Wire coil loading jig and wire coil heat treatment method using the same

Abstract

The present invention relates to a loading jig (1) for wire coils and a heat treatment method using the same, the loading jig having: a first placement plate (2) for placement of a lower wire coil (W1); a second placement plate (3) located above the first placement plate for placement of an upper wire coil (W2); a first support (4) interposed between the above-mentioned placement plates for supporting the second placement plate; a first cover (8) for closing the upper end of the lower wire coil; a second cover (9) for closing the upper end of the upper wire coil; a first gas flow path (11) for penetrating the first placement plate in the plate thickness direction for guiding a gas flow from below the first placement plate toward the upper side to the inner diameter hole (W1a) of the lower wire coil; and a second gas flow path (13) configured to include a flow path (26) formed in the interior of the first support in the axial direction for guiding a gas flow to the inner diameter hole (W2a) of the upper wire coil.

Description

Technical Field

[0001] This invention relates to a loading fixture for wire coils used in heat treatment of longitudinally stacked wire coils, and a heat treatment method for wire coils using the loading fixture. Background Technology

[0002] In the heat treatment of wire coils, which are formed by winding wire into coils, the heating or cooling gas flows along the outer periphery of the coil, while very little gas flows in the gaps between the wires forming the coil. Therefore, the temperature difference between the surface of the wire coil in contact with the gas and the interior where the gas does not come into contact increases, easily leading to quality problems such as decreased sphericity and increased decarburization.

[0003] To reduce the temperature difference between the inside and outside of the wire coil, one could consider slowing down the heating / cooling rate or extending the soaking time. However, this increases processing time and operating costs. Furthermore, the slow cooling rate under atmospheric conditions can easily lead to the formation of scale that is difficult to pickle, resulting in reduced pickling properties.

[0004] As a unit for reducing the temperature difference between the inside and outside of a wire coil, Patent Document 1 discloses a method that includes a sealing plate (cover) that closes the upper end of the wire coil. This allows gas blown upwards from below the inner diameter hole of the wire coil to flow from the inner diameter side to the outer diameter side and outwards, thereby heating the wire coil uniformly and quickly. However, the structure described in Patent Document 1 is based on the premise of not stacking multiple layers of wire coils. Patent Document 1 also discloses a specific structure for uniformly heating (cooling) multi-layered stacked wire coils.

[0005] Patent Document 1: Japanese Patent No. 2913727 Summary of the Invention

[0006] The purpose of this invention is, in light of the above circumstances, to provide a loading fixture for wire coils that can improve airflow during heat treatment of multilayer stacked wire coils and reduce the temperature difference between the inside and outside of the wire coils, as well as a heat treatment method for wire coils using the loading fixture.

[0007] In order to solve the above problems, the inventors of this invention have repeatedly conducted in-depth research and came up with the following invention.

[0008] The loading clamp for wire coils according to the first aspect of the present invention is specified in the following manner. That is,

[0009] A loading clamp for wire coils, which holds multiple wire coils in a vertically stacked state, has the following features:

[0010] The first mounting plate is used to mount the lower wire coil;

[0011] The second mounting plate is located above the first mounting plate and is used to mount the upper wire coil;

[0012] The first support column, which is located between the aforementioned mounting plates, supports the second mounting plate;

[0013] The first cover seals the upper end of the lower wire coil;

[0014] The second cover seals the upper end of the upper wire coil;

[0015] A first gas flow path, which penetrates the first mounting plate in the thickness direction, guides the upward-facing airflow from below the first mounting plate toward the inner diameter hole of the lower wire coil; and

[0016] The second gas flow path is configured to include a flow path formed axially inside the first support column, which guides the gas flow toward the inner diameter hole of the upper wire coil.

[0017] According to the first embodiment of the wire coil loading fixture, the airflow can be guided to the inner diameter hole of the lower wire coil using a first gas flow path, and the airflow can be guided to the inner diameter hole of the upper wire coil using a second gas flow path. That is, the airflow can be guided to the inner diameter holes of each longitudinally stacked wire coil.

