Ionic nitriding vacuum composite treatment device

Abstract

The utility model relates to the technical field of surface engineering, and discloses an ion nitriding vacuum composite treatment device which comprises an outer cover and a base, the bottom surface of the outer cover is connected with the top surface of the base, a plurality of electric heating plates are arranged on the outer cover along the inner wall, and the top of the outer cover is communicated with a gas inlet pipeline through a gas inlet. The gas inlet pipeline is connected with a nitriding gas pipe and a quenching gas pipe, a cooler is arranged below the quenching gas pipe and communicated with the lower portion of the outer cover through a quenching gas outlet, a quenching gas circulating pipe valve is arranged between the cooler and the quenching gas outlet, and a circulating fan is arranged between the quenching gas pipe and the cooler. The end, away from the cooler, of the air inlet pipeline is connected with the vacuum pump set. Through the cooperation of the air inlet pipeline, the vacuum pump set and the electric heating plate, the ion nitriding, vacuum quenching and vacuum tempering processes can be completed step by step in the same device, the operation is simple, a high-quality infiltrated layer can be obtained in a short time, the surface of a metal part can be efficiently strengthened, meanwhile, the equipment is simplified, and the cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of surface engineering, in particular to an ion nitriding vacuum composite processing device. Background Art

[0002] Ion nitriding is a metal parts surface strengthening process that can improve the surface hardness, fatigue resistance and corrosion resistance of metals. These excellent properties come from the compound layer and nitrogen-containing transition layer attached to the surface of metal parts. However, due to the shallow ion nitriding layer on the surface of metal parts, the concentration gradient is steep, and the bonding strength between the compound layer and the metal is low. When used under the action of complex stress, the compound layer is prone to peeling and microcracks on the surface. In addition, the ion nitriding process is not suitable for metal parts that need to be finely ground after heat treatment. Therefore, the ion nitriding process is often used in combination with vacuum heat treatment to obtain Fe-CN martensite by changing the phase structure of the nitriding layer and the distribution state of nitrogen atoms, increase the depth of the hardened layer, reduce the hardness gradient, and make the surface of the metal parts obtain residual compressive stress, improve its wear resistance and fatigue strength, and further strengthen the metal parts.

[0003] At present, independent ion nitriding equipment and vacuum heat treatment equipment are usually used to carry out ion nitriding and then vacuum quenching process. However, this method needs to be transferred to vacuum heat treatment equipment after the metal parts are ion nitrided. The operation is complicated and time-consuming, and multiple equipment are required, which is costly and occupies a large space. Therefore, improving the surface strengthening efficiency of metal parts and finding a device that can compositely handle ion nitriding process and vacuum heat treatment are the problems that need to be solved at present. Utility Model Content

[0004] In order to solve the technical problems that the surface strengthening of the above-mentioned metal parts requires the use of multiple devices, the operation is complicated, the processing time is long, and the cost is high, the utility model provides an ion nitriding vacuum composite processing device, so that the ion nitriding and vacuum heat treatment processes can be completed in the same equipment, the operation is convenient, the efficiency is high, and at the same time the heating time of the vacuum quenching process is shortened, the energy consumption is reduced, and the cost is saved.

[0005] The specific technical scheme of the utility model is: an ion nitriding vacuum composite processing device, including an outer cover and a base, the bottom surface of the outer cover is connected to the top surface of the base, the outer cover is provided with a plurality of electric heating plates along the inner wall, the top of the outer cover is connected with an air inlet pipeline through a gas inlet, the air inlet pipeline is connected with a nitriding gas pipe and a quenching gas pipe, a cooler is provided below the quenching gas pipe, the cooler is connected with the lower part of the outer cover through a quenching gas outlet, a quenching gas circulation pipe valve is provided between the cooler and the quenching gas outlet, a circulating fan is provided between the quenching gas pipe and the cooler, and the end of the air inlet pipeline away from the cooler is connected to a vacuum pump group.

