Hood-type annealing furnace and annealing process

Abstract

The present invention discloses a hood-type annealing furnace and annealing process, and relates to the technical field of annealing furnaces. The hood includes a furnace platform and a cooling furnace cover, and the cooling furnace cover is installed on the furnace platform when cooling the inner liner cover. The cooling furnace cover includes an inner cover and an outer furnace cover, and a gap is left between the inner cover and the outer furnace cover, and an air supply system is installed at the gap. The air supply system includes a plurality of air supply pipes, and one end of the air supply pipe is located inside the inner cover after passing through the inner cover. A plurality of pressure supply pipes are also installed at the gap between the inner cover and the outer furnace cover. The pressure supply pipe is connected with the air supply pipe, and a blower is installed at the bottom of the pressure supply pipe to actively provide air to the pressure supply pipe and the air supply pipe. The present invention improves the speed of air entering the inner cover through multiple groups of inner pipes with nozzles, top fans, cooling water pipes, and spray water racks, so as to make heat exchange more efficient, increase the turbulence of the air, thereby improving the heat exchange efficiency, realize double cooling of air cooling and water cooling, and accelerate the cooling speed.

Description

Technical Field

[0001] The invention relates to the technical field of annealing furnaces, in particular to a hood-type annealing furnace and an annealing process. Background Art

[0002] Hood annealing furnace is an industrial equipment used for heat treatment of metal materials. It is mainly composed of a furnace table, an inner cover, a heating cover and a cooling cover. During the annealing process, the material to be treated is placed on the furnace table, and the inner cover is buckled to form a sealed space. The material is heated by the heating cover to reach a specific annealing temperature. After a period of heat preservation, the cooling cover can be used for cooling. The hood annealing furnace can accurately control the temperature and time, effectively eliminate the internal stress of the material, and improve the organizational structure and performance of the material. It is widely used in steel, non-ferrous metals and other industries.

[0003] The cooling hoods of annealing furnaces currently popular in the market mostly use fans to draw external air into the cooling hood and exhaust it outside the cooling hood. However, since the suction force generated by the fan at different positions is different, the cooling speed and cooling effect of each part are different, which affects the annealing quality of the material. In view of this situation, the present invention proposes a new type of hood-type annealing furnace and a corresponding annealing process flow. Summary of the invention

[0004] The object of the present invention is to provide a bell-type annealing furnace and an annealing process to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a bell-type annealing furnace, comprising:

[0006] A furnace table and a cooling furnace cover, wherein the cooling furnace cover is installed on the furnace table when cooling the inner tank cover;

[0007] The cooling furnace cover comprises an inner cover and an outer cover, a gap is left between the inner cover and the outer cover, and an air supply system is installed in the gap;

[0008] The air supply system includes a plurality of air supply pipes, one end of which passes through the inner cover and is located inside the inner cover. A plurality of pressure supply pipes are installed in the gap between the inner cover and the outer furnace cover. The pressure supply pipe is connected to the air supply pipe and a blower is installed at the bottom of the pressure supply pipe to actively provide air to the pressure supply pipe and the air supply pipe.

[0009] The furnace table is provided with an opening and closing structure, and a fan is installed at the cooling furnace hood. The fan inhales cold air through the opening and closing structure, and then discharges the air provided by the air supply system from the fan outside the cooling furnace hood.

[0010] Further to this solution, the air supply system also includes at least two groups of side panels, each group of side panels is provided with two, the pressure supply pipe is installed between the two corresponding side panels, and the air supply pipes are connected to the pressure supply pipe after passing through the side panels.

[0011] Further to this solution, the inner cover is provided with a plurality of groups of inner tubes equidistantly distributed from top to bottom, each group of inner tubes is provided with a plurality of inner tubes connected with corresponding air supply tubes, and each inner tube is densely covered with nozzles facing the inner tank cover.

[0012] Furthermore, the outer surface of the inner cover is wrapped with a cooling water pipe, which is connected to an external water source. A water pipe is installed on the top of the cooling furnace cover. The water pipe is connected to the cooling water pipe and a vertical pipe is installed at the other end of the water pipe. The vertical pipe passes through the fan and is placed inside the cooling furnace cover. A spray water rack is installed at one end of the vertical pipe.

