A thin metal plate plasma carburizing composite heat treatment equipment and process

Abstract

This invention discloses a plasma carburizing composite heat treatment equipment and process for thin metal plates. The heat treatment equipment includes a furnace body, heating electrode plates, a pressurizing mechanism, a micro-motion mechanism, a plasma power supply, a gas supply system, and a control system. The heat treatment process includes the following steps: S1, pretreatment; S2, furnace loading and vacuuming; S3, ion bombardment cleaning; S4, first-stage pressurized carburizing; S5, micro-motion displacement; S6, second-stage pressurized carburizing; S7, diffusion; S8, quenching; S9, tempering. This invention integrates heating, pressurized shaping, plasma carburizing, quenching, and tempering into a single vacuum furnace, eliminating the need for intermediate workpiece transfer and avoiding oxidation and secondary deformation. The four-legged hollow clamping head design provides stable support and limitation for the thin metal plate while significantly reducing the contact area and forming uniformly distributed heat transfer points, effectively suppressing warping deformation of the thin plate at high temperatures and reducing carburizing blind zones.

Description

Technical Field

[0001] This invention relates to the field of metal heat treatment technology, specifically to a plasma carburizing composite heat treatment equipment and process for thin metal plates. Background Technology

[0002] Thin metal sheets are widely used in machinery manufacturing, automotive parts, and electronic equipment due to their light weight and compact structure. To improve the surface hardness, wear resistance, and fatigue performance of thin metal sheets, they are often subjected to carburizing heat treatment.

[0003] Existing carburizing processes mainly include gas carburizing (see reference 1) and plasma carburizing (see reference 2).

[0004] Reference 1: Chinese patent document with publication number CN109504935A.

[0005] Reference 1 describes a heat treatment process for thin sheet metal parts, including the following steps: preparation, preheating, temperature uniformization, strong infiltration, cooling, quenching, cleaning, drying, flattening, and post-treatment. First, preheating heats all parts of the workpiece, allowing it to enter a penetrating state. Temperature uniformization ensures a consistent temperature across the entire workpiece, resulting in a more uniform surface structure. Strong infiltration further penetrates the workpiece surface. Cooling allows the penetrating carbon and nitrogen atoms to diffuse, further homogenizing the surface structure. During quenching, the temperature decreases evenly across all parts, resulting in uniform thermal stress on the workpiece, reducing deformation and improving product quality. Finally, flattening further improves the flatness of the workpiece, thus enhancing its overall quality.

[0006] Reference 2: Chinese patent document with publication number CN 108330432A.

[0007] Reference 2 describes a method for preparing a hydrogen-free composite modified layer on the surface of steel. The method includes: 1. Pretreatment: Pretreatment of the surface of the steel workpiece; 2. Titanium infiltration: Placing the pretreated steel workpiece on the workpiece electrode stage in the vacuum chamber of a double-layer glow discharge plasma metal infiltration device, using a pure titanium plate as the source electrode and the steel workpiece as the working electrode for titanium infiltration; 3. Carburization: After titanium infiltration, the source electrode is replaced with high-purity graphite for carburization. After carburization, heating of the steel workpiece is stopped, and a carbon deposition layer is formed on the steel workpiece for 1-100 minutes, ultimately forming a hydrogen-free composite modified layer on the surface of the steel workpiece.

[0008] Plasma carburizing is particularly suitable for carburizing thin metal sheets due to its advantages such as fast carburizing speed, minimal workpiece deformation, and good surface quality. However, thin metal sheets have low rigidity and are prone to warping and deformation during the carburizing heating process due to uneven temperature and thermal stress. This results in substandard dimensional accuracy of the carburized workpiece and a high scrap rate. In addition, in traditional plasma carburizing, the workpiece needs to be suspended or placed in the furnace, and the heating method mostly relies on plasma glow discharge heating, which has the problems of slow heating speed and poor temperature uniformity. This further aggravates the deformation of thin sheets and makes it difficult to achieve simultaneous carburizing and shaping.

