Heat treatment apparatus

Abstract

A heat treatment apparatus for heat treating a metal strip includes a first heating section and a second heating section each configured to heat the metal strip using a heating unit that does not include an induction heating device, a first furnace body section that houses the first heating section, a second furnace body section that houses the second heating section, and an induction heating section that includes an induction heating device for heating the metal strip. The first heating section, the induction heating section, and the second heating section are arranged in this order in a conveying direction of the metal strip. The heat treatment apparatus includes a bypass passage for guiding a gas inside the second furnace body section to an inside of the first furnace body section while bypassing the induction heating section.

Description

Technical Field

[0001] This disclosure relates to a heat treatment apparatus. Background Technology

[0002] Induction heating devices are sometimes used as heating units in heat treatment equipment.

[0003] Patent document 1 describes a continuous annealing apparatus in which a steel strip is uniformly heated along its length to an annealing temperature exceeding the Curie point by using a gas burner, an electric heater, and an induction heating device.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 5135534 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, when using induction heating devices to enhance heating capacity in a continuous annealing furnace (heat treatment equipment) that includes a preheating zone and a heating zone, installing the induction heating device on the inlet side of the preheating zone (i.e., the upstream side of the continuous annealing furnace) is simpler in construction. In contrast, it is argued that by installing the induction heating device between the preheating zone and the heating zone, compared to installing it upstream of the preheating zone, the temperature of the metal strip in the preheating zone is lower, and the temperature difference between the metal strip and the furnace gas temperature increases, thus increasing the heat exchange between them and improving the heating efficiency in the continuous annealing furnace. However, in this case, high-temperature gas from the heating zone may flow into the preheating zone through the location of the induction heating device, thus exposing the induction heating device to high-temperature gas and increasing the risk of damage to the induction heating device due to high temperature.

[0009] In view of the above, at least one embodiment of the present invention aims to provide a heat treatment apparatus that can efficiently heat a metal strip while suppressing the risk of damage to the induction heating device.

[0010] Methods for solving problems

[0011] At least one embodiment of the heat treatment apparatus of the present invention is used for heat treatment of metal strip, wherein,

[0012] The heat treatment equipment includes:

[0013] The first heating section and the second heating section are respectively configured to heat the metal strip using a heating unit that does not include an induction heating device;

[0014] The first furnace body section houses the first heating section;

[0015] The second furnace body section, which houses the second heating section; and

[0016] The induction heating section includes an induction heating device for heating the metal strip.

[0017] The first heating unit, the induction heating unit, and the second heating unit are arranged sequentially in the conveying direction of the metal strip.

[0018] The heat treatment equipment has a bypass passage for guiding the gas inside the second furnace body to bypass the induction heating unit and into the first furnace body.

[0019] Invention Effects

[0020] According to at least one embodiment of the present invention, a heat treatment apparatus is provided that can efficiently heat a metal strip while suppressing the risk of damage to the induction heating device. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a heat treatment apparatus according to one embodiment.

[0022] Figure 2 This is a schematic diagram of a heat treatment apparatus according to one embodiment.

[0023] Figure 3 This is a schematic diagram of an induction heating section according to one embodiment. Detailed Implementation

[0024] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the constituent components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0025] Figure 1 and Figure 2 These are schematic diagrams of a heat treatment apparatus according to one embodiment. Figure 1 and Figure 2 As shown, the heat treatment apparatus 1 is an apparatus for heat treating a metal strip S, including a first heating section 6 and a second heating section 8 for heating the metal strip S. The second heating section 8 is disposed downstream of the first heating section 6 in the conveying direction of the metal strip S. Figure 2 As shown, the heat treatment apparatus 1 may also include a cooling section 30 located downstream of the second heating section 8 in the conveying direction of the metal strip S. The cooling section 30 may, for example, include a cooling nozzle 32 configured to blow cooling fluid onto the metal strip S.