[0013] Further to this scheme, a paddle pump is installed on the water conduit, a driving source is installed between the inner cover and the outer furnace cover, a driving wheel is fixed to the output end of the driving source, the fan and the driving wheel are connected by two transmission belts, a driven shaft is coaxially fixed on the top of the driving wheel, and the driven shaft and the rotating shaft of the paddle pump are connected by one transmission belt.

[0014] Further to this solution, the furnace table includes a base and a pedestal fixed to the top of the base, the middle parts of the base and the pedestal are connected from top to bottom, and the opening and closing structure is installed at the connection.

[0015] Further regarding this scheme, the opening and closing structure includes a lifting plate and an interlocking plate, the interlocking plate is provided with a plurality of air holes, a plurality of protrusions are fixed on the top of the lifting plate, the protrusions on the lifting plate correspond one to one to the air holes and a gap is provided between the lifting plate and the interlocking plate, the pedestal is located between the lifting plate and the interlocking plate and is provided with a plurality of through holes penetrating into the interior of the pedestal, and cold air enters the interior of the pedestal from the through holes.

[0016] Furthermore, regarding this scheme, a fixing frame is installed in the base, and a cylinder for controlling the vertical movement of the lifting plate is installed on the top of the fixing frame. A through hole is opened in the middle of the lifting plate, and a middle sleeve is fixed at the central bottom of the lifting plate. Notches are arranged around the middle sleeve, and a spring is arranged in the middle sleeve. A closed disk matching the inside of the through hole is arranged at the through hole, and the closed disk is fixed to the spring. A resist column is fixed in the middle of the mosaic disk, and a hole is opened in the middle of the resist column and passes through to the top of the mosaic disk. A circle of teeth is arranged at the bottom of the resist column to ensure that air can be discharged into the top of the mosaic disk through the resist column.

[0017] Furthermore, with regard to this solution, a carrying plate is installed on the top of the pedestal, and the carrying plate is in the shape of a grid plate, wherein the protrusion on the lifting plate fits in with the air hole, the thickness of the lifting plate fits in with the through hole, and the lifting plate moves vertically until the protrusion fits in with the air hole, and the lifting plate just blocks the through hole.

[0018] An annealing process, using the bell-type annealing furnace mentioned above, comprises the following steps:

[0019] Step 1: Install the furnace; place the metal material on the furnace table and install the inner liner cover to ensure that the inner liner cover is sealed;

[0020] Step 2: Oxygen purging: The oil cylinder controls the lifting plate to rise until the protrusion fits into the air hole, oxygen is introduced from the bottom of the furnace, and other impurities in the inner hood are discharged;

[0021] Step 3: Heating: Install the heating cover for heating;

[0022] Step 4: Heat preservation: When the metal material reaches the required annealing temperature, maintain the temperature for a period of time to allow the material to fully recrystallize and eliminate internal stress;

[0023] Step 5: Cooling; remove the heating cover, install the cooling furnace cover, start the fan and blower, and perform double cooling by water cooling and air cooling to speed up the cooling speed;

[0024] Step 6: Gas replacement: After cooling, nitrogen is introduced from the bottom of the furnace for purging to replace the protective gas in the inner cover to prevent the material from coming into contact with the air after leaving the furnace and causing oxidation and other reactions, which will last for a period of time;

[0025] Step 7: After taking the product out of the furnace and completing the gas replacement, the lifting plate is controlled to descend by the oil cylinder to allow air to enter from the perforations to speed up the cooling process.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The hood-type annealing furnace and annealing process increase the speed of air entering the inner hood through multiple groups of inner tubes with nozzles, top fans, cooling water pipes and spray water racks, making heat exchange more efficient, increasing the turbulence of the air to improve the heat exchange efficiency, achieving dual cooling of air cooling and water cooling, and accelerating the cooling speed.