[0006] This device realizes ion nitriding treatment of the workpiece through a vacuum pump group, an electric heating plate and an ion nitriding pipeline composed of a nitriding gas pipe and a gas inlet; a vacuum quenching pipeline composed of a quenching gas pipe, a gas inlet, a circulating fan, a cooler, a quenching gas circulation pipe valve and a quenching gas outlet, realizes vacuum quenching treatment of the workpiece; a vacuum pump group and an electric heating plate realize the vacuum tempering process of the workpiece. This device can complete vacuum ion nitriding and vacuum heat treatment (quenching, tempering) processes, improve processing efficiency, obtain high-quality carburized layers, efficiently strengthen the workpiece surface, and use the temperature of the workpiece body of ion nitriding to shorten the heating time of later vacuum quenching, save energy consumption and reduce costs. This device can be operated manually or automatically controlled.

[0007] Preferably, a cathode bracket is provided upward from the center of the top surface of the base; a cavity is provided in the base, a fan is provided in the cavity, a conical groove is provided above the fan, a ventilation layer is provided above the conical groove, the ventilation layer is embedded in the top surface of the base, a plurality of through holes are provided outside the middle of the ventilation layer, and the cathode bracket is located at the center of the ventilation layer.

[0008] The base is hemispherical or inverted bell-shaped. By setting a fan, the hot air in the device is driven to circulate, so that the temperature in the device is uniform; by setting a conical groove, the circulating airflow is guided, and the gas is evenly discharged from the groove, thereby improving the efficiency of hot air circulation. The fan drives the hot air circulation, and the airflow passes through the conical groove, through the through hole of the ventilation layer, and enters the outer cover.

[0009] Preferably, a motor is connected to the bottom of the fan, and the motor is connected to the fan through a through hole at the bottom of the base. An adaptable connecting sleeve is provided at the through hole of the base, so that the base forms a closed structure.

[0010] The motor is a variable frequency speed regulating motor, which can automatically adjust the speed according to the change of temperature, and thus adjust the hot air circulation rate.

[0011] Preferably, the outer cover is a double-layer structure, with a cooling water inlet pipe provided on its side and a cooling water outlet pipe provided on the top, and the cooling water inlet pipe and the cooling water outlet pipe lead to between the outer layer and the inner layer of the outer cover.

[0012] The operating temperature of the ion nitriding process and the vacuum heat treatment process is relatively high, and cooling water circulates between the outer layer and the inner layer of the outer cover to cool and protect the device and prevent the high temperature from being conducted outward.

[0013] Preferably, the outer cover is provided with a pressure measuring tube and a temperature measuring tube, the number of the pressure measuring tubes is not less than 2, and the number of the temperature measuring tubes is not less than 2.

[0014] The pressure measuring tube and the temperature measuring tube are arranged on the outer cover, and at least two of each are arranged, so as to monitor the vacuum degree and the temperature in the device in real time.

[0015] Preferably, a controller is provided outside the outer cover, and the electric heating plate, pressure measuring tube and temperature measuring tube in the outer cover are electrically connected to the controller; the vacuum pump group, cooler, circulating fan and quenching gas circulating pipe valve in the air intake pipeline are electrically connected to the controller.

[0016] By electrically connecting each component to the controller, the device can be automatically controlled, further simplifying the operation. The controller controls the start or stop of the electric heating plate by comparing the detected temperature with the internal temperature according to the temperature data provided by the temperature measuring tube; the controller controls the circulating fan by frequency conversion according to the temperature data provided by the temperature measuring tube to control the cooling speed of the workpiece quenching; the controller controls the operation of the vacuum pump group according to the pressure data provided by the pressure measuring tube.

[0017] Preferably, a nitriding gas valve is provided on the nitriding gas pipe, a quenching gas valve is provided on the quenching gas pipe, an intake valve is provided between the gas inlet and the nitriding gas pipe on the intake pipeline, and a vacuum valve is provided between the vacuum pump group and the intake valve on the intake pipeline; the nitriding gas valve, quenching gas valve, intake valve and vacuum valve are electrically connected to the controller.

[0018] The nitriding gas valve, quenching gas valve, air intake valve and vacuum valve are all solenoid valves, and the controller controls the switch sequence and duration. The device adopts automatic control, with higher control accuracy, can be adjusted to a balanced state quickly, and has high reliability.

[0019] Preferably, a plurality of heat insulation plates are provided between the outer cover and the electric heating plate.

