Box-type carburizing and nitriding multi-purpose furnace capable of accurately detecting temperature

Abstract

The utility model discloses a box type carburizing and nitriding multi-purpose furnace capable of accurately detecting temperature, which comprises a multi-purpose furnace, a double-branch thermocouple is arranged in the multi-purpose furnace, the double-branch thermocouple comprises a thermocouple cable and two temperature measuring probes, and the other end of the thermocouple cable is connected with a temperature control instrument positioned outside the multi-purpose furnace; an automatic winding mechanism for automatically winding a thermocouple cable is arranged on the side furnace wall in the front chamber of the multi-purpose furnace; the bracket in the multipurpose furnace is provided with a supporting rod, and the upper part of the supporting rod is provided with a locking mechanism connected with a thermocouple cable; the front chamber is provided with a guiding traction mechanism which is connected with a thermocouple cable between the locking mechanism and the automatic winding mechanism. According to the utility model, the telescoping of the thermocouple cable can be directionally guided, the problem that the thermocouple cable is easily twisted with a transmission mechanism in the multi-purpose furnace is solved, displacement or shedding of the thermocouple is avoided, and accurate temperature detection of a large-scale workpiece in the multi-purpose furnace is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of metal material heat treatment equipment, in particular to a box-type multi-purpose carbonitriding furnace with precise temperature detection. Background Art

[0002] Large hot-working molds made of H13 material and measuring approximately 2000x1000x650mm are gradually being adopted by the domestic automotive industry. However, the larger the mold, the more difficult it is to achieve good mechanical properties after heat treatment, and the risk of mold cracking and excessive deformation also increases accordingly.

[0003] Currently, domestic quenching of this type of mold primarily utilizes vacuum gas quenching furnaces, using nitrogen as the quenching medium. Faster cooling rates promote a better quenched structure and extend mold life. Larger workpieces cool more slowly. For hot-work molds with effective dimensions greater than 400x400x400mm, no vacuum gas quenching furnace currently meets the cooling rates recommended by the North American Die Casting Association: a minimum cooling rate of 28°C / min from the austenitizing temperature to 540°C. Cooling rates lower than this result in bainite formation. Slower cooling rates increase the amount of bainite and shorten mold life. Therefore, vacuum gas quenching furnaces are not ideal for quenching large H13 molds.

[0004] In addition, there are also multi-purpose furnaces that are used to quench workpieces. The cooling method for quenching in a multi-purpose furnace is to use quenching oil. The thermal conductivity of static oil is about twice that of 20 bar helium (helium has higher thermal conductivity than nitrogen). When the oil agitator is turned on, the thermal conductivity of the oil will increase to about twice that of static oil. Therefore, using a multi-purpose furnace to quench large molds can effectively solve the problem of insufficient cooling rate when quenching large molds. As a common multi-purpose furnace in this field, its specific structure can refer to the sealed box-type carbonitriding multi-purpose furnace produced by Jiangsu Yike Heat Treatment Equipment Co., Ltd. The multi-purpose furnace includes an antechamber, a heating chamber, a bracket for placing workpieces in the antechamber, an oil pool located below the antechamber, and a furnace door arranged between the antechamber and the heating chamber. The interior of the multi-purpose furnace is also provided with a driving mechanism for driving the bracket to move back and forth to the heating chamber and the oil pool respectively.

[0005] The entire heating and cooling process of quenching large hot-working molds requires thermocouples to be inserted on the workpiece surface and core for temperature measurement. This allows for constant monitoring of the mold's condition and reduces the risk of significant deformation and cracking. Since workpieces are heated and cooled in a vacuum gas quenching furnace, without any transfer, inserting thermocouples on the workpiece surface and core to monitor temperature is straightforward. However, when using a multi-purpose furnace, the workpiece is first placed in the antechamber, where the thermocouples are inserted and then transferred to the heating chamber for heating. After heating and holding, the workpiece is then transferred back to the antechamber, where it is immersed in an oil bath below for cooling. After cooling, the workpiece is raised to the antechamber. During this transfer process, the thermocouples can easily shift or even fall off, making it impossible to effectively monitor the workpiece temperature. Furthermore, the thermocouple cables can easily become entangled with the multi-purpose furnace's transmission mechanism, damaging the thermocouples.