[0009] To address the deformation issue during the carburizing process of thin metal sheets, existing technologies have attempted to use pressure to assist in shaping. However, conventional pressure structures often employ flat plate pressure, which completely obscures the surface of the thin metal sheet, preventing plasma and the carburizing atmosphere from contacting the surface and hindering effective carburizing. Furthermore, existing processes often utilize separate equipment; after carburizing, the workpiece must be transferred to other equipment for quenching and tempering. During this transfer, the workpiece is easily exposed to air and oxidizes. Additionally, the thin metal sheet is prone to secondary deformation due to vibration and temperature fluctuations during the transfer process, further reducing the yield. Moreover, existing pressure bumps are mostly single-contact structures, making it difficult to further reduce the contact area and leaving a risk of localized carburizing blind spots. In the gas quenching stage, nitrogen is often introduced throughout the furnace, resulting in insufficient cooling uniformity. Uneven cooling can easily cause deformation of the thin metal sheet, affecting the precision of the finished product. Summary of the Invention

[0010] The purpose of this invention is to solve the above-mentioned technical problems existing in the prior art and to provide a plasma carburizing composite heat treatment equipment and process for thin metal plates.

[0011] To address the shortcomings of the aforementioned technical problems, the present invention adopts the following technical solution:

[0012] A plasma carburizing composite heat treatment device for thin metal plates includes:

[0013] Furnace body; and

[0014] The heating electrode plate comprises two parallel plates, a first plate and a second plate, each containing an internal electric heating unit. Clamping heads are discretely distributed on their opposing working surfaces. Each clamping head has a four-legged structure, contacting the thin metal plate via four legs. A nitrogen nozzle is also located between the four legs of each clamping head.

[0015] A pressurizing mechanism is used to drive the first plate to move downward, applying compressive force to a thin metal plate placed between the first and second plates; and

[0016] A micro-motion mechanism, used to drive a thin metal plate to produce lateral displacement in the horizontal direction; and

[0017] A plasma power supply, with its anode electrically connected to a first and second plate and its cathode electrically connected to a thin metal plate, is used to apply a pulsed DC high voltage between the two heating electrode plates and the thin metal plate; and

[0018] A gas supply system, connected to the furnace body and the internal gas channels of the clamping head, is used to introduce hydrogen and carburizing gas into the furnace, and simultaneously to directly spray high-pressure nitrogen gas onto the surface of the thin metal plate through the gas channels of the clamping head during the gas quenching stage; and

[0019] The control system is connected to the heating power supply, plasma power supply, pressurization mechanism, micro-motion mechanism, gas supply system and furnace body respectively.

[0020] As a further optimization of the plasma carburizing composite heat treatment equipment for thin metal plates of the present invention: the clamping head is made of aluminum nitride ceramic or silicon carbide insulating ceramic.

[0021] As a further optimization of the plasma carburizing composite heat treatment equipment for thin metal plates of the present invention: the electric heating unit is a metal heating wire or a ceramic heating plate.

[0022] As a further optimization of the plasma carburizing composite heat treatment equipment for thin metal plates of the present invention: the first plate and the second plate are evenly distributed with a number of grooves, and metal heating wires or ceramic heating plates are embedded in the grooves. The groove openings are sealed with high-temperature resistant insulating glue.

[0023] As a further optimization of the plasma carburizing composite heat treatment equipment for thin metal plates of the present invention: the support foot has a built-in cathode rod, one end of the cathode rod extends out of the end face of the support foot, and the other end is connected to the plasma power supply through a wire.

[0024] As a further optimization of the plasma carburizing composite heat treatment equipment for thin metal plates of the present invention: the pressurizing mechanism is a high-temperature resistant cylinder, the cylinder body is fixed on the top of the furnace body, the cylinder piston rod passes through the furnace body sealing interface and is fixedly connected to the upper end face of the first plate, and the piston rod and the furnace body interface are sealed by a high-temperature resistant vacuum seal.

[0025] As a further optimization of the plasma carburizing composite heat treatment equipment for thin metal plates of the present invention: the micro-motion mechanism includes a mechanical gripper and a driving component. The driving component is a cylinder or an electric push rod, which is fixedly installed on the outer side wall of the furnace body. The mechanical gripper is connected to the telescopic end of the driving component and is used to clamp the edge area of ​​the thin metal plate in a relaxed state.