[0020] The heat insulation board material is cotton, which has good heat insulation performance. The heat insulation board is arranged between the outer cover and the electric heating plate to prevent heat transfer and insulate the device.

[0021] Preferably, the cathode rack is a "cross" shaped structure.

[0022] The workpiece is placed on the cathode rack for ion nitriding. The "cross"-shaped cathode rack has a wide range of applications. The workpiece can be placed directly on the cathode rack, hung on the crossbar of the cathode rack, or a cathode disk can be set on the cathode rack and the workpiece can be placed in the cathode disk according to its shape.

[0023] Preferably, the air inlet pipeline is provided with an exhaust pipe, the exhaust pipe is located above the gas inlet, and a safety valve is provided on the exhaust pipe.

[0024] An exhaust pipe is set up to prevent air blockage in the air intake pipeline, improve pipeline efficiency, reduce energy consumption, and protect pipeline safety.

[0025] The specific operation steps of the utility model are: workpiece cleaning, removing impurities and oil stains remaining on the surface of the workpiece; workpiece drying, loading the workpiece into an oven for drying treatment; workpiece loading into the device, placing the workpiece on the cathode rack; closing the device; evacuating, starting the vacuum pump group, and evacuating to the pressure inside the tank ≤100Pa; heating and igniting, starting the electric heating plate to heat and heat to a predetermined temperature, and igniting to start ion nitriding; ion nitriding, wait for the temperature of the device to rise to 520°C, start heat preservation nitriding, and the heat preservation time is not more than 10 hours; vacuum heating, turn off the ion nitriding power supply, turn on the electric heating plate to quickly raise the temperature in the device to a preset quenching temperature; vacuum quenching, turn on the gas cooling system to carry out a strong circulation gas cooling quenching process; vacuum tempering, after the temperature in the device reaches room temperature, evacuate and heat the device to the tempering temperature again; take out the parts, wait for the temperature of the device to drop to room temperature and then open the device to take out the parts.

[0026] Compared with the prior art, the utility model has the following advantages:

[0027] 1. It can realize ion nitriding and vacuum heat treatment in the same device, which is simple to operate and can effectively strengthen the surface of the workpiece. Through the cooperation of the air intake pipeline, vacuum pump group and electric heating plate, this device can complete the three processes of ion nitriding, vacuum quenching and vacuum tempering in steps, improve the processing efficiency, and obtain high-quality carburized layer in a shorter time; the workpiece only needs to be loaded into the device once, which simplifies the operation.

[0028] 2. Automatic control is adopted, with high control accuracy and high reliability. This device is connected to an external controller, and the vacuum pump group, electric heating plate, circulating fan, pressure measuring tube, temperature measuring tube and valves on the air intake pipeline are electrically connected to the controller to achieve full automatic control with high control accuracy, and can be adjusted to a balanced state quickly to improve the surface strengthening quality of the workpiece.

[0029] 3. Reduce energy consumption and save costs. A single device can achieve three process treatments that originally required multiple devices to complete, simplifying equipment and reducing costs; and using the workpiece body temperature of ion nitriding to shorten the heating time of subsequent vacuum quenching and save energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a schematic diagram of the structure of an ion nitriding vacuum composite processing device.

[0031] The accompanying drawings are marked as: 1-vacuum pump group, 2-cooling water outlet pipe, 3-pressure measuring tube, 4-outer cover, 5-insulation board, 6-electric heating plate, 8-cathode hanger, 9-guide rod, 10-temperature measuring tube, 11-cooling water inlet pipe, 14-motor, 15-fan, 16-lifting plunger, 17-quenching gas circulation pipe valve, 18-cooler, 19-circulating fan, 20-quenching gas pipe, 21-quenching gas valve, 22-nitriding gas pipe, 23-nitriding gas valve, 24-inlet pipeline, 25-inlet pipe valve, 26-emptying pipe, 27-safety valve, 28-vacuum valve, 29-controller, 30-gas inlet, 31-quenching gas outlet, 32-conical groove, 33-ventilation layer, 34-top surface of base. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the embodiments. The devices, connection structures and methods involved in the present invention are all devices, connection structures and methods known in the art unless otherwise specified.