[0018] Regarding the gas fed into the inner diameter holes of each wire coil, the cover prevents it from flowing out from the upper end of the inner diameter hole of the wire coil, allowing it to flow from the inner diameter side to the outer diameter side through the gaps between the wires constituting the wire coil. In this way, in the loading fixture for wire coils of the first embodiment, the airflow during heat treatment can be improved and the temperature difference between the inside and outside of the coil can be reduced in any multi-layered stacked wire coils.

[0019] The second aspect of the present invention is defined as follows: That is,

[0020] Based on the loading fixture for the wire coil specified in the first scheme, the first cover is configured to be movable along the axial direction of the first support, so that the first cover is placed on the upper end of the lower wire coil.

[0021] According to the second scheme of the wire coil loading fixture, even if the position of the upper end of the lower wire coil changes due to load imbalance, the first cover follows the lower wire coil, thus maintaining the state of sealing the upper end of the lower wire coil well.

[0022] The third aspect of the present invention is defined as follows:

[0023] Based on the loading fixture for the wire coil specified in the first or second scheme, a second support is provided above the first support and inside the inner diameter hole of the upper wire coil, and the airflow is guided to the inner diameter hole of the upper wire coil through the opening formed in the second support.

[0024] According to the third scheme of the specification, the loading fixture for the wire coil can suppress the load imbalance of the upper wire coil by means of the second support, and can control the blowing direction of the airflow towards the inner diameter hole of the upper wire coil by means of the opening formed in the second support.

[0025] The fourth aspect of the present invention is specified in the following manner. That is,

[0026] A heat treatment method for a wire coil utilizes a loading fixture for the wire coil specified in any of the first to third embodiments, wherein...

[0027] An airflow is supplied to the longitudinally stacked coil body from below and upwards, wherein the longitudinally stacked coil body is formed by placing the lower wire coil and the upper wire coil, whose upper ends are closed by the first cover and the second cover, respectively, on the first mounting plate and the second mounting plate of the loading fixture.

[0028] The airflow is introduced into the inner diameter hole of the lower wire coil through the first gas flow path, and into the inner diameter hole of the upper wire coil through the second gas flow path.

[0029] According to the heat treatment method for the wire coil specified in this way, the same effect as the first scheme can be achieved. Attached Figure Description

[0030] Figure 1 This is a perspective view of a loading clamp for a wire coil according to one embodiment of the present invention.

[0031] Figure 2 yes Figure 1 A longitudinal sectional view of the loading fixture for wire coils.

[0032] Figure 3 yes Figure 2 Sectional view III-III.

[0033] Figure 4 This is a diagram showing the structure of a heat treatment furnace used for heat treatment of longitudinally stacked coil bodies using a loading fixture for wire coils according to this embodiment.

[0034] Figure 5 yes Figure 4 A cross-sectional view of the heat treatment chamber of the heat treatment furnace.

[0035] Figure 6 This is a diagram showing the structure of a cooling device used to cool the longitudinally stacked coil body. Detailed Implementation

[0036] Next, a loading fixture for wire coils according to one embodiment of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 This is a perspective view showing the loading clamp for the wire coil according to this embodiment. Figure 2 This is a longitudinal sectional view of the loading fixture for wire coils.

[0037] exist Figure 1 , 2 In this context, 1 is a loading fixture for holding a wire coil, which is a heated object in which wire is wound into a coil shape, in a state of stacking two layers in the vertical direction. It is configured to include: a first mounting plate 2 for mounting the lower wire coil W1; a second mounting plate 3 for mounting the upper wire coil W2; a first support 4 located between the mounting plates 2 and 3; a second support 6 located above the second mounting plate 3; a first cover 8 for closing the upper end of the lower wire coil W1; and a second cover 9 for closing the upper end of the upper wire coil W2.