[0026] A plasma carburizing composite heat treatment process for thin metal plates, implemented using the aforementioned equipment, includes the following steps:

[0027] S1. Pretreatment: Clean the thin metal plate to be treated to remove surface oil, oxide film and impurities, and dry it for later use.

[0028] S2. Loading and Vacuuming: Place the pretreated thin metal plate between the first plate and the second plate, start the pressurizing mechanism to make the first plate and the second plate exert extrusion force on the thin metal plate, close the furnace, start the vacuum pump, and evacuate the furnace.

[0029] S3, Ion Bombardment Cleaning: Hydrogen gas is introduced into the furnace through the gas supply system, the plasma power supply is started, and a pulsed DC high voltage is applied between the heating electrode plate and the thin metal plate to generate a stable glow discharge, removing residual oxide film and impurities on the surface.

[0030] S4. First stage of pressurized carburizing: Start the heating power supply, control the heating electrode plate to heat up through the built-in heating unit, heat the thin metal plate to 850-950°C, introduce hydrogen and carbon-containing gas into the furnace through the gas supply system, adjust the furnace pressure and plasma power supply parameters to maintain stable glow discharge, and carry out the first stage of pressurized carburizing treatment.

[0031] S5. Micro-motion displacement: After the first stage of carburizing is completed, the pressure is released by controlling the pressurizing mechanism, and the thin metal plate is driven to move laterally by the micro-motion mechanism, so that the contact position between the thin metal plate and the support feet of the first plate and the second plate is misaligned.

[0032] S6. Second stage of pressurized carburizing: Start the pressurizing mechanism to reapply pressure, continue to introduce hydrogen and carbon-containing gas, maintain stable glow discharge, and carry out the second stage of carburizing treatment.

[0033] S7. Diffusion: Stop the introduction of carbon-containing gas, and only keep hydrogen gas introduced, maintaining the furnace temperature and vacuum level unchanged for 5 to 30 minutes;

[0034] S8. Quenching: High-pressure nitrogen gas is sprayed directly onto the surface of the thin metal plate through the nozzle of the clamping head via the gas supply system, so that the thin metal plate is cooled rapidly.

[0035] S9. Tempering: Control the temperature inside the furnace to 150-200℃ for low-temperature tempering. After tempering, control the temperature inside the furnace to cool to room temperature.

[0036] The carbon potential for both the first and second stage carburizing is 0.8%–1.2%C, and the carburizing time is 15–90 min.

[0037] The furnace pressure for the first and second stages of carburizing is 10–1000 Pa.

[0038] The present invention has the following beneficial effects:

[0039] 1. This invention integrates heating, pressure shaping, plasma carburizing, quenching, and tempering into the same vacuum furnace, eliminating the need for workpiece transfer and avoiding oxidation and secondary deformation during heat treatment.

[0040] 2. The present invention, through the design of a four-legged hollow clamping head, provides stable support and limitation for thin metal plates while significantly reducing the contact area and forming uniformly distributed heat transfer points, effectively suppressing the warping deformation of thin plates at high temperatures and reducing carburizing blind zones.

[0041] 3. By integrating a gas channel and an end nozzle inside the clamping head, the present invention allows nitrogen to be directly and uniformly sprayed onto the surface of the thin plate during gas quenching, which greatly improves the cooling speed and cooling uniformity, further reduces quenching deformation, and improves the dimensional accuracy and mechanical property stability of the workpiece. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the structure of the heat treatment equipment;

[0043] Figure 2 This is a schematic diagram of the clamping head in a heat treatment device;

[0044] Figure 3 This is a schematic diagram of the heat treatment process.