[0033] Example 1

[0034] like Figure 1As shown, an ion nitriding vacuum composite processing device includes an outer cover 4, a base and an air inlet pipeline 24. The outer cover 4 is provided with two temperature measuring tubes 10 and two pressure measuring tubes 3. The side of the outer cover 4 is provided with a cooling water inlet pipe 11, and the top surface is provided with a cooling water outlet pipe 2. The outer cover 4 is provided with a plurality of electric heating plates 6 along the inner wall. A heat insulation plate 5 is provided between the inner wall of the outer cover 4 and the electric heating plate 6. The heat insulation plate 5 is attached to the inner wall of the outer cover 4. The bottom surface of the outer cover 4 is connected to the top surface of the base; a cavity is provided in the base, and a fan 15 is provided in the cavity. The top surface of the fan 15 is connected to the bottom of the conical groove 32, and the notch of the conical groove 32 is connected to the ventilation layer 33. The ventilation layer 33 is embedded in the top surface 34 of the base and is higher than the top surface 34 of the base. A plurality of through holes are arranged outside the middle of the ventilation layer 33. A cathode hanger 8 is arranged in the center of the ventilation layer 33, and the installation direction is toward the top of the outer cover 4. The bottom of the fan 15 is connected to the motor 14, and the motor 14 is connected to the fan 15 through the through hole at the bottom of the base. A connecting sleeve of the same size is arranged at the through hole of the base, so that the base forms a closed structure; The gas pipeline 24 is arranged outside the outer cover 4, and is connected to the top of the outer cover 4 through the gas inlet 30. The gas inlet pipeline 34 is connected to the nitriding gas pipe 22 and the quenching gas pipe 20 located below the nitriding gas pipe 22. The nitriding gas pipe 22 is provided with a nitriding gas valve 23, and the quenching gas pipe 20 is provided with a quenching gas valve 21. A cooler 18 is provided below the quenching gas pipe 20. The side of the cooler 18 is connected to the lower part of the outer cover 4 through the quenching gas outlet 31. The cooler 18 and the quenching gas outlet 31 are connected. A quenching gas circulation pipe valve 17 is provided between the quenching gas pipe 20 and the cooler 18, a circulating fan 19 is provided between the quenching gas pipe 20 and the cooler 18, the end of the air intake pipeline 24 away from the cooler 18 is connected to the vacuum pump group 1, an exhaust pipe 26 is provided on the air intake pipeline 24, which is located above the gas inlet 30, a safety valve 27 is provided on the exhaust pipe 24, an air intake valve 25 is provided between the gas inlet 30 and the nitriding gas pipe 22 on the air intake pipeline 24, and a vacuum valve 28 is provided between the vacuum pump group 1 and the air intake valve 25 on the air intake pipeline 24.