[0006] Currently, existing multi-purpose furnaces lack equipment that can accurately monitor the surface and core temperatures of large workpieces in real time. Therefore, there is an urgent need to improve existing multi-purpose furnaces to meet the above-mentioned temperature measurement capabilities. Utility Model Content

[0007] The purpose of the present utility model is to provide a box-type carbonitriding multi-purpose furnace with precise temperature detection. On the one hand, by arranging an automatic winding mechanism, it is convenient to pull out and extend the extended length of the thermocouple cable and to automatically rewind the thermocouple cable, thereby facilitating the transfer of the workpiece inside the multi-purpose furnace, and further cooperating with the guide traction mechanism, the extension and contraction of the thermocouple cable can be guided in a direction, solving the problem that the thermocouple cable is easily entangled with the transmission mechanism inside the multi-purpose furnace; on the other hand, by arranging a support rod on the bracket to cooperate with the locking mechanism to lock the thermocouple cable, it can be ensured that the double-branch thermocouple will not be affected by the pulling of external force after being inserted into the temperature measuring hole of the workpiece, thereby effectively avoiding the problem of displacement or falling off of the double-branch thermocouple, so as to realize precise temperature detection of large workpieces located in the multi-purpose furnace.

[0008] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0009] A box-type multi-purpose furnace for carbonitriding with precise temperature detection comprises a multi-purpose furnace, wherein a double-branch thermocouple is provided inside the multi-purpose furnace, wherein the double-branch thermocouple comprises a thermocouple cable and two temperature probes respectively connected to one end of the thermocouple cable, and the other end of the thermocouple cable is connected to a temperature control instrument located outside the multi-purpose furnace; an automatic winding mechanism for automatically rewinding the thermocouple cable is provided on the side furnace wall in the front chamber of the multi-purpose furnace, and part of the thermocouple cable located in the multi-purpose furnace is wound and connected to the automatic winding mechanism; a support rod is provided on the bracket inside the multi-purpose furnace, and a locking mechanism is installed on the upper part of the support rod, and the thermocouple cable is connected to the locking mechanism at one end close to the two temperature probes; a guide traction mechanism is provided in the front chamber, and the guide traction mechanism is connected to the thermocouple cable located between the locking mechanism and the automatic winding mechanism.

[0010] Furthermore, a first positioning groove that is recessed upward is provided on the lower surface of the furnace door of the multi-purpose furnace, and the first positioning groove is located opposite to the support rod.

[0011] Furthermore, a door frame located at the furnace door of the multi-purpose furnace is provided with a second positioning groove that is recessed downward, and the second positioning groove and the first positioning groove together form a hole for the thermocouple cable to pass through.

[0012] Furthermore, the temperature measuring probe is an armored thermocouple.

[0013] Furthermore, the automatic winding mechanism includes a capstan, a spiral spring, and a tubular support column fixedly connected to the side furnace wall of the front chamber. The capstan has a positioning ring for winding and connecting the thermocouple cable. One end of the spiral spring is connected to the tubular support column, and the other end of the spiral spring is connected to the positioning ring.

[0014] Furthermore, the guide and traction mechanism includes a counterweight, a steel wire rope, a first fixed pulley, a second fixed pulley and a third fixed pulley, the first fixed pulley is rotatably mounted on the side furnace wall of the front chamber, the second fixed pulley is rotatably mounted on the top furnace wall of the front chamber, and the third fixed pulley is rotatably mounted on the upper part of the lifting frame in the front chamber, and the second fixed pulley, the third fixed pulley and the support rod are located in the same vertical plane; one end of the steel wire rope is connected to the counterweight, and the other end of the steel wire rope is sequentially overlapped with the first fixed pulley, the second fixed pulley and the third fixed pulley and then connected to the thermocouple cable.