[0026] In several embodiments, the heat treatment apparatus 1 may also be a continuous annealing apparatus comprising a first heating section 6 constituting a preheating zone, a second heating section 8 constituting a heating zone, and a cooling section 30 constituting a cooling zone, and for continuously annealing the metal strip S. The heat treatment apparatus 1, as a continuous annealing apparatus, may also further comprise a heat exchange zone 28 (see reference) disposed in the conveying direction of the metal strip S between the heating zone (second heating section 8) and the cooling zone (cooling section 30). Figure 2 ), and an over-aging zone (not shown) located downstream of the cooling zone.

[0027] It should be noted that the heat treatment equipment in several embodiments is not limited to annealing equipment. For example, in several embodiments, the heat treatment equipment may also include a heat treatment furnace for performing heat treatments other than annealing, such as quenching, tempering, and normalizing.

[0028] The heat treatment equipment 1 includes a furnace body 2 that houses a first heating section 6, a second heating section 8, and / or a cooling section 30. Figure 1 and Figure 2 The furnace body 2 shown includes a first furnace body section 2a that houses the first heating section 6 and a second furnace body section 2b that houses the second heating section 8.

[0029] Alternatively, multiple conveying rollers 4 for conveying the metal strip S can be installed inside the furnace body 2.

[0030] Heat treatment equipment 1 may include, for example, such as Figure 1 A horizontal furnace as shown, in which the metal strip S is conveyed horizontally in the first heating section 6 and the second heating section 8, or, for example, may include a furnace as shown in the figure. Figure 2 A vertical furnace that conveys the metal strip S in the vertical direction in the first heating section 6 and the second heating section 8, as shown.

[0031] In several embodiments, the first heating unit 6 and the second heating unit 8 are respectively configured to heat the metal strip S using a heating unit that does not include an induction heating device.

[0032] The first heating unit 6 can also be configured to heat the metal strip S using the heat of the atmosphere gas inside the first furnace body 2a. For example, the first heating unit 6 can also be configured to heat the metal strip S by convection heating generated by the atmosphere gas inside the first furnace body 2a. Alternatively, the first heating unit 6 can also be configured to heat the metal strip S by spraying a fluid (gas, etc.) heated outside the furnace body 2 onto the metal strip S using nozzles or the like provided inside the first furnace body 2a.

[0033] The second heating section 8 can also be configured to heat the metal strip S, which has been heated by the first heating section 6, to a temperature higher than the plate temperature at the outlet of the first heating section 6. In several embodiments, the second heating section 8 may also include a heating device 16 for heating the metal strip S (see reference 16). Figure 1 as well as Figure 2 ).

[0034] In one embodiment, the second heating section 8 may also be configured to burn fuel and use the heat generated by the combustion of fuel to heat the metal strip.

[0035] For example, the second heating section 8 may also include a burner as a heating device 16, which is configured to burn fuel and release the flame generated by the combustion of fuel toward the metal strip S. That is, the second heating section 8 may also be a direct flame furnace configured to directly heat the metal strip S using the flame of the burner. In this case, the combustion gas generated by the second heating section 8 may also be guided into the interior of the first furnace body section 2a and used as an atmosphere gas in the first heating section 6 for heating the metal strip S.

[0036] Alternatively, the second heating unit 8 may also include a radiant tube as a heating device 16, which is configured to be supplied with combustion gases generated by the combustion of fuel. In this case, the gas heated by heat exchange with the combustion exhaust gases discharged from the radiant tube to the outside may also be supplied to the first heating unit 6 as a heating fluid.

[0037] It should be noted that, for example, such as Figure 1 As shown, an exhaust pipe 20 for discharging atmospheric gas from the first heating section 6 may also be provided on the first furnace body section 2a.

[0038] In several implementations, for example, Figure 1 and Figure 2 As shown, the heat treatment apparatus 1 includes an induction heating unit 10, which includes an induction heating device 12 for heating the metal strip S. The induction heating unit 10 is disposed between the first heating unit 6 and the second heating unit 8 in the conveying direction of the metal strip S (i.e., downstream of the first heating unit 6 and upstream of the second heating unit 8). The induction heating unit 10 may also be housed in the third furnace body section 2c constituting the furnace body 2. Here, the first heating unit 6 and the second heating unit 8 may also be connected via the induction heating unit 10.