[0035] The outer cover 4 is a bell-shaped double-layer structure, and the cooling water inlet pipe 11 and the cooling water outlet pipe 2 lead from the outside to the outer layer and the inner layer of the outer cover 4, and the outer layer and the inner layer of the outer cover 4 are filled with circulating cooling water; the pressure measuring tube 3 and the temperature measuring tube 10 lead from the outside to the inner layer of the outer cover 4, and each pressure measuring tube 3 maintains a certain distance and is randomly distributed on the outer cover 4, and each temperature measuring tube 10 maintains a certain distance and is randomly distributed on the outer cover 4. The base is hemispherical. The insulation board 5 is made of cotton. A number of guide rods 9 and four jacking plungers 16 are provided on the side of the base, the top of the guide rod 9 is higher than the top surface 34 of the base, and the top surface of the jacking plunger 16 is against the bottom of the top surface 34 of the base. The top surface of the fan 15 is adapted to the bottom of the conical groove 32, and the notch of the conical groove 32 is adapted to the bottom surface of the ventilation layer 33. The ventilation layer 33 is embedded in and protrudes from the middle of the bottom top surface 34. The ventilation layer 33 is solid in the middle and has a through-hole structure outside the middle. A cathode rack 8 is provided at the center of the ventilation layer 33. The cathode rack 8 is in a "cross" shape and is installed toward the top of the outer cover 4. The crossbar length of the cathode rack 8 is the same as that of the ventilation layer 33. The cathode rack 8 is connected to an ion nitriding power supply. A controller 29 is provided outside the outer cover 4, and the ion nitriding power supply is electrically connected to the controller 29. The motor 14 is a variable frequency speed regulating motor, which is electrically connected to the controller 29 and can automatically adjust the motor speed according to the temperature change value. The air intake pipeline 24 includes an ion nitriding pipeline and a vacuum quenching pipeline. The ion nitriding pipeline includes a gas inlet 30, a nitriding gas pipe 22 and a nitriding gas valve 23. The nitriding gas pipe 22 is connected to the air intake pipeline 24. The nitriding gas valve 23 is provided on the nitriding gas pipe 22. The gas inlet 30 is arranged on the air intake pipeline 24 and is connected to the top of the outer cover 4; the vacuum quenching pipeline includes a gas inlet 30, a quenching gas pipe 20, a cooler 18, a quenching gas circulation pipe valve 17, a circulating fan 19 and a quenching gas outlet 31. The quenching gas pipe 20 is located below the nitriding gas pipe 22 and is connected to the air intake pipeline 24. The cooler 18 is arranged on the air intake pipeline 24, below the quenching gas pipe 20, and its side is connected to the lower part of the outer cover 4 through the quenching gas outlet 31. A quenching gas circulation pipe valve 17 is provided between the cooler 18 and the quenching gas outlet 31, and the circulating fan 19 is arranged between the quenching gas pipe 20 and the cooler 18. The quenching gas circulation pipe valve 17, the quenching gas valve 21, the nitriding gas valve 23, the air inlet pipe valve 25, the safety valve 27, and the vacuum valve 28 are all electromagnetic valves, which are electrically connected to the controller 29. The ion nitriding power supply, the vacuum pump group 1, the pressure measuring tube 3, the electric heating plate 6, the temperature measuring tube 10, the motor 14, the cooler 18, and the circulating fan 19 are electrically connected to the controller 29.

[0036] In this embodiment, the ion nitriding power supply, vacuum pump group 1, electric heating plate 6 and ion nitriding pipeline composed of nitriding gas pipe 22, nitriding gas valve 23 and gas inlet 30 work together to realize ion nitriding treatment of the workpiece; the vacuum pump group 1, electric heating plate 6 and vacuum quenching pipeline composed of gas inlet 30, quenching gas pipe 20, cooler 18, quenching gas circulation pipe valve 17, circulation fan 19 and quenching gas outlet 31 work together to realize vacuum quenching treatment of the workpiece; the vacuum pump group and electric heating plate work together to realize vacuum tempering process of the workpiece. The ion nitriding gas is NH3. The vacuum quenching gas is low-temperature nitrogen, liquid ammonia vapor or a mixture of the two. The vacuum quenching gas circulation method is as follows: the gas is introduced into the air inlet pipeline 24 from the quenching gas pipe 20, and is introduced into the device from the gas inlet 30. Driven by the circulating fan 19, the gas leaves the device from the quenching gas outlet 31 and enters the cooler 18 for cooling. The cooled gas leaves from the top of the cooler, flows toward the circulating fan 19, and then is introduced into the device from the gas inlet 30 for circulation.

[0037] In this embodiment, by filling cooling water in the interlayer of the outer cover 4, the cooling water flows into the interlayer from the cooling water inlet pipe 11 and overflows at the cooling water outlet 2. The cooling water circulates between the outer layer and the inner layer of the outer cover 4 to cool and protect the device and prevent high temperature from being conducted outward. By setting a heat insulation board 5 between the outer cover 4 and the electric heating plate 6, heat transfer is prevented and the device is insulated and heat-insulated. The heat insulation board material is cotton, which has good heat insulation performance. By setting a fan 15, the hot air circulation in the device is driven to make the temperature in the device uniform. By setting a conical groove 32, the circulating airflow is guided, and the gas is evenly discharged from the notch, thereby improving the hot air circulation efficiency. By setting a ventilation layer 33, the upper and lower gases are circulated at the through hole, and the middle part is a solid structure, which more firmly supports the cathode rack 8 and fixes its position. The purpose of setting a "cross" cathode rack 8 is that the structure has a wide range of applications and can load workpieces of different shapes. By setting a circulating fan 19, the quenching gas is driven to circulate, so that the quenching gas continues to enter the cooler 18 for cooling, and the low temperature state of the quenching gas is maintained. By setting a guide rod 9 and a lifting plunger 16, the outer cover 4 is combined with the base, and the combination method is: first place the workpiece on the cathode rack 8, then the base is positioned by the guide rod 9, and then lifted by the lifting plunger 16 to fit and lock the bell-shaped outer cover 4 to form a closed structure. By setting an exhaust pipe 26, air blockage is prevented from forming in the air intake pipeline, and the pipeline safety is protected at the same time.