[0015] Furthermore, the steel wire rope is connected to the thermocouple cable through a locking assembly, a stainless steel wire is connected between the locking assembly and the locking mechanism, and the length of the thermocouple cable between the locking assembly and the locking mechanism is longer than the length of the stainless steel wire.

[0016] Furthermore, the locking assembly includes a U-shaped locking plate for clamping the thermocouple cable and a bolt and nut assembly installed at the opening of the U-shaped locking plate. The bolt and nut assembly is connected to a hanging plate, and the hanging plate is provided with a binding hole for connecting the steel wire rope.

[0017] Furthermore, the stainless steel wire is 316 stainless steel wire with a diameter of 2 mm.

[0018] Furthermore, the locking mechanism includes a C-shaped clamp and a locking rod for enclosing and clamping the support rod, and the two ends of the C-shaped clamp are respectively provided with a first connecting end and a second connecting end, the first connecting end is provided with a threaded hole, and the second connecting end is provided with an assembly hole coaxially distributed with the threaded hole, the peripheral wall surface of the locking rod is provided with a thread matching the threaded hole, and the end of the locking rod is provided with a locking block, and the locking block is provided with a locking hole.

[0019] Compared with the existing technology, the utility model provides a box-type carbonitriding multi-purpose furnace with precise temperature detection, which has the following beneficial effects:

[0020] The utility model provides an automatic winding mechanism, which can not only facilitate pulling out and extending the extended length of the thermocouple cable but also automatically rewind the thermocouple cable, thereby facilitating the transfer of the workpiece inside the multi-purpose furnace, and further cooperates with the guide traction mechanism to provide directionally guided extension and retraction of the thermocouple cable, thereby solving the problem that the thermocouple cable is easily entangled with the transmission mechanism inside the multi-purpose furnace; in addition, by arranging a support rod on the bracket to cooperate with the locking mechanism to lock the thermocouple cable, it can be ensured that the double-branch thermocouple will not be affected by external pulling force after being inserted into the temperature measuring hole of the workpiece, thereby effectively avoiding the problem of displacement or falling off of the double-branch thermocouple, so as to realize accurate temperature detection of large workpieces located in the multi-purpose furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0022] Figure 1 It is a structural diagram of the utility model;

[0023] Figure 2 It is a structural diagram of the automatic winding mechanism;

[0024] Figure 3 Schematic diagram of the structure of the locking mechanism;

[0025] Figure 4Schematic diagram of the structure of the lock assembly;

[0026] Figure 5 This is a schematic diagram of the workpiece after entering the heating chamber;

[0027] Figure 6 This is a schematic diagram of the furnace door after closing;

[0028] Figure 7 This is a schematic diagram of the workpiece after entering the oil pool.

[0029] Reference numerals: 1, multi-purpose furnace; 11, front chamber; 12, bracket; 121, support rod; 13, heating chamber; 14, oil pool; 15, furnace door; 151, first positioning groove; 16, door frame; 161, second positioning groove; 17, lifting frame; 2, double-branch thermocouple; 21, thermocouple cable; 22, temperature probe; 3, automatic winding mechanism; 31, capstan; 311, positioning ring; 32, scroll spring; 33, tubular support column; 4, locking mechanism; 41, C-type clamp; 4 11. First connecting end; 412. Second connecting end; 413. Threaded hole; 414. Assembly hole; 42. Locking rod; 421. Thread; 422. Locking block; 423. Locking hole; 5. Guide and traction mechanism; 51. Counterweight; 52. Wire rope; 53. First fixed pulley; 54. Second fixed pulley; 55. Third fixed pulley; 6. Locking buckle assembly; 61. U-shaped locking plate; 62. Bolt and nut assembly; 63. Hanging plate; 631. Binding hole; 7. Stainless steel wire; 8. Temperature control instrument; 9. Workpiece. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solution of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0033] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, indirect connection through an intermediate medium, internal communication between two components, or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0034] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] The present invention will be further described below through detailed embodiments and in conjunction with the accompanying drawings.