[0039] Additionally, the heat treatment apparatus 1 includes a bypass passage 14, which is used to guide gas inside the second furnace body 2b around the induction heating unit 10 and into the first furnace body 2a. Figure 1 as well as Figure 2In the exemplary embodiment shown, the bypass passage 14 includes a pipe disposed on the outside of the first furnace body section 2a and the second furnace body section 2b. This pipe may also have two ends that are respectively connected to the first furnace body section 2a and the second furnace body section 2b.

[0040] Figure 3 This is a schematic diagram of an induction heating unit 10 according to one embodiment. (As shown) Figure 3 As shown, the induction heating device 12 includes a coil 36 for generating magnetic flux. The coil 36 of the induction heating device 12 can be configured to generate magnetic flux in the in-plane direction (e.g., the length direction of the metal strip S) of the metal strip S, or it can be configured to generate magnetic flux in the out-of-plane direction (e.g., the direction orthogonal to the surface of the metal strip S) of the metal strip S.

[0041] In the heat treatment apparatus 1 of the above embodiment, an induction heating device 12 is provided between the first heating section 6 and the second heating section 8. Therefore, compared with the case where the induction heating device 12 is provided upstream of the first heating section 6 in the conveying direction of the metal strip S, the plate temperature in the first heating section 6 is lower. As a result, the temperature difference between the atmospheric gas in the first heating section 6 and the metal strip S is larger, and the heat exchange between them is greater, thus enabling efficient heating of the metal strip S. In addition, in the heat treatment apparatus 1 described above, high-temperature gas (combustion gas, atmospheric gas) from the second heating section 8 can be guided to the first heating section 6 via the bypass passage 14 that bypasses the induction heating section 10. Therefore, the amount of high-temperature gas flowing from the second heating section 8 into the induction heating section 10 can be reduced, and the high-temperature gas from the second heating section 8 can be used to heat the metal strip S in the first heating section 6. Therefore, according to the heat treatment apparatus 1 described above, the induction heating device 12 can be protected from high temperature to reduce the risk of damage, and the metal strip S can be heated efficiently.

[0042] It should be noted that, in the second heating section 8, when the metal strip S is heated using a burner that releases a flame toward the metal strip S, the combustion gases generated by the combustion of fuel in the second heating section 8 (the interior of the second furnace body 2b) are guided to the first heating section 6 (the interior of the first furnace body 2a) via the bypass passage 14. Furthermore, in the second heating section, when the metal strip S is heated using a radiant tube, the atmospheric gases inside the second furnace body 2b are guided to the first heating section 6 (the interior of the first furnace body 2a) via the bypass passage 14.

[0043] In the case where the second heating section 8 is a direct flame furnace that uses a burner that releases flames toward the metal strip S to heat the metal strip S, the first heating section 6 may also include a combustion chamber 18 (see reference) for burning fuel contained in the gas inside the first furnace body 2a. Figure 1In addition, the first heating section 6 can also use the heat generated by the combustion of fuel in the combustion chamber 18 to heat the metal strip S.

[0044] Typically, when heating the metal strip S using a burner, an excess of fuel relative to air (or oxygen) is supplied to the burner to suppress oxidation of the metal strip S. In the second heating section 8, even when an excess of fuel is supplied to the burner, by providing an induction heating section 10 between the first heating section 6 and the second heating section 8, the temperature of the metal strip S in the first heating section 6 can be kept relatively low, as described above. Therefore, even if the remaining fuel contained in the combustion gas from the second heating section 8 is burned in the combustion chamber 18 or the like as a heat source in the first heating section 6, oxidation of the metal strip S in the first heating section 6 can be suppressed.