[0038] The specific operation steps of this embodiment can be divided into 11 steps. 1. Workpiece cleaning: Use cleaning agent and clean water to remove oil stains on the surface of the workpiece; steam cleaning can be used for heavy oil stains; ultrasonic cleaning can be used for small areas. 2. Workpiece drying: Use various heating methods to remove moisture from the surface of the workpiece and make the surface of the workpiece dry. 3. Workpiece loading device: Place the workpiece evenly on the cathode rack 8, and the slender rods can be hung. 4. Closing device: The base is positioned with a guide rod 9, and is closed and locked with the outer cover 4 under the action of the lifting plunger 16. 5. Vacuuming: Open the vacuum valve 28, start the vacuum pump group 1 to vacuum, and evacuate until the pressure in the device is ≤100Pa. 6. Heating and starting: The electric heating plate 6 is energized for heating, the motor 14 is started, the fan 15 is operated, and the device is ion nitrided and started. After heating to 300°C, the nitriding gas valve 23 is opened to introduce nitriding gas. 7. Ion nitriding: When the temperature in the tank reaches 520°C, the electric heating plate 6 is powered off, and the device is kept warm for continuous nitriding for 8 to 10 hours. 8. Vacuum heating: The electric heating plate 6 is powered on and quickly heated to the set temperature value, and the insulation time is ≥1 hour. 9. Vacuum quenching: The electric heating plate 6 is powered off, the quenching gas circulation pipe valve 17 is opened, the cooler 18 is opened, the circulating fan 19 is opened, the quenching gas valve 21 is opened, the vacuum quenching gas is sent in, and the workpiece is quickly quenched under the drive of the circulating fan 19. 10. Vacuum tempering: After completing the vacuum quenching process, wait for the temperature of the device to reach room temperature, start the vacuum tempering process, close all valves, reopen the vacuum valve 28, evacuate the device to a pressure of ≤100Pa, start the electric heating plate 6, power on and heat to the set temperature, keep warm for 1 to 2 hours, power off the electric heating plate 6, and the device slowly cools to room temperature. 11. Removal: Manually unlock the safety locking structure, separate the base from the outer cover 4 along the guide rod 9, and lower the base to the ground platform under the action of the jacking plunger 16 to remove the workpiece. For workpieces that do not require vacuum tempering process, after completing the vacuum quenching process, open the device to remove the workpiece after the temperature of the device drops to room temperature.

[0039] In this embodiment, the preset parameters and instructions of the controller 29 are: the pressure in the device is ≤100Pa, the electric heating plate 6 is powered on for heating; the temperature in the device reaches 300°C, ion nitriding gas is introduced, and ion ignition is performed; the temperature in the device reaches 520°C, the electric heating plate 6 is powered off, the device is insulated for ion nitriding, the insulation temperature range is 520°C±5°C, and the insulation time is ≥8h; the low-temperature vacuum quenching temperature is 750°C, and the vacuum quenching pipeline is in operation; the high-temperature vacuum quenching temperature is 1150°C and the vacuum quenching pipeline is in operation; the low-temperature tempering temperature is 280~320°C, kept warm for 1~2 hours, and then cooled to room temperature; the high-temperature tempering temperature is 560~620°C, kept warm for 1~2 hours, and then cooled to room temperature.

