Method and device for preparing complex hollow structure by adopting pulse direct current and induction eddy current cyclic loading auxiliary diffusion bonding

Abstract

The invention discloses a method and a device for preparing a complex hollow structure by adopting pulse direct current and induced eddy current cyclic loading auxiliary diffusion bonding, and relates to a method for auxiliary heating diffusion bonding. And efficient and uniform heating of the metal material is achieved. The method comprises the following steps: step 1, preparing a predetermined metal complex hollow structural member to be subjected to diffusion bonding, and polishing and cleaning the surface of the metal complex hollow structural member; 2, the metal complex hollow structural part is placed in a tool mold for mold filling, and the mold is placed in a vacuum furnace; 3, building a double-source control system; and 4, diffusion bonding is conducted under specified parameters, pressure relief and furnace cooling are conducted after diffusion time is over, and workpieces are taken after the workpieces are cooled to the normal temperature. According to the method, pulse direct current heating and induction eddy current heating are combined for diffusion bonding heating, the diffusion efficiency is improved, meanwhile, the temperature uniformity is guaranteed, the welding rate is improved, and the quality of a diffusion joint is improved.

Description

Technical Field

[0001] The present invention relates to a method for assisting heating diffusion bonding. Specifically, the present invention relates to a method and device for preparing complex hollow structures by using pulsed direct current and induced eddy current cyclic loading to assist diffusion bonding, which is used to control and optimize the diffusion bonding process between metals. Background Art

[0002] In the field of modern industrial manufacturing, especially in aviation, aerospace and high-end machinery manufacturing, diffusion bonding technology is a key material connection technology, which achieves permanent bonding between metal materials through diffusion between atoms. This technology is particularly suitable for application scenarios that have extremely high requirements for joint integrity, high temperature resistance and mechanical properties, such as aircraft wall panel structures and electronic component microchannel structures.

[0003] However, the common diffusion bonding process mainly relies on continuous in-furnace heating, which has many limitations and shortcomings. First, in-furnace heating usually requires a long heating and insulation process, resulting in high energy consumption and low efficiency. Secondly, global heating is difficult to achieve precise temperature control and local heating, and it is easy to introduce uneven thermal stress during the processing process, which may cause deformation or even damage to the material, affecting the quality and performance of the final product. In addition, although single electric pulse heating can provide rapid local heating effects, it also has some significant limitations, mainly because electric pulse heating is usually intermittent, which may lead to uneven heating, especially on large-area or complex-shaped workpieces, where it is difficult to maintain temperature consistency. High-intensity local heating of electric pulses may also cause rapid oxidation or other thermal damage to the surface of the material, further limiting its scope of application in precision manufacturing.

[0004] There are other auxiliary heating means in the prior art, such as the Chinese invention patent application with publication number CN116689929A, which discloses a method for welding alumina ceramics and titanium alloys with electric field assistance for rapid connection, wherein the alumina ceramics and titanium alloys to be welded are subjected to mechanical grinding and polishing, and a Nb layer is plated on the surface of the alumina ceramics to be welded by magnetron sputtering, and after being assembled into a furnace, the temperature is raised to 700-900°C at a heating rate of 5-15°C / min, and the temperature is kept for 1-2h before an electric field is applied again, and the temperature is cooled to 400°C at a cooling rate of 5-10°C / min, and finally the diffusion connection of the alumina ceramics and the titanium alloy is completed with furnace cooling. The advantage of this method is that it can greatly reduce the connection temperature and connection time required for welding, improve the efficiency of diffusion connection, and reduce production costs. However, single electric auxiliary heating can cause some areas of the material to heat too fast and other areas to heat insufficiently. In diffusion connection, this uneven heating may cause the quality of the connection interface to be different, affecting the performance and reliability of the final product.

[0005] Therefore, how to ensure the continuity and uniformity of heating during diffusion bonding, and further ensure the welding rate and diffusion bonding efficiency, has become a technical problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0006] In view of the above problems, the present invention proposes a method and device for preparing complex hollow structures by using pulsed direct current and induced eddy current cycle loading assisted diffusion connection, which combines induced eddy current heating and electric pulse cycle heating, utilizes the uniformity and deep heating capability of induced eddy current heating, and the rapid response and high energy efficiency of electric pulse heating, to achieve efficient and uniform heating of metal materials.

[0007] The technical solution of the present invention is: comprising the following steps: Step 1: Prepare a predetermined metal complex hollow structure to be diffusion-bonded, and polish and clean the surface of the metal complex hollow structure; Step 2: placing the metal complex hollow structural part in the tooling mold 3 for molding, and placing the tooling mold 3 into a vacuum furnace; Step 3: Build a dual-source control system; A pressure head for diffusion connection is arranged on the upper and lower sides of the tooling die 3, and an electrode 1 clamped on the pressure head is arranged on the pressure head, and the electrode 1 is connected to a pulse power supply through a pressure head protection circuit, and an induction coil 2 is arranged around the tooling die 3, and the induction coil 2 is connected to an induction eddy current power supply through a coil protection circuit; The pulse frequency of the pulse power supply and the modulation frequency of the induction eddy current power supply are set to be consistent, so that the pulse power supply and the induction eddy current power supply are turned on, and the induction eddy current power supply is powered on to supply heat during the duty period of the pulse power supply; Step 4: Set the diffusion bonding process parameters, pulsed DC electrode power supply parameters, and induced eddy current parameters. The vacuum furnace applies pressure to the mold through the pressure head, and diffusion bonding is performed under the specified parameters. After the diffusion time is over, the pressure is released and the mold is cooled with the furnace. The mold is removed after cooling to room temperature.