[0045] In several embodiments, the heat treatment apparatus 1 includes a sealing device 22, which is disposed in the conveying direction of the metal strip S at least one of the following: between the first heating section 6 and the induction heating section 10, and between the induction heating section 10 and the second heating section 8. This sealing device 22 is configured to prevent gas from flowing into the induction heating section 10 from inside the first furnace body 2a or the second furnace body 2b. Figure 1 and Figure 2 In the exemplary embodiment shown, sealing devices 22 are provided between the first heating part 6 and the induction heating part 10, and between the induction heating part 10 and the second heating part 8, respectively.

[0046] Thus, by providing a sealing device 22 between at least one of the first heating section 6 and the induction heating section 10, and between the induction heating section 10 and the second heating section 8, it is possible to more effectively suppress the inflow of high-temperature gas from the second heating section 8 (gas flowing directly from the second heating section 8 into the induction heating section 10, or gas guided from the second heating section 8 into the first furnace body section 2a via the bypass passage 14) into the induction heating section 10. Therefore, the risk of damage to the induction heating device 12 by high-temperature gas can be further reduced.

[0047] For example, such as Figure 3 As shown, the sealing device 22 may also include a sealing member 23 disposed facing the surface of the metal strip S. In one embodiment, the sealing member 23 may also include a sealing roller configured to contact the surface of the metal strip S and to rotate along with the conveying of the metal strip S. In one embodiment, the sealing member 23 may also include a plate-like or box-like door member having a flat opposing surface opposite the surface of the metal strip S. Figure 3 In the exemplary embodiment shown, the sealing device 22 includes a pair of sealing rollers (sealing members 23) respectively disposed on both sides facing the metal strip S.

[0048] The sealing member 23 can also be configured to be driven along a direction orthogonal to the surface of the metal strip S. For example, the sealing member 23 provided in the portion where the metal strip S is conveyed in a horizontal direction (see reference). Figure 1 or Figure 3 It can also be configured to be driven along the vertical direction (or the vertical direction). Additionally, a sealing member 23 (see reference) is provided in the portion where the metal strip S is conveyed along the vertical direction (or the vertical direction). Figure 2 It can also be configured to be driven in the horizontal direction.

[0049] Alternatively, the sealing device 22 may also include a drive unit (e.g., a motor or fluid pressure cylinder) for driving the sealing member 23, as described above.

[0050] In the above embodiment, the sealing member 23, which faces the surface of the metal strip S, can move along a direction orthogonal to the surface. Therefore, for example, by moving the sealing member 23 to increase the distance between the surface of the metal strip S and the sealing member 23, the metal strip S can pass smoothly through the location where the sealing member 23 is installed. Alternatively, by adjusting the position of the sealing member 23 according to the thickness of the metal strip S, the size of the gap between the metal strip S and the sealing member 23 can be appropriately maintained.

[0051] In several implementations, for example, Figures 1-3 As shown, the heat treatment equipment 1 includes a low-temperature gas supply unit 24, which supplies gas (combustion gas, atmosphere gas) that is colder than the gas (combustion gas, atmosphere gas) inside the second furnace body 2b to the induction heating unit 10. Figure 3 As shown, the cryogenic gas supply unit 24 may also include a supply pipe 24a disposed between a cryogenic gas storage unit (gas tank, etc., not shown) and an induction heating unit 10, and a supply valve 24b disposed on the supply pipe 24a.

[0052] The aforementioned cryogenic gas may also include reducing gases such as hydrogen or inactive gases such as nitrogen. Furthermore, when the oxidation of the metal strip S is minimal or not a concern (e.g., when the metal strip S is stainless steel), the cryogenic gas may be a gas other than the aforementioned reducing or inactive gases (e.g., air).

[0053] In the above embodiment, a gas at a lower temperature than that inside the second furnace body 2b can be supplied to the induction heating unit 10 via the low-temperature gas supply unit 24, thus more effectively protecting the induction heating unit 10 from high temperatures. Therefore, the risk of damage to the induction heating unit 10 can be further reduced.

