Graphite cushion block for hot pressing sintering furnace

Abstract

The utility model provides a graphite cushion block for a hot-pressing sintering furnace. The graphite cushion block comprises a graphite cushion block body, the graphite cushion blocks are correspondingly arranged at the upper end and the lower end of the sintering mold and arranged between the sintering mold and the electrode blocks, the graphite cushion blocks comprise flat cushion blocks and hollow heat conduction blocks, the flat cushion blocks are symmetrically arranged at the upper end and the lower end of the sintering mold, and the hollow heat conduction blocks are clamped between the corresponding flat cushion blocks and the electrode blocks. A hollow area is arranged in the middle of the hollow heat conduction block in the vertical axial direction, and induction current can be guided to preferentially flow along the periphery of the flat cushion block by adjusting the thickness of the hollow heat conduction block and the width of the hollow area, so that the temperature difference between the core of the sintering mold and the periphery is balanced. The hollow heat conduction block is additionally arranged between the flat cushion block and the electrode block, so that induced current is guided to flow from the periphery preferentially, the heating effect and the temperature effect of the periphery of the mold are improved, conduction of the induced current of a core part is reduced, and the temperature difference caused by heat loss generated by contact between the periphery and the outside is balanced.

Description

Technical Field

[0001] This utility model relates to the field of hot pressing sintering, and in particular to a graphite pad for a hot pressing sintering furnace. Background Technology

[0002] Hot pressing sintering is an important process for forming powder metallurgy materials using molds, and it is widely used in cutting tools, cemented carbide, and other fields. During hot pressing sintering, the graphite pads (or heat-conducting blocks) at the top and bottom of the mold play a crucial role in conducting heat and uniformly distributing the temperature field. Traditional solid pads are square or rectangular solid structures. When induced current is conducted to the mold through the pads, the current density is concentrated in the center of the pad surface. Due to the long heat dissipation path and rapid heat accumulation in the central area, while the edge areas have a large contact area with the external environment and a high heat dissipation rate, the temperature in the center of the mold is significantly higher than the surrounding areas. This temperature gradient causes uneven grain growth inside the product, directly affecting the consistency of the material's density, hardness, and mechanical strength.

[0003] Existing technology CN202323614806.3 discloses a polycrystalline diamond sintering mold, including a synthesis cavity, an insulating and thermally conductive layer surrounding the synthesis cavity, and a heating layer located outside the insulating and thermally conductive layer. Thinning portions are provided at both axial ends of the insulating and thermally conductive layer, and the heating layer includes embedded portions corresponding to the thinning portions. Although this solution can make the temperature field distribution within the synthesis cavity more uniform through the insulating and thermally conductive layer, it still has the following problems:

[0004] 1. While it optimizes the temperature field through the design of a thinner insulating and thermally conductive layer, it does not fundamentally solve the problem of current accumulation at the center of the pad surface. In addition, the solution has limited adjustment to the overall heat dissipation path of the mold, and there is still a temperature difference accumulation caused by excessive heat dissipation in the edge area. Furthermore, the insulating layer may introduce interfacial thermal resistance, reducing heat conduction efficiency.

[0005] 2. The solution adopts a composite structure of insulating and heat-conducting layer and heating layer. Temperature field optimization is achieved through precise matching of thinning part and embedding part. However, the processing and assembly process of multi-layer structure is complicated, and the requirements for coaxiality and thickness uniformity of mold are extremely high. In actual production, small dimensional deviations or interlayer gaps may lead to local stress concentration or sudden changes in heat conduction path, which will aggravate temperature non-uniformity and increase mold manufacturing cost and scrap rate. Utility Model Content

[0006] In view of this, the purpose of this utility model is to provide a graphite pad for a hot pressing sintering furnace. By adding a hollow heat-conducting block between the flat pad and the electrode block, the induced current is guided to flow preferentially from the surrounding area, thereby increasing the heating and temperature effects around the mold, reducing the conduction of the induced current in the core, and balancing the temperature difference caused by heat loss due to contact with the outside environment.