[0036] Please refer to Figures 1 to 7 This embodiment provides a box-type multi-purpose carbonitriding furnace with precise temperature detection, including a multi-purpose furnace 1. It should be noted that the multi-purpose furnace 1 of this embodiment can adopt the conventional multi-purpose furnace structure of the prior art. As an example, the specific structure can refer to the sealed box-type multi-purpose carbonitriding furnace produced by Jiangsu Yike Heat Treatment Equipment Co., Ltd., which includes an antechamber 11, a heating chamber 13, a bracket 12 disposed in the antechamber 11 for placing a workpiece 9, an oil pool 14 located below the antechamber 11, and a furnace door 15 disposed between the antechamber 11 and the heating chamber 13. The multi-purpose furnace 1 is also provided with a drive mechanism for driving the bracket 12 to move back and forth between the heating chamber 13 and the oil pool 14. This embodiment improves the structure of existing multi-purpose furnaces to achieve the purpose of precise temperature detection of workpieces located within the multi-purpose furnace.

[0037] Specifically, such as Figures 1 to 4As shown, the multi-purpose furnace 1 of this embodiment is provided with a double-branch thermocouple 2 inside, and the double-branch thermocouple 2 includes a thermocouple cable 21 and two temperature measuring probes 22 respectively connected to one end of the thermocouple cable 21, and the other end of the thermocouple cable 21 is connected to the temperature control instrument 8 located outside the multi-purpose furnace 1; the thermocouple cable 21 is composed of two strands of cable wound together, and the two strands of cable are respectively connected to the two temperature measuring probes 22. The side furnace wall in the front chamber 11 of the multi-purpose furnace 1 is provided with an automatic winding mechanism 3 for automatically rewinding the thermocouple cable 21. Part of the thermocouple cable 21 in the multi-purpose furnace 1 is wound and connected to the automatic winding mechanism 3. The bracket 12 inside the multi-purpose furnace 1 is provided with a support rod 121. The upper part of the support rod 121 is installed with a locking mechanism 4. The thermocouple cable 21 is connected to the locking mechanism 4 at one end near the two temperature probes 22. The front chamber 11 is provided with a guide traction mechanism 5. The guide traction mechanism 5 is connected to the thermocouple cable 21 located between the locking mechanism 4 and the automatic winding mechanism 3. When in use, one of the temperature probes is inserted into the surface temperature measuring hole of the workpiece to measure the surface temperature of the workpiece in real time, and the other temperature probe is inserted into the core temperature measuring hole of the workpiece to measure the core temperature of the workpiece in real time. By setting up an automatic winding mechanism, it is convenient to pull out and extend the extended length of the thermocouple cable and to automatically rewind the thermocouple cable, thereby facilitating the transfer of the workpiece inside the multi-purpose furnace, and further cooperating with the guide traction mechanism, the extension and contraction of the thermocouple cable can be guided in a direction, solving the problem that the thermocouple cable is easily entangled with the transmission mechanism inside the multi-purpose furnace; in addition, by arranging a support rod on the bracket to cooperate with the locking mechanism to lock the thermocouple cable, it can be ensured that the double-branch thermocouple will not be affected by external force after being inserted into the temperature measuring hole of the workpiece, thereby effectively avoiding the problem of displacement or falling off of the double-branch thermocouple, so as to realize accurate temperature detection of large workpieces located in the multi-purpose furnace.

[0038] In some embodiments, reference Figure 6 The lower surface of the furnace door 15 of the multi-purpose furnace 1 is provided with a first positioning groove 151 that is recessed upward. The first positioning groove 151 is located directly opposite the support rod 121. This facilitates the insertion of the stainless steel wire and the thermocouple cable into the first positioning groove when the furnace door is closed. The thermocouple cable will not be cut off when the furnace door is closed downward. In addition, the first positioning groove can be used to form a gap connecting the heating chamber and the front chamber, which also serves as a ventilation function.

