is, Figure 5 as well as Figure 6 As shown, the processing target portion 31 of the timepiece component blank 3 is formed to a size and shape that can be cut into the body 11 and lugs 15 of the timepiece case 10. Therefore, the timepiece case 10 can be manufactured by the cutting step S2.

[0045] In addition, the processing target portion 31 of the watch component blank 3 is formed to be able to cut out a variety of watch cases 10 of different shapes in size and shape. Figure 7 As shown, a timepiece case 10B having a body 11B and lugs 15B of different shapes can be cut out from a common timepiece component blank 3 .

[0046] Next, a finishing step S3 is performed in which the surface of the watch case 10 cut in the cutting step S2 is polished. Specifically, a polishing motor or abrasive is used to perform mirror finishing so that the surface of the watch case 10 becomes a mirror surface.

[0047] As mentioned above, Figure 3 As shown, the metal raw material 2 is subjected to a forging step S12 and a heat treatment step S13 to produce a timepiece component blank 3 , and the timepiece component blank 3 is subjected to a cutting step S2 and a finishing step S3 to produce a mirror-finished timepiece case 10 .

[0048] [Effects of the embodiment]

[0049] When manufacturing a watch case 10, which serves as a watch component, the metal raw material 2 prepared in step S11 is formed into a watch component blank 3 in a forging step S12 and then heat-treated in a heat treatment step S13. This allows the watch component blank 3 to be provided with a processing target portion 31 having a uniform grain size and an isotropic crystal orientation. Consequently, the grain size of the watch case 10 cut from the processing target portion 31 in the cutting step S2 is also uniform, and the crystal orientation is isotropic. Consequently, in the finishing step S3, the quality of the watch case 10 can be improved when the surface is polished and mirror-finished.

[0050] That is, when performing mirror finishing based on grinding, grinding is affected by the metal structure, and the grinding conditions of the watch case 10 cannot be changed according to each metal structure. Therefore, when the grain size is uneven, the mirror finishing quality is limited. In addition, since the grinding processability of each crystal orientation is different, when the crystal orientation is not consistent within a certain range, that is, when it is anisotropic, the mirror finishing quality is also limited. In contrast, in this embodiment, in step S1, the grain size of the processing object portion 31 of the watch component blank 3 is homogenized, and the crystal orientation is isotropic. The grain size of the watch case 10 cut from the processing object portion 31 by cutting is also homogenized, and the crystal orientation is isotropic. Therefore, the mirror finishing quality in the finishing step S3 can be further improved.

[0051] Therefore, the mirror finishing quality of the timepiece case 10 , which is a timepiece component, can be further improved, thereby providing a timepiece with a higher sense of luxury.

[0052] [Modification]

[0053] The watch component is not limited to the watch case 10; any component constituting the watch may be used, and particularly preferably, a component visible from the outside. Therefore, the watch component may also be various annular components such as a bezel, dial ring, glass rim, and a transparent back cover. Furthermore, the watch component is not limited to annular components; it may also include a dial, back cover, watch band, train bridge, pendulum, and the like. Furthermore, the shape of the processing target portion 31 of the watch component blank 3, i.e., the shape of the mold 20, can be set to match the watch component to be manufactured.

[0054] The grain size of the workpiece portion 31, i.e., the watch component, is not limited to the condition where all grains are within the range of 10 μm to 500 μm. It suffices as long as a certain percentage, for example, 95% or more, of the grains are 10 μm to 500 μm. A smaller grain size improves machinability, and therefore, it is more preferable that, for example, 95% or more of the grains are 10 μm to 50 μm.

[0055] The crystal orientation of the timepiece component, i.e., the processing target portion 31, is not limited to anything other than affecting the mirror finish. The relative intensity of the diffraction line by X-ray diffraction is not limited to a range of ±30% or less relative to the theoretical value.

[0056] The metal raw material 2 is not limited to being formed into a cylindrical shape, as long as it is a shape that matches the shape of the watch component to be manufactured. For example, when manufacturing a square watch case or watch band, a prismatic metal raw material 2 can also be used.

[0057] [Example]

[0058] Next, refer to Figure 8A 、 Figure 8B 、 Figure 9A 、 Figure 9B 、 Figure 10 Examples and comparative examples of the present disclosure will be described.

