Vacuum sintering furnace and sintering method thereof

Abstract

Embodiments of the present application provide a vacuum sintering furnace and a sintering method thereof, and relate to the field of sintering equipment. The vacuum sintering furnace comprises a gas inlet pipe, a heating cylinder and a containing cylinder; wherein the heating cylinder is sleeved on the containing cylinder, the heating cylinder is in a ring structure, an annular flow channel is formed on the heating cylinder, a heating block and a separation block are arranged in the annular flow channel, the heating cylinder is provided with a gas inlet and a gas outlet, the gas inlet pipe is communicated with the gas inlet, the gas inlet and the gas outlet are both communicated with the annular flow channel, and the gas inlet and the gas outlet are respectively located on the two sides of the separation block; the inner side of the containing cylinder is formed with a sintering cavity, the containing cylinder is provided with a second through hole, and the second through hole is communicated between the sintering cavity and the gas outlet. The vacuum sintering furnace and the sintering method thereof can reduce the collision between the low-temperature gas entering and the high-temperature gas after heating during the sintering operation, avoid the increase of energy consumption caused by the heating block meeting cold, ensure the stability of the atmosphere field in the furnace and the uniformity of the temperature field.

Description

Technical Field

[0001] This invention relates to the field of sintering equipment, and more specifically, to a vacuum sintering furnace and its sintering method. Background Technology

[0002] A vacuum sintering furnace is a furnace used for protective sintering of heated materials in a vacuum environment. It is widely used in the industrial production of materials such as cemented carbide and ceramics. The uniformity of the temperature field and atmosphere field in the sintering furnace are two key factors affecting the quality of the sintered products.

[0003] Due to the structural limitations of existing sintering furnaces, the introduced gas is prone to temperature differences. Furthermore, the newly introduced low-temperature gas is likely to collide with the already heated high-temperature gas, causing the heating blocks to cool down and increasing energy consumption. This also leads to instability in the furnace atmosphere and disrupts the uniformity of the furnace temperature field. Summary of the Invention

[0004] This invention provides a vacuum sintering furnace and its sintering method, which can reduce the collision between the introduced low-temperature gas and the already heated high-temperature gas, avoid the heating block from cooling and increasing energy consumption, and ensure the stability of the atmosphere field and the uniformity of the temperature field inside the furnace.

[0005] The embodiments of the present invention can be implemented as follows:

[0006] An embodiment of the present invention provides a vacuum sintering furnace, comprising:

[0007] Intake pipe, heating cylinder, and container cylinder;

[0008] The heating cylinder is fitted inside the receiving cylinder. The heating cylinder has an annular structure and an annular flow channel. A heating block and an isolation block are installed inside the annular flow channel. The heating cylinder has an air inlet and an air outlet. An air inlet pipe is connected to the air inlet. Both the air inlet and the air outlet are connected to the annular flow channel. The air inlet and the air outlet are located on both sides of the isolation block. The isolation block allows the gas to flow unidirectionally along the annular flow channel.

[0009] A sintering cavity is formed on the inner side of the container cylinder, and a second through hole is provided in the container cylinder, which connects the sintering cavity and the gas outlet.

[0010] Optionally, there are at least two heating blocks. An air inlet chamber and an air outlet chamber are formed between the isolation block and the two adjacent heating blocks, respectively. The air inlet is connected to the air inlet chamber, and the air outlet is connected to the air outlet chamber. A flow chamber is formed between the two adjacent heating blocks. The air inlet chamber, the flow chamber, and the air outlet chamber are connected in sequence to form an annular flow channel.

[0011] Optionally, the volume of the intake chamber is equal to the volume of the exhaust chamber, which in turn is equal to the volume of the flow chamber.

[0012] Optionally, the heating cylinder includes an inner ring wall and an outer ring wall, an annular flow channel is formed between the inner ring wall and the outer ring wall, an air inlet is opened in the outer ring wall, an air outlet is opened in the inner ring wall, a heating block and an isolation block are both connected between the inner ring wall and the outer ring wall, and a first through hole is provided through the heating block along the annular direction of the heating cylinder.

