A heat preservation treatment method after high-temperature sintering of a diamond blade

Abstract

The application discloses a heat preservation treatment method for diamond blades after high-temperature sintering, which comprises the following steps: placing the sintered diamond blades into a heat preservation cavity and supporting the blades in the heat preservation cavity in a rotatable manner around the axis of the blades; introducing inert protective gas into the heat preservation cavity and driving the blades to rotate slowly around the axis of the blades by the gas flow; and adjusting the flow rate of the inert protective gas according to the temperature change in the heat preservation cavity to realize dynamic heat preservation treatment. The application drives the rotation of the blades by the gas flow, and does not need mechanical transmission mechanism, thereby improving the reliability of the equipment under high-temperature working conditions. Meanwhile, the cooling intensity is adaptively adjusted in sections according to the material characteristics of the blades in different temperature intervals, so that the cooling rate is controlled within a reasonable range, the generation of thermal stress and phase change stress is effectively inhibited, and the yield and use performance of the diamond blades are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy technology, and more specifically, to a method for heat preservation treatment after high-temperature sintering of diamond cutting tools. Background Technology

[0002] Diamond cutting tools, as a type of superhard material tool, are widely used in the cutting and processing of hard and brittle materials such as stone, ceramics, glass, and concrete. Their manufacturing process typically involves powder metallurgy sintering, where diamond particles are mixed with a metal binder and then sintered under high temperature and pressure. After sintering, the cutting tool needs to be slowly cooled from the sintering temperature (usually 600-900℃) to room temperature to obtain the desired mechanical properties and microstructure.

[0003] During the cooling process after sintering, a complex temperature gradient is generated inside the diamond cutting tool, leading to the generation of thermal stress. If the cooling rate is not properly controlled, the concentration of thermal stress may cause tool deformation, microcracks, or even overall cracking, seriously affecting the product yield and service life. Therefore, how to achieve uniform and controllable cooling of the cutting tool after sintering has been a long-standing technical challenge in this field.

[0004] Currently, the existing cooling methods for diamond cutting tools after sintering mainly include the following:

[0005] Firstly, the natural cooling method. This method involves placing the sintered blade in an insulated container and relying on natural environmental heat dissipation for cooling. While simple to operate, this method suffers from uncontrollable cooling rates, resulting in significant differences in cooling speed across different parts of the blade. This can easily lead to uneven thermal stress and a high rate of product scrap.

[0006] Secondly, there is the forced air cooling method. This method accelerates cooling by introducing cooling gas into the insulation cavity and using the gas flow to remove heat. However, existing forced air cooling methods typically use fixed-position airflow jets, resulting in uneven airflow distribution and inconsistent cooling rates across different parts of the blade surface, making it difficult to ensure a uniform temperature field. Furthermore, using a constant gas flow rate throughout the cooling process makes it impossible to dynamically adjust according to the material properties of the blade in different temperature ranges (such as the binder softening zone and phase change sensitive zone), which can easily lead to stress concentration in the phase change sensitive zone.

[0007] Thirdly, there is the rotary cooling method. Some existing technologies use mechanical transmission mechanisms to drive the blades to rotate during the cooling process in order to improve temperature uniformity. However, mechanical transmission structures are prone to jamming and wear in high-temperature environments, and the transmission mechanism itself occupies a large space, increasing equipment complexity and maintenance costs. Furthermore, this type of method also lacks the ability to adaptively adjust the cooling intensity.

[0008] In summary, existing methods for heat preservation after sintering of diamond cutting tools generally suffer from the following shortcomings: poor cooling uniformity, lack of dynamic adjustment during the cooling process, high risk of thermal stress concentration, and low reliability of the transmission mechanism under high-temperature conditions. Therefore, there is an urgent need to provide a heat preservation method for diamond cutting tools after high-temperature sintering that can achieve uniform cooling, adaptively adjust the cooling rate, and has a simple and reliable structure. Summary of the Invention

[0009] In order to overcome the above-mentioned defects of the prior art, embodiments of the present invention provide a method for heat preservation treatment after high-temperature sintering of diamond cutting tools.

[0010] To achieve the above objectives, the innovative aspects of this invention are as follows: It includes the following steps:

[0011] The sintered diamond cutting tool is placed in a heat-insulating cavity and supported in the heat-insulating cavity in a manner that allows it to rotate around its own axis.

[0012] An inert protective gas is introduced into the insulation cavity, and the flow of the inert protective gas drives the diamond cutting tool to slowly rotate around its axis inside the insulation cavity.

[0013] During the rotation of the diamond blade, the average temperature inside the insulation chamber is calculated based on the temperature values ​​monitored in real time by temperature sensors located at at least two different positions inside the insulation chamber. The flow rate of the inert protective gas is adjusted according to the preset temperature-flow rate correspondence to control the cooling rate during the insulation process within the range of 3-8℃ / minute. The rotation speed of the diamond blade is determined according to the preset rotation speed-temperature curve.

[0014] The diamond cutting tool is supported in the insulation cavity by a rotating fixture that allows it to rotate around its own axis. The rotating fixture includes at least one rod rotatably disposed in the insulation cavity. The two ends of the rod are respectively provided with a first blade group and a second blade group. The rod is also coaxially provided with multiple annular supports for supporting and spacing the diamond cutting tool. The rotation of the diamond cutting tool is driven by the flow of inert protective gas. Specifically, when the inert protective gas flows through the first blade group and / or the second blade group, it applies a tangential force to the blades, thereby driving the rod to drive the multiple diamond cutting tools on it to rotate synchronously.