[0059] The examples are timepiece cases manufactured according to the above-described embodiment, and the comparative examples are examples in which a metal raw material 2 is plastically worked into the shape of a timepiece case by forging.

[0060] Figure 8A and Figure 8B This is a histogram that analyzes the metal composition of a watch case and shows the number of grains of each size. Figure 8A As shown, in the embodiment, the grain size is substantially uniform, and the histogram of the grain size also becomes a single peak. On the other hand, in the comparative example, the metal raw material 2 is plastically processed into the shape of the watch case 10 by forging, so there is a deviation in the grain size, and the histogram of the grain size also becomes a split peak. Figure 8A In the embodiment of , the average value of the grain size is 275.3 μm, the center value is 273.0 μm, and the standard deviation σ is 16.43 μm. Figure 8B In the comparative example, the average value of the grain size was 100.9 μm, the center value was 16.5 μm, and the standard deviation σ was 116.29 μm.

[0061] Figure 9A and Figure 9B This is the result of analyzing the crystal orientation of the metal composition of watch cases using X-ray diffraction. Figure 9A and Figure 9B The following table shows the measurement results for Examples and Comparative Examples. The vertical axis represents relative intensity based on the highest peak of the diffraction line. In each figure, black circles represent theoretical values. For example, for austenitic stainless steel, the theoretical value is highest at approximately 51 degrees at 2θ. If this intensity is defined as 999, the intensity at approximately 60 degrees is 446, and at approximately 90 degrees is 241.

[0062] exist Figure 9A In the illustrated example, the intensity is also highest at approximately 51 degrees 2θ. When this intensity is also defined as 999, the intensity is 421 at approximately 60 degrees 2θ, and 182 at approximately 90 degrees 2θ. Therefore, the example's relative strength to the theoretical value is 421 / 446 = 0.94 at approximately 60 degrees 2θ, and 182 / 214 = 0.85 at approximately 90 degrees 2θ, falling within a range of ±30% or less relative to the theoretical value.

[0063] On the other hand, Figure 9BIn the case of the comparative example shown, the intensity is highest at approximately 51 degrees at 2θ. When this intensity is also defined as 999, the intensity is 160 at approximately 60 degrees at 2θ, and 44 at approximately 90 degrees at 2θ. Therefore, in the example, relative to the theoretical value, the intensity is 160 / 446 = 0.36 at approximately 60 degrees, and 44 / 214 = 0.21 at approximately 90 degrees, falling outside the range of ±30% or less relative to the theoretical value.

[0064] The present inventors evaluated the quality of mirror finishes obtained by polishing and found that, if the relative intensity of diffraction lines by X-ray diffraction is within a range of ±30% or less relative to the theoretical value, crystal orientation does not affect the mirror quality. However, if the relative intensity of diffraction lines by X-ray diffraction is greater than ±30% relative to the theoretical value, deviation in crystal orientation does affect the mirror quality. Therefore, in this disclosure, crystal orientation is defined as isotropic within the range where it does not affect the mirror quality, that is, when the relative intensity of diffraction lines by X-ray diffraction is within a range of ±30% or less relative to the theoretical value, and as anisotropic outside this range.

[0065] Therefore, if Figure 9A and Figure 9B As shown, the crystal orientation of the example is isotropic, while the crystal orientation of the comparative example is anisotropic.

[0066] Figure 10 This section shows the evaluation results of mirror quality and machinability for stainless steel watch components, including the average value, standard deviation, and crystal orientation of the grain size in Examples and Comparative Examples. Mirror quality is indicated on a four-level scale: "◎: Very good," "○: Good," "△: Slightly poor," and "×: Poor." This evaluation can be based on the evaluator's visual perception or on measurements of glossiness and other properties that can be used to assess mirror quality.

[0067] The machinability is indicated by three levels: “⊚: good,” “∘: fair,” and “×: poor.” The machinability can be evaluated based on, for example, machining time, that is, productivity of watch parts.

