Heat treatment system

Abstract

To efficiently recover harmful mist generated during heat treatment.SOLUTION: A heat treatment system S includes a heat treatment device 1 having a heating device 11, and a suction device 2 which is provided near the heat treatment device for each heat treatment device and mist generated during heat treatment by the heat treatment device. The suction device may further include a suction part 13 in which a hole part for sucking the mist is formed, a transfer pipe 14 having one end connected to the suction part, and a negative pressure generation device 15 connected to the other end of the transfer pipe and generating negative pressure inside the transfer pipe and the suction part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a thermal processing system. [Background technology]

[0002] Patent Document 1 describes a smoke exhaust device that exhausts smoke and steam generated when a workpiece is heated and cooled by a high-frequency heating coil to the outside. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-286714 Summary of the Invention [Problem to be solved by the invention]

[0004] Harmful mists such as oily smoke generated during heat treatment such as induction hardening deteriorate the environment during heat treatment. Oily smoke can also cause fires. In view of this situation, the present invention aims to efficiently collect harmful mists generated during heat treatment. [Means for solving the problem]

[0005] In order to achieve the above object, the heat treatment system of the present invention comprises a heat treatment device having a heating device, and a suction device provided near each of the heat treatment devices for sucking up mist generated during heat treatment by the heat treatment device. [Effects of the Invention]

[0006] According to the present invention, harmful mist generated during heat treatment can be efficiently collected. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an explanatory diagram of an induction hardening system (hardening of the outer peripheral surface). [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 10 is a side cross-sectional view of another example of a suction device. [Figure 5] FIG. 10 is a side cross-sectional view of a suction device according to yet another example. [Figure 6] FIG. 1 is an explanatory diagram of an induction hardening system (heating of the inner peripheral surface). [Figure 7] FIG. 1 is an explanatory diagram of an induction hardening system (cooling of the inner peripheral surface, part 1). [Figure 8] FIG. 10 is an explanatory diagram of an induction hardening system (cooling of the inner peripheral surface, part 2). [Figure 9] FIG. 1 is an explanatory diagram of an induction hardening system (hardening of a flat surface). [Figure 10] FIG. 10 is another explanatory diagram of the induction hardening system (hardening of a flat portion). [Figure 11] FIG. [Figure 12] FIG. 10 is an explanatory diagram of the suction device as seen from another direction. [Figure 13] FIG. [Figure 14] FIG. 10 is an explanatory diagram showing another example of a suction device. [Figure 15] FIG. [Figure 16] FIG. 1 is an explanatory diagram of a high-frequency heating system. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiment described below.

[0009] Cutting oil or rust inhibitors may be applied to the surface of workpieces that are subject to heat treatments such as induction hardening and induction heating. When the workpiece is heated, oily smoke is generated due to the cutting oil or rust inhibitor. When the workpiece is cooled using a coolant, water vapor containing the coolant is generated. The oily smoke and water vapor mentioned above are collectively called harmful mist, or simply mist.

[0010] As shown in FIGS. 1 to 3, the induction hardening system S includes an induction hardening device 1 and a suction device 2 that sucks mist generated during induction hardening.

[0011] The induction hardening device 1 includes a heating coil 11 connected to a high-frequency oscillator (not shown) and a cylindrical cooling jacket 12 connected to a coolant supply device (not shown). The heating coil 11 and the cooling jacket 12 are arranged approximately coaxially with a predetermined gap between them so that the heating coil 11 is located above the cooling jacket 12. The relative positions of the heating coil 11 and the cooling jacket 12 do not change.

[0012] Injection holes 12-1 are formed on the inner peripheral surface of the cooling jacket 12. A coolant 22 is injected from these injection holes toward the cylindrical or rod-shaped workpiece 10.

[0013] The suction device 2 includes a suction section 13 that sucks in mist generated during induction hardening, a transfer pipe 14 having one end connected to the upper end face of the suction section and that transfers the mist, and a piping 15 to which the other end of the transfer pipe is connected.