[0015] Inert protective gas is introduced into the insulation cavity, specifically including: the insulation cavity is provided with a first annular gas distribution pipe and a second annular gas distribution pipe, the first annular gas distribution pipe has multiple first injection holes, the injection direction of the first injection holes is perpendicular to the blade surface of the first blade group, with an allowable deviation of ±15°, the second annular gas distribution pipe has multiple second injection holes, the injection direction of the second injection holes is perpendicular to the blade surface of the second blade group, with an allowable deviation of ±15°; the first annular gas distribution pipe and the second annular gas distribution pipe independently control their opening and closing state and gas flow rate.

[0016] The flow rate of the inert protective gas is adaptively adjusted according to the temperature changes inside the insulation cavity. Specifically, temperature sensors are installed at at least two different locations inside the insulation cavity to monitor the temperature in real time. When the average temperature detected is higher than 600℃, the flow rate of the inert protective gas is adjusted to 2-3 m / s; when the average temperature detected is between 400-600℃, the flow rate is adjusted to 1-2 m / s; and when the average temperature detected is lower than 400℃, the flow rate is adjusted to 0.5-1 m / s.

[0017] Furthermore, during the heat preservation process, the target rotational speed is determined based on the preset rotational speed-temperature curve, and one of the following control modes is selected based on the current average temperature range:

[0018] High-speed mode: Only activated when the average temperature is above 600℃. Simultaneously, the first and second annular gas distribution pipes are opened, and the gas flow rate is adjusted to 2-3 m / s.

[0019] Medium speed mode: Only activated when the average temperature is between 400-600℃, only one of the annular gas distribution pipes is turned on, and the gas flow rate is adjusted to 1-2 m / s;

[0020] Low speed mode: Only activated when the average temperature is below 400℃, only one annular gas distribution pipe is turned on, and the gas flow rate is adjusted to 0.5-1 m / s.

[0021] Furthermore, the diameter of the diamond cutting tool is 100-300mm; the first and second blade groups each include multiple curved blades evenly distributed along the circumference of the truss rod, the radius of curvature of the curved blades is 20-50mm, the number of blades in each group is 3-6, and the projected area of ​​each group of blades along the axial direction of the truss rod is 1 / 5-1 / 3 of the projected area of ​​the cutting tool.

[0022] Furthermore, the first and second annular gas distribution pipes are each connected to an independent flow control valve for independently adjusting the gas flow rate of each annular gas distribution pipe; the initial pressure of the inert protective gas is 0.1-0.3 MPa.

[0023] Furthermore, the vertical distance between the first annular air distribution pipe and the first blade group is 50-150mm, and the vertical distance between the second annular air distribution pipe and the second blade group is 50-150mm.

[0024] Furthermore, at least one end of the string rod is supported on the side wall or bracket of the insulation cavity by a high-temperature bearing, which is a graphite bearing or a ceramic bearing; when multiple string rods are installed, the string rods are arranged in parallel inside the insulation cavity.

[0025] Furthermore, the diamond cutting tools are arranged on the string rod as follows: an annular spacer is provided between adjacent diamond cutting tools. The annular spacer is fitted on the string rod. The difference between the outer diameter of the annular spacer and the outer diameter of the diamond cutting tool does not exceed 2mm. The difference between the material of the annular spacer and the coefficient of thermal expansion of the diamond cutting tool does not exceed 20%.

[0026] Furthermore, the diamond cutting tool rotates at a speed of 1-10 revolutions per minute, and the inert protective gas is nitrogen or argon with a purity of ≥99.99%.

[0027] Furthermore, the above method is carried out continuously throughout the entire cooling process of the diamond cutting tool from the sintering temperature of 600-900℃ to room temperature, with a total cooling time of 1.5-5 hours.

[0028] Furthermore, the metal binder of the diamond cutting tool is cobalt-based, and the diamond particle size is 100-400μm. The temperature boundary between 600℃ and 400℃ corresponds to the material properties of the diamond cutting tool. Above 600℃ is the binder softening zone, 400-600℃ is the binder phase transformation stress sensitive zone, and below 400℃ is the material shaping zone.

[0029] The technical effects and advantages of this invention are as follows:

[0030] 1. It achieves uniform cooling without mechanical transmission, significantly improving equipment reliability and cooling uniformity:

[0031] This invention utilizes a blade assembly fixedly connected to both ends of a cooling rod. The tangential force generated by the inert protective gas flowing through the blade assembly drives the cooling rod and diamond blades to rotate synchronously, eliminating the need for additional motors, gears, or other mechanical transmission mechanisms. This design effectively avoids problems such as jamming, wear, and lubrication failure in mechanical transmission components under high-temperature environments, significantly improving the operational reliability of the equipment under high-temperature conditions. Simultaneously, multiple injection holes on the annular air distribution pipe ensure that airflow is evenly sprayed onto the blade surface circumferentially, driving the blades to rotate smoothly and at a constant speed. This ensures that all parts of the blades receive uniform cooling airflow, eliminating localized temperature differences caused by uneven airflow distribution in traditional fixed cooling methods. This significantly improves the temperature uniformity of the cooling process and effectively reduces the risk of thermal stress concentration caused by temperature gradients.