[0054] In several implementations, for example, Figures 1-3As shown, the heat treatment equipment 1 may also include a low-temperature gas discharge section 26, which is used to discharge the gas (including low-temperature gas) inside the induction heating section 10 to the outside of the furnace body 2. Figure 3 As shown, the low-temperature gas discharge section 26 may also include a discharge pipe 26a for discharging the gas in the induction heating section 10 to the outside and a discharge valve 26b provided on the discharge pipe 26a.

[0055] In this way, by providing the low-temperature gas discharge section 26, the low-temperature gas supplied to the induction heating section 10 can be discharged to the outside of the furnace body 2, thereby preventing the low-temperature gas in the induction heating section 10 from flowing into the first heating section 6 and the second heating section 8 through the sealing device 22. Therefore, the reduction in the heating efficiency of the metal strip S in the heat treatment equipment 1 can be suppressed.

[0056] In several implementations, for example, Figure 3 As shown, the induction heating device 12 may also include a heat insulation element 38 disposed between the coil 36 and the metal strip S.

[0057] In this way, by providing a heat insulation member 38 between the coil 36 and the metal strip S of the induction heating device 12, the heat from the high-temperature gas flowing into the induction heating section 10 is difficult to transfer to the coil 36. Therefore, the induction heating section 10 can be more effectively protected from high temperatures, and the risk of damage to the induction heating device 12 can be further reduced.

[0058] In several implementations, for example, Figure 3 As shown, the induction heating device 12 may also include an airtight element 40, which separates the space through which the metal strip S passes from the space where the coil 36 is located inside the furnace body 2, thereby preventing furnace gases from entering the space where the coil 36 is located. The airtight element 40 may also comprise a sheet made of resin such as silicon or Teflon (registered trademark). The airtight element 40 may also be arranged to surround the coil 36. The airtight element 40 may also be fixed to the furnace body 2 by bolts.

[0059] By providing the aforementioned airtight component 40, the possibility of the coil 36 being exposed to high-temperature gas can be reduced, thereby more effectively protecting the induction heating part 10 from the effects of high temperature.

[0060] It should be noted that in annealing furnaces that include preheating zones and heating zones, in order to enhance heating capacity, an induction heating device is also considered to be installed upstream of the preheating zone (i.e., the inlet side of the annealing furnace). In this case, due to the constraints of the overall equipment length of the annealing furnace, the preheating zone is sometimes reduced. In such cases, as a heat recovery unit replacing the preheating zone, a self-heating recovery type burner can also be used in the heating zone (direct-fire zone). A self-heating recovery type burner is a burner equipped with a heat exchanger for exchanging heat between the combustion gases generated in the burner and the fuel or air burning in the burner, using the heat of the combustion gases to preheat the fuel or air.

[0061] The contents described in the above embodiments are as follows, for example.

[0062] [1] A heat treatment apparatus (1) according to at least one embodiment of the present invention is used to heat treat a metal strip (S), wherein,

[0063] The heat treatment equipment (1) includes:

[0064] The first heating section (6) and the second heating section (8) are respectively configured to heat the metal strip using a heating unit that does not include an induction heating device;

[0065] The first furnace body (2a) houses the first heating section;

[0066] The second furnace body (2b) houses the second heating section; and

[0067] The induction heating unit (10) includes an induction heating device (12) for heating the metal strip.

[0068] The first heating unit, the induction heating unit, and the second heating unit are arranged sequentially in the conveying direction of the metal strip.

[0069] The heat treatment equipment (1) has a bypass passage (14) for guiding the gas inside the second furnace body to bypass the induction heating unit and into the interior of the first furnace body.

[0070] In the structure described above [1], an induction heating device is provided between the first heating section and the second heating section. Therefore, compared with the case where the induction heating device is provided upstream of the first heating section in the direction of metal strip transport, the plate temperature in the first heating section is lower. As a result, the temperature difference between the atmosphere gas in the first heating section and the metal strip is larger, and the heat exchange between them is larger. Therefore, the metal strip can be heated efficiently. In addition, in the structure described above [1], high-temperature gas (combustion gas, atmosphere gas) from the second heating section can be guided to the first heating section via a bypass passage that bypasses the induction heating section. Therefore, the amount of high-temperature gas flowing from the second heating section to the induction heating section can be reduced, and the metal strip can be heated in the first heating section using the high-temperature gas from the second heating section. Therefore, according to the structure described above [1], the induction heating device can be protected from high temperature to reduce the risk of damage, and the metal strip can be heated efficiently.

