Tunnel type annealing furnace

Abstract

The invention provides a tunnel type annealing furnace, and relates to the technical field of heat treatment equipment. The tunnel type annealing furnace comprises an annealing furnace body, a conveying device, a heating device, a cooling device, an atmosphere protection device and a temperature control system, the annealing furnace body is of a long-tunnel-shaped structure, and a preheating area, a heating area and a cooling area are sequentially arranged in the annealing furnace body. A heating device is arranged in the heating area, a conveying device is arranged in the annealing furnace body, the cooling area comprises a rapid cooling area and a slow cooling area, the rapid cooling area is arranged at the front part of the cooling area and is close to one side of the heating area, the slow cooling area is arranged at the rear part of the cooling area and is far away from the heating area, and a sectional combined cooling device is arranged in the cooling area; and an atmosphere protection device for controlling a protective atmosphere is also arranged in the heating area. The mode of combining rapid cooling and slow cooling is adopted, so that the cooling process is efficient and uniform, and the thermal stress problem caused by temperature difference can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of heat treatment equipment, and in particular to a tunnel annealing furnace. Background Art

[0002] Tunnel annealing furnace is an important heat treatment equipment, which is widely used in the annealing process of metal materials. Through the annealing process, the internal structure of the metal material is optimized, and its mechanical properties, hardness and toughness are significantly improved. In industrial production, tunnel annealing furnace is particularly suitable for workpieces with complex shapes and strict heat treatment requirements, such as grooved pipe fittings and malleable cast iron pipe fittings, because it can realize continuous processing and high-efficiency processing of workpieces.

[0003] Tunnel annealing furnaces in the prior art can be used to gradually heat and cool workpieces. Among them, the design of the cooling zone usually adopts a single cooling method, such as spray cooling or natural air cooling, to reduce the temperature of the workpiece. However, for workpieces such as grooved pipe fittings and malleable cast iron pipe fittings with complex structures and high requirements for cooling uniformity, this single cooling design is prone to uneven cooling during the cooling process. Once the temperature gradient on the surface and inside of the workpiece is too large, it may cause significant thermal stress, resulting in cracking or deformation of the workpiece, seriously affecting the quality and subsequent performance of the workpiece.

[0004] The cooling zone design of the existing tunnel annealing furnace fails to fully meet the demand for combining rapid cooling with uniform slow cooling during the cooling process of grooved pipe fittings or malleable cast iron pipe fittings. Due to the single cooling method, the workpiece is prone to uneven cooling during the cooling process, resulting in excessive local temperature differences, which in turn causes quality defects in the workpiece. Summary of the invention

[0005] The present application provides a tunnel annealing furnace, which is used to solve the problem that the tunnel annealing furnace in the prior art has a single cooling method in the cooling zone, which leads to uneven cooling of the workpiece during the temperature reduction process.

[0006] The present application is implemented as follows: a tunnel annealing furnace includes an annealing furnace body, a conveying device, a heating device, a cooling device, an atmosphere protection device and a temperature control system;

[0007] The annealing furnace body is in a long tunnel-like structure, and a preheating zone, a heating zone and a cooling zone are sequentially arranged inside along the length direction; the heating zone is provided with the heating device for heating the workpiece, and the annealing furnace body is provided with the conveying device for conveying the workpiece. The cooling zone includes a rapid cooling zone and a slow cooling zone. The rapid cooling zone is arranged in front of the cooling zone and adjacent to one side of the heating zone, and is used to quickly reduce the surface temperature of the workpiece. The slow cooling zone is arranged at the rear of the cooling zone and away from the heating zone, and is used to gradually release the internal heat of the workpiece and reduce the generation of thermal stress. A segmented combined cooling device is arranged in the cooling zone; the heating zone is also provided with the atmosphere protection device for controlling the protective atmosphere; the temperature control system includes a plurality of temperature sensors arranged in the preheating zone, the heating zone and the cooling zone, and a PLC controller electrically connected to the heating device, and the PLC controller adjusts the output power of the heating device in real time by receiving the feedback signal of the temperature sensor.

[0008] In an optional embodiment, the conveying device includes a conveying chain arranged at the inner bottom of the annealing furnace body and extending along the length direction of the annealing furnace body, the inner bottom of the annealing furnace body is provided with grooves arranged along the length direction, the conveying chain is installed in the grooves, and a plurality of connecting rods arranged vertically and extending out of the grooves are arranged at intervals on the conveying chain, and the conveying chain is connected to a supporting cross bar kept at a distance from the conveying chain through the connecting rods.

[0009] In an optional embodiment, the heating device includes a plurality of heating units arranged on the top and both sides of the heating zone, the heating units are connected to the inner furnace wall of the annealing furnace body through a fixed bracket, and are arranged at intervals along the length direction of the heating zone, each of the heating units is electrically connected to the PLC controller, and the PLC controller is set in a control box outside the annealing furnace body.