[0013] Optionally, there may be multiple first through holes, and an array of multiple first through holes may be configured.

[0014] Optionally, the vacuum sintering furnace also includes a movable plate with a third through hole. The movable plate is slidably fitted with the receiving cylinder so that a pressure regulating flow channel is formed between the third through hole and the second through hole, or the movable plate can close the second through hole.

[0015] Optionally, the pressure regulating flow channel is oriented towards the air outlet.

[0016] Optionally, the movable plate is arc-shaped, and the arc-shaped inner wall of the movable plate contacts the outer wall of the receiving cylinder.

[0017] Optionally, the vacuum sintering furnace also includes an insulation cylinder, which is fitted inside the heating cylinder, and the air inlet pipe passes through the insulation cylinder.

[0018] An embodiment of the present invention also provides a sintering method for a vacuum sintering furnace, used in the aforementioned vacuum sintering furnace, comprising the following steps:

[0019] The heating block is heated to the first preset temperature, and a vacuum operation is performed on the annular flow channel and the sintering chamber.

[0020] Argon gas is introduced into the annular flow channel through the air inlet via the air inlet pipe. The argon gas is heated as it flows along the annular flow channel.

[0021] Argon gas, which is controlled to rise in temperature, enters the sintering chamber sequentially through the outlet and the second through hole.

[0022] The beneficial effects of the vacuum sintering furnace and the sintering method of the vacuum sintering furnace according to embodiments of the present invention include, for example:

[0023] The vacuum sintering furnace includes an inlet pipe, a heating cylinder, and a receiving cylinder. The heating cylinder is fitted inside the receiving cylinder and has an annular structure. An annular flow channel is formed on the heating cylinder, and heating blocks and isolation blocks are arranged within the annular flow channel. The heating cylinder has an inlet and an outlet, and the inlet pipe is connected to the inlet. Both the inlet and outlet are connected to the annular flow channel, and the inlet and outlet are located on opposite sides of the isolation blocks. A sintering cavity is formed inside the receiving cylinder, and a second through hole is provided, connecting the sintering cavity and the outlet. During sintering, the inlet pipe can deliver gas to the annular flow channel through the inlet, allowing the gas to flow unidirectionally along the annular flow channel. The gas is heated through contact with the heating blocks, which reduces the collision between the introduced low-temperature gas and the already heated high-temperature gas, preventing the heating blocks from cooling down and increasing energy consumption. Furthermore, the heating block can uniformly heat the flowing gas, and the heated gas then enters the sintering chamber through the gas outlet and the second through hole, thereby ensuring the stability of the atmosphere field and the uniformity of the temperature field inside the furnace. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a first-view structural schematic diagram of the vacuum sintering furnace provided in an embodiment of the present invention;

[0026] Figure 2 This is a second-view structural schematic diagram of the vacuum sintering furnace provided in an embodiment of the present invention;

[0027] Figure 3 This is a third-view structural schematic diagram of the vacuum sintering furnace provided in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram showing the location of the air inlet provided in an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram showing the location of the air outlet in an embodiment of the present invention;

[0030] Figure 6 This is a first-view structural schematic diagram of the accommodating cylinder and the movable plate provided in an embodiment of the present invention;

[0031] Figure 7 This is a structural schematic diagram of the accommodating cylinder and the movable plate provided in an embodiment of the present invention from a second perspective.

[0032] Figure 8 for Figure 7 Schematic diagram of cross section AA.