[0028] At the same time, by sharing the power source, the number of driving sources is reduced and the cost is reduced. The opening and closing structure of the furnace can select the corresponding cooling method according to the material characteristics, which is convenient for adjusting the cooling speed and efficiency. It can not only meet the cooling needs of low oxidation sensitivity materials, but also ensure that high oxidation sensitivity materials are isolated from the outside during heating, which is suitable for annealing of various materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of the cooling cover in the existing design of the present invention;

[0030] Figure 2 It is a schematic diagram of the overall structure of the present invention;

[0031] Figure 3 It is a schematic diagram of the structure of the air supply system of the present invention;

[0032] Figure 4 It is a schematic diagram of the cross-sectional structure of a cooling furnace cover of the present invention;

[0033] Figure 5 It is a schematic diagram of the furnace structure of the present invention;

[0034] Figure 6 It is a schematic diagram of the cross-sectional structure of the furnace table of the present invention.

[0035] In the figure: 1, furnace table; 101, base; 102, pedestal; 103, perforation; 2, cooling furnace cover; 201, inner cover; 202, outer furnace cover; 3, side plate; 4, air supply pipe; 5, inner pipe; 6, cooling water pipe; 7, water guide pipe; 8, vertical pipe; 9, water spraying rack; 10, paddle pump; 11, driving wheel; 12, driven shaft; 13, transmission belt one; 14, transmission belt two; 15, fan; 16, driving source; 17, pressure supply pipe; 18, blower; 19, lifting plate; 191, protrusion; 192, middle sleeve; 1921, through hole; 1922, notch; 193, spring; 194, closed plate; 195, fixed frame; 196, oil cylinder; 20, embedded plate; 2001, air hole; 2002, column; 21, bearing plate. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] like Figure 1 As shown, Figure 1The schematic diagram of the cooling hood of the hood-type annealing furnace in the prior art is shown in FIG. The surface of the cooling hood is provided with air inlet holes, and two fans are installed on the top of the hood. The cold air is sucked into the hood from the air inlet holes through the fans, and the hot air after absorbing heat is discharged from the fans. For the convenience of understanding, we divide the cooling hood from top to bottom into three areas - A, B, and C. It can be clearly understood that since the fan is installed at the top of the hood, area A is closest to the fan and area C is farthest from the fan. That is to say, when the fan sucks air into the hood from the air inlet holes, area A The wind force sucked into the cover body by area C decreases gradually. Therefore, when the inner liner cover of the annealing furnace is cooled by the cooling cover, the cooling speed of area C is not as fast as that of area A. In addition, since the fan is installed on the outside of the cover body, after the cold air is sucked into the cover body from the air inlet, a considerable part of the air will immediately move along the inner wall of the cover and then be discharged from the fan. Therefore, in this case, this part of the air is discharged from the cooling cover without having a good heat absorption effect, and a considerable part of the heat absorption efficiency of the cold air is wasted. Therefore, in view of the above situation, we propose the following equipment.

[0038] like Figure 2 , Figure 3 and Figure 4 As shown, the present invention provides a novel technical solution: a hood-type annealing furnace, comprising: a furnace table 1 and a cooling furnace hood 2, the cooling furnace hood 2 is installed on the furnace table 1 when the inner liner cover is cooled, wherein the cooling furnace hood 2 comprises an inner hood 201 and an outer hood 202, a gap is left between the inner hood 201 and the outer hood 202, an air supply system is installed in the gap, the air supply system actively provides air to the inside of the cooling furnace hood 2, a fan 15 is installed at the top of the cooling furnace hood 2, the fan 15 inhales air from the bottom of the cooling furnace hood 2, and after completing heat absorption, it entrains the air provided by the air supply system to discharge the hot air from the cooling furnace hood 2 from the fan 15.

[0039] like Figure 4 As shown, the air supply system includes at least two groups of side panels 3, each group of side panels 3 is provided with two side panels, and a plurality of air supply pipes 4 are fixed to the side panels 3. The end of the air supply pipe 4 away from the side panel 3 passes through the inner cover 201 and is located inside the inner cover 201. The air supply pipe 4 is equidistantly arranged from the top to the bottom of the cooling furnace cover 2. A pressure supply pipe 17 is installed between the two side panels 3 of each group. The pressure supply pipe 17 is connected to the air supply pipes 4 at the two adjacent side panels 3, and a blower 18 is installed at the bottom of the pressure supply pipe 17. The blower 18 provides air to the air supply pipe 4 and actively blows air into the interior of the inner cover 201. In this way, the speed at which air enters the inner cover 201 is increased, so that the air entering the inner cover 201 can contact the inner tank cover in a shorter time, thereby improving the heat exchange efficiency. In addition, by actively pumping, the attenuation of wind flow velocity caused by passive suction can be reduced.