[0010] In an optional embodiment, the cooling device includes a first cooling device arranged in the rapid cooling zone and adopting a combination of spray cooling and air cooling, and a second cooling device arranged in the slow cooling zone and performing air cooling in cooperation with a guide cover. The first cooling device includes a spray cooling device and a high-speed air cooling device, and the second cooling device includes a low-speed air cooling device. The spray cooling device is arranged at the top and both sides of the rapid cooling zone, and the high-speed air cooling device is arranged below the rapid cooling zone. The guide cover for guiding the uniform distribution of the air-cooling airflow is arranged in the slow cooling zone. The guide cover is an arc-shaped structure, and guide holes are evenly opened on the guide cover. The low-speed air cooling device is arranged at the top of the slow cooling zone and is located above the guide cover.

[0011] In an optional embodiment, the atmosphere protection device includes a protective gas delivery pipe and a plurality of protective gas nozzles, the protective gas delivery pipe is arranged in the upper area of ​​the heating zone and arranged along the length direction of the heating zone, the air inlet end of the protective gas delivery pipe extends upward from the annealing furnace body, and a flow control valve is provided on the pipeline of the protective gas delivery pipe outside the annealing furnace body, a plurality of the protective gas nozzles are evenly arranged on the protective gas delivery pipe, and the protective gas delivery pipe is connected to a protective gas source.

[0012] In an optional embodiment, the nozzle of the protective gas nozzle is directed vertically downward and perpendicular to the conveying direction of the workpiece.

[0013] In an optional embodiment, the cooling zone is provided with the temperature sensor in the rapid cooling zone and the slow cooling zone respectively, and the temperature sensor is also provided at a position between the rapid cooling zone and the slow cooling zone.

[0014] In an optional embodiment, a cover plate is provided on the groove, and a through hole is formed on the cover plate for the connecting rod to extend out of the groove, and the through hole is arranged along the length direction of the cover plate. There are two groups of conveying chains, and the two groups of conveying chains are arranged symmetrically on the left and right and are driven synchronously by a motor. The number of the grooves is two and they are arranged corresponding to the two groups of conveying chains. The conveying chains are respectively connected with sprockets at the front and rear ends in the conveying direction, and a transmission shaft is fixedly connected between the two sprockets at the front ends of the two groups of conveying chains and between the two sprockets at the rear ends. The motor is fixedly installed on the outside of the annealing furnace body, and the output end of the motor is connected to one of the transmission shafts.

[0015] In an optional embodiment, the annealing furnace body is provided with a furnace body inlet at the outer end of the preheating zone, and a furnace body outlet at the outer end of the cooling zone. The annealing furnace body is provided with heat insulation plates at the furnace body inlet and at the junction between the heating zone and the cooling zone, respectively. A workpiece conveying port for the workpiece to pass through during transportation is provided at the lower end of the heat insulation plate, and a protective gas nozzle for forming a gas curtain at the workpiece conveying port is provided on the inner side of the heat insulation plate above the workpiece conveying port, and downward wind holes are provided on the protective gas nozzle. The air inlet end of the protective gas nozzle extends out of the annealing furnace body and is connected to the protective gas conveying pipeline outside the annealing furnace body.

[0016] Compared with the prior art, this application has the following beneficial effects:

[0017] 1. The tunnel annealing furnace of the present application adopts a design in which the cooling zone is divided into a rapid cooling zone and a slow cooling zone, and a segmented combined cooling device is provided, which can realize the staged control of the workpiece during the cooling process, and quickly reduce the surface temperature of the workpiece by arranging the rapid cooling zone close to the heating zone, and gradually release the internal heat of the workpiece by arranging the slow cooling zone far away from the heating zone. This combination of rapid cooling and slow cooling makes the cooling process efficient and uniform, which can significantly reduce the thermal stress problem caused by temperature difference, thereby reducing the cracking or deformation of the workpiece, and further provides reliable technical guarantee for grooved pipe fittings, malleable cast iron pipe fittings and other workpieces with high requirements for cooling uniformity.

[0018] 2. The present application sets an atmosphere protection device in the heating zone, which can provide protective gas to the heating zone during the high-temperature heating process to control the protective atmosphere and prevent oxidizing air from entering the heating zone during the high-temperature heating process, causing surface quality defects of the workpiece due to oxidation, thereby improving the overall stability of the annealing process. The atmosphere protection device can effectively control the atmosphere environment, which is more suitable for the processing needs of workpieces with strict surface quality requirements such as grooved pipe fittings and malleable cast iron pipe fittings.

[0019] 3. The temperature control system of the present application is combined with the setting of multiple temperature sensors and PLC controllers, so that the temperature sensors are distributed in various areas, which can realize real-time monitoring of the temperature of the preheating zone, heating zone and cooling zone, and can dynamically control the heating device in the heating zone to stabilize the temperature of the heating zone within the set range, thereby improving the accuracy of temperature control during the heat treatment of the workpiece, and thus better adapting to the heating requirements of heat treatment of different workpieces, making the use of the tunnel annealing furnace more flexible. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 It is a schematic diagram of the overall structure of a tunnel annealing furnace provided in one embodiment of the present application.

[0022] Figure 2 It is a schematic diagram of the overall structure of the tunnel annealing furnace provided in one embodiment of the present application from another angle.

[0023] Figure 3 It is a schematic diagram of the arrangement of a conveying device provided in an embodiment of the present application in a tunnel annealing furnace.