[0033] Icons: 100-Vacuum sintering furnace; 110-Inlet pipe; 120-Heating cylinder; 1201-Inlet; 1202-Outlet; 121-Annular flow channel; 1211-Inlet chamber; 1212-Flow chamber; 1213-Outlet chamber; 122-Heating block; 1221-First through hole; 123-Isolation block; 128-Inner ring wall; 129-Outer ring wall; 130-Containing cylinder; 131-Sintering chamber; 132-Second through hole; 140-Moving plate; 141-Third through hole; 150-Pressure regulating flow channel; 160-Insulation cylinder. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0036] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0037] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0038] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0039] The terms “comprising,” “including,” or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0040] Unless otherwise explicitly specified and limited, terms such as "setup" and "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0042] A vacuum sintering furnace is a furnace used for protective sintering of heated materials in a vacuum environment. It is widely used in the industrial production of materials such as cemented carbide and ceramics. The uniformity of the temperature and atmosphere fields within the sintering furnace are two key factors affecting the quality of the sintered products. The inventors' research revealed that existing sintering furnaces, due to their structural limitations, are prone to temperature differences in the introduced gas. Furthermore, the newly introduced low-temperature gas easily collides with the already heated high-temperature gas, causing the heated blocks to cool down, increasing energy consumption, and leading to an unstable atmosphere field within the furnace, thus disrupting the uniformity of the temperature field.

[0043] Please refer to Figures 1-8 The vacuum sintering furnace 100 and the sintering method of the vacuum sintering furnace 100 provided in the embodiments of the present invention can solve the above problems, and will be described in detail below.

[0044] refer to Figures 1-3 The vacuum sintering furnace 100 includes an air inlet pipe 110, a heating cylinder 120, and a receiving cylinder 130;

[0045] The heating cylinder 120 is sleeved on the receiving cylinder 130. The heating cylinder 120 has an annular structure and an annular flow channel 121 is formed on the heating cylinder 120. A heating block 122 and an isolation block 123 are arranged in the annular flow channel 121. The heating cylinder 120 has an air inlet 1201 and an air outlet 1202. An air inlet pipe 110 is connected to the air inlet 1201. Both the air inlet 1201 and the air outlet 1202 are connected to the annular flow channel 121. The air inlet 1201 and the air outlet 1202 are located on both sides of the isolation block 123, respectively. A sintering cavity 131 is formed on the inner side of the receiving cylinder 130. The receiving cylinder 130 has a second through hole 132, which is connected between the sintering cavity 131 and the air outlet 1202.

[0046] During sintering operations, the vacuum sintering furnace 100 allows the gas inlet pipe 110 to supply gas to the annular flow channel 121 through the inlet port 1201. The gas flows unidirectionally along the annular flow channel 121, heating up through contact with the heating block 122. This reduces the likelihood of collisions between the introduced low-temperature gas and the already heated high-temperature gas, preventing the heating block 122 from cooling down and increasing energy consumption. Furthermore, the heating block 122 can uniformly heat the flowing gas. The heated gas then enters the sintering chamber 131 through the outlet port 1202 and the second through-hole 132, ensuring a stable atmosphere and uniform temperature within the furnace.

[0047] The vacuum sintering furnace 100 also includes a furnace door. When the heating cylinder 120 and the housing cylinder 130 are open at one end, the furnace door is used to close the open end to ensure the overall airtightness of the vacuum sintering furnace 100. When the heating cylinder 120 and the housing cylinder 130 are open at both ends, the furnace door is used to close both open ends respectively. Of course, the heating cylinder 120 and the housing cylinder 130 can be independently connected to a door structure, which can achieve independent sealing of the heating cylinder 120 and the housing cylinder 130.

[0048] Furthermore, the container 130 is made of graphite, which is chemically inert and corrosion-resistant, making it suitable as a sintering container. In addition, by setting the heating cylinder 120 into an annular structure, it is easy to form an annular flow channel 121, which helps to ensure that the gas has a sufficient path during flow, thereby facilitating the orderly heating of the gas to a suitable temperature.

[0049] refer to Figures 1-5The number of heating blocks 122 is at least two. An air inlet chamber 1211 and an air outlet chamber 1213 are formed between the isolation block 123 and the two adjacent heating blocks 122, respectively. The air inlet 1201 is connected to the air inlet chamber 1211, and the air outlet 1202 is connected to the air outlet chamber 1213. A flow chamber 1212 is formed between the two adjacent heating blocks 122. The air inlet chamber 1211, the flow chamber 1212 and the air outlet chamber 1213 are connected in sequence to form an annular flow channel 121.