[0007] The technical solution adopted by the present utility model to solve its technical problems is as follows:

[0008] Provide a graphite cushion block for a hot press sintering furnace, including: a graphite cushion block; the graphite cushion blocks are respectively arranged at the upper and lower ends of the sintering mold, and are respectively arranged between the sintering mold and the electrode block.

[0009] The graphite cushion block includes a flat cushion block and a hollow heat-conducting block. The flat cushion blocks are symmetrically arranged at the upper and lower ends of the sintering mold. The hollow heat-conducting block is clamped between the corresponding flat cushion block and the electrode block. A hollow area is provided along the vertical axis in the middle of the hollow heat-conducting block, and by adjusting the thickness of the hollow heat-conducting block and the width of the hollow area, the induced current can be guided to flow preferentially along the periphery of the flat cushion block to balance the temperature difference between the core and the periphery of the sintering mold.

[0010] It should be noted that the shape of the hollow area can be annular, polygonal or special-shaped. When the hot press sintering furnace is working, the electrode block is energized to generate an induced current. Since there is a hollow area in the middle of the hollow heat-conducting block, the conduction path of the current is changed, so that the induced current preferentially flows along the periphery of the flat cushion block. In this way, more heat is generated around the sintering mold, thereby balancing the temperature difference originally existing between the core and the periphery of the sintering mold; effectively solving the problem of uneven temperature between the core and the periphery of the sintering mold during the hot press sintering process, making the sintering process more stable, and improving the quality and consistency of the product.

[0011] Preferably, the shape of the hollow area is square, the hollow heat-conducting block is integrally in a hollow structure in the shape of a square frame, and the inner frame size of the hollow heat-conducting block is adapted to the cavity size of the sintering mold.

[0012] It should be noted that the hollow heat-conducting block is in a hollow structure in the shape of a square frame, and the inner frame size is adapted to the cavity size of the sintering mold. This structural design makes the current more concentrated on the periphery of the sintering mold during the conduction process, further enhancing the balancing effect on the temperature difference, further optimizing the conduction path of the current, more precisely controlling the heat distribution around the sintering mold, and improving the temperature balance effect.

[0013] Preferably, the inner frame size of the hollow heat-conducting block can be adjusted by nesting hollow adjusting blocks of different sizes. The thickness of the hollow adjusting block is the same as that of the hollow heat-conducting block, and the material of the hollow adjusting block is graphite material.

[0014] It should be noted that by nesting hollow adjusting blocks of different sizes to adjust the inner frame size of the hollow heat-conducting block, the conduction path of the current and the heat distribution can be changed to adapt to sintering molds of different sizes and process requirements, increasing the versatility and flexibility of the graphite cushion block, which can be adjusted according to different sintering requirements, and improving the applicability of the equipment.

[0015] Preferably, the outer surface of the hollow adjusting block is provided with a plurality of evenly distributed positioning protrusions, and the inner frame of the hollow heat-conducting block is provided with positioning grooves corresponding to the positioning protrusions. The hollow adjusting block is nested in the inner frame of the hollow heat-conducting block through the cooperation of the positioning protrusions and the positioning grooves.

[0016] It should be noted that the positioning protrusion of the hollow adjusting block and the positioning groove of the inner frame of the hollow heat-conducting block cooperate with each other to ensure that the hollow adjusting block can be accurately installed during the nesting process and will not shift during the hot pressing and sintering process. This ensures the stability of the current conduction path and heat distribution, improves the accuracy and stability of the hollow adjusting block installation, and further ensures the effect of temperature balance.

[0017] Preferably, the hollow heat-conducting block is formed by stacking several heat-conducting plates, and the thickness of the hollow heat-conducting block can be adjusted by increasing or decreasing the number of heat-conducting plates, and adjacent heat-conducting plates are connected by graphite adhesive or tenon and mortise structure.