[0024] Figure 4It is a schematic diagram of the arrangement of a conveying device in a cooling zone of a tunnel annealing furnace provided in one embodiment of the present application.

[0025] Figure 5 This is a schematic diagram from another perspective of a conveying device of a tunnel annealing furnace provided in an embodiment of the present application in a cooling zone.

[0026] Figure 6 It is a schematic diagram of the arrangement of a conveying device of a tunnel annealing furnace in a heating zone according to an embodiment of the present application.

[0027] Figure 7 It is a schematic diagram of the overall structure of a conveying device provided in one embodiment of the present application.

[0028] In the figure, 100 is an annealing furnace body; 101 is a groove; 102 is a cover plate; 103 is a through hole; 110 is a preheating zone; 120 is a heating zone; 130 is a cooling zone; 131 is a rapid cooling zone; 132 is a slow cooling zone; 200 is a conveying device; 210 is a conveying chain; 211 is a connecting rod; 212 is a supporting cross bar; 220 is a sprocket; 230 is a transmission shaft; 240 is a motor; 300 is a heating device; 310 is a conveying chain; 311 is a connecting rod; 312 is a supporting cross bar; 310 is a sprocket; 310 is a transmission shaft; 310 is a motor; 311 is a heating device; 312 is a conveying chain; 312 is a connecting rod; 312 is a supporting cross bar ... - heating unit; 320- fixed bracket; 400- cooling device; 410- spray cooling device; 420- high-speed air cooling device; 430- low-speed air cooling device; 440- guide cover; 500- atmosphere protection device; 510- protective gas delivery pipeline; 520- protective gas nozzle; 600- temperature sensor; 700- heat insulation board; 710- workpiece delivery port; 720- protective gas nozzle; 800- control box. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0030] like Figure 1-Figure 7 As shown, an embodiment of the present application provides a tunnel annealing furnace that can be used for annealing of metal materials or parts (such as grooved pipe fittings and malleable cast iron pipe fittings). The tunnel annealing furnace includes an annealing furnace body 100, a conveying device 200, a heating device 300, a cooling device 400, an atmosphere protection device 500 and a temperature control system.

[0031] The annealing furnace body 100 is a long tunnel-shaped structure, and a preheating zone 110, a heating zone 120 and a cooling zone 130 are sequentially arranged inside along the length direction; a heating device 300 for heating the workpiece is arranged in the heating zone 120, and a conveying device 200 for conveying the workpiece is arranged in the annealing furnace body 100. The cooling zone 130 includes a rapid cooling zone 131 and a slow cooling zone 132. The rapid cooling zone 131 is arranged in front of the cooling zone 130 and adjacent to one side of the heating zone 120, and is used to quickly reduce the surface temperature of the workpiece. The slow cooling zone 132 is arranged in the cooling zone 130 is located at the rear of the preheating zone 110 and away from the heating zone 120, and is used to gradually release the internal heat of the workpiece and reduce the generation of thermal stress. A segmented combined cooling device 400 is provided in the cooling zone 130; an atmosphere protection device 500 for controlling the protective atmosphere is also provided in the heating zone 120; the temperature control system includes a plurality of temperature sensors 600 arranged in the preheating zone 110, the heating zone 120 and the cooling zone 130, and a PLC controller electrically connected to the heating device 300, and the PLC controller adjusts the output power of the heating device 300 in real time by receiving the feedback signal of the temperature sensor 600. The tunnel annealing furnace of the embodiment of the present application optimizes the heating and cooling efficiency of the workpiece during the annealing process through reasonable structural design and functional zoning, especially under the combined control of rapid cooling and slow cooling, which can improve the quality of the annealing process and is suitable for metal workpieces that require efficient and uniform annealing treatment.

[0032] When using the tunnel annealing furnace provided in the embodiment of the present application, the workpieces to be annealed are first placed one by one on the conveying device 200. The conveying device 200 sequentially conveys the workpieces into the preheating zone 110, the heating zone 120 and the cooling zone 130 along the length direction of the annealing furnace body 100 at a preset conveying speed.

[0033] In the preheating zone 110 , the workpiece is gradually heated up by heat conduction and heat radiation, which reduces the temperature difference transition from room temperature to high temperature, reduces the thermal stress of the workpiece, and lays a temperature foundation for the subsequent heating process.

[0034] In the heating zone 120, the workpiece is uniformly heated at high temperature by the heating device 300. At the same time, under the action of the atmosphere protection device 500, the protective gas (nitrogen or inert gas) fills the heating zone, isolating the oxygen in the outside air and preventing the workpiece from being oxidized at high temperature, thereby improving the surface quality of the workpiece. During the heating process, the temperature control system monitors the temperature of the heating zone 120 in real time, and dynamically adjusts the output power of the heating device 300 through the PLC controller to ensure that the workpiece can be heated stably and uniformly.