[0071] [2] In several embodiments, based on the structure described in [1] above,

[0072] The second heating section is configured to burn fuel and use the heat generated by the combustion of the fuel to heat the metal strip.

[0073] The first heating section is configured to heat the metal strip by convection heating generated by the atmosphere gas inside the first furnace body.

[0074] According to the structure described above [2], in a heat treatment apparatus including a first heating section and a second heating section, as described above [1], efficient heating of the metal strip is possible, and the metal strip can be heated in the first heating section using high-temperature gas from the second heating section while reducing the amount of high-temperature gas passing through the induction heating device. The first heating section heats the metal strip using convective heating generated by the atmospheric gas, and the second heating section heats the metal strip using heat generated by the combustion of fuel. Therefore, according to the structure described above [2], the induction heating device can be protected from high temperatures, reducing the risk of damage, and the metal strip can be heated efficiently.

[0075] [3] In several embodiments, based on the structure described in [2] above,

[0076] The second heating unit includes a burner configured to burn the fuel and release the flame generated by the combustion of the fuel toward the metal strip.

[0077] In the second heating section, the combustion gases generated by the combustion of the fuel are guided into the interior of the first furnace section via the bypass passage.

[0078] According to the structure described above [3], the second heating section includes a burner that releases a flame toward the metal strip. Therefore, the high-temperature combustion gas generated by the combustion of fuel in the burner is guided to the first heating section via a bypass passage. Thus, in the first heating section, the metal strip can be effectively heated by convective heating generated by an atmosphere containing the combustion gas, and the high-temperature combustion gas passing through the induction heating device can be reduced. Therefore, according to the structure described above [3], the induction heating device can be protected from high temperatures to reduce the risk of damage, and the metal strip can be heated efficiently.

[0079] In addition, when heating a metal strip using a burner, fuel is sometimes supplied to the burner in excess of air (or oxygen) in order to suppress oxidation of the metal strip. Even in such cases, in the structure described above [3], by providing an induction heating section between the first heating section and the second heating section, as described above, the temperature of the metal strip in the first heating section is suppressed to a relatively low level. Therefore, even if the excess fuel contained in the combustion gas from the second heating section is burned and used as a heat source in the first heating section, oxidation of the metal strip in the first heating section can be suppressed.

[0080] [4] In several embodiments, based on the structure described in [1] above,

[0081] The second heating element includes a radiant tube configured to heat the metal strip.

[0082] The first heating section is configured to heat the metal strip by convection heating generated by the atmosphere gas inside the first furnace body.

[0083] The atmospheric gas inside the second furnace body is guided into the interior of the first furnace body through the bypass passage.

[0084] According to the structure described above [4], in a heat treatment apparatus including a first heating section and a second heating section, as described above [1], efficient heating of the metal strip is possible, and the metal strip can be heated in the first heating section using high-temperature gas from the second heating section while reducing the amount of high-temperature gas passing through the induction heating device. The first heating section heats the metal strip by convection heating generated by the atmospheric gas, and the second heating section heats the metal strip using a radiant tube. Therefore, according to the structure described above [4], the induction heating device can be protected from high temperatures, reducing the risk of damage, and the metal strip can be heated efficiently.

[0085] [5] In several embodiments, based on any of the structures described in [1] to [4] above,

[0086] The bypass passage includes pipes disposed on the outside of the first furnace body and the second furnace body.

[0087] According to the structure described above [5], a bypass passage that bypasses the induction heating unit can be formed with a simple structure including pipes provided on the outside of the first furnace body and the second furnace body. As a result, the metal strip can be heated efficiently while protecting the induction heating device from high temperature and reducing the risk of damage.