[0038] The first mounting plate 2 is formed in a circular plate shape, and a first through hole 10 is formed in its center, which is composed of four holes 10a, 10b, 10c, and 10d that extend circumferentially and are arc-shaped when viewed from above; and a second through hole 12 that is circular when viewed from above, which is located inside the through hole 10. Figure 3 As shown, the first through hole 10 and the second through hole 12 are formed to be further inside the inner circumferential surface of the lower wire coil W1 placed on the first mounting plate 2 when viewed from above.

[0039] In this embodiment, the first through hole 10 constitutes a first gas flow path 11 that guides airflow from below and upward on the first mounting plate 2 to the inner diameter hole W1a of the lower wire coil W1. Furthermore, the second through hole 12 constitutes part of a second gas flow path 13 that guides the airflow to the inner diameter hole W2a of the upper wire coil W2.

[0040] Furthermore, the portion between the first through hole 10 and the second through hole 12 of the first mounting plate 2 becomes a support portion 15 that supports the first support column 4 (see reference). Figure 2 ).

[0041] The first support column 4 is located between the first mounting plate 2 and the second mounting plate 3, supporting the second mounting plate 3 and suppressing deformation of the lower wire coil W1 caused by load imbalance, etc. The lower end of the first support column 4 is integrally joined to the support column support portion 15 of the first mounting plate 2. On the other hand, at the upper end of the first support column 4, the corner where its upper end surface and outer peripheral surface 17 intersect is cut circumferentially to form a narrow diameter portion 18 located at the top in the installation posture, and a stepped surface 19 continuously facing upward relative to the narrow diameter portion 18. Figure 2 As shown, the stepped surface 19 contacts the lower surface of the second mounting plate 3, thus supporting the second mounting plate 3.

[0042] The first support column 4 is a hollow cylindrical body with an axially extending flow path 26 inside. This flow path 26 communicates with the second through hole 12 of the first mounting plate 2 to form part of a second gas flow path 13 that guides airflow into the inner diameter hole W2a of the upper wire coil W2. The airflow flowing through this second gas flow path 13 does not flow out into the inner diameter hole W1a of the lower wire coil W1 midway, but is instead delivered into the inner diameter hole W2a of the upper wire coil W2.

[0043] The first cover 8 is placed on the upper end of the lower wire coil W1, sealing the upper end of the lower wire coil W1. The first cover 8 is formed in an approximately circular plate shape, and a bending portion 30 is formed on its periphery to suppress the deformation of the lower wire coil W1 caused by load imbalance, etc.

[0044] In addition, a circular through hole 32 is formed at the center of the first cover 8. The through hole 32 is formed to be slightly larger than the diameter of the outer peripheral surface 17 of the first support 4, and the first cover 8 is guided by the outer peripheral surface 17 of the first support 4 inserted into the through hole 32 and can move along the axial direction of the first support 4.

[0045] The second mounting plate 3 is formed in the shape of a circular plate, and a circular through hole 34 is formed in its center. The through hole 34 is formed to be slightly larger than the narrow diameter portion 18 of the first support column 4. When the through hole 34 and the narrow diameter portion 18 of the first support column 4 are engaged, the edge of the through hole 34 of the second mounting plate 3 is supported by the stepped surface 19 of the first support column 4.

[0046] The second support column 6 suppresses the deformation of the upper wire coil W2 caused by load imbalance and controls the airflow direction towards the inner diameter hole W2a. It is positioned above the first support column 4 and within the inner diameter hole W2a of the upper wire coil W2, and is concentric with the first support column 4.

[0047] The second support column 6 comprises a plurality of columnar members 38, which are erected at intervals around the upper opening 21 of the first support column 4; and a connecting plate 39 that connects the upper ends of the columnar members 38. In this embodiment, gas flowing through the internal flow path 26 of the first support column 4 is introduced into the interior of the second support column 6 and flows out through the opening 40 formed between adjacent columnar members 38 into the inner diameter hole W2a of the upper wire coil W2. In this embodiment, the internal space 41 and the opening 40 of the second support column 6 also constitute part of the second gas flow path 13.