[0050] In the above technical solution, the isolation block 123 can separate the annular flow channel 121, so that after the gas enters the annular flow channel 121, it flows unidirectionally from the inlet chamber 1211 to the flow chamber 1212 to the outlet chamber 1213. On the one hand, it avoids the expansion of the newly filled gas at the inlet 1201 with the heated high-temperature gas, and on the other hand, it can make the gas flow in an orderly manner and heat evenly, further ensuring the stability and uniformity of the atmosphere field and temperature field.

[0051] It is worth noting that the heating block 122 is a solid structure. The heating block 122 can be a solid heat-conducting material that generates heat through an external power source; the heating block 122 can also be a hollow structure with heating wires arranged inside, which generate heat and then the heat is transferred through the side wall of the heating block 122.

[0052] refer to Figure 3 The volume of the intake chamber 1211 is equal to the volume of the exhaust chamber 1213, which is equal to the volume of the flow chamber 1212.

[0053] In the above technical solution, the volume of each cavity is equal, that is, the spacing between the heating block 122 and the isolation block 123 is consistent, which can avoid significant differences in the heating efficiency of the gas in different cavities, thereby ensuring the uniformity of the temperature field.

[0054] In this embodiment, there are nine heating blocks 122 and one isolation block 123, with all heating blocks 122 and isolation blocks 123 arranged at equal intervals. Of course, in other embodiments of the present invention, the specific number of heating blocks 122 can be two, three, six, ten, etc., and the specific number is not limited.

[0055] refer to Figure 1 , Figure 3 and Figure 5The heating cylinder 120 includes an inner ring wall 128 and an outer ring wall 129. An annular flow channel 121 is formed between the inner ring wall 128 and the outer ring wall 129. An air inlet 1201 is opened in the outer ring wall 129, and an air outlet 1202 is opened in the inner ring wall 128. The heating block 122 and the isolation block 123 are both connected between the inner ring wall 128 and the outer ring wall 129. The heating block 122 has a first through hole 1221 through it along the annular direction of the heating cylinder 120.

[0056] In the above technical solution, the heating block 122 is connected to both the inner ring wall 128 and the outer ring wall 129, which can be separated to form adjacent flow cavities 1212. By opening the first through hole 1221, the gas can flow between the adjacent flow cavities 1212, and the gas flowing along the annular flow channel 121 will inevitably come into contact with the heating block 122 and the first through hole 1221, thereby ensuring the heating efficiency of the gas.

[0057] refer to Figure 5 The number of first through holes 1221 is multiple, and multiple first through holes 1221 are arranged in an array.

[0058] In the above technical solution, by arraying multiple first through holes 1221, the flow can be evenly distributed, while ensuring the flow efficiency of gas between adjacent flow chambers 1212.

[0059] In this embodiment, the first through holes 1221 on a single heating block 122 are arranged in two rows and multiple columns, and the cross-section of the first through holes 1221 is circular, which can avoid the presence of sharp corners that affect gas flow.

[0060] refer to Figure 3 , Figure 6 and Figure 8 The vacuum sintering furnace 100 also includes a movable plate 140, which has a third through hole 141. The movable plate 140 is slidably engaged with the accommodating cylinder 130 so that a pressure regulating flow channel 150 is formed between the third through hole 141 and the second through hole 132, or the movable plate 140 can close the second through hole 132.

[0061] In the above technical solution, the relative sliding of the movable plate 140 and the accommodating cylinder 130 causes a change in the overlapping area of ​​the second through hole 132 and the third through hole 141. When the second through hole 132 and the third through hole 141 partially overlap, a pressure regulating flow channel 150 can be formed, facilitating the entry of heated gas into the sintering chamber 131. The overlapping area can be adjusted to change the passage size of the pressure regulating flow channel 150, thereby achieving a pressure regulating effect. When the second through hole 132 and the third through hole 141 do not overlap, i.e., the movable plate 140 closes the second through hole 132 and the pressure regulating flow channel 150 is closed, it can prevent heated gas from entering the sintering chamber 131.

[0062] refer to Figure 2 and Figure 3 The pressure regulating flow channel 150 is set towards the air outlet 1202.

[0063] In the above technical solution, by limiting the setting direction of the pressure regulating flow channel 150, the gas flowing out of the outlet 1202 can quickly enter the sintering chamber 131 through the pressure regulating flow channel 150.