[0032] 2. It achieves adaptive segmented precise control of the cooling rate, effectively suppressing the risk of cracking caused by phase transformation stress:

[0033] This invention establishes a segmented control strategy tailored to the material properties of diamond cutting tools across different temperature ranges: In the high-temperature zone (above 600℃), high flow rates are used to enhance convective heat transfer, achieving rapid and uniform initial cooling and improving production efficiency; in the phase transformation stress-sensitive zone (400-600℃), the cooling rate is precisely controlled within the range of 3-8℃ / minute, effectively avoiding internal stress concentration caused by binder phase transformation; in the low-temperature zone (below 400℃), low flow rates and gentle cooling are employed to avoid thermal shock damage. By monitoring the cavity temperature in real time with a temperature sensor and automatically switching control modes, this invention achieves precise and adaptive adjustment of the cooling rate, ensuring the entire cooling process remains within the optimal cooling intensity range. This eliminates quality defects such as product cracking and deformation caused by improper cooling rates at the source of the process, significantly improving the yield and performance of diamond cutting tools. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the device structure used to perform the heat preservation treatment method in an embodiment of the present invention.

[0035] Figure 2 This is a structural diagram showing the relative positions of the first annular air distribution pipe and the first blade group.

[0036] Figure 3 This is a control flowchart of the heat preservation treatment method in an embodiment of the present invention.

[0037] Figure 4 This is a schematic diagram of the temperature-flow rate control curve in an embodiment of the present invention, where the horizontal axis represents temperature (°C) and the vertical axis represents gas flow rate (m / s). The curve is segmented at 600°C and 400°C, corresponding to flow rate ranges of 2-3 m / s, 1-2 m / s and 0.5-1 m / s, respectively.

[0038] Figure 5 This is a schematic diagram of the speed-temperature control curve in an embodiment of the present invention, where the horizontal axis represents temperature (°C) and the vertical axis represents speed (rpm). The curve is segmented at 600°C and 400°C, corresponding to speed ranges of 5-10 rpm, 3-5 rpm, and 1-3 rpm, respectively.

[0039] In the picture:

[0040] 10-Insulation chamber; 20-Diamond blade; 30-Stringing rod; 31-High temperature bearing; 32-Annular support; 33-Annular spacer; 41-First blade group; 42-Second blade group; 51-First annular air distribution pipe; 52-Second annular air distribution pipe; 511-First injection hole; D-Vertical distance between the annular air distribution pipe and the corresponding blade group (50-150mm); O-Stringing rod rotation axis (center); 60-Temperature sensor Detailed Implementation

[0041] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Example 1

[0043] This embodiment provides a method for heat preservation treatment of diamond cutting tools after high-temperature sintering. This method aims to solve problems such as deformation and cracking caused by thermal stress concentration during the cooling process after sintering. Its core lies in utilizing flowing inert protective gas to achieve dynamic heat preservation while driving the cutting tool to rotate at a uniform speed, and adaptively adjusting the cooling intensity according to temperature changes.

[0044] Specifically, this method utilizes a dedicated thermal insulation device. For example... Figure 1 As shown, the device includes a heat-insulating cavity 10. The sintered diamond cutting tool 20 is placed inside the heat-insulating cavity 10 and supported within the heat-insulating cavity 10 by a rotating tool that can rotate about its own axis.

[0045] In this embodiment, the rotating fixture includes at least one rotatable rod 30 disposed within the insulation cavity 10. A first blade group 41 and a second blade group 42 are respectively disposed at both ends of the rod 30. Multiple annular supports 32 are coaxially disposed on the rod 30 for supporting and spacing the diamond cutting tools 20. The diamond cutting tools 20 are fixed to the rod 30 via the annular supports 32, thus allowing them to rotate together with the rod 30.

[0046] At least one end of the stringer 30 is supported on the side wall or bracket of the insulation cavity 10 by a high-temperature bearing 31. In this embodiment, the high-temperature bearing 31 is preferably a graphite bearing or a ceramic bearing to adapt to the high-temperature working environment. When batch processing is required, multiple stringers 30 can be set and arranged in parallel within the insulation cavity 10 to improve processing efficiency.

[0047] Figure 2 The structure that drives the tremie rod 30 to rotate is specifically shown. For example... Figure 2 As shown, the cross-section of the connecting rod 30 is circular, with its center O being the axis of rotation of the connecting rod 30. A first blade group 41 is provided on the outer periphery of the connecting rod 30. The first blade group 41 consists of multiple curved blades evenly distributed circumferentially. Figure 2(Taking two symmetrically distributed blade cross-sections as an example). The root of each blade is connected to the connecting rod 30, and the curved surface of the blade protrudes radially outward toward the connecting rod 30. The structure of the second blade group 42 is exactly the same as that of the first blade group 41. For the sake of simplicity, the first blade group 41 will be used as an example for explanation.

