Heat treatment vacuum furnace

Abstract

The invention relates to the technical field of heat treatment vacuum furnaces, in particular to a heat treatment vacuum furnace which comprises a furnace body and a furnace door which are arranged in a matched mode, a vacuum pump, an air pump and a pressure relief pump are arranged at the top end of the furnace body in a matched mode, a partition plate is fixedly arranged in a furnace cavity of the furnace body, and the furnace cavity of the furnace body is divided into a first cavity and a second cavity through the partition plate. A heating inner furnace is fixedly arranged in the first cavity, and a placing plate provided with a honeycomb hole array is placed on the heating inner furnace. The honeycomb hole array is formed in the placement plate to enhance the heat dissipation capacity, the area is divided into the central area, the transition area and the edge area, the central area resists principal stress through a dense honeycomb structure, the transition area relieves thermal stress through a single-edge communication design, and the edge area accelerates heat dissipation through a full-edge communication design; therefore, the cooling efficiency of the workpiece is improved while the thermal deformation resistance is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of heat treatment vacuum furnaces, and in particular to a heat treatment vacuum furnace. Background Art

[0002] A heat treatment vacuum furnace is a specialized industrial furnace used to heat treat materials in a controlled environment without air or other gases. Common heat treatment types include annealing, precipitation hardening, tempering, normalizing, and stress relieving. These processes ensure that the material achieves the desired properties and a bright, contamination-free surface.

[0003] Current heat treatment vacuum furnaces generally place the workpiece directly on the heating platform during the workpiece heating process. This can easily lead to temperature gradients in the workpiece due to uneven heating, thereby affecting the uniformity and accuracy of its phase change or physical property reaction, and ultimately causing deviations in subsequent workpiece inspection results. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem in the prior art of placing the workpiece directly on the heating platform, which easily leads to the generation of temperature gradients in the workpiece due to uneven heating, and to propose a heat treatment vacuum furnace.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A heat treatment vacuum furnace comprises a furnace body and a furnace door which are arranged in a matching manner. A vacuum pump, an air pump and a pressure relief pump are arranged on the top of the furnace body. A partition is fixedly arranged in the furnace cavity of the furnace body, and the furnace cavity of the furnace body is divided into a first chamber and a second chamber by the partition. A heating inner furnace is fixedly arranged in the first chamber, and heating components are fixedly installed on the inner walls of the left and right sides of the heating inner furnace. A circulation fan is fixedly arranged in the second chamber, and the impeller part of the circulation fan extends into the heating inner furnace. A placement plate with an array of honeycomb holes is placed on the heating inner furnace, and sealed doors that can be opened and closed automatically are arranged on the upper and lower sides of the heating inner furnace. Ventilation ports whose opening and closing are controlled by a valve body are installed on the upper and lower sides of the partition. A heat converter is fixedly installed on the side of the furnace body away from the furnace door, and the working end of the heat converter extends into the second chamber.

[0006] Preferably, the furnace body is a cylindrical structure as a whole, at least four supporting legs are provided at the bottom end of the furnace body, and the furnace door is installed by flange installation or hinge installation.

[0007] Preferably, the furnace door is fixedly connected to a base rod on the side close to the furnace body, and the base rod is slidably connected to a connecting rod away from the furnace door. An end of the base rod close to the connecting rod is provided with a placement cavity for placing an elastic layer, and the elastic layer is movably abutted against the connecting rod. An end of the connecting rod away from the base rod is fixedly connected to a heat insulation board.

[0008] Preferably, the elastic layer can be a polyurethane elastomer layer or a metal spring layer.

[0009] Preferably, the second chamber is a truncated cone-shaped chamber structure, the smaller diameter end of the second chamber is close to the heat converter, and the larger diameter end of the second chamber is close to the partition.

[0010] Preferably, the area of ​​the heating inner furnace for placing the placement plate is composed of a plurality of strip-shaped reinforcing ribs, and the surface of the placement plate is divided into a central area, a transition area and an edge area. The central area is provided with a fully enclosed hexagonal honeycomb hole array, the honeycomb hole array in the transition area is connected on one side using a °Y-type connection, and the honeycomb hole array in the edge area is set to be fully connected. The thickness of the honeycomb hole wall in the central area is 1.2 times that of the transition area, and the thickness of the honeycomb hole wall in the transition area is 1.15 times that of the edge area. The inner side of the honeycomb hole wall on the placement plate is provided with diamond convex patterns.

[0011] Preferably, the heating inner furnace is a rectangular structure, and the interlayer of the heating inner furnace is filled with Al-Si alloy microcapsules.