[0040] like Figure 4 As shown, in order to cool down each part of the inner liner cover at a relatively even speed, multiple groups of inner tubes 5 are arranged inside the inner liner 201, each group of inner tubes 5 is provided with a plurality of inner tubes 5 and each inner tube 5 is connected to a corresponding air supply pipe 4, each inner tube 5 is densely covered with nozzles facing the inner liner cover, and air is ejected from the nozzles and contacts the inner liner cover. In this way, the air is allowed to flow out in a relatively dense manner and contact the inner liner cover to complete the heat exchange process;

[0041] During the heat exchange process, the fan 15 can quickly discharge the air in the cooling furnace hood 2, and the fan 15 sucks in cold air from the bottom of the cooling furnace hood 2 during operation. The cold air can also have a heat exchange effect during the upward movement. The cold air sucked in by the fan 15 will also meet the air ejected from the inner tube 5 during the upward movement. The meeting of the two air streams will produce a certain amount of turbulence, which increases the turbulence of the air, makes the air flow more complicated, and makes the air have a higher convective heat transfer coefficient, which can further increase the heat exchange efficiency and improve the quality and speed of cooling.

[0042] Usually, when cooling the inner shell, water spraying is usually used for cooling. This is because water has a high specific heat capacity and relatively efficient heat exchange. A cooling water pipe 6 is wrapped on the outer surface of the inner shell 201 of the cooling furnace shell 2. The cooling water pipe 6 is connected to an external water source. A water pipe 7 is installed on the top of the cooling furnace shell 2. The water pipe 7 is connected to the cooling water pipe 6. A vertical pipe 8 is installed at the other end of the water pipe 7. The vertical pipe 8 passes through the fan 15 and is placed inside the cooling furnace shell 2. A water spraying rack 9 is installed at one end of the vertical pipe 8 away from the water pipe 7. Water is drawn from the outside through the cooling water pipe 6, and water is sprayed from the water spraying rack 9 after passing through the water pipe 7. The cooling of the inner shell is achieved by cold air heat exchange and water heat exchange. The two cooling methods are superimposed to improve the cooling efficiency.

[0043] like Figure 3 and Figure 4As shown, in order to achieve the above purpose, a paddle pump 10 is installed on the water pipe 7, and a driving source 16 is installed between the interlayer of the inner cover 201 and the outer furnace cover 202. A driving wheel 11 is fixed to the output end of the driving source 16. In this embodiment, the fan 15 is a turbofan, the middle of which is hollowed out, and the fan 15 is rotatably installed on the top of the cooling furnace cover 2 at the outer wall through which it passes, and can be installed through bearings, etc., which is a prior art and will not be described in detail here. The fan 15 is connected to the driving wheel 11 through a transmission belt 2 14, and when the driving source 16 provides power, the fan 15 can be driven to rotate. A driven shaft 12 is also coaxially fixed to the top of the driving wheel 11, and the driven shaft 12 is connected to the rotating shaft of the paddle pump 10 through a transmission belt 1 13. When the driving source 16 provides power, the paddles of the paddle pump 10 are driven to rotate at the same time, thereby achieving the water pumping effect of the paddle pump 10, realizing power source sharing, reducing the number of driving sources 16, and reducing costs.