[0048] The second cover 9 is placed on the upper end of the upper wire coil W2, sealing the upper end of the upper wire coil W2. Similar to the first cover 8, it is formed in an approximately circular plate shape, with a bend 30 formed on its periphery. The bend 30 not only suppresses the deformation of the upper wire coil W2, but also prevents the cover 9 from falling off the upper wire coil W2 during transport.

[0049] In this embodiment, a longitudinally stacked coil body 44 is assembled from wire coils W1 and W2 using a loading fixture 1 configured as described above. The longitudinally stacked coil body 44 can be heat-treated to reduce the temperature difference between the inside and outside of the wire coil, for example, by using a heat treatment furnace and a cooling device as shown below.

[0050] Next, the heat treatment furnace and cooling device used in the heat treatment of the longitudinally stacked coil body 44 will be described. Figure 4 In the heating furnace 50, the longitudinally stacked coil body 44 is subjected to a batch heat treatment process for annealing. In the heating furnace 50, the longitudinally stacked coil body 44 is subjected to heating, homogenization and cooling processes. Then, the longitudinally stacked coil body 44 extracted from the heating furnace 50 is subjected to atmospheric cooling (rapid cooling) using the cooling device 80 described later.

[0051] Furthermore, the cooling process of the longitudinally stacked coil body 44 can be modified as needed. For example, cooling in the heating furnace 50 can be omitted and implemented only in the cooling device 80 described later, or cooling can be implemented only in the heating furnace 50 and the cooling in the cooling device 80 described later can be omitted.

[0052] The heating furnace 50 has a loading and unloading worktable 52 at the left end of the figure and a heat treatment chamber 54. The heat treatment chamber 54 has an opening 54a on the left front side of the figure, through which the longitudinally stacked coil bodies 44 are loaded and unloaded. The opening 54a can be closed by a door 55. The door 55 is suspended by a pulley 56 via wire and is raised and lowered by the rotation of the pulley 56.

[0053] The heat treatment chamber 54 is capable of accommodating six longitudinally stacked coil bodies 44-1, 44-2, ..., 44-6, and is virtually divided into six regions for accommodating each longitudinally stacked coil body 44. Rollers 57, serving as conveying units, are arranged in each region.

[0054] The heat treatment chamber 54 is equipped with multiple radiant tube burners 68, which serve as heating units for heating the gases inside the chamber. The output of the radiant tube burners 68 is controlled so that each area of ​​the chamber is set to a predetermined temperature. In addition, the heat treatment chamber 54 has gas supply piping (not shown) that can appropriately supply reducing gases such as nitrogen and RX gas into the chamber.

[0055] Figure 5 This is a cross-sectional view of the heat treatment chamber 54 in a direction orthogonal to the transport direction of the longitudinally stacked coil body 44, showing the state in which the longitudinally stacked coil body 44 is installed in the chamber.

[0056] In addition to the radiant tube burner 68, a gas circulation device 70 is provided in the heat treatment chamber 54 for blowing gas into the longitudinally stacked coil body 44.

[0057] The gas circulation device 70 includes: a pipe 72; a circulation fan 74 housed inside the pipe 72; and a drive motor 75 that drives the circulation fan 74 to rotate. The pipe 72, as shown in the figure, is formed in a bent shape, with a gas outlet 72a formed at one end, opening upwards directly below the longitudinally stacked coil body 44. On the other hand, a gas inlet 72b is formed at the other end of the pipe 72, opening downwards. The circulation fan 74 is positioned directly above the gas inlet 72b. Additionally, 77 is a temperature sensor. In this embodiment, a control unit (not shown) connected to the temperature sensor 77 controls the combustion of the radiant tube burner 68 in such a way that the temperature of the gas detected by the temperature sensor 77 matches a preset target atmosphere temperature.