[0012] Preferably, the heating component is a graphite heating element, a metal heating element, or a ceramic composite heating element.

[0013] Preferably, cylinders for controlling the opening and closing of the sealing door are provided on the pin shafts on the upper and lower sides of the furnace body.

[0014] Preferably, the vent is a truncated cone-shaped vent or a rectangular cone-shaped vent, and the valve body matched with the vent is a pneumatic high vacuum baffle valve or an electric ventilation butterfly valve.

[0015] Compared with the prior art, the present invention has the following advantages: 1. The present invention opens a honeycomb hole array on the placement plate to enhance the heat dissipation capacity, and divides the area into a central area, a transition area and an edge area: the central area resists the main stress through a dense honeycomb structure, the transition area relieves thermal stress with a single-side connected design, and the edge area accelerates heat dissipation with a full-side connected design, thereby ensuring anti-thermal deformation performance while improving the cooling efficiency of the workpiece.

[0016] 2. In the present invention, an elastic layer is provided in the base rod to counteract the movement of the connecting rod, thereby compensating for the deformation space of the insulation board caused by thermal expansion and contraction, effectively ensuring the sealing performance of the heating furnace, thereby ensuring the vacuum degree of the internal space of the heating furnace.

[0017] 3. The circulating fan in the present invention significantly enhances convective heat transfer and improves the heat exchange rate by forcibly stirring the gas in the furnace. This not only allows heat to be transferred to various surfaces of the workpiece and every corner of the furnace more quickly and evenly, significantly reducing the temperature gradient, but also accelerates the conduction of heat from the heating element to the workpiece, thereby effectively shortening the overall heating cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the three-dimensional structure of a heat treatment vacuum furnace proposed by the present invention; Figure 2 A half-section view of a heat treatment vacuum furnace proposed by the present invention; Figure 3 For the present invention Figure 2 Another perspective diagram proposed in; Figure 4 This is a schematic diagram of the connection structure of the base rod, connecting rod and heat insulation board of a heat treatment vacuum furnace proposed by the present invention; Figure 5 A half-section view of a base rod and a connecting rod of a heat treatment vacuum furnace proposed by the present invention; Figure 6 This is a schematic structural diagram of a placement plate of a heat treatment vacuum furnace proposed by the present invention from a first perspective; Figure 7 This is a schematic structural diagram of a placement plate of a heat treatment vacuum furnace proposed in the present invention from a second perspective.

[0019] In the figure: 1. furnace body; 2. furnace door; 3. partition; 4. first chamber; 5. second chamber; 6. heating inner furnace; 7. heating component; 8. circulation fan; 9. sealing door; 10. vent; 11. heat converter; 12. placement plate; 13. base rod; 14. connecting rod; 15. placement chamber; 16. insulation board; 17. cylinder; 18. vacuum pump; 19. air pump; 20. pressure relief pump; 21. central area; 22. transition area; 23. edge area. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0021] Reference Figure 1-Figure 7 A heat treatment vacuum furnace includes a furnace body 1 and a furnace door 2 that are arranged in a matching manner. The furnace body 1 is a cylindrical structure as a whole. At least four supporting legs are arranged at the bottom of the furnace body 1. The furnace door 2 is installed by flange mounting or hinge mounting. It should be noted that: the furnace door 2 has a built-in cooling system and is equipped with a locking mechanism. Since the above are all conventional settings of the furnace door 2, they will not be elaborated on.