[0018] It should be noted that the hollow heat-conducting block is composed of several stacked heat-conducting plates. The thickness of the hollow heat-conducting block can be adjusted by increasing or decreasing the number of heat-conducting plates. Different thicknesses affect the current conduction path and heat distribution, thereby achieving temperature difference regulation. Adjacent heat-conducting plates are connected by graphite adhesive or tenon and mortise structures, ensuring the integrity and stability of the hollow heat-conducting block. The thickness of the hollow heat-conducting block can be flexibly adjusted according to the specific hot-pressing sintering process and temperature requirements to further optimize the temperature balance effect. At the same time, the connection method of graphite adhesive or tenon and mortise structures ensures the structural strength of the hollow heat-conducting block.

[0019] Preferably, the outer upper edge of the heat-conducting plate is provided with an annular protective protrusion, and the height of the protective protrusion is less than the thickness of the heat-conducting plate, and the outer lower edge of the heat-conducting plate can be nested in the corresponding protective protrusion.

[0020] It should be noted that when the heat-conducting plates are stacked, the lower outer edge of the next heat-conducting plate is embedded into the protective protrusion of the previous heat-conducting plate, forming a mechanical connection similar to a "mortise and tenon joint". The nested structure increases the contact area between adjacent heat-conducting plates, reduces the risk of misalignment caused by thermal expansion, and ensures the overall structural stability of the hollow heat-conducting block. At the same time, the sealing flange forms a mechanical seal through physical nesting, and combined with graphite adhesive filling the gaps, it prevents the adhesive from overflowing under high temperature and pressure, ensuring the connection strength and sealing performance between the heat-conducting plates.

[0021] Preferably, the contact surfaces of the flat pad and the hollow heat-conducting block are provided with mutually cooperating positioning structures. The positioning structures are positioning pins and positioning holes. The positioning pins are detachably mounted on the flat pads, and the hollow heat-conducting block is provided with positioning holes corresponding to the positioning pins. The hollow heat-conducting block is mounted on the flat pads through the cooperation of the positioning pins and positioning holes.

[0022] It should be noted that the flat pad and the hollow heat-conducting block are connected by a locating pin and a locating hole. The locating pin is detachably mounted on the flat pad, facilitating the installation and removal of the hollow heat-conducting block. This ensures the accurate relative position between the flat pad and the hollow heat-conducting block, guaranteeing the stability of the current conduction path and heat distribution. It also improves the accuracy and convenience of installing the flat pad and the hollow heat-conducting block, ensuring the stability of the connection between them, further optimizing the temperature balance effect. Furthermore, when replacing hollow adjustment blocks of different specifications or performing equipment maintenance, the detachable locating pin allows for quick and convenient disassembly and installation of the hollow heat-conducting block, improving work efficiency.

[0023] The beneficial effects of this utility model are:

[0024] This utility model provides a graphite pad for a hot-press sintering furnace. Through the hollow area design of the hollow heat-conducting block, the induced current is forced to flow preferentially along the periphery of the flat pad, enhancing the heating effect around the sintering mold. This effectively compensates for heat loss caused by rapid heat dissipation at the edges, balancing the temperature difference between the core and the periphery, thereby solving the problem of uneven temperature distribution during sintering and improving the consistency of product density, hardness, and mechanical properties. The U-shaped hollow structure is adapted to the mold cavity size, further strengthening the peripheral heating effect and precisely controlling the temperature field distribution. Furthermore, the inner frame size of the hollow heat-conducting block can be adjusted by nesting hollow adjustment blocks of different specifications, and the stacked heat-conducting plate design allows for increasing or decreasing thickness. This enables the graphite pad to quickly adapt to sintering molds of different sizes and process parameters, significantly improving the equipment's versatility and process compatibility. Attached Figure Description

[0025] Figure 1 This is a three-dimensional structural diagram of a graphite pad for a hot-pressing sintering furnace according to Embodiment 1 of this utility model.