[0039] As an improved implementation method, refer to Figure 6The door frame 16 of the multi-purpose furnace 1 is provided with a second, downwardly recessed positioning groove 161. The second positioning groove 161 and the first positioning groove 151 together form a hole for the thermocouple cable 21 to pass through. Providing the second positioning groove on the door frame and forming a hole with the first positioning groove further facilitates the smooth insertion of the stainless steel wire and the thermocouple cable, preventing them from being pinched or cut.

[0040] Furthermore, as an example, Figure 6 As shown, the cross-sectional shape of the first positioning groove 151 is semicircular, and the cross-sectional shape of the second positioning groove 161 is semicircular. In this way, when the furnace door is closed downward, the friction with the stainless steel wire can be reduced, and the pulling force on the support rod can be reduced.

[0041] In some specific embodiments, reference Figure 2 The automatic winding mechanism 3 includes a capstan 31, a spiral spring 32, and a tubular support column 33 fixedly connected to the side furnace wall of the front chamber 11. The capstan 31 has a positioning ring 311 for winding and connecting the thermocouple cable 21. One end of the spiral spring 32 is connected to the tubular support column 33, and the other end of the spiral spring 32 is connected to the positioning ring 311. By winding the portion of the thermocouple cable that needs to be retracted around the capstan, the installed spiral spring can ensure that the capstan can rotate back to its initial position when it is not under force or under little force after rotation, ensuring that the thermocouple cable can be pulled out and retracted, and preventing the thermocouple cable from being too long and contacting the transmission mechanism. As an example, the diameter of the capstan 31 is 0.6m. In this way, the diameter of the capstan is large enough that a turn of the thermocouple cable wound around the capstan is approximately 1.8m long, which is sufficient for use and convenient for freely pulling out or rewinding the thermocouple cable as the workpiece is transferred.

[0042] In some specific embodiments, the temperature probe 22 is a sheathed thermocouple, which can be securely mounted on the workpiece and is not easily dislodged or removed. For example, the diameter of the temperature probe 22 is 1.5 mm. The sheathed thermocouple is made of high-temperature-resistant stainless steel and can withstand significant tension, allowing the thermocouple cable to be directly pulled to drive the capstan.

[0043] In some specific embodiments, reference Figure 1 、 Figures 4 to 7The guide and traction mechanism 5 includes a counterweight 51, a steel wire rope 52, a first fixed pulley 53, a second fixed pulley 54, and a third fixed pulley 55. The first fixed pulley 53 is rotatably mounted on the side furnace wall of the front chamber 11, the second fixed pulley 54 is rotatably mounted on the top furnace wall of the front chamber 11, and the third fixed pulley 55 is rotatably mounted on the upper portion of the lifting frame 17 in the front chamber 11. The second fixed pulley 54, the third fixed pulley 55, and the support rod 121 are located in the same vertical plane. One end of the steel wire rope 52 is connected to the counterweight 51, and the other end of the steel wire rope 52 is sequentially overlapped with the first fixed pulley 53, the second fixed pulley 54, and the third fixed pulley 55 before being connected to the thermocouple cable 21. By adding a counterweight at the end of the steel wire rope, the thermocouple cable can be pulled. The first fixed pulley, the second fixed pulley and the third fixed pulley respectively play a guiding role, among which the first fixed pulley can guide the steel wire rope with the added weight downward along the side furnace wall of the front chamber without hindering the operation of the transmission mechanism; and the third fixed pulley fixed on the lifting frame is in the same vertical plane as the support rod, the second fixed pulley and the first positioning groove on the furnace door, which can play a positioning role, making it convenient to guide the steel wire rope to tighten the stainless steel wire protecting the thermocouple cable, ensuring that the stainless steel wire and the thermocouple cable are aligned with the first positioning groove on the furnace door, to avoid being pinched off when closing the furnace door.