[0014] The suction part 13 has a ring-shaped outer shape and is arranged coaxially with the heating coil 11 and the cooling jacket 12 at a predetermined distance from the heating coil 11 so as to be located above the heating coil 11. The suction part 13 has a ring-shaped hollow part 13-2 formed therein and a slit or hole part 13-1 formed on the inner peripheral surface and communicating with the hollow part 13-2. This slit can be formed around the entire inner peripheral surface with the slit width direction aligned with the axial direction of the suction part 13. Alternatively, multiple slits may be formed at intervals in the circumferential direction.

[0015] The transfer pipe 14 has a first end 14-1 connected to the upper end face of the suction section 13 and extending vertically into the hollow section 13-2, a second end 14-2 extending diagonally downward and connecting to the vertically extending piping 15, and a main body 14-3 connecting the first end 14-1 and the second end 14-2 and extending approximately horizontally.

[0016] The transfer pipe 14 is connected to a midpoint of the piping 15. The piping 15 has a compressed air supply pipe 15-1 located above the connection with the transfer pipe 14 and connected to a compressed air supply device (not shown), and a connection pipe 15-2 located below the connection and connected to a recovery device (not shown) that recovers the mist.

[0017] When performing induction hardening, the workpiece 10 is fixed vertically and placed in the hollow portion of the heating coil 11 and cooling jacket 12. Then, while the heating coil 11 and the cooling jacket 12 are moved upward, heating by the heating coil 11 and cooling by the cooling jacket are performed sequentially, thereby hardening the outer peripheral surface of the workpiece 10. Alternatively, the heating coil 11 and the cooling jacket 12 may be fixed, and the outer peripheral surface of the workpiece 10 may be hardened while the workpiece 10 is moved downward.

[0018] The workpiece 10 is heated to the hardening temperature by the heating coil 11. The heated area is indicated by the reference numeral 40. During this heating, oily smoke 20 is generated due to the cutting oil or rust inhibitor applied to the outer peripheral surface of the workpiece 10. The heated area 40 is cooled by the injection of coolant 22 from the cooling jacket 12. The area in which a hardened layer is formed by cooling is indicated by the reference numeral 41. During cooling, steam 21 containing the coolant 22 is generated.

[0019] In the piping 15, compressed air 30 supplied from a compressed air supply device flows from top to bottom. Accordingly, negative pressure is generated inside the hollow portion 13-2 of the suction part 13 and the transfer pipe 14. As a result, the generated mist (i.e., oily smoke 20 and water vapor 21) rises along the axial direction of the workpiece 10, is sucked into the hollow portion 13-2 through the slit 13-1 of the suction part 13, and is sent to the recovery device through the inside of the transfer pipe 14 and the connecting pipe 15-2.

[0020] The process of collecting mist will now be described in detail. Step 1: Compressed air is supplied to the pipe 15, and the cavity 13-2 of the suction part 13 is made to have a negative pressure. Step 2: A high frequency current is supplied to the heating coil 11, and high frequency induction heating is performed on the outer peripheral surface of the workpiece 10 for a predetermined time until the temperature reaches the hardening temperature. Step 3: High-frequency heating is performed while the induction hardening device 1 is moved upward or the workpiece 10 is moved downward over a predetermined distance. Step 4: Coolant is pumped into the cooling jacket 12, and the coolant 22 is sprayed from the injection holes 12-1 toward the outer surface of the workpiece 10 heated in step 3, thereby cooling the outer surface of the workpiece 10 and forming a hardened layer. Step 5: During high-frequency induction heating, cutting oil and rust-preventive oil adhering to the outer peripheral surface of the workpiece 10 vaporize, generating oily smoke 20. When the coolant is sprayed, the heat from the outer peripheral surface of the workpiece 10, which has been heated to the quenching temperature, vaporizes the coolant 22, generating steam 21. Step 6: The mist (oil smoke 20 and water vapor 21) is sucked through the slit 13-1 of the suction unit 13 by the negative pressure generated in the cavity 13-2 of the suction unit 13 in step 1. Step 7: The mist collected in step 6 is sent to the collection device through the transfer pipe 14 and the connecting pipe 15-2. Steps 2, 3, and 4 are performed in parallel, and steps 5 and 6 are performed in parallel.