[0058] In the heat treatment chamber 54 configured in this way, by rotating the circulating fan 74 of the gas circulation device 70, the gas heated by the radiant tube burner 68 is drawn into the pipe 72 through the gas inlet 72b and blown upward from the gas outlet 72a of the pipe 72.

[0059] Furthermore, a portion of the upward airflow is delivered into the inner diameter hole W1a of the lower wire coil W1 through the first gas flow path 11 of the longitudinally stacked coil body 44. Regarding the gas delivered into the inner diameter hole W1a of the lower wire coil W1, the first cover body 8 prevents it from flowing out from the upper end of the inner diameter hole W1a, allowing it to flow from the inner diameter side to the outer diameter side as shown by the arrow through the gaps in the wires constituting the lower wire coil W1. This minimizes the temperature difference between the inside and outside of the wire coil while heating the lower wire coil W1 to a predetermined heating temperature in a short time.

[0060] Similarly, another portion of the upward airflow is delivered into the inner diameter hole W2a of the upper wire coil W2 through the second gas flow path 13 of the longitudinally stacked coil body 44. Regarding the gas delivered into the inner diameter hole W2a of the upper wire coil W2, the second cover 9 prevents it from flowing out from the upper end of the inner diameter hole W2a, allowing it to flow from the inner diameter side to the outer diameter side as indicated by the arrow through the gaps in the wires constituting the upper wire coil W2. This minimizes the temperature difference between the inside and outside of the wire coil while simultaneously heating the upper wire coil W2 to the specified heating temperature in a short time.

[0061] In the heating furnace 50, after heating, homogenization and cooling are carried out. In the cooling process, similar to the heating process, gas at a specified temperature is allowed to flow from the inner diameter side to the outer diameter side through the gap between the wires constituting the wire coils W1 and W2, so as to keep the temperature difference between the inside and outside of the wire coils to a minimum while cooling the lower wire coil W1 and the upper wire coil W2.

[0062] Figure 6 This diagram shows the structure of a cooling device 80 for cooling the longitudinally stacked coil body 44, illustrating the state in which the longitudinally stacked coil body 44 is installed within a processing chamber 81. In this diagram, 82 is a blower that supplies upward-facing cold air (atmosphere) to the longitudinally stacked coil body 44, with its gas outlet 82a positioned directly below the longitudinally stacked coil body 44. 84 is a gas exhaust pipe formed on the upper part of the side wall of the processing chamber 81.

[0063] In the cooling device 80 of this embodiment, unheated air is taken in from the gas inlet 82b as cooling gas and blown upward from the gas outlet 82a of the blower 82.

[0064] Furthermore, a portion of the upward airflow is delivered to the inner diameter hole W1a of the lower wire coil W1 through the first gas flow path 11 of the longitudinally stacked coil body 44, while another portion of the upward airflow is delivered to the inner diameter hole W2a of the upper wire coil W2 through the second gas flow path 13 of the longitudinally stacked coil body 44. Therefore, in this cooling process, similar to the heating process, the cooling gas flows from the inner diameter side to the outer diameter side through the gap between the wires constituting the wire coils W1 and W2, minimizing the temperature difference between the inside and outside of the wire coils while cooling the lower wire coil W1 and the upper wire coil W2. Additionally, the cooling gas is discharged to the outside through the gas discharge pipe 84.

[0065] As described above, the loading fixture 1 according to this embodiment can improve the airflow between the lower wire coil W1 and the upper wire coil W2 of the multilayer stack, and reduce the temperature difference between the inside and outside of the coil during heat treatment. Therefore, the loading fixture 1 according to this embodiment does not require deliberately slowing down the heating / cooling rate to reduce the temperature difference, and can achieve rapid heating / rapid cooling, thereby shortening the heat treatment time and reducing operating costs. In addition, rapid cooling can suppress the formation of difficult-to-pickle scales and improve pickling performance.