[0045] Marked in the image:

[0046] 1. Furnace body;

[0047] 2. Heating electrode plates;

[0048] 201. First plate;

[0049] 202. Second plate;

[0050] 3. Clamping head;

[0051] 301. Support legs;

[0052] 302. Nitrogen nozzle;

[0053] 303. Cathode rod;

[0054] 4. Pressurization mechanism;

[0055] 401. Cylinder block;

[0056] 402. Piston rod;

[0057] 5. Micro-motion mechanism;

[0058] 501. Mechanical gripper;

[0059] 502. Drive components. Detailed Implementation

[0060] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0061] <Example 1>

[0062] like Figure 1 and 2 As shown: A plasma carburizing composite heat treatment device for thin metal plates includes a furnace body 1, a heating electrode plate 2, a pressurizing mechanism 4, a micro-motion mechanism 5, a heating power supply, a plasma power supply, a gas supply system, and a control system.

[0063] The heating electrode plate 2 includes two parallel plates, a first plate 201 and a second plate 202, each with an internal electric heating unit.

[0064] The electric heating unit can be either a metal heating wire or a ceramic heating element. The metal heating wire is a high-temperature resistant alloy heating wire (such as Cr20Ni80 nickel-chromium alloy or Fe-Cr-Al iron-chromium-aluminum alloy). The ceramic heating element is an alumina ceramic heating element or a silicon nitride ceramic heating element. Uniformly distributed grooves are machined inside the heating electrode plate 2. The metal heating wire or ceramic heating element is embedded in these grooves and then sealed and fixed with high-temperature resistant insulating adhesive to ensure a tight fit between the heating unit and the electrode plate, improving heat transfer efficiency and preventing the heating unit from becoming loose.

[0065] Clamping heads 3 are discretely distributed on the working surfaces of the first plate 201 and the second plate 202. The clamping head 3 has a four-legged structure and contacts the thin metal plate through four legs 301. A nitrogen nozzle 302 is also provided between the four legs 301 of the clamping head 3.

[0066] The core improved structure is the clamping head 3, which contacts the thin metal plate through four legs, while the rest of the structure is hollow, which allows for more contact points and a smaller contact area, minimizing the obstruction of carburizing. At the same time, the hollow structure provides a flow channel for plasma and carburizing atmosphere, which can improve the uniformity of carburizing.

[0067] The total contact area of ​​the four legs of the clamping head accounts for about 5% of the working surface area of ​​the electrode plate. This contact area ratio ensures that the legs and the thin metal plate form a uniform contact heat transfer matrix. Combined with the good thermal conductivity of the high-temperature resistant material of the protrusions, it enables rapid and uniform heat transfer and avoids the heat transfer effect being affected by insufficient contact area.

[0068] The clamping head 3 has a through gas channel inside. One end of the gas channel is connected to the gas supply system, and the other end is placed in the hollow structure of the clamping head 3 to form a spray outlet, which is used to spray high-pressure nitrogen directly onto the surface of the thin metal plate during the gas quenching stage to achieve direct cooling.

[0069] The pressurizing mechanism 4 is used to drive the first plate 201 to move downward, and apply a light pressure of 0.1 to 0.5 MPa to the thin metal plate placed between the first plate 201 and the second plate 202. It only serves to prevent deformation and ensure that the protruding support foot contacts the thin plate for heat transfer.

[0070] It is foreseeable that the pressurizing mechanism 4 uses a high-temperature resistant cylinder. Its cylinder body 401 is fixed to the top of the furnace body 1. The piston rod 402 passes through the sealing interface of the furnace body 1 and is fixedly connected to the upper end face of the first plate 201. The interface between the piston rod 402 and the furnace body 1 is sealed by a high-temperature resistant vacuum seal. The cylinder is connected to an external air circuit system via an air pipe. The control system adjusts the air circuit pressure, thereby controlling the extension of the piston rod and the magnitude of the applied pressure, achieving a light pressure output of 0.1–0.5 MPa.

[0071] The micro-motion mechanism 5 is used to drive the thin metal plate to generate lateral displacement in the horizontal direction, so that the contact position between the thin metal plate and the protrusion support is misaligned, thus eliminating the carburizing blind zone caused by the protrusion blocking.

[0072] It is foreseeable that the micro-motion mechanism 5 includes a mechanical gripper 501 and a drive component 502, which are fixedly installed on the outer side wall of the furnace body 1. The mechanical gripper 501 is connected to the telescopic end of the drive component 502 and is used to clamp the edge area of ​​the thin metal plate in the relaxed state.