[0088] [6] In several embodiments, based on any of the structures described in [1] to [5] above,

[0089] The heat treatment equipment includes a sealing device (22) which is disposed in the conveying direction of the metal strip between at least one of the first heating section and the induction heating section and between the induction heating section and the second heating section, and is configured to prevent gas from the interior of the first furnace section or the interior of the second furnace section from flowing into the induction heating section.

[0090] According to the structure described above [6], a sealing device is provided between at least one of the first heating section and the induction heating section and between the induction heating section and the second heating section, thereby more effectively suppressing the inflow of high-temperature gas from the second heating section into the induction heating section. Therefore, the risk of damage to the induction heating device by high-temperature gas can be further reduced.

[0091] [7] In several embodiments, based on the structure described in [6] above,

[0092] The sealing device includes a sealing member (23) disposed facing the surface of the metal strip and configured to be driven along a direction orthogonal to the surface of the metal strip.

[0093] According to the structure described above [7], the sealing member provided on the surface facing the metal strip can move in a direction orthogonal to the surface. Therefore, for example, by moving the sealing member to increase the distance between the surface of the metal strip and the sealing member, the metal strip can pass smoothly through the location where the sealing member is provided, or by adjusting the position of the sealing member according to the thickness of the metal strip, the size of the gap between the metal strip and the sealing member can be appropriately maintained.

[0094] [8] In several embodiments, based on the structure described in [6] or [7] above,

[0095] The heat treatment equipment includes a low-temperature gas supply unit (24) for supplying gas that is colder than the gas inside the second furnace body to the induction heating unit.

[0096] According to the structure described above [8], a gas at a lower temperature than that inside the second furnace body can be supplied to the induction heating unit using a low-temperature gas supply unit, thus more effectively protecting the induction heating unit from high temperatures. Therefore, the risk of damage to the induction heating unit can be further reduced.

[0097] [9] In several embodiments, based on any of the structures described in [1] to [8] above,

[0098] The induction heating device includes:

[0099] Coil (36), which is used to generate magnetic flux; and

[0100] A heat insulation element (38) is disposed between the coil and the metal strip.

[0101] According to the structure described above [9], a heat insulation component is provided between the coil and the metal strip of the induction heating device, so the heat from the high-temperature gas flowing into the induction heating section is difficult to transfer to the coil. Therefore, the induction heating device can be more effectively protected from high temperatures, and the risk of damage to the induction heating section can be further reduced.

[0102]

[10] In several embodiments, based on any of the structures described in [1] to [9] above,

[0103] The heat treatment equipment includes a cooling section (30) which is disposed downstream of the second heating section in the conveying direction of the metal strip and is used to cool the metal strip.

[0104] According to the structure described above

[10] , in a heat treatment apparatus (e.g., a continuous annealing apparatus) in which a cooling section (e.g., a cooling strip) is provided downstream of the first heating section (e.g., a preheating zone) and the second heating section (e.g., a heating strip), as described above [1], the metal strip can be heated efficiently, and the flow of high-temperature gas from the second heating section to the induction heating section can be reduced. Therefore, according to the structure described above

[10] , the induction heating device can be protected from high temperature to reduce the risk of damage, and the metal strip can be heated efficiently.

[0105] The embodiments of the present invention have been described above, but the present invention is not limited to the embodiments described above, and also includes modifications to the embodiments described above, and appropriate combinations of these embodiments.

[0106] In this specification, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" that indicate relative or absolute configurations not only strictly indicate such configurations, but also indicate the state of relative displacement by angle or distance with tolerance or to the extent that the same function can be obtained.

[0107] For example, expressions such as "same," "equal," and "homogeneous" that indicate the state of equality of things not only indicate a state of strict equality, but also indicate a state of difference where there is a tolerance or a degree of difference in the ability to obtain the same function.

[0108] Furthermore, in this specification, the terms "quadrilateral shape," "cylindrical shape," etc., not only refer to quadrilateral shapes and cylindrical shapes in a strict geometric sense, but also to shapes that include concave and convex parts, chamfered parts, etc., within the range that can achieve the same effect.