[0021] In the above embodiment, one suction device (suction unit 13) is provided for the induction hardening apparatus 1 equipped with a heating device (heating ring 11) and a cooling device (cooling jacket 12). In other words, a suction device (suction unit 13) is provided for each induction hardening apparatus 1 near the mist generation source. This increases the likelihood that the mist will be sucked in before it spreads throughout the furnace. This allows for efficient collection of the mist, and also provides a clean and safe environment for the heat treatment work.

[0022] In addition, because the mist is collected near the source, it is possible to prevent the oily smoke contained in the mist from igniting and keep the inside of the quenching equipment clean. In addition, because the collection method uses negative pressure generated by compressed air, there are no mechanical moving parts in the suction section, which reduces the occurrence of malfunctions and other problems.

[0023] In the above embodiment, a moving hardening method is used in which the induction hardening apparatus 1 and the workpiece 10 are moved relative to each other. However, a stationary one-shot hardening method in which the induction hardening apparatus 1 and the workpiece 10 are not moved relative to each other may also be used. However, in the illustrated apparatus, the heating apparatus and the cooling apparatus are positioned at an interval, so after heating is completed, the cooling apparatus and the workpiece are moved relative to each other so that the heated area can be cooled.

[0024] In the heating step without relative movement, only oily smoke 20 is collected. In the cooling step without relative movement, only water vapor 21 is collected.

[0025] When the induction hardening device 1 is moved relative to the workpiece 10, the transfer pipe 15 can be made of a flexible tube that is resistant to oil and chemicals.

[0026] The heat treatment is not limited to induction hardening, but can also be reheating of carburized and hardened products or products that have undergone carburizing and annealing using induction. For example, the mist generated during partial annealing and heating of carburized and hardened products can be sucked in by the above-mentioned suction device. As a result, it becomes possible to use a radiation thermometer and adopt PID control for the carburizing and quenching equipment. Furthermore, this method is not limited to heat treatments such as quenching, but can also be applied to the brazing of metal materials in air. Generally, in brazing work, it is necessary to apply flux to the joining area of ​​the materials to be joined to remove oxide films that cover the surfaces. By using the above-mentioned suction device to suck up the vaporized flux smoke that is generated during brazing heating, it becomes possible to use a radiation thermometer, allowing for accurate brazing temperature control. This is particularly effective for brazing low-melting point metals such as aluminum, where the temperature was estimated based on the molten state of the brazing material. The embodiments of the present invention are also applicable to high-frequency partial annealing heating of carburized and quenched products, high-frequency brazing, high-frequency soldering, and the like.

[0027] As shown in FIG. 4, the axial dimension Ha of the cavity 13a-2 of the suction portion 13a may be smaller than the axial dimension H of the cavity 13-2 of the suction portion 13 (FIG. 3).

[0028] As shown in FIG. 5, the second end 14-2a of the transfer pipe 14 may be horizontal and connected to the piping 15 at a right angle.

[0029] 6 shows how induction hardening is performed on the inner peripheral surface of a cylindrical workpiece 10a. The heating coil 11 and cooling jacket 12 are located in the hollow portion 10b of the workpiece 10a. A high-frequency current is supplied from the high-frequency oscillator 3 to the heating coil 11, causing induction heating of the workpiece 10, and a heated region 40 is created on the inner peripheral surface of the workpiece 10a. Oily smoke 21 generated by heating rises along the axial direction of the workpiece 10a and is sucked into the hollow portion 13-2 through the slit 13-1.

[0030] Fig. 7 shows the cooling process that follows the heating process shown in Fig. 6. In the cooling process shown in Fig. 7, the heating ring 11, cooling jacket 12, and suction part 13 shown in Fig. 6 are moved relative to the workpiece 10a without changing their relative positions, thereby cooling the heated area 40 (Fig. 6). As a result, a cooled area 41 is created.