[0048] To enable the diamond cutting tool 20 to rotate using the flow of inert protective gas, the device in this embodiment also includes a gas supply system. Specifically, a first annular gas distribution pipe 51 and a second annular gas distribution pipe 52 are provided inside the insulation cavity 10. Figure 2 As shown, the first annular gas distribution pipe 51 is coaxially disposed around the periphery of the first blade group 41, and has multiple first injection holes 511 on the side facing the first blade group 41. These injection holes 511 are evenly distributed circumferentially. The injection direction of the inert protective gas ejected from the first injection holes 511 is basically perpendicular to the blade surface of the first blade group 41 (allowing a deviation of ±15°). When the airflow impacts the blade, it applies a tangential force to the blade, thereby driving the connecting rod 30 to slowly rotate the diamond blade 20 on it around its own axis (i.e., the axis O of the connecting rod 30). The second annular gas distribution pipe 52 and the second blade group 42 have the same cooperation relationship, and the two can work together to provide greater driving force for the connecting rod 30.

[0049] In the heat preservation process, the core of this embodiment lies in adaptively adjusting the flow rate of the inert protective gas according to the temperature changes within the heat preservation cavity 10, thereby achieving dynamic heat preservation. Its control logic is as follows: Figure 3 As shown.

[0050] After the insulation process begins, the system monitors the temperature inside the insulation cavity 10 in real time using temperature sensors 60 located at at least two different positions within the cavity, and calculates the average temperature T. avg Based on the average temperature T avg When the value is determined, the system enters the judgment step and adaptively adjusts the gas flow rate to control the cooling rate.

[0051] In this embodiment, to precisely control the cooling process, the cooling rate is strictly controlled within the range of 3-8°C / minute. This range is set based on the material properties of the diamond cutting tool, which ensures cooling efficiency while effectively avoiding internal material defects caused by excessively fast or slow cooling.

[0052] like Figure 3 As shown in the control flowchart, the system is based on the average temperature T avg The value determines the automatic selection of different control modes, which corresponds to... Figure 4 and Figure 5 The segmented control strategy shown.

[0053] Specifically, when the monitored average temperature exceeds 600°C, corresponding to the softening zone of the diamond cutting tool's metal binder, enhanced convective heat transfer is required at this stage to achieve rapid and uniform initial cooling. Therefore, the system adjusts the flow rate of the inert protective gas to 2-3 m / s (see...). Figure 4 In this mode, such as Figure 3 As shown, the first annular air distribution pipe 51 and the second annular air distribution pipe 52 can be opened simultaneously to provide maximum driving force and cooling intensity, driving the shunt rod 30 to rotate at a high speed, for example, 5-10 revolutions per minute (see...). Figure 5 ).

[0054] When the monitored average temperature is between 400-600℃, it corresponds to the phase transformation stress sensitive zone of the binder. The cooling rate must be strictly controlled during this stage to avoid internal stress caused by the phase transformation. Therefore, the system adjusts the flow rate of the inert protective gas to 1-2 m / s (see...). Figure 4 In this mode, such as... Figure 3 As shown, only one of the first annular air distribution pipe 51 or the second annular air distribution pipe 52 can be opened to provide a moderate driving force, driving the tremie rod 30 to rotate at a speed of 3-5 revolutions per minute (see...). Figure 5 This ensures that the cooling rate is strictly controlled within the range of 3-8℃ / minute.

[0055] When the monitored average temperature is below 400°C, it corresponds to the material sizing zone. At this stage, the blade is essentially sizing, but still requires gentle cooling to avoid thermal shock. Therefore, the system further adjusts the flow rate of the inert protective gas to 0.5-1 m / s (see...). Figure 4 ), and continue to open only one of the annular air distribution pipes, driving the shunt rod 30 to rotate slowly at a speed of 1-3 revolutions per minute (see Figure 5 The heat treatment process continues until the blade temperature drops below a set threshold. This threshold is preferably 50°C, meaning that when the blade temperature is below 50°C, it can be considered to have reached a state "close to room temperature," at which point the heat treatment process ends. This temperature threshold is chosen based on the following considerations: below this temperature, the internal structure of the blade is completely stable, further cooling has no substantial impact on product quality, and energy waste due to over-cooling can be avoided.

[0056] like Figure 3 As shown, Figure 3 This is a control flowchart of the heat preservation treatment method in an embodiment of the present invention, which specifically illustrates the control logic of adaptively adjusting the flow rate of the inert protective gas and the rotation speed of the diamond cutting tool according to the temperature change in the heat preservation cavity.

[0057] After the heat preservation process begins, the sintered diamond cutting tool 20 is first placed in the heat preservation cavity 10 and is rotatably supported by the connecting rod 30 and the first blade group 41 and the second blade group 42 set at both ends of it.

[0058] Subsequently, the system monitors the temperature inside the insulation cavity in real time using temperature sensors located at at least two different positions within the cavity 10, and calculates the average temperature T. avg .

[0059] Based on average temperature T avg Upon receiving the specified value, the system enters a judgment step and selects one of the following three control modes:

[0060] (a) High-speed mode

[0061] When the average temperature T avg Above 600℃, the system activates high-speed mode. In this mode, the first annular gas distribution pipe 51 and the second annular gas distribution pipe 52 are simultaneously opened, adjusting the flow rate of the inert protective gas to 2-3 m / s, and driving the connecting rod 30 to rotate at a speed of 5-10 rpm. This mode corresponds to the softening zone of the diamond blade binder, achieving rapid and uniform initial cooling by enhancing convective heat transfer.