[0026] Figure 2 This is a reference diagram showing the usage state of a graphite pad for a hot pressing sintering furnace according to Embodiment 1 of this utility model.

[0027] Figure 3 This is a three-dimensional structural diagram of a graphite pad for a hot-pressing sintering furnace according to Embodiment 2 of this utility model.

[0028] Figure 4 This is an exploded structural diagram of a graphite pad for a hot-pressing sintering furnace according to Embodiment 2 of this utility model.

[0029] Figure 5 This is a reference diagram showing the usage state of a graphite pad for a hot pressing sintering furnace according to Embodiment 2 of this utility model.

[0030] Figure 6 This is a schematic diagram of the heat-conducting plate in Embodiment 2 of this utility model.

[0031] In the figure: 1. Graphite spacer block; 11. Flat spacer block; 12. Hollow heat-conducting block; 121. Positioning groove; 122. Heat-conducting plate; 13. Hollow adjusting block; 131. Positioning projection; 14. Hollow area; 2. Sintering die; 3. Electrode block; 4. Protective convex edge; 5. Positioning structure; 51. Positioning pin; 52. Positioning hole.

[0032] It should be noted that these drawings and text descriptions do not limit the scope of the concept of the present utility model in any way, but illustrate the concept of the present utility model to those skilled in the art by referring to specific embodiments. Specific embodiments

[0033] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0034] Embodiment 1

[0035] As Figure 1 and Figure 2 shown, a graphite spacer block for a hot-pressing sintering furnace includes: a graphite spacer block 1; the graphite spacer blocks 1 are respectively arranged at the upper and lower ends of the sintering die 2, and are respectively arranged between the sintering die 2 and the electrode block 3.

[0036] The graphite spacer block 1 includes a flat spacer block 11 and a hollow heat-conducting block 12. The flat spacer blocks 11 are symmetrically arranged at the upper and lower ends of the sintering die 2. The hollow heat-conducting block 12 is clamped between the corresponding flat spacer block 11 and the electrode block 3. A hollow area 14 is provided in the middle of the hollow heat-conducting block 12 along the vertical axis, and by adjusting the thickness of the hollow heat-conducting block 12 and the width of the hollow area 14, the induced current can be guided to flow preferentially along the periphery of the flat spacer block 11 to balance the temperature difference between the core and the periphery of the sintering die 2.

[0037] The shape of the hollow area 14 is square. The hollow heat-conducting block 12 is integrally in a square hollow structure. The inner frame size of the hollow heat-conducting block 12 is adapted to the cavity size of the sintering die 2.

[0038] The hollow heat-conducting block 12 is formed by stacking a plurality of heat-conducting plates 122, and the thickness of the hollow heat-conducting block 12 can be adjusted by increasing or decreasing the number of heat-conducting plates 122. The adjacent heat-conducting plates 122 are connected by graphite adhesive or tenon-mortise structure.

[0039] The working principle and usage method of a graphite spacer block for a hot-pressing sintering furnace in this embodiment:

[0040] This embodiment provides a graphite pad for a hot-press sintering furnace. A flat pad 11 serves as the basic support structure, directly contacting the sintering mold 2. Its flat surface ensures uniform heat conduction between the sintering mold 2 and the graphite pad 11, avoiding localized stress concentration. A hollow heat-conducting block 12 is sandwiched between the flat pad 11 and the electrode block 3. Its central hollow region 14 (a square U-shaped structure) forms a low-conductivity cross-sectional area, forcing the induced current to bypass the hollow region 14 and preferentially flow along the periphery of the flat pad 11 and the outer frame of the hollow heat-conducting block 12, thus strengthening the sintering mold. 2. The edge heating effect compensates for the temperature loss caused by rapid heat dissipation, achieving a balance between the core and the periphery in terms of temperature difference. The thickness of the hollow heat-conducting block 12 can be changed by increasing or decreasing the number of heat-conducting plates 122. The thickness adjustment directly affects the resistance value of the current path. Thicker heat-conducting block: resistance increases, and the current tends to flow more towards the periphery (strengthening periphery heating); thinner heat-conducting block: resistance decreases, and the current distribution is more uniform (suitable for low temperature difference scenarios). By increasing or decreasing the number of heat-conducting plates 122 to adjust the thickness of the hollow heat-conducting block 12, the resistance distribution of the current path is changed, achieving precise control of the temperature field.