[0035] After entering the cooling zone 130, the workpiece passes through the rapid cooling zone 131 and the slow cooling zone 132 in sequence. In the rapid cooling zone 131, the high temperature on the surface of the workpiece can be rapidly reduced by means of efficient spray cooling and forced air cooling to reduce oxidation problems caused by long exposure to high temperatures. In the slow cooling zone 132, the workpiece can gradually release internal heat through natural cooling or a low-speed air cooling device to achieve a uniform transition between the surface and internal temperatures, reduce thermal stress concentration, and avoid cracking or deformation of the workpiece due to uneven cooling.

[0036] The tunnel annealing furnace provided in the embodiment of the present application adopts a design in which the cooling zone 130 is divided into a rapid cooling zone 131 and a slow cooling zone 132, and a segmented combined cooling device 400 is provided, which can realize staged control of the workpiece during the cooling process, and quickly reduce the surface temperature of the workpiece by arranging the rapid cooling zone 131 close to the heating zone 120, and gradually release the internal heat of the workpiece by arranging the slow cooling zone 132 far away from the heating zone 120. This combination of rapid cooling and slow cooling makes the cooling process both efficient and uniform, and can significantly reduce the thermal stress problem caused by temperature difference, thereby reducing the cracking or deformation of the workpiece, and further provides reliable technical guarantee for grooved pipe fittings, malleable cast iron pipe fittings and other workpieces with high requirements for cooling uniformity.

[0037] At the same time, in this embodiment, an atmosphere protection device 500 is set in the heating zone 120, which can provide protective gas to the heating zone 120 during the high-temperature heating process to control the protective atmosphere and prevent oxidizing air from entering the heating zone during the high-temperature heating process to cause surface quality defects of the workpiece due to oxidation, thereby improving the overall stability of the annealing process. Moreover, the atmosphere protection device 500 can be used to effectively control the atmosphere environment, which is more suitable for the processing needs of workpieces with strict surface quality requirements such as grooved pipe fittings and malleable cast iron pipe fittings.

[0038] In addition, the temperature control system of the embodiment of the present application is combined with the setting of multiple temperature sensors 600 and a PLC controller, so that the temperature sensors are distributed in various areas, which can realize real-time monitoring of the temperatures of the preheating zone 110, the heating zone 120 and the cooling zone 130, and can dynamically control the heating device 300 in the heating zone 120, so that the temperature of the heating zone is stabilized within the set range, thereby improving the accuracy of temperature control of the workpiece heat treatment heating process, and thus better adapting to the heating requirements of different workpiece heat treatments, making the use of the tunnel annealing furnace more flexible.

[0039] In some embodiments, the conveying device 200 includes a conveying chain 210 arranged at the bottom inner of the annealing furnace body 100 and extending along the length direction of the annealing furnace body 100. The conveying chain 210 is made of a high-temperature resistant metal material, and the surface of the chain can be coated with a high-temperature resistant protective coating. The inner bottom of the annealing furnace body 100 is provided with grooves arranged along the length direction. The conveying chain 210 is installed in the grooves 101. A plurality of connecting rods 211 arranged vertically and extending out of the grooves 101 are arranged at intervals on the conveying chain 210. The conveying chain 210 is connected to a supporting cross bar 212 which is spaced apart from the conveying chain 210 through the connecting rods 211.

[0040] In the above embodiment, the conveyor chain 210 is hidden and installed in the groove 101 at the bottom of the annealing furnace body 100, and the groove 101 is arranged along the length direction of the annealing furnace. This design method can form a natural heat insulation area at the bottom of the furnace body, reducing the direct impact of high temperature on the conveyor chain. The connecting rods 211 arranged at intervals on the conveyor chain 210 extend vertically out of the groove 101 and are connected to the supporting crossbar 212. This method can form a support structure for the workpiece. The supporting crossbar 212 maintains an appropriate interval with the conveyor chain 210, so that the workpiece is always located on the support surface of the crossbar 212 during the conveying process.

[0041] In some embodiments, the heating device 300 includes a plurality of heating units 310 arranged on the top and both sides of the heating zone 120. The heating units 310 are connected to the inner furnace wall of the annealing furnace body 100 through a fixed bracket 320 and are arranged at intervals along the length direction of the heating zone 120. The heating units 310 can use resistance heating elements, which can not only heat up quickly, but also have high temperature control accuracy, which is suitable for annealing processes that require precise temperature control. In addition, the use of resistance heating elements as heating units also has the advantage of low maintenance cost, which is suitable for the modular arrangement of tunnel annealing furnaces. Each heating unit 310 is electrically connected to a PLC controller, which is arranged in a control box 800 outside the annealing furnace body 100.

[0042] In the above embodiment, the heating unit 310 is arranged at the top and both sides of the heating zone 120, and is connected to the inner furnace wall of the annealing furnace body 100 through a fixed bracket 320. This three-sided surrounding layout can effectively improve the heating uniformity of the workpiece. The heating unit on the top can provide vertical heat radiation, so that the upper surface of the workpiece can obtain a uniform heat supply, while the heating units on both sides can supplement the lateral heat distribution to prevent the problem of uneven heating due to insufficient heat on both sides of the workpiece. In application, through the three-sided surrounding heating method, the workpiece can be subjected to uniform heat radiation and heat conduction in the entire heating zone 120, avoiding local overheating or overcooling, thereby further improving the quality of the annealing process. Such a design is more suitable for workpieces with complex shapes or large sizes (such as grooved pipe fittings or malleable cast iron pipe fittings), and can ensure the uniformity and stability of its overall heating.