[0044] like Figure 5 and Figure 6 As shown, in the above process, it is necessary to draw air from the bottom of the cooling furnace cover 2 and ensure that the water discharged into the cooling furnace cover 2 can be discharged smoothly, such as Figure 5 As shown, the furnace table 1 includes a base 101 and a pedestal 102 fixed to the top of the base 101. The middle parts of the base 101 and the pedestal 102 are connected from top to bottom, and an opening and closing structure is provided at the through-through position. The opening and closing structure includes a lifting plate 19 and a fitting plate 20, wherein the fitting plate 20 is provided with a plurality of air holes 2001, and a plurality of protrusions 191 are fixed to the top of the lifting plate 19. The protrusions 191 on the lifting plate 19 correspond to the air holes 2001 one by one, and a gap is provided between the lifting plate 19 and the fitting plate 20, and the pedestal 102 is located between the lifting plate 19 and the fitting plate 20. A plurality of through holes 103 penetrating into the interior of the base 102 are provided. When the fan 15 is working, cold air enters the cooling furnace hood 2 and the inner liner hood through the through holes 103, passes through the interlocking disk 20, and then enters the cooling furnace hood 2 and the inner liner hood. The cold air entering the cooling furnace hood 2 and the inner liner hood will destroy the inert gas in the inner liner hood. It is suitable for materials with low oxidation sensitivity, such as copper or pure aluminum. For materials with high oxidation sensitivity, the furnace base 1 is always kept sealed and not in contact with the outside air. The inner liner hood is cooled by the air actively pumped in by the cooling furnace hood 2, and the hot air is discharged by the fan 15.

[0045] like Figure 5 and Figure 6As shown, when heating the material, it is necessary to ensure that the inside of the inner liner cover is isolated from the outside, and it is also necessary to ensure that the rare gas can enter the inner liner cover from the inside of the furnace 1 to cooperate with the heating to process the material. A fixing frame 195 is installed in the base 101, and a cylinder 196 is installed on the top of the fixing frame 195 to control the lifting plate 19 to move in the vertical direction. Among them, a through hole 1921 is opened in the middle of the lifting plate 19, and a middle sleeve 192 is fixed to the central bottom of the lifting plate 19. The middle sleeve 192 There are gaps 1922 around to facilitate air circulation, a spring 193 is arranged in the middle sleeve 192, and a closed disk 194 adapted to the inner wall of the through hole 1921 is arranged at the through hole 1921, and the closed disk 194 is fixed to the spring 193. A support column 2002 is fixed in the middle of the embedded disk 20, and a hole is opened in the middle of the support column 2002 and penetrates to the top of the embedded disk 20. A circle of teeth is arranged at the bottom of the support column 2002 to ensure that air can pass through the support column 2002 and be discharged to the top of the embedded disk 20;

[0046] In order to ensure the smooth implementation of the above embodiment, a carrier plate 21 is installed on the top of the pedestal 102. The carrier plate 21 is in the shape of a grid plate. When the material is heated, the lifting plate 19 is driven by the oil cylinder 196 to move upward until the protrusion 191 is engaged with the air hole 2001, and at this time, the edge of the lifting plate 19 just blocks the perforation 103. In this case, the outside air cannot enter the interior of the inner shell from the perforation 103. At the same time, when lifting, the support column 2002 will press the closed plate 194 to move downward, and the closed plate 19 When moving downward, the rare gas can enter through the notch 1922, and enter the inner shell after passing through the support column 2002, so as to realize the injection of the rare gas. When cooling, it is only necessary to control the lifting plate 19 to move downward through the oil cylinder 196, open the through hole 103 and the air hole 2001, and the cold air can enter from the outside to realize the circulation of the cold air. Therefore, the setting of the opening and closing structure can control the external gas to enter and exit the inner shell from the furnace table 1 at any time, so as to facilitate the selection of the corresponding cooling method according to the characteristics of each material, and facilitate the adjustment of the cooling speed and efficiency.

[0047] Based on the above bell-type annealing furnace equipment, we propose an annealing furnace annealing process that relies on the above equipment, and the specific steps are as follows:

[0048] Step 1: Install the furnace; place the metal material on the furnace table 1 and install the inner tank cover to ensure that the inner tank cover is sealed;

[0049] Step 2: oxygen purging; the lifting plate 19 is raised by the oil cylinder 196 until the protrusion 191 is engaged with the air hole 2001, oxygen is introduced from the bottom of the furnace 1, and other impurities in the inner shell are discharged;

[0050] Step 3: Heating: Install the heating cover for heating;

[0051] Step 4: Heat preservation: When the metal material reaches the required annealing temperature, maintain the temperature for a period of time to allow the material to fully recrystallize and eliminate internal stress;