[0064] Of course, in other embodiments of the present invention, the orientation of the pressure regulating flow channel 150 can be adjusted as needed.

[0065] refer to Figure 6 The movable plate 140 is arc-shaped, and the arc-shaped inner wall of the movable plate 140 is in contact with the outer wall of the accommodating cylinder 130.

[0066] In the above technical solution, the movable plate 140 can be tightly attached to the outer wall of the accommodating cylinder 130. On the one hand, this avoids the leakage of gas due to the gap between the second through hole 132 and the third through hole 141. On the other hand, the movable plate 140 is not directly set in the sintering cavity 131, which can fully ensure the sintering space and facilitate the relative sliding between the movable plate 140 and the accommodating cylinder 130.

[0067] It is worth noting that a sliding drive can be provided on the outside of the accommodating cylinder 130. The sliding drive is connected to the movable plate 140 and is used to drive the movable plate 140 to slide relative to the accommodating cylinder 130.

[0068] refer to Figures 1-3 The vacuum sintering furnace 100 also includes a heat preservation cylinder 160, which is sleeved on the heating cylinder 120, and the air inlet pipe 110 is installed through the heat preservation cylinder 160.

[0069] In the above technical solution, by setting up the heat insulation cylinder 160, the heating cylinder 120 can be kept warm to a certain extent, and heat leakage inside the heating cylinder 120 can be prevented.

[0070] An embodiment of the present invention also provides a sintering method for a vacuum sintering furnace 100, used in the aforementioned vacuum sintering furnace 100, comprising the following steps:

[0071] S1: Control the heating block 122 to heat to the first preset temperature, and perform vacuuming operation on the annular flow channel 121 and the sintering chamber 131. Specifically, the range of the first preset temperature is 575℃~625℃, preferably 600℃; and before vacuuming, hydrogen gas can be introduced to expel the gas in the furnace.

[0072] It is worth noting that the hydrogen gas is introduced to remove the paraffin-laden air from the sintering chamber 131. This is because powder metallurgy involves fusing metal powder with a binder, followed by a sintering process to enhance mechanical properties. Under high temperature and pressure, the wax will evaporate; if hydrogen gas is introduced immediately, the paraffin vapor will not evaporate completely. Furthermore, since the air inlet 1201 is on the outside of the container 130, while the opening for collecting the wax is inside the container 130, directly creating a vacuum would require the gas to move slowly through permeation, significantly impacting operational efficiency.

[0073] S2: The intake pipe 110 is controlled to inject argon gas into the annular flow channel 121 through the intake port 1201. The argon gas is heated while flowing along the annular flow channel 121. Before injecting argon gas, it can be further heated to a second preset temperature, which is in the range of 1275℃~1325℃, preferably 1300℃. Injecting argon gas is mainly used to pressurize the system.

[0074] It is worth noting that argon is an inert gas and is mainly used to protect metal powder from reacting with oxygen during the sintering process.

[0075] Furthermore, there is a significant temperature difference between the second preset temperature and the first preset temperature because, under the first preset temperature condition, paraffin will decompose into carbon and hydrogen at high temperatures. The decomposed hydrogen will be carried away along with the undecomposed paraffin vapor, while the carbon will be retained as a binder for the metal powder. Under high temperature and high pressure conditions, the adhesion between the metal powders can be improved.

[0076] S3: The argon gas controlled by heating enters the sintering chamber 131 through the outlet 1202 and the second through hole 132 in sequence.

[0077] It is worth noting that after being pressurized with argon gas for a period of time, the furnace can be continuously heated to a third preset temperature, which is in the range of 1425℃~1475℃, preferably 1450℃; then the pressure is maintained and the temperature is lowered for a period of time, followed by depressurization and cooling for a period of time, and finally the furnace door is opened to allow air to enter for rapid cooling.

[0078] Furthermore, the bonding reaction of carbon to metal powder will continue during the heating process to the third preset temperature until the metal powder and the adhesive are stably bonded together under pressure and temperature, and then the furnace door is opened for rapid cooling.