[0043] In addition, in the above embodiment, the heating units 310 are arranged at intervals along the length direction of the heating zone 120, which can form a segmented heat supply mode, which can optimize the heat distribution of the heating zone 120. The segmented arrangement of the heating units 310 can adjust the power output of different heating units 310 according to the transmission speed and heat demand of the workpiece, so that the heat supply matches the heating demand of the workpiece. The interval arrangement can also effectively reduce the thermal interference between the heating units and improve the heat utilization rate. Moreover, during the transmission process, the workpiece can be gradually and evenly heated under the heating of the heating units at different positions, realizing an efficient and controllable heating process and improving the heating efficiency.

[0044] In some embodiments, the cooling device 400 includes a first cooling device provided in the rapid cooling zone 131 and using a combination of spray cooling and air cooling, and a second cooling device provided in the slow cooling zone 132 and using air cooling in cooperation with the air guide 440, wherein the first cooling device includes a spray cooling device 410 and a high-speed air cooling device 420, and the second cooling device includes a low-speed air cooling device 430. Optionally, the high-speed air cooling device 420 uses a high-speed axial flow fan or a centrifugal fan, and the wind speed can be controlled at 10 to 20 m / s; the low-speed air cooling device 430 uses a low-speed axial flow fan, and the wind speed can be controlled at 3 to 8 m / s. The spray cooling device 410 is arranged at the top and both sides of the rapid cooling zone 131, and is used to spray coolant on the surface of the workpiece from multiple directions. The high-speed air cooling device 420 is arranged below the rapid cooling zone 131, and is used to cool the bottom of the workpiece. The slow cooling zone 132 is provided with a guide cover 440 for guiding the uniform distribution of the air-cooling airflow. The guide cover 440 is an arc-shaped structure, and the guide holes are evenly opened on the guide cover 440. Specifically, the guide cover 440 can adopt a concave arc structure to guide the cooling airflow from the low-speed air cooling device 430 at the top to form a uniform airflow distribution close to the surface of the workpiece. The low-speed air cooling device 430 is arranged at the top of the slow cooling zone 132 and is located above the guide cover 440, and is used to form a soft airflow to achieve slow and uniform cooling. In actual applications, the high-speed air cooling device 420 and the low-speed air cooling device 430 can be electrically connected to the control box 800 for easy control.

[0045] In this embodiment, the rapid cooling zone 131 adopts a first cooling device, and the cooling efficiency of the rapid cooling zone 131 can be improved by cooperating with the spray cooling device 410 and the high-speed air cooling device 420. The spray cooling device 410 is arranged on the top and both sides of the rapid cooling zone 131, and can spray coolant on the surface of the workpiece from multiple directions, so that the coolant directly contacts the surface of the workpiece and quickly absorbs heat, while the high-speed air cooling device 420 is arranged below the rapid cooling zone 131, and can provide forced airflow to take away heat through airflow assistance, and further take away the heat generated by the evaporation of the coolant, thereby improving the overall cooling efficiency. This combination can effectively reduce the high temperature on the surface of the workpiece.

[0046] During use, after the workpiece enters the rapid cooling zone 131, the temperature can be quickly reduced from a high temperature to a safe temperature range, providing a good starting point for the subsequent slow cooling process. Moreover, this rapid cooling method can effectively prevent the oxidation problem of the workpiece during high temperature exposure, while avoiding thermal stress concentration caused by uneven temperature.

[0047] An arc-shaped air guide 440 and a low-speed air cooling device 430 are provided in the slow cooling zone 132. The use of the air guide 440 can effectively guide the cooling airflow to cover the workpiece. In use, the low-speed air cooling device 430 at the top of the slow cooling zone 132 is used to provide a uniform and soft cooling airflow, and the arc-shaped air guide 440 guides the airflow to the surface and both sides of the workpiece to form a stable airflow distribution and reduce the situation of insufficient local cooling. This method can not only gradually release the heat inside the workpiece, but also avoid the local temperature difference caused by airflow turbulence, thereby ensuring the smooth progress of the slow cooling process. Especially in the later stage of annealing, the setting of the slow cooling zone 132 can reduce the thermal stress caused by the large temperature difference between the inside and the surface of the workpiece, thereby improving the cooling quality and annealing effect of the workpiece.

[0048] This embodiment organically combines rapid cooling and slow cooling through the zoning design of the first cooling device and the second cooling device, and can meet the cooling requirements of the workpiece at different stages. The spray cooling device 410 and the high-speed air cooling device 420 of the rapid cooling zone 131 focus on the rapid drop in surface temperature, providing efficient initial cooling for high-temperature workpieces; the low-speed air cooling device 430 and the air guide hood 440 of the slow cooling zone 132 focus on the gradual release of internal heat to ensure a smooth transition of temperature.