[0044] As an improved implementation method, refer to Figure 1 、 Figures 4 to 7 The steel wire rope 52 is connected to the thermocouple cable 21 through a locking assembly 6. A stainless steel wire 7 is connected between the locking assembly 6 and the locking mechanism 4. The length of the thermocouple cable 21 between the locking assembly 6 and the locking mechanism 4 is longer than the length of the stainless steel wire 7. The locking assembly provided can securely connect the steel wire rope, the thermocouple cable, and the stainless steel wire together. In addition, since the section of thermocouple cable between the locking assembly and the locking mechanism is longer than the stainless steel wire, under the action of gravity, this section of thermocouple cable is naturally drooping, thereby ensuring that after the workpiece enters the heating chamber of the multi-purpose furnace, when the furnace door is closed, the furnace door will first press on the stainless steel wire, preventing the furnace door from directly pressing and pulling the thermocouple cable, and the tension of the steel wire rope mainly acts on the stainless steel wire, thereby protecting the thermocouple cable.

[0045] In some specific embodiments, such as Figure 4As shown, the locking assembly 6 includes a U-shaped locking piece 61 for clamping the thermocouple cable 21 and a bolt and nut assembly 62 installed at the opening of the U-shaped locking piece 61. The bolt and nut assembly 62 is connected to a hanging plate 63, and the hanging plate 63 is provided with a binding hole 631 for connecting the steel wire rope 52. The bolt and nut assembly can be used to lock the U-shaped locking piece to clamp and fix the thermocouple cable, and the hanging plate can be installed and fixed at the same time as the U-shaped locking piece is locked. The binding holes in the hanging plate make it easy to bind the steel wire rope and stainless steel wire to the hanging plate.

[0046] In some specific embodiments, the stainless steel wire 7 is 316 stainless steel wire with a diameter of 2 mm, which has good toughness and is resistant to high temperatures. Even if part of it enters the heating chamber and is heated to a very high temperature, it is not afraid of breaking.

[0047] In some specific embodiments, reference Figure 3 The locking mechanism 4 includes a C-shaped clamp 41 and a locking rod 42 for enclosing and clamping the support rod 121. The two ends of the C-shaped clamp 41 are respectively provided with a first connecting end 411 and a second connecting end 412. The first connecting end 411 is provided with a threaded hole 413, and the second connecting end 412 is provided with an assembly hole 414 coaxially distributed with the threaded hole 413. The peripheral wall surface of the locking rod 42 is provided with a thread 421 that cooperates with the threaded hole 413. The end of the locking rod 42 is provided with a locking block 422, and the locking block 422 is penetrated by a locking hole 423. Specifically, as an example, the shape of the locking hole 423 is circular. By twisting and rotating the locking rod, the C-shaped clamp can be locked and fixed to the support rod; by providing a locking hole on the locking block, it is convenient to tie the thermocouple cable and the stainless steel wire to the locking block respectively.

[0048] Directions:

[0049] (1)Reference Figure 1 , place the workpiece 9 (such as a large hot working mold) on the bracket 12, send the workpiece 9 into the front chamber 11 of the multi-purpose furnace 1, insert two temperature measuring probes 22 into the surface temperature measuring hole and the core temperature measuring hole on the workpiece 9 respectively, and connect the output end of the thermocouple cable 21 to the temperature control instrument 8 outside the multi-purpose furnace 1.

[0050] (2)Reference Figure 5 and Figure 6, open the furnace door 15, put the workpiece 9 into the heating chamber 13, and close the furnace door. Since the thermocouple cable 21 is fixedly connected to the support rod 121 at one end near the two temperature probes 22 through the locking mechanism 4, as the bracket 12 moves, the support rod 121 can automatically pull out the thermocouple cable 21 of a suitable length. When the furnace door 15 is closed, under the guiding and traction action of the guiding and traction mechanism 5, the thermocouple cable 21 and the stainless steel wire 7 are embedded in the first positioning groove 151 at the bottom of the furnace door 15 and will not be pinched off. Moreover, the two temperature probes 22 are not easily displaced or fallen off.