[0062] (ii) Medium speed mode

[0063] When the average temperature T avg Between 400-600℃, the system switches to medium-speed mode. In this mode, only one of the first annular gas distribution pipe 51 or the second annular gas distribution pipe 52 is opened, and the gas flow rate is adjusted to 1-2 m / s, driving the tremie rod 30 to rotate at a speed of 3-5 rpm. This mode corresponds to the phase change stress sensitive area of ​​the binder. By reducing the cooling intensity, the cooling rate is strictly controlled within the range of 3-8℃ / min to avoid internal stress caused by phase change.

[0064] (iii) Low speed mode

[0065] When the average temperature T avg Below 400℃, the system enters low-speed mode. In this mode, only one of the first annular air distribution pipe 51 or the second annular air distribution pipe 52 is opened, and the gas flow rate is further adjusted to 0.5-1 m / s, driving the guide rod 30 to rotate slowly at a speed of 1-3 rpm. This mode corresponds to the material shaping zone, avoiding thermal shock through gentle cooling until the blade temperature drops below the set threshold.

[0066] After all three modes have been executed, the system proceeds to the "continuous cooling to room temperature" step. In actual control, "room temperature" is quantified as a specific temperature threshold, such as 50°C. When the temperature sensor 60 detects that the average temperature inside the insulation cavity 10 is lower than this threshold, the system determines that the cooling process is complete. The entire process lasts 1.5-5 hours until the cooling ends.

[0067] Through the above control process, the present invention achieves adaptive adjustment of cooling intensity in different temperature ranges, effectively reducing the risk of thermal stress concentration in diamond cutting tools during the cooling process after sintering.

[0068] like Figure 4 As shown, Figure 4 This is a schematic diagram of the temperature-flow rate control curve in an embodiment of the present invention, specifically illustrating the control logic of the inert protective gas flow rate changing with the average temperature inside the insulation cavity. The horizontal axis represents temperature (°C), and the vertical axis represents gas flow rate (m / s).

[0069] According to the technical solution of the present invention, the flow rate control adopts a segmented interval strategy, which corresponds to the material properties of the diamond cutting tool:

[0070] (a) Low temperature range (below 400℃)

[0071] When the average temperature is below 400℃, the system controls the gas flow rate within the range of 0.5-1 m / s in the corresponding material shaping zone. Figure 4 The flow rate range is represented by the shaded area between 0.5 and 1 on the vertical axis, and is indicated by extending horizontally to 400°C on the horizontal axis, showing that the flow rate remains within this temperature range.

[0072] (ii) Medium temperature range (400℃ to 600℃)

[0073] When the average temperature is between 400℃ and 600℃, corresponding to the binder phase transformation stress sensitive area, the system controls the gas flow rate within the range of 1-2 m / s. Figure 4 The shaded area between 1 and 2 on the vertical axis represents the flow velocity range, which extends horizontally to between 400°C and 600°C on the horizontal axis.

[0074] (III) High-temperature range (above 600℃)

[0075] When the average temperature is above 600℃, corresponding to the binder softening zone, the system controls the gas flow rate within the range of 2-3 m / s. Figure 4 The shaded area between 2 and 3 on the vertical axis represents the flow rate range, extending to the right from 600°C on the horizontal axis to the upper limit of the sintering temperature (e.g., 900°C).

[0076] The above segmented control strategy is achieved through Figure 4The stepped distribution of the three horizontal shaded zones is clearly shown. As the temperature drops from high to low, the gas flow rate decreases in a stepped manner, matching the varying cooling intensity requirements of the diamond cutting tool in different temperature ranges. Through this control logic, the present invention achieves precise control of the cooling rate, effectively reducing the risk of thermal stress concentration.

[0077] like Figure 5 As shown, Figure 5 This is a schematic diagram of the speed-temperature control curve in an embodiment of the present invention, specifically illustrating the control logic of the diamond blade speed changing with the average temperature inside the insulation chamber. The horizontal axis represents temperature (°C), and the vertical axis represents speed (rpm).

[0078] According to the technical solution of the present invention, the rotational speed control adopts a segmented interval strategy, which is matched with the material properties and cooling requirements of the diamond cutting tool:

[0079] (a) Low temperature range (below 400℃)

[0080] When the average temperature is below 400℃, the system controls the blade speed in the corresponding material shaping zone within the range of 1-3 revolutions per minute. Figure 5 The shaded area between 1 and 3 on the vertical axis represents this speed range, and the horizontal extension to 400°C on the horizontal axis indicates that the speed remains within this temperature range. Lower speeds help maintain a uniform temperature field under mild cooling conditions, avoiding thermal shock.

[0081] (ii) Medium temperature range (400℃ to 600℃)

[0082] When the average temperature is between 400℃ and 600℃, corresponding to the binder phase transformation stress sensitive area, the system controls the blade rotation speed within the range of 3-5 revolutions per minute. Figure 5 The shaded area between 3 and 5 on the vertical axis represents this rotational speed range, extending horizontally to between 400℃ and 600℃ on the horizontal axis. The moderate rotational speed, combined with reduced cooling intensity, allows the cooling rate to be precisely controlled at 3-8℃ / minute, effectively suppressing phase transformation stress.