[0109] Furthermore, in this specification, expressions such as "having," "comprising," or "possessing" a constituent element are not exclusive expressions that exclude the existence of other constituent elements.

[0110] Explanation of reference numerals in the attached figures:

[0111] 1. Heat treatment equipment

[0112] 2 Furnace body

[0113] 2a First furnace body

[0114] 2b Second furnace body

[0115] 2c Third furnace body

[0116] 4 Conveyor Rollers

[0117] 6 First heating section

[0118] 8 Second heating section

[0119] 10 Induction heating unit

[0120] 12 Induction heating device

[0121] 14 Bypass Path

[0122] 16 Heating device

[0123] 18. Afterburning chamber

[0124] 20 Exhaust pipe

[0125] 22 Sealing device

[0126] 23 Sealing components

[0127] 24. Cryogenic Gas Supply Department

[0128] 24a Supply Pipe

[0129] 24b Supply Valve

[0130] 26. Low-temperature gas exhaust section

[0131] 26a Discharge pipe

[0132] 26b Discharge valve

[0133] 28 Tropical

[0134] 30 Cooling section

[0135] 32 Cooling Nozzles

[0136] 36 coils

[0137] 38 Thermal insulation components

[0138] 40 Airtight components

[0139] S-shaped metal strip.

Claims

1. A heat treatment apparatus for heat treating a metal strip, wherein, The heat treatment equipment includes: The first heating section and the second heating section are respectively configured to heat the metal strip using a heating unit that does not include an induction heating device; The first furnace body section houses the first heating section; The second furnace body section, which houses the second heating section; and The induction heating section includes an induction heating device for heating the metal strip. The first heating unit, the induction heating unit, and the second heating unit are arranged sequentially in the conveying direction of the metal strip. The heat treatment equipment has a bypass passage for guiding the gas inside the second furnace body to bypass the induction heating unit and into the first furnace body.

2. The heat treatment equipment according to claim 1, wherein, The second heating section is configured to burn fuel and use the heat generated by the combustion of the fuel to heat the metal strip. The first heating section is configured to heat the metal strip by convection heating generated by the atmosphere gas inside the first furnace body.

3. The heat treatment equipment according to claim 2, wherein, The second heating unit includes a burner configured to burn the fuel and release the flame generated by the combustion of the fuel toward the metal strip. In the second heating section, the combustion gases generated by the combustion of the fuel are guided into the interior of the first furnace section via the bypass passage.

4. The heat treatment equipment according to claim 1, wherein, The second heating element includes a radiant tube configured to heat the metal strip. The first heating section is configured to heat the metal strip by convection heating generated by the atmosphere gas inside the first furnace body. The atmospheric gas inside the second furnace body is guided into the interior of the first furnace body through the bypass passage.

5. The heat treatment equipment according to any one of claims 1 to 4, wherein, The bypass passage includes pipes disposed on the outside of the first furnace body and the second furnace body.

6. The heat treatment equipment according to any one of claims 1 to 4, wherein, The heat treatment equipment includes a sealing device disposed in the conveying direction of the metal strip between at least one of the first heating section and the induction heating section and between the induction heating section and the second heating section, and configured to prevent gas from the interior of the first furnace section or the interior of the second furnace section from flowing into the induction heating section.

7. The heat treatment equipment according to claim 6, wherein, The sealing device includes a sealing member configured to face the surface of the metal strip and be driven in a direction orthogonal to the surface of the metal strip.

8. The heat treatment equipment according to claim 6, wherein, The heat treatment equipment includes a low-temperature gas supply unit for supplying the induction heating unit with a gas that is colder than the gas inside the second furnace body.

9. The heat treatment apparatus according to any one of claims 1 to 4, wherein, The induction heating device includes: Coils, which are used to generate magnetic flux; and A heat insulation element is disposed between the coil and the metal strip.

10. The heat treatment apparatus according to any one of claims 1 to 4, wherein, The heat treatment equipment includes a cooling section, which is disposed downstream of the second heating section in the conveying direction of the metal strip, for cooling the metal strip.

Images