[0049] In some embodiments, the atmosphere protection device 500 includes a protective gas delivery pipeline 510 and a plurality of protective gas nozzles 520. The protective gas delivery pipeline 510 is disposed in the upper area of ​​the heating zone 120 and arranged along the length direction of the heating zone 120, so that the protective gas can cover the entire heating area of ​​the workpiece when in use. The air inlet end of the protective gas delivery pipeline 510 extends upward from the annealing furnace body 100, and a flow control valve is provided on the pipeline of the protective gas delivery pipeline 510 outside the annealing furnace body 100. A plurality of protective gas nozzles 520 are evenly arranged on the protective gas delivery pipeline 510. The protective gas nozzles 520 can be spiral nozzles. During use, the gas flow resistance is small and is suitable for long-term use. The protective gas delivery pipeline 510 is connected to a protective gas source.

[0050] In the above embodiment, the protective gas delivery pipeline 510 is located in the upper area of ​​the heating zone 120, and the protective gas is ejected from the nozzle 520 to form a uniform downward airflow, which covers the surface of the workpiece and the surrounding space to avoid airflow dead corners. In this embodiment, the protective gas forms a stable protective atmosphere in the heating zone 120 through this arrangement, and prevents the invasion of the oxidizing atmosphere by isolating the outside air, which is beneficial to improving the surface quality of the workpiece. The protective gas nozzles 520 are evenly distributed on the protective gas delivery pipeline 510, and each nozzle independently sprays the protective gas downward, which improves the utilization efficiency of the protective gas and can ensure that the atmosphere protection effect runs through the entire heating process.

[0051] In addition, the air inlet end of the protective gas delivery pipeline 510 is arranged outside the annealing furnace body 100 and connected to the protective gas source, and a flow control valve is arranged on the pipeline, so that the design facilitates the adjustment of the gas flow. In actual use, according to the specifications and annealing process requirements, the flow control valve can be conveniently controlled to adjust the flow of the protective gas, effectively reducing the oxidation risk caused by insufficient gas flow, so that in the application process, the requirements for the protective atmosphere under different process conditions are met, while avoiding excessive waste of protective gas.

[0052] In some embodiments, the nozzle of the protective gas nozzle 520 is oriented vertically downward and perpendicular to the conveying direction of the workpiece, so that the protective gas ejected by the protective gas nozzle 520 can directly cover the entire upper surface of the workpiece. Such a spraying path reduces the coverage blind area caused by the deviation or diffusion of the airflow during the spraying process, and the gas directly contacts the surface of the workpiece to form a more stable protective atmosphere. Moreover, during use, it is possible to reduce the airflow disturbance caused by the transfer of the workpiece, and keep the protective gas forming a uniform covering layer on the surface of the workpiece. At the same time, this nozzle orientation makes it easier to control the airflow range and prevent gas waste or airflow diffusion.

[0053] In some embodiments, the cooling zone 130 is provided with temperature sensors 600 in the rapid cooling zone 131 and the slow cooling zone 132 respectively, and a temperature sensor 600 is also provided at a position between the rapid cooling zone 131 and the slow cooling zone 132. Optionally, the temperature sensor 600 can be an infrared temperature sensor.

[0054] In the above embodiment, by setting the temperature sensor 600 in the rapid cooling zone 131 and the slow cooling zone 132, the surface temperature change of the workpiece during the rapid cooling and slow cooling stages can be monitored in real time. The temperature in the rapid cooling zone 131 changes dramatically, and the setting of the temperature sensor 600 can provide real-time feedback, so as to facilitate the targeted control of the spray cooling device 410 and the high-speed air cooling device 420 to avoid overcooling or insufficient cooling. The temperature sensor 600 in the slow cooling zone 132 is responsible for monitoring the temperature state of the workpiece during the slow cooling process, so as to implement more appropriate air cooling through the low-speed air cooling device 430. In addition, in this embodiment, the temperature sensor 600 is set at the position between the rapid cooling zone 131 and the slow cooling zone 132, which can realize the temperature monitoring at the boundary position of the cooling zone, so as to timely discover the temperature connection problem between the rapid cooling and slow cooling stages, and then facilitate the adjustment of the cooling device 400 to ensure the smoothness of the temperature transition, which is conducive to avoiding the sudden change of the temperature difference between the rapid cooling and slow cooling stages, and making the cooling airflow and the heat release of the workpiece more coordinated.

[0055] In some embodiments, a cover plate 102 is provided on the groove 101, and a through hole 103 is opened on the cover plate 102 for the connecting rod 211 to extend out of the groove 101, and the through hole 103 is arranged along the length direction of the cover plate 102, and a heat insulation layer is provided on the entire groove wall surface of the groove 101. The cover plate 102 is a high temperature resistant heat insulation plate. There are two groups of conveying chains 210, and the two groups of conveying chains 210 are arranged symmetrically on the left and right and are synchronously driven by a motor 240. The number of grooves 101 is two and they are arranged corresponding to the two groups of conveying chains 210. The conveying chains 210 are respectively connected with sprockets 220 at the front and rear ends in the conveying direction, and a transmission shaft 230 is fixedly connected between the two sprockets 220 at the front ends of the two groups of conveying chains 210 and between the two sprockets 220 at the rear ends. The motor 240 is fixedly installed on the outside of the annealing furnace body 100, and the output end of the motor 240 is connected to one of the transmission shafts 230.