[0083] (III) High-temperature range (above 600℃)

[0084] When the average temperature is above 600℃, corresponding to the binder softening zone, the system controls the blade rotation speed within the range of 5-10 revolutions per minute. Figure 5 The shaded area between 5 and 10 on the vertical axis represents this rotational speed range, extending to the right from 600°C on the horizontal axis to the upper limit of the sintering temperature (e.g., 900°C). Higher rotational speeds enhance convective heat transfer between the blade and the protective gas, achieving rapid and uniform initial cooling.

[0085] The above segmented control strategy is achieved through Figure 5The stepped distribution of the three horizontal shaded zones is clearly shown. As the temperature drops from high to low, the blade rotation speed decreases in a stepped manner, corresponding to the different cooling intensity requirements of each temperature range. Through this control logic, the present invention effectively reduces the risk of thermal stress concentration while ensuring cooling efficiency.

[0086] During actual control, the system monitors the temperature changes inside the insulation cavity in real time using temperature sensors and calculates the cooling rate per unit time. When the measured cooling rate deviates from the target range of 3-8℃ / min, the system fine-tunes the gas flow rate within the corresponding temperature range (2-3 m / s for high temperature, 1-2 m / s for medium temperature, and 0.5-1 m / s for low temperature): if the cooling rate is too fast, the flow rate is reduced; if the cooling rate is too slow, the flow rate is increased. Through this closed-loop regulation, the cooling rate is ensured to remain within the range of 3-8℃ / min throughout the entire cooling process.

[0087] Example 2

[0088] This embodiment further optimizes the adaptive adjustment control mode based on Embodiment 1. The target speed is determined according to a preset speed-temperature curve, and one of the following control modes is selected based on the current average temperature range:

[0089] High-speed mode: Activated only when the average temperature exceeds 600℃. Simultaneously, the first annular gas distribution pipe 51 and the second annular gas distribution pipe 52 are opened, and the gas flow rate is adjusted to 2-3 m / s. In this mode, the duct 30 rotates at a speed of 5-10 rpm to achieve rapid cooling.

[0090] Medium-speed mode: This mode is only activated when the average temperature is between 400-600℃. Only one of the annular gas distribution pipes (first annular gas distribution pipe 51 or second annular gas distribution pipe 52) is opened, and the gas flow rate is adjusted to 1-2 m / s. In this mode, the connecting rod 30 rotates at a speed of 3-5 rpm to smoothly pass through the phase change sensitive zone.

[0091] Low-speed mode: Activated only when the average temperature is below 400℃, only one annular gas distributor is opened, and the gas flow rate is adjusted to 0.5-1 m / s. In this mode, the shunt rod 30 rotates at a speed of 1-3 revolutions per minute to avoid thermal shock.

[0092] The preset rotation speed-temperature curve is coupled with a preset temperature-flow rate relationship. Specifically: in the high-temperature range (above 600℃), the target rotation speed is 5-10 rpm, corresponding to a flow rate of 2-3 m / s; in the medium-temperature range (400-600℃), the target rotation speed is 3-5 rpm, corresponding to a flow rate of 1-2 m / s; and in the low-temperature range (below 400℃), the target rotation speed is 1-3 rpm, corresponding to a flow rate of 0.5-1 m / s. For diamond inserts of different diameters, this rotation speed-temperature curve can be adaptively adjusted: for large-diameter inserts (≥200mm), the rotation speed can be appropriately reduced, while for small-diameter inserts (≤150mm), the rotation speed can be appropriately increased to ensure optimal temperature uniformity.

[0093] It should be noted that the above-mentioned speed range is a general value applicable to standard-sized diamond cutting tools (e.g., diameter 100-300mm). In practical applications, this preset speed-temperature curve can be fine-tuned according to the specific diameter, thickness, and binder material characteristics of the cutting tool to further optimize cooling uniformity. For example, for large-diameter or thick-walled cutting tools, the speed can be appropriately reduced to avoid uneven temperature distribution caused by centrifugal force; for small-diameter cutting tools, the speed can be appropriately increased to enhance heat exchange efficiency.

[0094] By setting an independent control mode, the adjustment of process parameters becomes more precise and stable.

[0095] Example 3

[0096] This embodiment optimizes the specific structural parameters of the rotating tooling to suit common diamond cutting tool specifications. The diameter of the diamond cutting tool is 100-300mm. The first blade group 41 and the second blade group 42 each include multiple curved blades evenly distributed along the circumference of the connecting rod 30, with a radius of curvature of 20-50mm. Each group has 3-6 blades, and the projected area of ​​each group of blades along the axial direction of the connecting rod 30 is set to 1 / 5-1 / 3 of the projected area of ​​the cutting tool. This area ratio ensures that the driving force generated by the airflow is sufficient to overcome the resistance during cutting tool rotation, while also preventing the uniformity of airflow within the insulation cavity from being affected by excessively large blades.

[0097] The installation angle of the curved blades in the first and second blade groups is set such that when the first injection hole of the first annular air distributor injects airflow, the airflow direction is basically perpendicular to the blade surface (allowing a deviation of ±15°), so as to maximize the tangential force generated when the airflow impacts the blades, while avoiding excessive axial force that could cause axial movement of the duct. The matching of the blade curvature radius and the number of blades should ensure that the duct can start smoothly and rotate continuously at a speed of 1-10 revolutions per minute within the gas flow velocity range of 0.5-3 m / s, without jamming or shaking.