[0066] Furthermore, in the loading clamp 1 for the wire coil in this embodiment, the first cover 8 is configured to be movable along the axial direction of the first support 4 and placed on the upper end of the lower wire coil W1. Therefore, even if the position of the upper end of the lower wire coil W1 changes due to load imbalance, the first cover 8 can follow the lower wire coil W1 and maintain the state of closing the upper end of the lower wire coil W1.

[0067] In addition, in the loading fixture 1 for the wire coil in this embodiment, a second support 6 is provided above the first support 4 and inside the inner diameter hole W2a of the upper wire coil W2, and airflow is guided to the inner diameter hole W2a of the upper wire coil W2 through the opening 40 formed in the second support 6.

[0068] Therefore, it is possible to suppress the deformation of the second support column 6 caused by load imbalance of the upper wire coil W2, and to control the blowing direction of the airflow towards the inner diameter hole W2a of the upper wire coil W2 by using the opening 40 formed in the second support column 6.

[0069] The embodiments of the present invention have been described in detail above, but these are merely examples. For instance, the shape and size of the first through hole and the second through hole formed in the first mounting plate to allow airflow are not limited to the embodiments described above and can be appropriately modified. Furthermore, the shape and size of the second support provided in the inner diameter hole of the upper wire coil can be appropriately modified, and a structure without the second support can be adopted depending on the situation. The present invention can be implemented with various modifications without departing from its spirit.

[0070] This application is based on Japanese Patent Application 2020-163762, filed on September 29, 2020, the contents of which are incorporated herein by reference.

[0071] Explanation of the label

[0072] 1. Loading fixture for wire coils

[0073] 2 First mounting plate

[0074] 3. Second mounting plate

[0075] 4. Pillar 1

[0076] 6. Pillar 2

[0077] 8. First cover

[0078] 9. Second cover

[0079] 11 First gas flow path

[0080] 13 Second gas flow path

[0081] 26 flow path

[0082] 40 Opening

[0083] 44. Vertically stacked coil bodies

[0084] W1 lower wire coil

[0085] W2 upper wire coil

[0086] W1a, W2a inner diameter hole

Claims

1. A loading jig for a wire coil, which holds a plurality of wire coils in a state of being vertically stacked in a vertical direction in a heating furnace having a heat treatment chamber that blows heated gas from a lower side of the placed coil toward an upper side, characterized by comprising: a first placement plate for placement of a lower side wire coil; a second placement plate located above the first placement plate for placement of an upper side wire coil; a first support column interposed between the placement plates for supporting the second placement plate, the first support column being a hollow cylindrical body; a second support column provided above the first support column and within a bore of the upper side wire coil, the second support column having an opening; a first cover that closes an upper end of the lower side wire coil; a second cover that closes an upper end of the upper side wire coil; a first gas flow path that penetrates the first placement plate in a plate thickness direction and guides a gas flow from below the first placement plate toward the bore of the lower side wire coil; and a second gas flow path configured to include a flow path formed in an axial direction inside the first support column and guide the gas flow toward the bore of the upper side wire coil, wherein the first cover is provided to be movable in an axial direction of the first support column and placed on the upper end of the lower side wire coil.

2. The loading jig for a wire coil according to claim 1, characterized in that the first cover is formed in a circular plate shape and has a bent portion at a periphery thereof.

3. The loading jig for a wire coil according to claim 1 or 2, characterized in that the gas flow is guided toward the bore of the upper side wire coil through the opening formed in the second support column.

4. A heat treatment method for a wire coil using the loading jig for a wire coil according to any one of claims 1 to 3, characterized in that the vertically stacked coil body is formed by placing the lower side wire coil and the upper side wire coil, whose upper ends are closed by the first cover and the second cover, respectively, on the first placement plate and the second placement plate of the loading jig, the gas flow is introduced to the bore of the lower side wire coil through the first gas flow path, and the gas flow is introduced to the bore of the upper side wire coil through the second gas flow path. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ supplying an air flow from below toward above of the longitudinally stacked coil body, wherein ​ ​

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