[0031] The heating step shown in Fig. 6 may be followed by a cooling step shown in Fig. 8. In the cooling step shown in Fig. 8, the relative positional relationship between the heating ring 11 and the cooling jacket 12 shown in Fig. 6 is maintained unchanged, and the relative positional relationship between the workpiece 10a and the suction part 13 shown in Fig. 6 is maintained unchanged. Then, the heating ring 11 and the cooling jacket 12 are moved relative to the workpiece 10a and the suction part 13, and the heating area 40 (Fig. 6) is cooled. As a result, a cooling area 41 is generated.

[0032] FIG. 9 shows induction hardening of a workpiece having a flat surface 10c as the portion to be hardened, and FIGS. 10 to 13 show a suction device 2 used when induction hardening the flat surface 10c. The x-axis direction is to the right of the paper in FIG. 9 and is parallel to the flat surface 10c. The induction hardening device 1 moves in the positive direction of the x-axis, parallel to the flat surface 10c. The y-axis direction is the direction from the front to the back of the paper in FIG. 9, and the z-axis direction is the upward direction of the paper in FIG. 9.

[0033] The workpiece having the flat surface 10c as the part to be hardened is, for example, the bed of a lathe, and the flat surface 10c is the sliding surface of the bed. A heating coil 11 is positioned above the flat surface 10c, parallel to and at a required distance from the flat surface 10c. A cooling jacket 12 is positioned at a required distance from the heating coil 11 in the negative x-axis direction (to the left of the heating coil 11 on the paper). The coolant injection holes 12-1 of the cooling jacket 12 are not directed directly downward, but rather obliquely downward (diagonally downward and left on the paper) so that the injected coolant 22 moves away from the heating coil 11 as it heads toward the horizontal surface of the flat surface 10c.

[0034] Suction portion 13b is located above cooling jacket 12. Suction portion 13b is a rectangular plate-like member that is parallel to flat portion 10c and has a longitudinal direction parallel to the y-axis. A plurality of holes 13-1 are formed at intervals in the circumferential direction on the outer peripheral surface of suction portion 13b. Of the plurality of holes 13-1, hole 13-1a formed on the outer peripheral surface on the positive x-axis side mainly draws in oily smoke 20, hole 13-1b formed on the outer peripheral surface on the negative x-axis side mainly draws in water vapor 21, and hole 13-1c formed on the outer peripheral surface on both sides in the y-axis direction draw in oily smoke 20 and water vapor 21.

[0035] The oily smoke 20 generated from the heating area 40 moves horizontally (to the left on the paper) between the heating coil 11 and the flat portion 10c toward the cooling jacket 12, then rises between the heating coil 11 and the cooling jacket 12 and is sucked in by the suction portion 13b. Moreover, the water vapor 21 generated from the cooling region 41 rises in the region farther from the heating coil 11 across the cooling jacket 12, and is sucked in by the suction part 13b.

[0036] The dimension W2 in the y-axis direction of suction portion 13c shown in Figures 14 and 15 is larger than the dimension W1 in the y-axis direction of suction portion 13b shown in Figure 12. In this way, when the dimension in the y-axis direction of suction portion 13c is relatively large, two transfer pipes 14-1 and 14-2 may be provided spaced apart in the y-axis direction, and both transfer pipes may be integrated into one transfer pipe 14 midway from suction portion 13c to piping 15.

[0037] FIG. 16 shows the high-frequency heating system Sa. Unlike the high-frequency hardening system S shown in FIG. 1, the high-frequency heating system Sa does not include a cooling jacket 12. The male thread portion 40-2 of the carburized and hardened workpiece 40 is brittle as is, and there is a possibility that the threaded portion will chip when a nut is fastened. For this reason, high-frequency heating is performed by the high-frequency heating system Sa on the male thread portion 40-2 of the carburized and hardened workpiece 40, with the aim of softening only the male thread portion 40-2.

[0038] Since cooling oil is used as a refrigerant in the cooling process of carburizing and quenching, cooling oil adheres to the surface of the workpiece 40 after carburizing and quenching is completed. When high-frequency heating is performed to soften the male thread portion 40-2, this cooling oil is also heated, generating oily smoke 20. This oily smoke 20 is sucked by the suction unit 13. However, unlike the case of high-frequency hardening, no cooling by injecting a coolant is performed after high-frequency heating, so water vapor 21 is not generated.