[0098] Example 4

[0099] This embodiment refines the control of the gas supply system. The first annular gas distribution pipe 51 and the second annular gas distribution pipe 52 are each connected to an independent flow control valve, used to independently adjust the gas flow rate of each annular gas distribution pipe. The initial pressure of the inert protective gas is set to 0.1-0.3 MPa to ensure sufficient power to drive the blades to rotate, while avoiding excessive pressure that could impact the insulation chamber 10.

[0100] Example 5

[0101] This embodiment optimizes the relative position between the annular air distributor and the blade assembly. For example... Figure 2 As shown, the vertical distance D between the first annular air distribution pipe 51 and the first blade group 41 is 50-150mm. Similarly, the vertical distance between the second annular air distribution pipe 52 and the second blade group 42 is also 50-150mm. This reasonable setting of distance ensures a balance between the impact force of the airflow injection and the driving efficiency, guaranteeing sufficient tangential force to drive the connecting rod 30 while avoiding excessive airflow concentration due to excessively close distances, which would affect the uniformity of cooling.

[0102] Example 6

[0103] This embodiment further defines the support structure and arrangement of the duct rod 30. At least one end of the duct rod 30 is supported on the side wall or bracket of the insulation cavity 10 by a high-temperature bearing 31, which is preferably a graphite bearing or a ceramic bearing. When multiple blades need to be processed, multiple duct rods 30 are set up and arranged in parallel within the insulation cavity 10. This arrangement can maximize the utilization of the internal space of the insulation cavity 10, improve the throughput of a single processing cycle, and ensure that the blades on each duct rod 30 receive uniform cooling airflow.

[0104] Example 7

[0105] This embodiment optimizes the arrangement of the diamond cutting tool 20 on the guide rod 30. For example... Figure 1 As shown, an annular spacer 33 is provided between adjacent diamond cutting tools 20, and the annular spacer 33 is fitted onto the guide rod 30. The difference between the outer diameter of the annular spacer 33 and the outer diameter of the diamond cutting tool 20 does not exceed 2mm, to ensure that the spacer can provide good support and spacing, preventing collision or adhesion between the cutting tools. In addition, the difference between the coefficient of thermal expansion of the material of the annular spacer 33 and the diamond cutting tool 20 does not exceed 20%, which can effectively avoid additional stress caused by inconsistent thermal expansion during the cooling process, thereby protecting the cutting tool from damage.

[0106] Example 8

[0107] This embodiment optimizes key parameters in the processing. The rotation speed of the diamond cutting tool 20 is 1-10 revolutions per minute, which matches the segmented control of the gas flow rate, ensuring uniform cooling at each stage. The inert protective gas used is nitrogen or argon with a purity ≥99.99% to prevent oxidation of the cutting tool at high temperatures and ensure product quality.

[0108] Example 9

[0109] This embodiment defines the scope of application of the method. The method is carried out continuously during the entire cooling process of the diamond cutting tool 20 from a sintering temperature of 600-900℃ to room temperature, with a total cooling time of 1.5-5 hours. This total time is determined comprehensively based on the tool size and material properties, and can efficiently complete the entire heat preservation process while ensuring a cooling rate (3-8℃ / minute).

[0110] Example 10

[0111] This embodiment further clarifies the material science basis for the temperature cutoff points. In this invention, the metal binder of the diamond cutting tool 20 is cobalt-based, and the diamond particle size is 100-400 μm. The two temperature cutoff points of 600℃ and 400℃ correspond to the material characteristics of the diamond cutting tool. Above 600℃ is the binder softening zone, where the material has good plasticity and can withstand strong cooling; 400-600℃ is the binder phase transformation stress sensitive zone, where phase transformation may occur within the material, requiring strict control of the cooling rate; below 400℃ is the material solidification zone, where the material is basically solidified and only gentle cooling is needed. This segmented control strategy based on material characteristics is one of the core innovations of this invention.

[0112] The temperature cutoff points of 600℃ and 400℃ mentioned above were determined through thermal analysis experiments (DSC / TG) on cobalt-based bonded diamond cutting tools: above 600℃, the binder exhibits obvious softening and flow characteristics, and the cooling rate can be appropriately increased; in the 400-600℃ range, the binder undergoes an austenitic transformation with a volume change rate of approximately 0.5%-1.2%, and the cooling rate needs to be strictly controlled; below 400℃, the binder microstructure is basically stable and can be cooled gently. The establishment of these cutoff points has clear experimental material science basis.

[0113] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change.