[0022] The top of the furnace body 1 is equipped with a vacuum pump 18, an air pump 19 and a pressure relief pump 20. A partition 3 is fixedly provided in the furnace cavity of the furnace body 1. The furnace cavity of the furnace body 1 is divided into a first chamber 4 and a second chamber 5 by the partition 3. A heating inner furnace 6 is fixedly provided in the first chamber 4. The heating inner furnace 6 is a rectangular structure. The internal corners of the rectangular cavity of the heating inner furnace 6 are all designed with rounded corners to reduce stress concentration and facilitate cleaning. The interlayer of the heating inner furnace 6 is filled with Al-Si alloy microcapsules. Al-Si alloy is a phase change material. It melts when absorbing heat and stores a large amount of latent heat. It solidifies and releases heat when releasing heat. Therefore, the filling The Al-Si alloy microcapsules filled in the interlayer can effectively absorb heat fluctuations during the operation of the furnace body 1, significantly improving the uniformity and stability of the temperature in the furnace, reducing thermal shock, and improving process quality and energy efficiency. Heating components 7 are fixedly installed on the inner walls of the left and right sides of the heating inner furnace 6. The heating components 7 can be made of graphite heating elements, metal heating elements, or ceramic composite heating elements. By flexibly arranging modular heating components 7 on the six walls of the rectangular cavity of the heating inner furnace 6, the installation position can be selected according to actual process requirements to form multiple independent temperature control zones, realize zoned precise temperature control, and ensure uniform heating of the workpiece; The furnace door 2 is fixedly connected to the side of the furnace body 1 with a base rod 13, and the base rod 13 is slidably connected to the connecting rod 14 away from the furnace door 2. The end of the base rod 13 close to the connecting rod 14 is provided with a placement cavity 15 for placing an elastic layer. The elastic layer and the connecting rod 14 are movably opposed to each other. The elastic layer can be made of a polyurethane elastomer layer or a metal spring layer. The polyurethane elastomer layer or the metal spring layer has good heat resistance. It should be noted that at least two groups of base rods 13 and connecting rods 14 are provided, and the sliding mode between the base rod 13 and the connecting rod 14 can adopt a slide rail and a slider or a slide groove and a slider, as shown below: Select slide rails and sliders, the slide rails are fixedly connected to the base rod 13, and the sliders are fixedly connected to the connecting rod 14. The sliding connection between the slide rails and the sliders prevents the connecting rod 14 from being separated from the base rod 13. At the same time, the slide rails and the sliders are added without destroying the original structure of the base rod 13 and the connecting rod 14. A chute and a slider are selected. The chute is fixedly connected to the base rod 13, and the slider is fixedly connected to the connecting rod 14. The sliding connection between the chute and the slider prevents the connecting rod 14 from being separated from the base rod 13. At the same time, the slider is always located in the chute, which can effectively ensure the sealing between the connecting rod 14 and the base rod 13. The end of the connecting rod 14 away from the base rod 13 is fixedly connected to the insulation board 16. The insulation board 16 is made of insulation material, but the insulation material will expand and contract when affected by high temperature. The heating inner furnace 6 will generate a higher temperature when in operation, so that the insulation board 16 will inevitably expand to a certain extent in volume under the influence of high temperature. However, the insulation board 16 is installed on the furnace door 2 through the base rod 13 and the connecting rod 14 that are slidably connected. At the same time, the insulation board 16 closes the heating inner furnace 6 as the furnace door 2 closes the furnace body 1. Therefore, after the insulation board 16 expands, it will drive the connecting rod 14 to move toward the base rod 13. The connecting rod 14 will squeeze the elastic layer during the movement, and the compressible space of the elastic layer will absorb the deformation of the insulation board 16 caused by thermal expansion and contraction, thereby eliminating the assembly gap between the two, thereby maintaining the sealing performance under high temperature conditions and ensuring the stability of the vacuum degree in the furnace.

[0023] A circulation fan 8 is fixedly installed in the second chamber 5, and the impeller part of the circulation fan 8 extends into the heating inner furnace 6. The circulation fan 8 significantly enhances the flow intensity and turbulence of the gas in the furnace through forced convection, thereby greatly improving the convective heat transfer efficiency and heat exchange rate between the gas and the workpiece. This not only accelerates and evens out the transfer of heat to the various surfaces of the workpiece, effectively reduces the temperature gradient in the furnace, and improves thermal uniformity, but also the heat conduction path and efficiency from the heating element through the gas medium to the workpiece will be significantly optimized, which helps to shorten the overall heating cycle of the workpiece. At the same time, the circulation fan 8 and the heat converter 11 work together to help accelerate the heat exchange between the high-temperature gas and the cooling medium, thereby shortening the cooling process cycle.