[0039] The following notes are provided regarding the embodiments described above. <Appendix 1> a heat treatment device having a heating device; a suction device provided near each of the heat treatment devices for sucking mist generated during heat treatment by the heat treatment device; A heat treatment system comprising: <Appendix 2> The suction device further comprises: a suction section having a hole through which the mist is sucked; a transfer tube having one end connected to the suction portion; a negative pressure generating device connected to the other end of the transfer pipe and configured to generate negative pressure inside the transfer pipe and the suction unit; 2. The heat treatment system of claim 1, comprising: <Appendix 3> the heating device is a high-frequency induction heating coil, the suction part is ring-shaped, a cavity is formed inside the suction part, and the hole is formed on the circumferential surface and communicates with the cavity, The heating device and the suction part are arranged coaxially and spaced apart in the longitudinal direction of the elongated heat treatment object. 3. The heat treatment system of claim 1 or 2. <Appendix 4> the heating device is a high-frequency induction heating coil, the heat treatment device comprises a cylindrical coolant jet; the suction part is ring-shaped, a cavity is formed inside the suction part, and the hole is formed on the circumferential surface and communicates with the cavity, The heating device, the coolant injection device, and the suction part are arranged coaxially and spaced apart in the longitudinal direction of the elongated heat treatment object. 3. The heat treatment system of claim 1 or 2. <Appendix 5> The object to be heat-treated is a plate-like body placed horizontally, the heating device and the coolant injection device are horizontally adjacent to each other; the suction part is disk-shaped, a cavity is formed inside the suction part, and the hole is formed on the outer circumferential surface and communicates with the cavity, The suction section is disposed above the coolant injection device. 3. The heat treatment system of claim 1 or 2.

[0040] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made based on the technical concept of the present invention. [Explanation of symbols]

[0041] S Induction Hardening System 1. High-frequency hardening equipment 10 Work 11 Heating coil 12 Cooling jacket 12-1 Injection hole 2 Suction device 13 Suction part 13-1 Slits or holes 13-2 Cavity 14 Transfer pipe 14-1 First end 14-2 Second end 14-3 Main body 15 Piping 15-1 Compressed air supply pipe 15-2 Connecting pipe 20 Oil smoke 21 Water Vapor 22 Coolant 30 Compressed air

Claims

1. a heat treatment device having a heating device; a suction device provided near each of the heat treatment devices for sucking mist generated during heat treatment by the heat treatment device; A heat treatment system comprising:

2. The suction device further comprises: a suction section having a hole through which the mist is sucked; a transfer tube having one end connected to the suction portion; a negative pressure generating device connected to the other end of the transfer pipe and configured to generate negative pressure inside the transfer pipe and the suction unit; The thermal processing system of claim 1 , comprising:

3. the heating device is a high-frequency induction heating coil, the suction part is ring-shaped, a cavity is formed inside the suction part, and the hole is formed on the circumferential surface and communicates with the cavity, The heating device and the suction part are arranged coaxially and spaced apart in the longitudinal direction of the elongated heat treatment object. The heat treatment system according to claim 1 or 2.

4. the heating device is a high-frequency induction heating coil, the heat treatment device comprises a cylindrical coolant jet; the suction part is ring-shaped, a cavity is formed inside the suction part, and the hole is formed on the circumferential surface and communicates with the cavity, The heating device, the coolant injection device, and the suction part are arranged coaxially and spaced apart in the longitudinal direction of the elongated heat treatment object. The heat treatment system according to claim 1 or 2.

5. The object to be heat-treated is a plate-like body placed horizontally, the heating device and the coolant injection device are horizontally adjacent to each other; the suction part is disk-shaped, a cavity is formed inside the suction part, and the hole is formed on the outer circumferential surface and communicates with the cavity, The suction section is disposed above the coolant injection device. The heat treatment system according to claim 1 or 2.

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