[0114] Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0115] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for heat preservation treatment after high-temperature sintering of diamond cutting tools, characterized in that: Includes the following steps: The sintered diamond cutting tool is placed in a heat-insulating cavity and supported in the heat-insulating cavity in a manner that allows it to rotate around its own axis. An inert protective gas is introduced into the insulation cavity, and the flow of the inert protective gas drives the diamond cutting tool to slowly rotate around its axis within the insulation cavity. During the rotation of the diamond blade, the average temperature inside the insulation chamber is calculated based on the temperature values ​​monitored in real time by temperature sensors located at at least two different positions inside the insulation chamber. The flow rate of the inert protective gas is adjusted according to a preset temperature-flow rate correspondence to control the cooling rate during the insulation process within the range of 3-8℃ / minute. The rotation speed of the diamond blade is determined according to a preset rotation speed-temperature curve. The diamond cutting tool is supported within the insulation cavity by a rotating fixture that allows it to rotate around its own axis. The rotating fixture includes at least one rod rotatably disposed within the insulation cavity. A first blade group and a second blade group are respectively disposed at both ends of the rod. Multiple annular supports for supporting and spacing the diamond cutting tools are also coaxially disposed on the rod. The rotation of the diamond cutting tools is driven by the flow of inert protective gas, specifically by the inert protective gas applying a tangential force to the blades as it flows through the first and / or second blade groups, thereby driving the rod to synchronously rotate the multiple diamond cutting tools on it. The process of introducing inert protective gas into the insulation cavity specifically includes: the insulation cavity is provided with a first annular gas distribution pipe and a second annular gas distribution pipe; the first annular gas distribution pipe has multiple first injection holes, the injection direction of the first injection holes is perpendicular to the blade surface of the first blade group, with an allowable deviation of ±15°; the second annular gas distribution pipe has multiple second injection holes, the injection direction of the second injection holes is perpendicular to the blade surface of the second blade group, with an allowable deviation of ±15°; the first annular gas distribution pipe and the second annular gas distribution pipe are each independently controlled in terms of their opening and closing states and gas flow rates; The adaptive adjustment of the inert protective gas flow rate according to the temperature change in the insulation cavity is specifically as follows: temperature sensors are installed at at least two different locations in the insulation cavity to monitor the temperature in the insulation cavity in real time. When the average temperature monitored is higher than 600℃, the flow rate of the inert protective gas is adjusted to 2-3 m / s; when the average temperature monitored is between 400-600℃, the flow rate is adjusted to 1-2 m / s; and when the average temperature monitored is lower than 400℃, the flow rate is adjusted to 0.5-1 m / s.

2. The method for heat preservation treatment after high-temperature sintering of diamond cutting tools according to claim 1, characterized in that: During the heat preservation process, the target rotational speed is determined based on the preset rotational speed-temperature curve, and one of the following control modes is selected based on the current average temperature range: High-speed mode: Only activated when the average temperature is above 600℃. Simultaneously, the first and second annular gas distribution pipes are opened, and the gas flow rate is adjusted to 2-3 m / s. Medium speed mode: Only activated when the average temperature is between 400-600℃, only one of the annular gas distribution pipes is turned on, and the gas flow rate is adjusted to 1-2 m / s; Low speed mode: Only activated when the average temperature is below 400℃, only one annular gas distribution pipe is turned on, and the gas flow rate is adjusted to 0.5-1 m / s.

3. The method for heat preservation treatment after high-temperature sintering of diamond cutting tools according to claim 1, characterized in that: The diameter of the diamond cutting tool is 100-300mm; the first blade group and the second blade group each include multiple curved blades evenly distributed along the circumference of the string rod, the radius of curvature of the curved blades is 20-50mm, the number of blades in each group is 3-6, and the projected area of ​​each group of blades along the axial direction of the string rod is 1 / 5-1 / 3 of the projected area of ​​the cutting tool.

4. The method for heat preservation treatment after high-temperature sintering of diamond cutting tools according to claim 1, characterized in that: The first and second annular gas distribution pipes are each connected to an independent flow control valve for independently adjusting the gas flow rate of each annular gas distribution pipe; the initial pressure of the inert protective gas is 0.1-0.3 MPa.

5. The method for heat preservation treatment after high-temperature sintering of diamond cutting tools according to claim 1, characterized in that: The vertical distance between the first annular air distribution pipe and the first blade group is 50-150mm, and the vertical distance between the second annular air distribution pipe and the second blade group is 50-150mm.

6. The method for heat preservation treatment after high-temperature sintering of diamond cutting tools according to claim 1, characterized in that: At least one end of the string rod is supported on the side wall or bracket of the insulation cavity by a high-temperature bearing, which is a graphite bearing or a ceramic bearing; when multiple string rods are provided, the string rods are arranged in parallel inside the insulation cavity.

7. The method for heat preservation treatment after high-temperature sintering of diamond cutting tools according to claim 1, characterized in that: The diamond cutting tools are arranged on the string rod as follows: an annular spacer is provided between adjacent diamond cutting tools. The annular spacer is fitted on the string rod. The difference between the outer diameter of the annular spacer and the outer diameter of the diamond cutting tool does not exceed 2mm. The difference between the material of the annular spacer and the coefficient of thermal expansion of the diamond cutting tool does not exceed 20%.

8. The method for heat preservation treatment after high-temperature sintering of diamond cutting tools according to claim 1, characterized in that: The diamond cutting tool rotates at a speed of 1-10 revolutions per minute, and the inert protective gas is nitrogen or argon with a purity of ≥99.99%.

9. The method for heat preservation treatment after high-temperature sintering of diamond cutting tools according to claim 1, characterized in that: The method is carried out continuously during the entire cooling process of the diamond cutting tool from the sintering temperature of 600-900℃ to room temperature, with a total cooling time of 1.5-5 hours.

10. The method for heat preservation treatment after high-temperature sintering of diamond cutting tools according to claim 1, characterized in that: The metal binder of the diamond cutting tool is cobalt-based, and the diamond particles have a diameter of 100-400μm. The temperature boundary between 600℃ and 400℃ corresponds to the material properties of the diamond cutting tool. Above 600℃ is the binder softening zone, 400-600℃ is the binder phase transformation stress sensitive zone, and below 400℃ is the material shaping zone.

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