[0068] As shown in Examples 1 to 7, the standard deviation is as small as 50 μm. In the histogram showing the number of each grain size, Figure 8A So it becomes a single peak, and as Figure 9A When the crystal orientation is isotropic, the mirror quality can be improved to "○" or "◎". In particular, if the average grain size is reduced to 100μm or less and the standard deviation is also reduced to 30μm or less, the grains are small and uniform, which can greatly improve the mirror quality and machinability.

[0069] On the other hand, in Comparative Examples 1 to 6, it was found that the standard deviation of the grain size was larger than 50 μm or the crystal orientation was anisotropic, and therefore the mirror surface quality could not be improved or the machinability was degraded.

[0070] Therefore, as disclosed in the present invention, a blank 3 for a watch component having a processing object portion 31 with a uniform grain size and isotropic crystal orientation is manufactured by forging and heat treating a metal raw material 2, and a watch component is manufactured by performing finishing processing including cutting and grinding on the processing object portion 31 of the blank 3 for a watch component, thereby confirming that the mirror quality is high and the cutting processability is also good.

[0071] [Summary of the present disclosure]

[0072] The manufacturing method of watch components disclosed in the present invention is characterized in that it has the following steps: preparing a metal raw material; forging and heat treating the metal raw material to produce a watch component blank having a processing object portion that is an object of cutting processing; and cutting out the watch component from the processing object portion of the watch component blank by cutting and grinding it. During the forging, the metal raw material is formed using a mold designed so that the strain of the processing object portion in the watch component blank is within a specified range. The heat treatment is performed under heat treatment conditions set according to the strain of the processing object portion in the watch component blank formed by the forging, so that the grain size of the processing object portion is uniform and the crystal orientation is isotropic.

[0073] According to the present disclosure, a metal raw material is forged and heat-treated to produce a blank for a watch component having a processing target portion. The forging die is designed so that the strain of the processing target portion in the watch component blank is within a specified range, thereby forming a processing target portion with little deformation and a strain that is approximately constant within the specified range. Therefore, by performing heat treatment under heat treatment conditions set according to the strain of the processing target portion, the grain size of the processing target portion can be uniformed and the crystal orientation can be isotropic. Therefore, the watch component cut from the processing target portion by cutting can also maintain a state in which the grain size is uniformed and the crystal orientation is isotropic. Therefore, the mirror quality of the watch component when the surface is finished by grinding can be improved.

[0074] In the manufacturing method of watch parts disclosed in the present invention, it is preferred that, regarding the homogenization of the grain size of the processing object portion achieved by the heat treatment, the grain size of the processing object portion is made greater than 10 μm and less than 500 μm, and the standard deviation of the grain size of the processing object portion is made less than 50 μm.

[0075] According to the present disclosure, the grain size is set to 10 μm or more and 500 μm or less, and the standard deviation of the grain size in the processing target portion is set to 50 μm or less. This can suppress the variation in grain size and improve the mirror surface quality by polishing.

[0076] In the method for manufacturing a timepiece component disclosed herein, it is preferred that the isotropy of the crystal orientation of the processing target portion achieved by the heat treatment is such that the relative intensity of the diffraction line of the processing target portion based on X-ray diffraction is less than ±30% of the theoretical value.

[0077] According to the present invention, when the relative intensity of the diffraction line based on the X-ray diffraction method is less than ±30% of the theoretical value, the crystal orientation is isotropic, so the deviation of the crystal orientation does not affect the mirror quality based on polishing, and the mirror quality can be improved.

[0078] In the method for manufacturing a timepiece component of the present disclosure, it is preferable that the forging is hot forging.

[0079] According to the present disclosure, since the blank for watch components is processed by hot forging, the metal raw material is heated to a high temperature, making it easy to process the metal raw material into the raw material for watch components. In addition, hot forging shrinks during cooling, resulting in variations in precision, while watch components are cut out by cutting, making it possible to manufacture watch components with high precision.

[0080] In the manufacturing method of watch parts disclosed in the present invention, it is preferred that the metal raw material is formed into a cylindrical shape, and the watch part blank has: a circular plate-shaped central portion; and a peripheral portion, which is formed into a circular ring along the outer periphery of the central portion and has a thickness dimension larger than that of the central portion, and the processing object portion is composed of the peripheral portion.