[0040] This embodiment adopts automatic control, with high control accuracy, and keeps the device running in a stable state. The multi-point arranged pressure measuring tubes 3 and temperature measuring tubes 10 monitor the vacuum degree and temperature in the device at all times, and feedback the values ​​to the controller 29. The pressure value in the device is preset in the controller 29. When the pressure value detected by the pressure measuring tube 3 is greater than the preset value, the controller 29 instructs the vacuum valve 28 to open and the vacuum pump group 1 to start; when the pressure value detected by the pressure measuring tube 3 is less than the built-in pressure value, the controller 29 instructs the vacuum pump 1 to stop and the vacuum valve 28 to close. The temperature values ​​of each stage in the device are preset in the controller 29. When the temperature value detected by the temperature measuring tube 10 is less than the preset value, the controller 29 instructs the electric heating plate 6 to turn on the power for heating; when the temperature value detected by the temperature measuring tube 10 is greater than the preset value, the controller 29 instructs the heating plate 6 to turn off the power. The temperature values ​​of each stage are: ion nitriding heating temperature T1, vacuum quenching heating temperature T2, and low-temperature tempering temperature T3. According to the type of metal material, the temperature of each stage can be set to a holding time of 1 to 24 hours. The temperature measuring tubes 10 are distributed at different positions on the outer cover 4. When the temperature values ​​measured at different positions have a large difference, the controller 29 issues a fast fan rotation instruction to the motor 14; when the temperature values ​​measured at different positions have a small difference, the controller 29 issues a low-speed fan rotation instruction to the motor 14. In the vacuum quenching stage, the controller 29 adjusts the speed of the circulating fan 19 according to the temperature data measured by the temperature measuring tubes 10 to control the cooling speed of the workpiece quenching.

[0041] Example 2

[0042] The difference between this embodiment and embodiment 1 is that, in this embodiment, four pressure measuring tubes 3 are arranged, which are symmetrically distributed on both sides of the outer cover 4 along the center of the cathode rack 8; three pressure measuring tubes 3 are arranged, which are distributed on the top and both sides of the outer cover 4; the base is in an inverted bell shape; the ventilation layer 33 is embedded in the top surface 34 of the base, and its height is consistent with the top surface 34 of the base, and a plurality of through holes are arranged outside the middle of the ventilation layer 33.

[0043] Test Example 1

[0044] This test example adopts the device of Example 1, and uses 3Cr2W8V hot working die steel to carry out ion nitriding and vacuum heat treatment experiments. The experimental process is as follows: the 3Cr2W8V hot working die steel is cleaned, dried, loaded into the device, and evacuated. When the pressure in the device is ≤100Pa, the electric heating plate 6 is started for heating, and the ion nitriding power supply is turned on. When the temperature rises to 300°C, the nitriding gas is introduced, and the temperature in the device continues to rise to 520°C. The electric heating plate 6 is powered off, and the nitriding is continued for at least 8 hours of insulation. The nitriding power supply is turned off, and the electric heating plate 6 is powered on to quickly heat to 750°C~820°C, and the temperature is kept for 1 hour. The electric heating plate 6 is powered off, and the vacuum quenching gas is introduced. The gas cooling system is turned on for strong circulation gas cooling and quenching. After the temperature of the device drops to room temperature, the device is opened to take out the parts.

[0045] After the above treatment, the surface performance of 3Cr2W8V hot working die steel can reach 810HV0.3; the depth of the full martensite layer is 0.35 mm. This test case uses sub-temperature quenching, and the quenching temperature range is 750℃~820℃, which effectively reduces the change of workpiece size. After the inspection experiment, the appearance and size of 3Cr2W8V hot working die steel meet the component size requirements. After ion nitriding composite vacuum heat treatment, the average hardness of the surface layer (0~0.35mm) of 3Cr2W8V hot working die steel is improved, thereby improving its toughness and surface crack resistance. And because of the low quenching temperature and small deformation, the ion nitriding vacuum composite heat treatment effectively expands the depth of the hardened layer, making up for the weakness of the extremely thin nitride compound layer, and the service life of the parts using the original single heat treatment process is increased by 2~3 times.

[0046] The cross-sectional metallographic analysis of 3Cr2W8V hot working die steel shows that ion nitriding vacuum composite treatment can change the phase structure and nitrogen atom distribution state of the carburized layer to obtain Fe-CN martensite; the γ' phase and ε content of 3Cr2W8V hot working die steel after ion nitriding composite heat treatment are increased, and an ideal surface wear-resistant phase structure can be obtained to improve wear resistance.