[0051] (3) After that, the workpiece 9 is heated and the surface temperature and core temperature of the workpiece are monitored at the same time: Since the thermal conductivity of the hot working mold is relatively poor, a large temperature difference is easily generated during the heating process. The larger the mold, the more obvious the temperature difference between the surface and the core, and the greater the stress generated. The greater the stress, the more likely the mold will deform and crack. Therefore, two stages of preheating are often added during the quenching and heating process of the hot working mold. The first stage of preheating is usually in the temperature range of 600-650℃. When the temperature difference between the mold surface and the core is less than 110℃, the temperature is raised to the second stage of preheating. The second stage of preheating is usually in the temperature range of 820-850℃. When the temperature difference between the mold surface and the core is less than 15℃, the temperature is raised to the quenching temperature of the mold. After the temperature in the furnace reaches the set austenitizing temperature, the temperature difference between the mold surface and the core is less than 15℃, and then heated for 30 minutes before quenching. In this way, formulating the process according to the temperature difference between the surface and the core can not only reduce the risk of deformation and cracking, but also avoid waste caused by excessive heating time, especially in the final austenitization stage. If the holding time is too long, it will lead to coarse quenching structure, increase the risk of cracking during quenching, and also have an adverse effect on the life of the mold.

[0052] (4) After the insulation is completed, refer to Figure 1 , open the furnace door 15, transfer the workpiece 9 from the heating chamber 13 to the front chamber 11, and close the furnace door 15. During the transfer of the workpiece 9 from the heating chamber 13 to the front chamber 11, the thermocouple cable 21 can be automatically reeled under the rewinding force of the spiral spring 32, thereby preventing the thermocouple cable 21 from being too long and getting entangled with the transmission mechanism.

[0053] (5)Reference Figure 7, then, lower the lifting frame 17 and immerse the workpiece 9 in the oil pool 14 below the front chamber 11 for quenching. The difficulty of using a multi-purpose furnace for oil-cooling quenching of large molds is that due to the fast cooling rate of the oil and the large thickness of the mold, the temperature difference between the surface and the core is particularly large. The greater the temperature difference, the greater the thermal stress generated, and the greater the risk of mold cracking. Therefore, when the mold surface temperature reaches 400℃~450℃, it must be kept isothermal for a period of time. When quenching with oil cooling, the workpiece can be lifted from the oil pool and wait until the temperature difference between the surface temperature and the core temperature is less than 110℃, and then the workpiece is immersed in oil again to continue cooling until the quenching is completed. During the downward movement of the workpiece 9, the thermocouple cable 21 will be stretched again and will be wound up by the automatic winding mechanism 3 when the workpiece 9 moves upward.

[0054] Excessively high isothermal temperatures can produce poor quenching microstructures, impacting mold performance; while excessively low isothermal temperatures fail to reduce thermal stress and can easily cause mold cracking. This demonstrates the importance of being able to effectively and accurately detect both the surface and core temperatures of a workpiece. The present invention utilizes dual thermocouples to measure real-time temperature changes at both the surface and core of the workpiece, enabling timely adjustment of heat treatment process parameters. This allows for a reasonable heat treatment process, resulting in a favorable quenching microstructure while minimizing the risk of cracking. Furthermore, this prevents thermocouple displacement or detachment during workpiece transfer.

[0055] The above embodiments are merely illustrative of the concepts and technical solutions of this utility model and are not intended to limit this utility model. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by persons skilled in the art without departing from the spirit and technical concepts disclosed in this utility model shall be covered by the claims of this utility model.

[0056] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation method can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A box-type carbonitriding multi-purpose furnace with precise temperature detection, including a multi-purpose furnace, characterized in that: The multi-purpose furnace is provided with a double-branch thermocouple inside, and the double-branch thermocouple includes a thermocouple cable and two temperature probes respectively connected to one end of the thermocouple cable, and the other end of the thermocouple cable is connected to the temperature control instrument located outside the multi-purpose furnace; the side furnace wall located in the front chamber of the multi-purpose furnace is provided with an automatic winding mechanism for automatically rewinding the thermocouple cable, and part of the thermocouple cable located in the multi-purpose furnace is wound and connected with the automatic winding mechanism; the bracket located inside the multi-purpose furnace is provided with a support rod, and a locking mechanism is installed on the upper part of the support rod, and the thermocouple cable is connected to the locking mechanism at one end close to the two temperature probes; the front chamber is provided with a guide traction mechanism, and the guide traction mechanism is connected to the thermocouple cable located between the locking mechanism and the automatic winding mechanism.