[0024] A placement plate 12 with a honeycomb hole array is placed on the heating inner furnace 6. The area of ​​the heating inner furnace 6 for placing the placement plate 12 is composed of a plurality of strip-shaped reinforcement ribs. The surface of the placement plate 12 is divided into a central area 21, a transition area 22 and an edge area 23. The central area 21 is provided with a fully enclosed hexagonal honeycomb hole array. The thickness of the honeycomb hole wall in the central area 21 is 1.2 times that of the transition area 22, and the thickness of the honeycomb hole wall in the transition area 22 is 1.15 times that of the edge area 23. Local thickening and strengthening are implemented in the central area 21 to improve the creep stiffness and thermal fatigue life of the central area 21, and the edge area 23 is gradient thinned to enhance the airflow permeability and heat dissipation efficiency. Diamond convex patterns are provided on the inner side of the honeycomb hole wall on the placement plate 12. The ridges of the diamond convex patterns form micro reinforcement ribs to increase the honeycomb hole thickness. The effective thickness and neutral axis distance of the hole wall cross section, as well as the optimization of the stress transfer path through the oblique edges of the diamond-shaped convex pattern, help to suppress local buckling deformation under high temperature. The material of the central area 21 is TZM molybdenum alloy. Since the contact area between the workpiece and the central area 21 is the largest, the mass of the workpiece carried by the central area 21 is also the largest. Therefore, the central area 21 needs to have the highest creep resistance on the placement plate 12. TZM molybdenum alloy has good creep resistance, thermal expansion matching and anti-workpiece adhesion and excellent high-temperature strength. At the same time, the fully enclosed hexagonal honeycomb hole array can provide the central area 21 with the highest in-plane stiffness of the placement plate 12. At the same time, the fully enclosed hexagonal honeycomb hole array can effectively reduce high-temperature radiation heat loss, which helps to ensure temperature uniformity in the center of the workpiece. The material of the transition zone 22 is isostatic graphite. The transition zone 22 needs to balance the temperature difference between the central zone 21 and the edge zone 23 when heated. The transition zone 22 can absorb 0.11×10 -6 / K expansion difference, thereby achieving the balance of the temperature difference between the central area 21 and the edge area 23 when heated. The honeycomb hole array in the transition area 22 is interconnected by a 120° Y-shaped structure, thereby forming a directional thermal deformation conduction channel, which guides the thermal expansion strain generated by the placement plate 12 under the working state to the edge area 23. At the same time, the 120° geometric configuration optimizes the flow pattern of the working medium in the flow channel. The 120° Y-shaped structure has a continuous and smooth force flow without sudden changes in direction, and the angle between the principal stress direction and the hole wall is ≤30°, making the thermal expansion strain more uniform and avoiding the accumulation of local plastic strain. The material of the edge area 23 is reaction-sintered SiC. The high-temperature rigidity of reaction-sintered SiC is higher than that of molybdenum alloy, which helps to prevent the edge area 23 from softening and deforming due to high temperature. At the same time, the honeycomb hole array in the edge area 23 is fully connected, which significantly improves the gas exhaust efficiency, allowing heat to be quickly carried away from the edge area 23 by the gas, which helps to improve the cooling efficiency of the workpiece. At the same time, since the edge area 23 has less constraints, the edge area 23 allows moderate deformation, which helps to avoid cracking caused by thermal stress accumulation.

[0025] Sealed doors 9 that can be opened and closed automatically are provided on the upper and lower sides of the heating inner furnace 6. Cylinders 17 for controlling the opening and closing of the sealed doors 9 are provided on the pin shafts on the upper and lower sides of the furnace body 1. Vents 10 that are opened and closed by valve bodies are installed on the upper and lower sides of the partition 3. The vents 10 are truncated cone-shaped vents or rectangular cone-shaped vents. The valve bodies matched with the vents 10 are pneumatic high vacuum baffle valves or electric ventilation butterfly valves. A heat converter 11 is fixedly installed on the side of the furnace body 1 away from the furnace door 2. The working end of the heat converter 11 extends into the second chamber 5. The second chamber 5 is a truncated cone-shaped cavity structure. The smaller diameter end of the second chamber 5 is close to the heat converter 11, and the larger diameter end of the second chamber 5 is close to the partition 3.

[0026] The present invention can be explained through the following operation mode: Pull out the placement plate 12 and place the workpiece on it. At this time, select the corresponding number of hexagonal limiting rods according to the appearance of the workpiece. It should be noted that the geometric characteristics of the hexagonal limiting rods correspond to the geometric characteristics of the honeycomb holes on the placement plate 12. Insert the hexagonal limiting rods into the corresponding honeycomb holes to complete the fixed position of the workpiece. Finally, push the placement plate 12 back into the heating furnace 6. Close the furnace door 2 so that the heat insulation board 16 seals the open end of the heating inner furnace 6, thereby ensuring the sealing of the furnace cavity of the furnace body 1; Start the vacuum pump 18 to make the furnace chamber of the furnace body 1 reach the preset vacuum degree to ensure a non-oxidizing environment, start the cylinder 17 to cover the sealing door 9, thereby completing the sealing operation of the heating inner furnace 6, and control the vent 10 to be closed through the valve body, start the heating component 7 and the circulation fan 8, and control the heating rate according to the preset process curve. When the workpiece temperature reaches the set process temperature, it enters the insulation stage. After the insulation is completed, it is cooled according to the process requirements, and the air pump 19 is started to quickly fill the furnace with high-pressure and high-purity inert gas. At the same time, the heat converter 11 is started to force the gas to flow through the surface of the workpiece at a high speed, and through forced convection heat exchange with the high-temperature workpiece, the heat is efficiently removed and cooled; When the workpiece cools to a safe temperature, the pressure relief pump 20 is started to discharge the high-pressure gas to normal pressure.