[0081] According to the present disclosure, the metal raw material is formed into a cylindrical shape, thereby enabling the use of commercially available steel bars and the like, thereby reducing costs. Furthermore, since the processing target portion of the watch component blank is formed into a circular ring, annular watch components such as the watch case body, glass rim, transparent back cover, and dial ring can be easily manufactured by cutting the processing target portion.

[0082] The present disclosure is a method for manufacturing a blank for a watch component, characterized in that the blank for a watch component is an object for cutting a watch component, and the method for manufacturing a blank for a watch component has the following steps: a step of preparing a metal raw material; and forging and heat treating the metal raw material to manufacture a blank for a watch component having a processing object portion that is an object of cutting processing, wherein during the forging, the metal raw material is formed using a mold designed so that the strain of the processing object portion in the blank for a watch component is within a specified range, and the heat treatment is performed under heat treatment conditions set corresponding to the strain of the processing object portion in the blank for a watch component formed by the forging, thereby making the grain size of the processing object portion uniform and making the crystal orientation isotropic.

[0083] According to the present disclosure, a metal raw material is forged and heat-treated to produce a watch component blank having a processing target portion. The forging die is designed so that the strain of the processing target portion in the watch component blank is within a specified range, thereby forming a processing target portion with little deformation and a strain that is approximately constant within the specified range. Therefore, by performing heat treatment under heat treatment conditions set accordingly to the strain of the processing target portion, the grain size of the processing target portion can be uniformed and the crystal orientation can be isotropic. Therefore, when the surface of the watch component cut from the processing target portion of the watch component blank by cutting is finished by grinding, the mirror quality can be improved.

[0084] The watch component of the present invention is characterized in that the watch component is manufactured by forging and heat treating a metal raw material to produce a watch component blank having a processing object portion that is an object of cutting processing, and then is cut out from the processing object portion by cutting and polished, thereby being manufactured, and the grain size of the watch component is uniformized and the crystal orientation is isotropic.

[0085] According to the watch component disclosed herein, a metal raw material is forged and heat-treated to produce a watch component blank having a processing target portion, and the grain size of the watch component cut from the processing target portion by cutting is made uniform, and the crystal orientation is made isotropic. Therefore, when the surface of the watch component is fine-processed by grinding, the mirror quality can be improved.

[0086] In the timepiece component of the present disclosure, preferably, the grain size of the timepiece component is 10 μm or more and 500 μm or less, and the standard deviation of the grain size of the timepiece component is 50 μm or less.

[0087] According to the present disclosure, it is possible to suppress variations in grain size and improve the mirror surface quality by polishing.

[0088] In the timepiece component of the present invention, it is preferred that the relative intensity of diffraction lines of the timepiece component by X-ray diffraction method is ±30% or less relative to a theoretical value.

[0089] According to the present invention, since the crystal orientation is isotropic, the deviation of the crystal orientation will not affect the quality of the polished mirror surface, and the quality of the mirror surface can be improved.

[0090] In the timepiece component of the present invention, it is preferable that the material of the timepiece component is any one of stainless steel, titanium, platinum alloy, and gold alloy.

[0091] According to the present disclosure, it is possible to manufacture a timepiece component having a high-quality feel that is particularly suitable for mirror finishing.

[0092] In the timepiece component of the present disclosure, it is preferable that the timepiece component is any one of a case body, a glass edge, and a back cover of a timepiece case.

[0093] According to the present disclosure, a timepiece component that is visible as an exterior component of a timepiece can be mirror-finished, thereby providing a timepiece having a high-quality feel.

[0094] The blank for watch components of the present invention is characterized in that the blank for watch components is an object for cutting out watch components, the blank for watch components is manufactured by forging and heat treating a metal raw material, and has a processing object portion that is an object of cutting processing, the grain size of the processing object portion is uniform, and the crystal orientation is isotropic.

[0095] According to the watch component blank of the present invention, since the grain size of the processing target portion is uniform and the crystal orientation is isotropic, the mirror quality can be improved when the surface of the watch component cut from the processing target portion of the watch component blank by cutting is finished by grinding.

[0096] In the watch component blank disclosed herein, it is preferred that the watch component blank has: a disk-shaped central portion; and a peripheral portion formed in an annular shape along the outer periphery of the central portion and having a thickness larger than that of the central portion, and the processing target portion is constituted by the peripheral portion.