2. The box-type multi-purpose carbonitriding furnace with precise temperature detection according to claim 1 is characterized in that: A first positioning groove that is concave upward is provided on the lower surface of the furnace door of the multi-purpose furnace, and the first positioning groove is located opposite to the support rod.

3. The box-type multi-purpose carbonitriding furnace with precise temperature detection according to claim 2 is characterized in that: A door frame located at the furnace door of the multi-purpose furnace is correspondingly provided with a second positioning groove that is recessed downward, and the second positioning groove and the first positioning groove together form a hole for the thermocouple cable to pass through.

4. The box-type multi-purpose carbonitriding furnace with precise temperature detection according to claim 1 is characterized in that: The temperature measuring probe is an armored thermocouple.

5. The box-type multi-purpose carbonitriding furnace with precise temperature detection according to any one of claims 1 to 4, characterized in that: The automatic winding mechanism includes a capstan, a spiral spring, and a tubular support column fixedly connected to the side furnace wall of the front chamber. The capstan has a positioning ring for winding and connecting the thermocouple cable. One end of the spiral spring is connected to the tubular support column, and the other end of the spiral spring is connected to the positioning ring.

6. The box-type multi-purpose carbonitriding furnace with precise temperature detection according to any one of claims 1 to 4, characterized in that: The guide and traction mechanism includes a counterweight, a steel wire rope, a first fixed pulley, a second fixed pulley and a third fixed pulley. The first fixed pulley is rotatably mounted on the side furnace wall of the front chamber, the second fixed pulley is rotatably mounted on the top furnace wall of the front chamber, and the third fixed pulley is rotatably mounted on the upper part of the lifting frame in the front chamber. The second fixed pulley, the third fixed pulley and the support rod are located in the same vertical plane. One end of the steel wire rope is connected to the counterweight, and the other end of the steel wire rope is sequentially overlapped with the first fixed pulley, the second fixed pulley and the third fixed pulley and then connected to the thermocouple cable.

7. The box-type multi-purpose carbonitriding furnace with precise temperature detection according to claim 6 is characterized in that: The steel wire rope is connected to the thermocouple cable through a locking assembly. A stainless steel wire is connected between the locking assembly and the locking mechanism. The length of the thermocouple cable between the locking assembly and the locking mechanism is longer than the length of the stainless steel wire.

8. The box-type multi-purpose carbonitriding furnace with precise temperature detection according to claim 7, characterized in that: The locking assembly includes a U-shaped locking plate for clamping the thermocouple cable and a bolt and nut assembly installed at the opening of the U-shaped locking plate. The bolt and nut assembly is connected to a hanging plate, and the hanging plate is provided with a binding hole for connecting the steel wire rope.

9. The box-type multi-purpose carbonitriding furnace with precise temperature detection according to claim 7, characterized in that: The stainless steel wire is 316 stainless steel wire with a diameter of 2 mm.

10. The box-type multi-purpose carbonitriding furnace with precise temperature detection according to any one of claims 1 to 4, characterized in that: The locking mechanism includes a C-shaped clamp and a locking rod for enclosing and clamping the support rod, and the two ends of the C-shaped clamp are respectively provided with a first connecting end and a second connecting end, the first connecting end is provided with a threaded hole, and the second connecting end is provided with an assembly hole coaxially distributed with the threaded hole, the peripheral wall surface of the locking rod is provided with a thread matching the threaded hole, and the end of the locking rod is provided with a locking block, and the locking block is provided with a locking hole.

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