[0073] A high-temperature resistant cylinder or a high-temperature resistant electric actuator is selected as the driving component. The telescopic end of the driving component faces the thin metal plate and is fixedly connected to the mechanical gripper. The driving component is electrically connected to the control system to control the telescopic stroke and adapt to micro-movement requirements. The mechanical gripper is made of high-temperature resistant alloy material and is used to hold the non-carburized working area of ​​the thin metal plate's edge when it is loosely compressed. The gripping force is adjustable to ensure stable movement of the thin plate without damaging its surface.

[0074] When micro-motion is required, the pressurizing mechanism simultaneously releases pressure, disengaging the legs of the upper and lower gripping heads from the thin metal plate. The mechanical gripper closes to hold the edge of the thin plate, and the drive component extends or retracts, causing the mechanical gripper and the thin metal plate to make a slight lateral displacement, thus misaligning the contact position between the thin plate and the gripping head. After the micro-motion is completed, the pressurizing mechanism re-pressurizes synchronously, the mechanical gripper releases, and the initial state is restored.

[0075] The plasma power supply has its anode electrically connected to the first plate 201 and the second plate 202, and its cathode electrically connected to the thin metal plate, for applying a pulsed DC high voltage between the two heating electrode plates 2 and the thin metal plate. Specifically, the support 301 has a cathode rod 303 built into it, one end of which extends out of the end face of the support 301, and the other end is connected to the plasma power supply through a wire.

[0076] The gas supply system is connected to the internal gas channels of the furnace body 1 and the clamping head 3, respectively, for introducing hydrogen and carbon-containing carburizing gas into the furnace, and for directly spraying high-pressure nitrogen gas onto the surface of the thin metal plate through the gas channel of the clamping head 3 during the gas quenching stage.

[0077] The control system is connected to the heating power supply, plasma power supply, pressurization mechanism 4, micro-motion mechanism 5, gas supply system, and furnace body 1. It is used to control the operating parameters of the entire device, including temperature, pressure, voltage, gas flow rate, processing time, micro-motion displacement, and nitrogen injection pressure and flow rate, to achieve fully automated control of the entire process.

[0078] <Example 2>

[0079] like Figure 3 The diagram shown is a schematic flow chart of the plasma carburizing composite heat treatment process for thin metal plates. Specifically:

[0080] Thin metal sheet to be processed: 20CrMnTi thin sheet, 1.5mm thick, with an original carbon content of 0.20%.

[0081] The surface of the 20CrMnTi thin plate was cleaned with acetone to remove oil stains and then dried.

[0082] Place the thin plate between the upper and lower heating electrode plates, apply a pressure of 0.3 MPa to make the four protruding feet contact the thin plate, close the furnace body, and evacuate to 5 Pa.

[0083] Introduce hydrogen gas, start the plasma power supply, and perform glow discharge cleaning for 10 minutes.

[0084] Turn on the heating power supply and heat the electrode plate to 900℃. Through the contact heat conduction of the four-legged convex support, the heat is quickly transferred to the thin plate. Because the support forms a uniform heat transfer matrix and has tight contact, the temperature of the thin plate can be stabilized at 900℃ in only 8 to 10 minutes, achieving rapid and uniform heating. Introduce hydrogen (flow rate 5L / min) and methane (flow rate 1L / min), control the furnace pressure at 50Pa, carbon potential at 1.0%C, and carburizing time at 30 minutes. The convex hollow part allows the plasma and carburizing atmosphere to circulate, reducing the carburizing blind zone.

[0085] Release the pressurizing mechanism and drive the thin plate to move laterally by 2mm through the transverse micro-motion mechanism. During the micro-motion process, maintain the vacuum and 900℃ temperature inside the furnace.

[0086] Reapply pressure of 0.3 MPa, continue to introduce hydrogen and methane, keep furnace parameters unchanged, and carburizing time of 30 min.

[0087] Stop introducing methane and only introduce hydrogen gas, then keep warm for 20 minutes.