[0041] In use, first place the flat pads 11 symmetrically at the upper and lower ends of the sintering mold 2, ensuring that the flat pads 11 are tightly fitted to the sintering mold 2 and that the center of the flat pads 11 is aligned with the center of the sintering mold 2 to ensure uniform heat conduction; then determine the number of heat-conducting plates 122 as needed and stack them sequentially; (if graphite adhesive is used for connection, apply adhesive evenly to the mating surfaces of adjacent heat-conducting plates 122, then align and press the heat-conducting plates 122 to fully fill the gaps with adhesive; if mortise and tenon structure is used for connection, accurately align the tenons and mortises and install them in place); next, clamp the assembled hollow heat-conducting block 12 between the flat pads 11 and the electrode block 3, ensuring that the inner frame of the hollow heat-conducting block 12 is aligned with the mold cavity of the sintering mold 2 to ensure that the induced current can flow according to the designed path; turn on the hot press sintering furnace. Based on the characteristics of the sintering material, the mold size, and the parameters of the hollow heat-conducting block 12, set appropriate parameters such as current, pressure, and time; start the equipment and begin heating. During the heating process, closely observe the temperature changes of the core and surrounding areas of the sintering mold 2. If the temperature difference is not as expected, it can be adjusted by increasing or decreasing the number of heat-conducting plates 122. For example, if the edge temperature of the sintering mold 2 is too low, the number of heat-conducting plates 122 can be increased appropriately; if the temperature difference between the core and the edge is small, the number of heat-conducting plates 122 can be reduced. When the temperature reaches the set value, enter the heat preservation stage and maintain it for a certain period of time to allow the material to be fully sintered. After the heat preservation is completed, cool it according to the specified cooling rate to avoid stress and cracks inside the material due to excessive cooling. After sintering is completed, wait for the equipment to cool to room temperature, disassemble the graphite pad 1 and the sintering mold 2, and take out the sintered parts.

[0042] Example 2

[0043] As Figures 3-6 shown, a graphite spacer block for a hot pressing sintering furnace in this embodiment includes: a graphite spacer block 1; the graphite spacer blocks 1 are respectively arranged at the upper and lower ends of a sintering mold 2, and are respectively arranged between the sintering mold 2 and electrode blocks 3.

[0044] The graphite spacer block 1 includes a flat spacer block 11 and a hollow heat-conducting block 12. The flat spacer blocks 11 are symmetrically arranged at the upper and lower ends of the sintering mold 2. The hollow heat-conducting block 12 is clamped between the corresponding flat spacer block 11 and the electrode block 3. A hollow area 14 is provided along the vertical axis in the middle of the hollow heat-conducting block 12, and by adjusting the thickness of the hollow heat-conducting block 12 and the width of the hollow area 14, the induced current can be guided to preferentially flow along the periphery of the flat spacer block 11 to balance the temperature difference between the core and the periphery of the sintering mold 2.

[0045] The shape of the hollow area 14 is square. The hollow heat-conducting block 12 as a whole has a square-shaped hollow structure. The inner frame size of the hollow heat-conducting block 12 is adapted to the cavity size of the sintering mold 2.

[0046] The inner frame size of the hollow heat-conducting block 12 can be adjusted by nesting hollow adjusting blocks 13 of different sizes. The thickness of the hollow adjusting block 13 is the same as that of the hollow heat-conducting block 12, and the material of the hollow adjusting block 13 is graphite material.