[0052] Step 5: Cooling; remove the heating cover, install the cooling furnace cover 2, start the fan 15 and the blower 18, and perform double cooling by water cooling and air cooling to accelerate the cooling speed;

[0053] Step 6: gas replacement; after cooling, nitrogen is introduced from the bottom of the furnace 1 for purging to replace the protective gas inside the inner cover 201 to prevent the material from coming into contact with the air after being taken out of the furnace and causing oxidation and other reactions and maintaining for a period of time;

[0054] Step 7: After the material is taken out of the furnace and the gas replacement is completed, the lifting plate 19 is controlled to descend by the oil cylinder 196 to allow air to enter from the perforation 103. At this time, the fan 15, the spray water rack 9 and the blower 18 are used to simultaneously perform air cooling and water cooling on the inside and outside of the inner shell until the material is cooled to room temperature, completing the annealing step.

[0055] For low oxidation sensitive materials, an annealing process relying on the above equipment is proposed, and the specific steps are as follows:

[0056] Step 1: Install the furnace; place the metal material on the furnace table 1 and install the inner tank cover to ensure that the inner tank cover is sealed;

[0057] Step 2: oxygen purging; the lifting plate 19 is raised by the oil cylinder 196 until the protrusion 191 is engaged with the air hole 2001, oxygen is introduced from the bottom of the furnace 1, and other impurities in the inner shell are discharged;

[0058] Step 3: Heating: Install the heating cover for heating;

[0059] Step 4: Heat preservation: When the metal material reaches the required annealing temperature, maintain the temperature for a period of time to allow the material to fully recrystallize and eliminate internal stress;

[0060] Step 5: Cooling; remove the heating cover, open the opening and closing structure to allow cold air to enter from the furnace 1, install the cooling furnace cover 2, start the fan 15 and the blower 18, and perform double cooling by water cooling and air cooling to accelerate the cooling speed.

[0061] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is limited by the attached embodiments and their equivalents.

Claims

1. A bell-type annealing furnace, characterized in that: include: A furnace table (1) and a cooling furnace cover (2), wherein the cooling furnace cover (2) is installed on the furnace table (1) when cooling the inner tank cover; The cooling furnace cover (2) comprises an inner cover (201) and an outer furnace cover (202), a gap is left between the inner cover (201) and the outer furnace cover (202), and an air supply system is installed in the gap; The air supply system comprises a plurality of air supply pipes (4), one end of the air supply pipe (4) passes through the inner cover (201) and is located inside the inner cover (201), a plurality of pressure supply pipes (17) are installed in the gap between the inner cover (201) and the outer furnace cover (202), the pressure supply pipe (17) is connected to the air supply pipe (4), and a blower (18) is installed at the bottom end of the pressure supply pipe (17) for actively supplying air to the pressure supply pipe (17) and the air supply pipe (4); The furnace table (1) is provided with an opening and closing structure, and a fan (15) is installed at the cooling furnace cover (2). The fan (15) sucks cold air through the opening and closing structure, entrains air provided by the air supply system, and then discharges the cold air from the fan (15) to the outside of the cooling furnace cover (2); The furnace table (1) comprises a base (101) and a pedestal (102) fixed to the top of the base (101); the middle parts of the base (101) and the pedestal (102) are connected vertically, and the opening and closing structure is installed at the connection; The opening and closing structure comprises a lifting plate (19) and a fitting plate (20), the fitting plate (20) being provided with a plurality of air holes (2001), a plurality of protrusions (191) being fixed on the top of the lifting plate (19), the protrusions (191) on the lifting plate (19) corresponding to the air holes (2001) one by one, and a gap being provided between the lifting plate (19) and the fitting plate (20), the pedestal (102) being located between the lifting plate (19) and the fitting plate (20) and being provided with a plurality of air holes (2001) extending through the pedestal (102). 02) has a through hole (103) inside, and cold air enters the inside of the pedestal (102) from the through hole (103). A fixing frame (195) is installed inside the base (101). A cylinder (196) for controlling the vertical movement of the lifting plate (19) is installed on the top of the fixing frame (195). A through hole (1921) is opened in the middle of the lifting plate (19). A middle sleeve (192) is fixed to the central bottom of the lifting plate (19). The middle sleeve (192) is provided with notches ( 1922, a spring (193) is arranged in the middle sleeve (192), a sealing disk (194) adapted to the inside of the through hole (1921) is arranged at the through hole (1921), the sealing disk (194) and the spring (193) are fixed, a support column (2002) is fixed in the middle of the embedded disk (20), a hole is opened in the middle of the support column (2002) and penetrates to the top of the embedded disk (20), and a circle of teeth is arranged at the bottom of the support column (2002) to ensure that air can pass through the support column (2002). The column (2002) is arranged above the engaging plate (20), and a carrying plate (21) is installed on the top of the pedestal (102), wherein the carrying plate (21) is in the shape of a grid plate, wherein the protrusion (191) on the lifting plate (19) is engaged with the air hole (2001), and the thickness of the lifting plate (19) is matched with the through hole (103). When the lifting plate (19) moves vertically until the protrusion (191) is engaged with the air hole (2001), the lifting plate (19) just blocks the through hole (103).