[0056] In the above embodiment, a cover plate 102 is provided on the groove 101, and a through hole 103 is provided on the cover plate 102 for the connecting rod 211 to extend out of the groove 101. Such a design can effectively protect the conveying chain 210. The cover plate 102 provided on the groove 101 forms a heat insulation barrier in structure, which helps to reduce the direct radiation of the high-temperature gas in the annealing furnace body 100 to the conveying chain 210 and reduce the impact on the operation of the conveying chain 210. The through hole 103 is arranged along the length direction of the cover plate 102, which can ensure that the connecting rod 211 extends smoothly without affecting the transmission of the workpiece. In addition, the two groups of conveying chains 210 arranged symmetrically on the left and right are synchronously driven by the motor 240 to provide more stable transmission support for the workpiece.

[0057] The sprockets 220 at the front and rear ends of the two transmission chains 210 are connected through the transmission shaft 230, and the output end of the motor 240 is connected to one of the transmission shafts 230. This transmission structure design can ensure the synchronous operation of the two transmission chains 210. In addition, the motor 240 is installed outside the annealing furnace body 100, which can avoid the influence of the high temperature environment on the motor performance, so that it can operate reliably and is also convenient for maintenance of the motor 240.

[0058] In some embodiments, the annealing furnace body 100 is provided with a furnace body inlet at the outer end of the preheating zone 110, and a furnace body outlet at the outer end of the cooling zone 130. The annealing furnace body 100 is provided with heat insulation plates 700 at the furnace body inlet and at the junction between the heating zone 120 and the cooling zone 130, respectively. A workpiece conveying port 710 is provided at the lower end of the heat insulation plate 700 for the workpiece to pass through during transportation. A protective gas nozzle 720 for forming a gas curtain at the workpiece conveying port 710 is provided on the inner side of the heat insulation plate 700 above the workpiece conveying port 710. The protective gas nozzle 720 is provided with downward air holes. The air inlet end of the protective gas nozzle 720 extends out of the annealing furnace body 100 and is connected to the protective gas conveying pipeline 510 outside the annealing furnace body 100.

[0059] In the above embodiment, a heat shield 700 is provided at the entrance of the annealing furnace and at the junction of the heating zone 120 and the cooling zone 130, and a workpiece conveying port 710 is provided at the lower end of the heat shield 700 to provide a channel for the transmission of the workpiece. This design method is conducive to achieving effective isolation of the atmosphere inside and outside the furnace. The use of the heat shield 700 blocks the outside air from directly entering the annealing furnace, and at the same time plays a role of heat insulation between the heating zone 120 and the cooling zone 130, reducing the heat exchange and gas interference between the two areas.

[0060] A protective gas nozzle 720 is arranged on the inner side of the heat insulation board 700 above the workpiece conveying port 710. The protective gas nozzle 720 is provided with downward wind holes. During use, the protective gas ejected by the protective gas nozzle 720 through wind control can form a gas curtain. The gas curtain utilizes the downward injection of the protective gas to form a continuous airflow barrier at the conveying port 710, so as to further enhance the effect of atmosphere isolation, isolate the outside air from entering the furnace, and significantly reduce the risk of oxidation of the workpiece during high-temperature transmission.

[0061] In addition, the air inlet end of the protective gas nozzle 720 extends out of the annealing furnace body 100 and is connected to the external pipeline of the protective gas delivery pipeline 510. This arrangement enables the protective gas nozzle 720 to be used as an extension of the atmosphere protection device 500 and to share the gas source of the protective gas delivery pipeline 510, thereby ensuring the continuity and stability of the gas curtain. In this way, the cost of arranging additional gas pipelines is also reduced.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A tunnel annealing furnace, characterized in that: It comprises an annealing furnace body (100), a conveying device (200), a heating device (300), a cooling device (400), an atmosphere protection device (500) and a temperature control system; The annealing furnace body (100) is in the form of a long tunnel, and a preheating zone (110), a heating zone (120) and a cooling zone (130) are sequentially arranged inside along the length direction; the heating zone (120) is provided with the heating device (300) for heating the workpiece, the annealing furnace body (100) is provided with the conveying device (200) for conveying the workpiece, the cooling zone (130) includes a rapid cooling zone (131) and a slow cooling zone (132), the rapid cooling zone (1031) is arranged in front of the cooling zone (130) and adjacent to one side of the heating zone (120), and is used to quickly reduce the surface temperature of the workpiece, and the slow cooling zone (132) is arranged in the cooling zone (130) is located at the rear of the workpiece and away from the heating zone (120), and is used to gradually release the internal heat of the workpiece to reduce the generation of thermal stress. The cooling zone (130) is provided with a segmented combined cooling device (400); the heating zone (120) is also provided with an atmosphere protection device (500) for controlling the protective atmosphere; the temperature control system includes a plurality of temperature sensors (600) arranged in the preheating zone (110), the heating zone (120) and the cooling zone (130), and a PLC controller electrically connected to the heating device (300), and the PLC controller adjusts the output power of the heating device (300) in real time by receiving the feedback signal of the temperature sensor (600).