[0047] A number of uniformly distributed positioning protrusions 131 are provided on the outer side surface of the hollow adjusting block 13. Positioning grooves 121 are provided at the corresponding positions of the inner frame of the hollow heat-conducting block 12 for the positioning protrusions 131. The hollow adjusting block 13 is nested in the inner frame of the hollow heat-conducting block 12 through the cooperation of the positioning protrusions 131 and the positioning grooves 121.

[0048] The hollow heat-conducting block 12 is formed by stacking a number of heat-conducting plates 122, and the thickness of the hollow heat-conducting block 12 can be adjusted by increasing or decreasing the number of heat-conducting plates 122. The adjacent heat-conducting plates 122 are connected by graphite adhesives or tenon and mortise structures.

[0049] An annular protective convex edge 4 is provided on the upper edge of the outer side of the heat-conducting plate 122, and the height of the protective convex edge 4 is less than the thickness of the heat-conducting plate 122. The lower edge of the outer side of the heat-conducting plate 122 can be nested in the corresponding protective convex edge 4.

[0050] A mutually matching positioning structure 5 is provided on the contact surface between the flat spacer block 11 and the hollow heat-conducting block 12. The positioning structure 5 is a positioning pin 51 and a positioning hole 52. The positioning pin 51 is detachably arranged on the flat spacer block 11, and the hollow heat-conducting block 12 is provided with a positioning hole 52 corresponding to the positioning pin 51. The hollow heat-conducting block 12 is arranged on the flat spacer block 11 through the cooperation of the positioning pin 51 and the positioning hole 52.

[0051] Compared with Example 1:

[0052] This embodiment provides a graphite pad for a hot-press sintering furnace. By nesting hollow adjusting blocks 13 of different sizes inside the hollow heat-conducting block 12, the size of the inner frame can be flexibly adjusted, allowing the same set of graphite pads 1 to adapt to various sintering molds 2 of different specifications, greatly improving the versatility of the graphite pads 1. By selecting a suitable size hollow adjusting block 13, the degree to which the induced current preferentially flows along the periphery of the flat pad 11 can be precisely controlled according to the specific needs of different sintering molds 2, thereby more effectively balancing the temperature difference between the core and the periphery of the sintering mold 2, improving the quality and consistency of the sintered product. The positioning protrusion 131 on the outer side of the hollow adjusting block 13 cooperates with the positioning groove 121 of the inner frame of the hollow heat-conducting block 12, ensuring that the hollow adjusting block 13 can be accurately installed during the nesting process and will not shift during the hot-press sintering process, ensuring the stability of the current conduction path and heat distribution, and further improving the temperature balance effect. The lower outer edge of the heat-conducting plate 122 can be nested in the corresponding protective protrusion 4, forming a mechanical connection similar to a "mortise and tenon joint". This nested structure increases the contact area between adjacent heat-conducting plates 122, reduces the risk of misalignment caused by thermal expansion, and ensures the overall stability of the hollow heat-conducting block 12. Simultaneously, the sealing flange forms a mechanical seal through physical nesting, combined with graphite adhesive filling the gaps, preventing adhesive overflow under high temperature and pressure, thus ensuring the connection strength and sealing performance between the heat-conducting plates 122. The flat pad 11 and the hollow heat-conducting block 12 are connected through the cooperation of the positioning pin 51 and the positioning hole 52, ensuring accurate relative positioning between the flat pad 11 and the hollow heat-conducting block 12; ensuring the stability of the current conduction path and heat distribution, and avoiding uneven temperature caused by installation position deviations; the positioning pin 51 is detachably mounted on the flat pad 11, facilitating the installation and removal of the hollow heat-conducting block 12; when replacing hollow adjusting blocks 13 of different specifications or performing equipment maintenance, the disassembly and installation of the hollow heat-conducting block 12 can be completed quickly and conveniently, improving work efficiency.