[0097] According to the timepiece component blank of the present invention, since the processing target portion is formed into an annular shape, annular timepiece components such as a watch case body, glass edge, transparent back cover, and dial ring can be easily manufactured by cutting the processing target portion.

Claims

1. A method for manufacturing a watch component, characterized in that: The method for manufacturing a timepiece component comprises the following steps: Prepare metal raw materials; Forging and heat-treating the metal raw material to produce a blank for a watch component having a portion to be cut; as well as A timepiece component is cut out from the processing target portion of the timepiece component blank by cutting and then ground. In the forging, the metal raw material is formed using a die designed so that the magnitude of strain at the processing target portion of the timepiece component blank falls within a predetermined range. The heat treatment is performed under heat treatment conditions set according to the magnitude of strain in the processing target portion of the timepiece component blank formed by the forging, thereby making the grain size of the processing target portion uniform and the crystal orientation isotropic.

2. The method for manufacturing a timepiece component according to claim 1, wherein: Regarding the uniformization of the grain size of the processing target portion achieved by the heat treatment, The grain size of the processing target portion is set to be greater than or equal to 10 μm and less than or equal to 500 μm. The standard deviation of the grain size of the processing target portion is set to 50 μm or less.

3. The method for manufacturing a timepiece component according to claim 1, wherein: Regarding the isotropy of the crystal orientation of the processing target portion achieved by the heat treatment, The relative intensity of the diffraction line of the processing target portion determined by X-ray diffraction is set to be ±30% or less relative to the theoretical value.

4. The method for manufacturing a timepiece component according to claim 1, wherein: The forging is hot forging.

5. The method for manufacturing a timepiece component according to claim 1, wherein: The metal raw material is formed into a cylindrical shape, The timepiece component blank comprises: a disc-shaped central portion; and The outer peripheral portion is formed in an annular shape along the outer periphery of the central portion and has a thickness greater than that of the central portion. The processing target portion is constituted by the outer peripheral portion.

6. A method for manufacturing a blank for a watch component, characterized in that: The watch component blank is an object for cutting into watch components. The method for manufacturing a blank for a watch component comprises the following steps: The process of preparing metal raw materials; and The metal raw material is forged and heat-treated to produce a blank for a watch component having a processing target portion to be cut. In the forging, the metal raw material is formed using a die designed so that the magnitude of strain at the processing target portion of the timepiece component blank falls within a predetermined range. The heat treatment is performed under heat treatment conditions set according to the magnitude of strain in the processing target portion of the timepiece component blank formed by the forging, thereby making the grain size of the processing target portion uniform and the crystal orientation isotropic.

7. A watch component, characterized in that: The watch component is manufactured by forging and heat-treating a metal raw material to produce a watch component blank having a processing target portion to be cut, and then cutting and grinding the processing target portion to produce a watch component blank. The crystal grain size of the timepiece component is made uniform, and the crystal orientation is made isotropic.

8. The timepiece component according to claim 7, wherein: The grain size of the timepiece component is 10 μm or more and 500 μm or less. The standard deviation of the crystal grain size of the timepiece component is 50 μm or less.

9. The timepiece component according to claim 7, wherein: The relative intensity of diffraction lines of the timepiece component determined by X-ray diffraction is ±30% or less relative to a theoretical value.

10. The timepiece component according to claim 7, wherein The material of the watch component is any material selected from stainless steel, titanium, platinum alloy, and gold alloy.

11. The timepiece component according to claim 7, wherein: The timepiece component is any one of a case body, a glass edge, and a back cover of a timepiece case.

12. A blank for a watch component, characterized in that: The watch component blank is an object for cutting into watch components. The timepiece component blank is manufactured by forging and heat treating a metal raw material, and has a processing target portion to be cut. The grain size of the processing target portion is made uniform, and the crystal orientation is made isotropic.

13. The blank for a timepiece component according to claim 12, wherein: The timepiece component blank comprises: a disc-shaped central portion; and The outer peripheral portion is formed in an annular shape along the outer periphery of the central portion and has a thickness greater than that of the central portion. The processing target portion is constituted by the outer peripheral portion.

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