2. A bell-type annealing furnace according to claim 1, characterized in that: The air supply system further comprises at least two groups of side panels (3), each group of side panels (3) being provided with two side panels, the pressure supply pipe (17) being installed between the two corresponding side panels (3), and the air supply pipes (4) passing through the side panels (3) and then connected to the pressure supply pipe (17).

3. A bell-type annealing furnace according to claim 1, characterized in that: The inner cover (201) is provided with a plurality of groups of inner tubes (5) equidistantly distributed from top to bottom, each group of inner tubes (5) is provided with a plurality of inner tubes (5) connected to corresponding air supply tubes (4), and each inner tube (5) is densely covered with nozzles facing the inner liner cover.

4. A bell-type annealing furnace according to claim 1, characterized in that: The outer surface of the inner cover (201) is wrapped with a cooling water pipe (6), the cooling water pipe (6) is connected to an external water source, a water guide pipe (7) is installed on the top of the cooling furnace cover (2), the water guide pipe (7) is connected to the cooling water pipe (6), and a vertical pipe (8) is installed at the other end of the water guide pipe (7), the vertical pipe (8) passes through the fan (15) and is placed inside the cooling furnace cover (2), and a water spraying rack (9) is installed at one end of the vertical pipe (8) away from the water guide pipe (7).

5. A bell-type annealing furnace according to claim 4, characterized in that: A paddle pump (10) is installed on the water guide pipe (7), and a driving source (16) is installed between the inner cover (201) and the outer furnace cover (202). A driving wheel (11) is fixed to the output end of the driving source (16), and the fan (15) and the driving wheel (11) are connected via a second transmission belt (14). A driven shaft (12) is coaxially fixed to the top of the driving wheel (11), and the driven shaft (12) and the rotating shaft of the paddle pump (10) are connected via a first transmission belt (13).

6. An annealing process, using the bell-type annealing furnace according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: Install the furnace; place the metal material on the furnace table (1) and install the inner tank cover to ensure that the inner tank cover is sealed; Step 2: oxygen purging; the lifting plate (19) is raised by the oil cylinder (196) until the protrusion (191) is engaged with the air hole (2001), oxygen is introduced from the bottom of the furnace (1), and other impurities in the inner shell are discharged; Step 3: Heating: Install the heating cover for heating; Step 4: Heat preservation: When the metal material reaches the required annealing temperature, maintain the temperature for a period of time to allow the material to fully recrystallize and eliminate internal stress; Step 5: Cooling; The heating cover is removed, the cooling furnace cover (2) is installed, the fan (15) and the blower (18) are started, and dual cooling is performed by water cooling and air cooling to accelerate the cooling speed; Step 6: gas replacement; after cooling, nitrogen is introduced from the bottom of the furnace (1) for purging to replace the protective gas in the inner cover (201) to prevent the material from coming into contact with air after leaving the furnace and causing an oxidation reaction which lasts for a period of time; Step 7: After the furnace is taken out and the gas replacement is completed, the lifting plate (19) is controlled to descend by the oil cylinder (196) to allow air to enter from the perforation (103) to accelerate the cooling speed.

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