[0027] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A heat treatment vacuum furnace, comprising a furnace body (1) and a furnace door (2) arranged in a matching manner, wherein a vacuum pump (18), an air pump (19) and a pressure relief pump (20) are arranged in a matching manner on the top of the furnace body (1), characterized in that: A partition (3) is fixedly provided in the furnace cavity of the furnace body (1), and the furnace cavity of the furnace body (1) is divided into a first chamber (4) and a second chamber (5) by the partition (3). A heating inner furnace (6) is fixedly provided in the first chamber (4), and heating components (7) are fixedly installed on the inner walls of the left and right sides of the heating inner furnace (6). A circulation fan (8) is fixedly provided in the second chamber (5), and the impeller part of the circulation fan (8) extends into the heating inner furnace (6). A placement plate (12) with a honeycomb hole array is placed on the heating inner furnace (6). The upper and lower sides of the heating inner furnace (6) are both provided with sealing doors (9) that can be opened and closed automatically. Ventilation ports (10) that are controlled to open and close by a valve body are installed on the upper and lower sides of the partition (3). A heat converter (11) is fixedly installed on the side of the furnace body (1) away from the furnace door (2), and the working end of the heat converter (11) extends into the second chamber (5).

2. A heat treatment vacuum furnace according to claim 1, characterized in that: The furnace body (1) is a cylindrical structure as a whole. At least four supporting legs are provided at the bottom end of the furnace body (1). The furnace door (2) is installed in a flange-type installation or a hinge-type installation.

3. A heat treatment vacuum furnace according to claim 1, characterized in that: The furnace door (2) is fixedly connected to a base rod (13) on a side close to the furnace body (1), and the base rod (13) is slidably connected to a connecting rod (14) away from the furnace door (2). An end of the base rod (13) close to the connecting rod (14) is provided with a placement cavity (15) for placing an elastic layer, and the elastic layer and the connecting rod (14) are movably opposed to each other. An end of the connecting rod (14) away from the base rod (13) is fixedly connected to a heat insulation board (16).

4. A heat treatment vacuum furnace according to claim 3, characterized in that: The elastic layer can be a polyurethane elastomer layer or a metal spring layer.

5. A heat treatment vacuum furnace according to claim 1, characterized in that: The second chamber (5) is a truncated cone-shaped cavity structure, the smaller diameter end of the second chamber (5) is close to the heat converter (11), and the larger diameter end of the second chamber (5) is close to the partition (3).

6. A heat treatment vacuum furnace according to claim 1, characterized in that: The area of ​​the heating inner furnace (6) for placing the placement plate (12) is composed of a plurality of strip-shaped reinforcing ribs. The surface of the placement plate (12) is divided into a central area (21), a transition area (22) and an edge area (23). The central area (21) is provided with a fully enclosed hexagonal honeycomb hole array. The honeycomb hole array of the transition area (22) is connected on one side using a 120° Y-type connection. The honeycomb hole array of the edge area (23) is set to be connected on all sides. The thickness of the honeycomb hole wall of the central area (21) is 1.2 times that of the transition area (22). The thickness of the honeycomb hole wall of the transition area (22) is 1.15 times that of the edge area (23). The inner side of the honeycomb hole wall on the placement plate (12) is provided with diamond convex patterns.

7. A heat treatment vacuum furnace according to claim 1, characterized in that: The heating inner furnace (6) is a rectangular structure, and the interlayer of the heating inner furnace (6) is filled with Al-Si alloy microcapsules.

8. The heat treatment vacuum furnace according to claim 1, characterized in that: The heating component (7) is selected from graphite heating elements, metal heating elements or ceramic composite heating elements.

9. The heat treatment vacuum furnace according to claim 1, characterized in that: Pins on the upper and lower sides of the furnace body (1) are provided with cylinders (17) for controlling the opening and closing of the sealing door (9).

10. The heat treatment vacuum furnace according to claim 1, characterized in that: The vent (10) is a truncated cone-shaped vent or a rectangular cone-shaped vent, and the valve body matched with the vent (10) is a pneumatic high vacuum baffle valve or an electric ventilation butterfly valve.

Images