[0088] High-pressure nitrogen (0.9MPa, 12L / min) is supplied to the gas channel of the protrusion point through the gas supply system and sprayed directly onto the surface of the thin plate through the support foot spray outlet. At the same time, nitrogen is introduced into the furnace to assist in cooling and cool it to room temperature.

[0089] The temperature was raised directly to 180°C in the same furnace and tempered for 1.5 hours.

[0090] <Example 3>

[0091] Thin metal sheet to be processed: 18Cr2Ni4WA thin sheet, 2.0mm thick, with an original carbon content of 0.18%.

[0092] Clean the surface of the thin plate with an alkaline cleaning solution to remove the oxide film and oil stains, and then let it air dry.

[0093] Place the thin plate between the upper and lower heating electrode plates, apply a pressure of 0.2 MPa to make the four protruding feet contact the thin plate, close the furnace body, and evacuate to 3 Pa.

[0094] Introduce hydrogen gas, start the plasma power supply, and perform glow discharge cleaning for 8 minutes.

[0095] Turn on the heating power supply and heat the electrode plate to 880℃. Through the contact heat conduction of the four-legged convex support, utilizing the advantages of short-path heat transfer and uniform heat transfer matrix, heat is quickly transferred to the thin plate. The temperature of the thin plate can be stabilized at 880℃ in 10-12 minutes. Introduce hydrogen (flow rate 6L / min) and propane (flow rate 0.8L / min), control the furnace pressure at 80Pa, carbon potential at 1.1%C, and carburizing time at 45 minutes.

[0096] Release the pressurizing mechanism and drive the thin plate to move laterally by 2.5mm through the lateral micro-motion mechanism to maintain the vacuum and temperature of 880℃ inside the furnace.

[0097] Reapply pressure of 0.2 MPa, continue to introduce hydrogen and propane, keep furnace parameters unchanged, and carburizing time of 45 min.

[0098] Stop the propane supply and only supply hydrogen gas, then keep warm for 25 minutes.

[0099] High-pressure nitrogen (1.0MPa, 10L / min) is supplied to the gas channel of the protrusion point through the gas supply system. It is then sprayed directly onto the surface of the thin plate through the support foot spray outlet. Nitrogen is simultaneously introduced into the furnace to assist in cooling, and the plate is cooled to room temperature.

[0100] The temperature was raised directly to 160℃ in the same furnace and tempered for 2 hours.

[0101] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A thin metal plate plasma carburizing and complex heat treatment apparatus, characterized by, include: Furnace body (1); as well as The heating electrode plate (2) includes two parallel plates (201) and a second plate (202). Both plates (201 and 202) have built-in electric heating units. Clamping heads (3) are discretely distributed on their opposing working surfaces. Each clamping head (3) has a four-legged structure and contacts the thin metal plate via four legs (301). A nitrogen nozzle (302) is also provided between the four legs (301) of each clamping head (3). A pressurizing mechanism (4) for driving the first plate (201) downward to apply a compressive force to a thin metal plate placed between the first plate (201) and the second plate (202); and The micro-motion mechanism (5) is used to drive the thin metal plate to generate lateral displacement in the horizontal direction; as well as A plasma power supply, whose anode is electrically connected to a first plate (201) and a second plate (202), and whose cathode is electrically connected to a thin metal plate, is used to apply a pulsed DC high voltage between the heating electrode plate (2) and the thin metal plate; and A gas supply system, which is connected to the internal gas channels of the furnace body (1) and the clamping head (3), is used to introduce hydrogen and carbon-containing carburizing gas into the furnace, and simultaneously to directly spray high-pressure nitrogen gas onto the surface of the thin metal plate through the gas channel of the clamping head (3) during the gas quenching stage; and The control system is connected to the heating power supply, plasma power supply, pressurization mechanism (4), micro-motion mechanism (5), gas supply system and furnace body (1), respectively.

2. The apparatus for thin metal plate plasma carburizing and compound heat treatment of claim 1, wherein: The clamping head (3) is made of aluminum nitride ceramic or silicon carbide insulating ceramic.

3. The apparatus for thin metal plate plasma carburizing and composite heat treatment of claim 1, wherein: The electric heating unit is a metal heating wire or a ceramic heating plate.