[0047] The chemical corrosion stripping method was used to measure 3Cr2W8V hot working die steel on a X-ray stress testing machine. The results showed that for sub-temperature quenching in vacuum, the lower the quenching temperature or the shorter the heating time, the higher the surface nitrogen concentration. Due to the large specific volume of martensite, the amount of undissolved ferrite in the core increases, which leads to an increase in surface residual compressive stress and improves the fatigue resistance of the components in later use.

[0048] The controller involved in the present invention is a conventional controller in the prior art and is not the technical key point of the present invention.

[0049] The above description is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Any simple modification, change and equivalent structural transformation made to the above embodiments according to the technical essence of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. An ion nitridation vacuum composite processing device, comprising an outer cover and a base, wherein the bottom surface of the outer cover is connected to the top surface of the base, characterized in that: The outer cover is provided with a plurality of electric heating plates along the inner wall, the top of the outer cover is connected with the air inlet pipeline through the gas inlet, the air inlet pipeline is connected with the nitriding gas pipe and the quenching gas pipe, a cooler is provided below the quenching gas pipe, the cooler is connected with the lower part of the outer cover through the quenching gas outlet, a quenching gas circulation pipe valve is provided between the cooler and the quenching gas outlet, a circulation fan is provided between the quenching gas pipe and the cooler, and the end of the air inlet pipeline away from the cooler is connected with the vacuum pump group.

2. The ion nitriding vacuum composite processing device according to claim 1, characterized in that: A cathode bracket is provided upward from the center of the top surface of the base; a cavity is provided in the base, a fan is provided in the cavity, a conical groove is provided above the fan, a ventilation layer is provided above the conical groove, the ventilation layer is embedded in the top surface of the base, a plurality of through holes are provided outside the middle of the ventilation layer, and the cathode bracket is located at the center of the ventilation layer.

3. The ion nitriding vacuum composite processing device according to claim 2, characterized in that: The bottom of the fan is connected with a motor, which is connected to the fan through a through hole at the bottom of the base. An adaptable connecting sleeve is provided at the through hole of the base, so that the base forms a closed structure.

4. The ion nitriding vacuum composite processing device according to claim 1, characterized in that: The outer cover is a double-layer structure, with a cooling water inlet pipe on its side and a cooling water outlet pipe on the top. The cooling water inlet pipe and the cooling water outlet pipe lead to the outer layer and the inner layer of the outer cover.

5. The ion nitriding vacuum composite processing device according to claim 1, characterized in that: The outer cover is provided with a pressure measuring tube and a temperature measuring tube, the number of the pressure measuring tubes is not less than 2, and the number of the temperature measuring tubes is not less than 2.

6. The ion nitridation vacuum composite processing device according to claim 5, characterized in that: A controller is arranged outside the outer cover, and the electric heating plate, pressure measuring tube and temperature measuring tube in the outer cover are electrically connected to the controller; the vacuum pump group, cooler, circulating fan and quenching gas circulating pipe valve in the air intake pipeline are electrically connected to the controller.

7. The ion nitriding vacuum composite processing device according to claim 6, characterized in that: The nitriding gas pipe is provided with a nitriding gas valve, the quenching gas pipe is provided with a quenching gas valve, an intake valve is provided between the gas inlet and the nitriding gas pipe on the intake pipeline, and a vacuum valve is provided between the vacuum pump group and the intake valve on the intake pipeline; the nitriding gas valve, quenching gas valve, intake valve and vacuum valve are electrically connected to the controller.

8. An ion nitriding vacuum composite processing device according to claim 1 or 4, characterized in that: A plurality of heat insulation plates are arranged between the outer cover and the electric heating plate.

9. The ion nitridation vacuum composite processing device according to claim 2, characterized in that: The cathode rack is a "cross" shaped structure.

10. The ion nitridation vacuum composite processing device according to claim 1, characterized in that: The air inlet pipeline is provided with an exhaust pipe, which is located above the gas inlet and has a safety valve.

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