2. The tunnel annealing furnace according to claim 1, characterized in that: The conveying device (200) comprises a conveying chain (210) arranged at the bottom inner of the annealing furnace body (100) and extending along the length direction of the annealing furnace body (100); the bottom inner of the annealing furnace body (100) is provided with grooves (101) arranged along the length direction; the conveying chain (210) is installed in the grooves (101); a plurality of connecting rods (211) arranged vertically and extending out of the grooves (101) are arranged at intervals on the conveying chain (210); the conveying chain (210) is connected to a supporting cross bar (212) spaced apart from the conveying chain (210) via the connecting rods (211).

3. The tunnel annealing furnace according to claim 1 or 2, characterized in that: The heating device (300) comprises a plurality of heating units (310) arranged at the top and both sides of the heating zone (120); the heating units (310) are connected to the inner furnace wall of the annealing furnace body (100) via a fixing bracket (320) and are arranged at intervals along the length direction of the heating zone (120); each of the heating units (310) is electrically connected to the PLC controller, and the PLC controller is arranged in a control box (800) outside the annealing furnace body (100).

4. The tunnel annealing furnace according to claim 3, characterized in that: The cooling device (400) comprises a first cooling device arranged in the rapid cooling zone (131) and adopting a combination of spray cooling and air cooling, and a second cooling device arranged in the slow cooling zone (132) and adopting air cooling in cooperation with a guide cover (440), wherein the first cooling device comprises a spray cooling device (410) and a high-speed air cooling device (420), and the second cooling device comprises a low-speed air cooling device (430). The spray cooling device (410) is arranged in the rapid cooling zone (131) and the second cooling device comprises a low-speed air cooling device (430). The top and both sides of the zone (131), the high-speed air cooling device (420) is arranged below the rapid cooling zone (131), the slow cooling zone (132) is provided with the guide cover (440) for guiding the air cooling airflow to be evenly distributed, the guide cover (440) is an arc-shaped structure, and the guide holes are evenly opened on the guide cover (440), and the low-speed air cooling device (430) is arranged at the top of the slow cooling zone (132) and is located above the guide cover (440).

5. The tunnel annealing furnace according to claim 1, characterized in that: The atmosphere protection device (500) comprises a protective gas delivery pipeline (510) and a plurality of protective gas nozzles (520); the protective gas delivery pipeline (510) is arranged in an area above the heating zone (120) and arranged along the length direction of the heating zone (120); the air inlet end of the protective gas delivery pipeline (510) extends upward from the annealing furnace body (100); and a flow control valve is arranged on the pipeline of the protective gas delivery pipeline (510) outside the annealing furnace body (100); a plurality of protective gas nozzles (520) are evenly arranged on the protective gas delivery pipeline (510); and the protective gas delivery pipeline (510) is connected to a protective gas source.

6. The tunnel annealing furnace according to claim 5, characterized in that: The nozzle of the protective gas nozzle (520) is oriented vertically downward and perpendicular to the conveying direction of the workpiece.

7. The tunnel annealing furnace according to claim 4, characterized in that: The cooling zone (130) is provided with the temperature sensor (600) in the rapid cooling zone (131) and the slow cooling zone (132), respectively, and the temperature sensor (600) is also provided at a position between the rapid cooling zone (131) and the slow cooling zone (132).

8. The tunnel annealing furnace according to claim 2, characterized in that: A cover plate (102) is provided on the groove (101), and a through hole (103) is provided on the cover plate (102) for the connecting rod (211) to extend out of the groove (101), and the through hole (103) is arranged along the length direction of the cover plate (102). The conveying chains (210) are in two groups, and the two groups of conveying chains (210) are arranged symmetrically on the left and right and are synchronously driven by a motor (240). The number of the grooves (101) is two and is connected to the two groups of conveying chains ( The conveying chains (210) are arranged correspondingly to each other, the conveying chains (210) are respectively connected to sprockets (220) at the front and rear ends in the conveying direction, a transmission shaft (230) is respectively fixedly connected between the two sprockets (220) at the front ends and between the two sprockets (220) at the rear ends of the two groups of conveying chains (210), the motor (240) is fixedly installed on the outside of the annealing furnace body (100), and the output end of the motor (240) is connected to one of the transmission shafts (230).

9. The tunnel annealing furnace according to claim 5, characterized in that: The annealing furnace body (100) is provided with a furnace body inlet at an outer end of the preheating zone (110), and is provided with a furnace body outlet at an outer end of the cooling zone (130). The annealing furnace body (100) is provided with heat insulation plates (700) at the furnace body inlet and at the junction between the heating zone (120) and the cooling zone (130), respectively. A workpiece conveying port (710) is provided at the lower end of the heat insulation plate (700) for the workpiece to pass through during transportation. A protective gas nozzle (720) for forming a gas curtain at the workpiece conveying port (710) is arranged on the inner side of the heat insulation plate (700) above the workpiece conveying port (710), and downward wind holes are arranged on the protective gas nozzle (720). The air inlet end of the protective gas nozzle (720) extends out of the annealing furnace body (100) and is connected to a pipeline of the protective gas conveying pipeline (510) outside the annealing furnace body (100).

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