4. The apparatus for thin metal plate plasma carburizing and composite heat treatment of claim 3, wherein: The first plate (201) and the second plate (202) are evenly distributed with a number of grooves, and metal heating wires or ceramic heating plates are embedded in the grooves. The groove openings are sealed with high-temperature resistant insulating glue.

5. The plasma carburizing composite heat treatment equipment for thin metal plates as described in claim 1, characterized in that: The support (301) has a cathode rod (303) built in it. One end of the cathode rod (303) extends out of the end face of the support (301), and the other end is connected to the plasma power supply through a wire.

6. The plasma carburizing composite heat treatment equipment for thin metal plates as described in claim 1, characterized in that: The pressurizing mechanism (4) is a high-temperature resistant cylinder. Its cylinder body (401) is fixed on the top of the furnace body (1). The piston rod (402) passes through the sealing interface of the furnace body (1) and is fixedly connected to the upper end face of the first plate (201). The interface between the piston rod (402) and the furnace body (1) is sealed by a high-temperature resistant vacuum seal.

7. The plasma carburizing composite heat treatment equipment for thin metal plates as described in claim 1, characterized in that: The micro-motion mechanism (5) includes a mechanical gripper (501) and a drive component (502). The drive component (502) is a cylinder or an electric push rod, which is fixedly installed on the outer side wall of the furnace body (1). The mechanical gripper (501) is connected to the telescopic end of the drive component (502) and is used to clamp the edge area of ​​the thin metal plate in the relaxed state.

8. A plasma carburizing composite heat treatment process for thin metal plates, characterized in that, Based on the device according to any one of claims 1-7, the implementation includes the following steps: S1. Pretreatment: Clean the thin metal plate to be treated to remove surface oil, oxide film and impurities, and dry it for later use. S2. Loading and Vacuuming: Place the pretreated thin metal plate between the first plate and the second plate, start the pressurizing mechanism to make the first plate and the second plate exert extrusion force on the thin metal plate, close the furnace, start the vacuum pump, and evacuate the furnace. S3, Ion Bombardment Cleaning: Hydrogen gas is introduced into the furnace through the gas supply system, the plasma power supply is started, and a pulsed DC high voltage is applied between the heating electrode plate and the thin metal plate to generate a stable glow discharge, removing residual oxide film and impurities on the surface. S4. First stage of pressurized carburizing: Start the heating power supply, control the heating electrode plate to heat up through the built-in heating unit, heat the thin metal plate to 850-950°C, introduce hydrogen and carbon-containing gas into the furnace through the gas supply system, adjust the furnace pressure and plasma power supply parameters to maintain stable glow discharge, and carry out the first stage of pressurized carburizing treatment. S5. Micro-motion displacement: After the first stage of carburizing is completed, the pressure is released by controlling the pressurizing mechanism, and the thin metal plate is driven to move laterally by the micro-motion mechanism, so that the contact position between the thin metal plate and the support feet of the first plate and the second plate is misaligned. S6. Second stage of pressurized carburizing: Start the pressurizing mechanism to reapply pressure, continue to introduce hydrogen and carbon-containing gas, maintain stable glow discharge, and carry out the second stage of carburizing treatment. S7. Diffusion: Stop the introduction of carbon-containing gas, and only keep hydrogen gas introduced, maintaining the furnace temperature and vacuum level unchanged for 5 to 30 minutes; S8. Quenching: High-pressure nitrogen gas is sprayed directly onto the surface of the thin metal plate through the nozzle of the clamping head via the gas supply system, so that the thin metal plate is cooled rapidly. S9. Tempering: Control the temperature inside the furnace to 150-200℃ for low-temperature tempering. After tempering, control the temperature inside the furnace to cool to room temperature.

9. The plasma carburizing composite heat treatment process for thin metal plates as described in claim 8, characterized in that: The carbon potential for both the first and second stage carburizing is 0.8%–1.2%C, and the carburizing time is 15–90 min.

10. The plasma carburizing composite heat treatment process for thin metal plates as described in claim 8, characterized in that: The furnace pressure for the first and second stages of carburizing is 10–1000 Pa.

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