[0079] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A vacuum sintering furnace, characterized in that, include: Air inlet pipe (110), heating cylinder (120) and receiving cylinder (130); The heating cylinder (120) is sleeved on the receiving cylinder (130). The heating cylinder (120) has an annular structure and an annular flow channel (121) is formed on the heating cylinder (120). A heating block (122) and an isolation block (123) are arranged in the annular flow channel (121). The heating cylinder (120) has an air inlet (1201) and an air outlet (1202). The air inlet pipe (110) is connected to the air inlet (1201). The air inlet (1201) and the air outlet (1202) are both connected to the annular flow channel (121). The air inlet (1201) and the air outlet (1202) are located on both sides of the isolation block (123). The isolation block (123) allows the gas to flow unidirectionally along the annular flow channel (121). A sintering cavity (131) is formed on the inner side of the accommodating cylinder (130), and a second through hole (132) is provided in the accommodating cylinder (130). The second through hole (132) is connected between the sintering cavity (131) and the gas outlet (1202).

2. The vacuum sintering furnace according to claim 1, characterized in that, The number of heating blocks (122) is at least two. An air inlet chamber (1211) and an air outlet chamber (1213) are formed between the isolation block (123) and the two adjacent heating blocks (122), respectively. The air inlet (1201) is connected to the air inlet chamber (1211), and the air outlet (1202) is connected to the air outlet chamber (1213). A flow chamber (1212) is formed between the two adjacent heating blocks (122). The air inlet chamber (1211), the flow chamber (1212), and the air outlet chamber (1213) are connected in sequence to form the annular flow channel (121).

3. The vacuum sintering furnace according to claim 2, characterized in that, The volume of the air inlet chamber (1211) is equal to the volume of the air outlet chamber (1213) and the volume of the flow chamber (1212).

4. The vacuum sintering furnace according to claim 1, characterized in that, The heating cylinder (120) includes an inner ring wall (128) and an outer ring wall (129). The annular flow channel (121) is formed between the inner ring wall (128) and the outer ring wall (129). The air inlet (1201) is opened on the outer ring wall (129), and the air outlet (1202) is opened on the inner ring wall (128). The heating block (122) and the isolation block (123) are both connected between the inner ring wall (128) and the outer ring wall (129). The heating block (122) has a first through hole (1221) through it along the annular direction of the heating cylinder (120).

5. The vacuum sintering furnace according to claim 4, characterized in that, The number of the first through holes (1221) is multiple, and the multiple first through holes (1221) are arranged in an array.

6. The vacuum sintering furnace according to any one of claims 1-5, characterized in that, The vacuum sintering furnace also includes a movable plate (140), which has a third through hole (141). The movable plate (140) is slidably engaged with the accommodating cylinder (130) so that a pressure regulating flow channel (150) is formed between the third through hole (141) and the second through hole (132), or the movable plate (140) closes the second through hole (132).

7. The vacuum sintering furnace according to claim 6, characterized in that, The pressure regulating flow channel (150) is positioned toward the air outlet (1202).

8. The vacuum sintering furnace according to claim 6, characterized in that, The movable plate (140) is arc-shaped, and the arc-shaped inner wall of the movable plate (140) is in contact with the outer wall of the accommodating cylinder (130).

9. The vacuum sintering furnace according to any one of claims 1-5, characterized in that, The vacuum sintering furnace also includes a heat preservation cylinder (160), which is sleeved on the heating cylinder (120), and the air inlet pipe (110) is arranged through the heat preservation cylinder (160).

10. A sintering method in a vacuum sintering furnace, characterized in that, The vacuum sintering furnace according to any one of claims 1-9 comprises the following steps: The heating block (122) is heated to a first preset temperature, and a vacuum operation is performed on the annular flow channel (121) and the sintering chamber (131). The air inlet pipe (110) is controlled to fill argon gas into the annular flow channel (121) through the air inlet (1201), and the argon gas is heated while flowing along the annular flow channel (121); Argon gas, which is controlled to rise in temperature, enters the sintering chamber (131) sequentially through the outlet (1202) and the second through hole (132).

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