[0053] Finally, it should be noted that the above description is only a preferred embodiment of this utility model and is used only to illustrate the technical solution of this utility model, and is not intended to limit the protection scope of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model are included within the protection scope of this utility model.

[0054] In the description of this utility model, it should be understood that the terms "upper", "lower", "upper end", "lower end", "upper surface", "lower surface", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model 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. Therefore, they should not be construed as limitations on this utility model.

[0055] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

Claims

1. A graphite pad for a hot-pressing sintering furnace, comprising: Graphite spacer block (1); the graphite spacer blocks (1) are respectively arranged at the upper and lower ends of the sintering die (2), and are respectively arranged between the sintering die (2) and the electrode block (3), and are characterized in that: The graphite spacer block (1) includes a flat spacer block (11) and a hollow heat-conducting block (12). The flat spacer blocks (11) are symmetrically arranged at the upper and lower ends of the sintering die (2). The hollow heat-conducting block (12) is clamped between the corresponding flat spacer block (11) and the electrode block (3). A hollow area (14) is provided along the vertical axis in the middle of the hollow heat-conducting block (12), and by adjusting the thickness of the hollow heat-conducting block (12) and the width of the hollow area (14), the induced current can be guided to preferentially flow along the periphery of the flat spacer block (11) to balance the temperature difference between the core and the periphery of the sintering die (2).

2. The graphite pad for a hot-pressing sintering furnace as described in claim 1, characterized in that: The shape of the hollow area (14) is square. The hollow heat-conducting block (12) is in an overall square-shaped hollow structure, and the inner frame size of the hollow heat-conducting block (12) is adapted to the cavity size of the sintering die (2).

3. A graphite pad for a hot-pressing sintering furnace as described in claim 2, characterized in that: The inner frame size of the hollow heat-conducting block (12) can be adjusted by nesting hollow adjusting blocks (13) of different sizes. The thickness of the hollow adjusting block (13) is the same as that of the hollow heat-conducting block (12), and the material of the hollow adjusting block (13) is graphite material.

4. A graphite pad for a hot-pressing sintering furnace as described in claim 3, characterized in that: A number of uniformly distributed positioning protrusions (131) are provided on the outer side surface of the hollow adjusting block (13). Positioning grooves (121) are provided at the corresponding positions of the inner frame of the hollow heat-conducting block (12) for the positioning protrusions (131). The hollow adjusting block (13) is nested in the inner frame of the hollow heat-conducting block (12) through the cooperation of the positioning protrusions (131) and the positioning grooves (121).

5. A graphite pad for a hot-pressing sintering furnace as described in claim 2, characterized in that: The hollow heat-conducting block (12) is stacked by a number of heat-conducting plates (122), and the thickness of the hollow heat-conducting block (12) can be adjusted by increasing or decreasing the number of heat-conducting plates (122). The adjacent heat-conducting plates (122) are connected by graphite adhesive or mortise and tenon structure.

6. A graphite pad for a hot-pressing sintering furnace as described in claim 5, characterized in that: An annular protective convex edge (4) is provided on the upper edge of the outer side of the heat-conducting plate (122), and the height of the protective convex edge (4) is less than the thickness of the heat-conducting plate (122). The lower edge of the outer side of the heat-conducting plate (122) can be nested in the corresponding protective convex edge (4).

7. A graphite pad for a hot-pressing sintering furnace as described in claim 2, characterized in that: A positioning structure (5) is provided on the contact surface between the flat spacer block (11) and the hollow heat-conducting block (12). The positioning structure (5) is a positioning pin (51) and a positioning hole (52). The positioning pin (51) is detachably arranged on the flat spacer block (11). A positioning hole (52) is provided on the hollow heat-conducting block (12) corresponding to the positioning pin (51). The hollow heat-conducting block (12) is arranged on the flat spacer block (11) through the cooperation of the positioning pin (51) and the positioning hole (52).

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