[0008] The specific pretreatment of metal complex hollow structural parts in step 1 is: Use boron nitride spray to spray a layer of coating on the non-diffusion connection area of ​​the metal complex hollow structural parts as a solder stop, then blow dry with cold air, and then use 120#, 400#, 800#, 1500# sandpaper to polish the diffusion connection area of ​​the metal complex hollow structural parts step by step, then use mirror polishing paste and soft cloth or polishing wheel to polish the metal surface, gradually increase the polishing degree until the surface reaches a mirror effect. Then use different immersion liquids for different metal materials to wash off the surface grease and residual polishing paste, and finally put them in alcohol for ultrasonic cleaning, blow dry with cold air, and seal the cleaned parts for storage.

[0009] In step 3, set the pulse power supply parameters as follows: pulse frequency 5~100Hz; duty cycle 20%~80%; current density 0.1~100A / mm 2 ; The parameters of the induction eddy current power supply are set as follows: oscillation frequency is 1~500kHz; modulation frequency is 5~100Hz; induction current is 0~150A.

[0010] In step 4, before the diffusion connection temperature and pressure increase, the vacuum valve is used to evacuate the vacuum to 10 - 3 Pa and below, then start to increase temperature and pressure; For magnesium alloy, after vacuuming, 15KPa argon gas needs to be passed into the furnace through a gas cylinder connected to a gas pipe.

[0011] The combined heating rate of pulsed DC heating and induction eddy current heating is 100°C / min~200°C / min, and the heating is stopped after the temperature reaches the specified temperature of diffusion bonding; For steel, the specified temperature range for diffusion bonding is 900°C to 1200°C; For aluminum alloys, the specified temperature range for diffusion bonding is 400°C to 600°C; For titanium alloys, the specified temperature range for diffusion bonding is 750°C to 1000°C; For magnesium alloys, the specified temperature range for diffusion bonding is 400°C to 600°C.

[0012] After the temperature reaches the specified temperature for diffusion bonding, the control electrode (1) applies pressure to the tooling die (3), and after 1 minute, the pressure is raised to 1-10 MPa and then the pressure is stopped; After reaching the temperature and pressure, stabilize the dual-source control parameters and keep warm for 1 to 4 hours. After the heat preservation and pressure maintenance are completed, the furnace is opened and the parts are taken out as the furnace cools to room temperature to obtain the finished product.

[0013] The present invention combines pulsed DC heating and induction eddy current heating for diffusion connection heating, which improves the diffusion efficiency while ensuring temperature uniformity, and improves the welding rate and the quality of the diffusion joint, and has the following beneficial effects: 1. The present invention provides a method of combining pulsed DC with induction eddy current cycle loading assisted diffusion connection, wherein pulsed DC heating provides localized, high-energy heat input, which helps to quickly increase the temperature of a specific area. High temperature can increase the movement rate of atoms in the material and promote diffusion between atoms. In this way, pulsed DC heating can accelerate the atomic redistribution and recrystallization process of the material around the hole, thereby filling the hole, and the welding rate after eliminating the hole can reach more than 95%.

[0014] Second, the present invention provides a method for pulsed direct current and induced eddy current cycle loading assisted diffusion connection, wherein the induced eddy current heating effect mainly affects the surface layer of the workpiece, especially in the edge area of ​​the material. During the heating process, the heat generated in the edge area is transmitted to the central area through heat conduction, which helps to reduce the temperature difference between the center and the edge, further improves the temperature uniformity, and makes the temperature difference between the lowest temperature and the highest temperature of the entire metal complex hollow structure less than 5°C.

[0015] 3. The present invention effectively combines the two, and the dual-source linkage can fill the duty cycle of single pulse DC heating and significantly improve the heating efficiency. Pulse DC heating can quickly apply high energy to the material and quickly heat up. Induction eddy current heating generates eddy currents inside the material through the generated electromagnetic field, and these eddy currents quickly generate heat through the resistance effect. The combination of these two heating methods can achieve a very fast temperature rise rate, thereby shortening the time the material needs to stay at high temperature. Reducing the residence time can effectively reduce excessive grain growth, improve the quality of diffusion bonding joints while improving the efficiency of diffusion bonding. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the diffusion connection method using pulsed direct current and induced eddy current circulation assistance in the present invention; Figure 2 It is a schematic diagram of manufacturing a thin-walled hollow structural member of a rare earth magnesium alloy slot waveguide antenna by using a pulsed direct current and an induction eddy current circulation assisted diffusion connection method in the present invention; Figure 3 The cross section of the thin-walled hollow structure of the rare earth magnesium alloy slot waveguide antenna; the schematic diagram of the diffusion connection area and the combined support block for auxiliary diffusion connection; Figure 4 It is a schematic diagram of a stainless steel multilayer microchannel hollow structure; Figure 5 It is a composite loading waveform of pulsed DC and induced eddy current.

[0017] The reference numerals in the accompanying drawings represent the following: 1. pressure head / electrode; 2. induction coil; 3. tooling mold; 4. magnesium alloy slot waveguide antenna thin-walled hollow structural member; 5. stainless steel multi-layer microchannel hollow structural member cover plate; 6. stainless steel multi-layer microchannel hollow structural member substrate. DETAILED DESCRIPTION

[0018] In order to clearly illustrate the technical features of this patent, this patent is elaborated in detail below through a specific implementation method and in combination with its accompanying drawings. Example

[0019] The present invention proposes an innovative solution, in which induction eddy current heating can provide a stable and extensive thermal field, suitable for large-area heating, while electric pulse heating can quickly increase the temperature when needed, solving the problem that a single heating technology is difficult to balance speed and uniformity. Through this combined technology, the present invention can not only significantly improve the heating efficiency of diffusion bonding, but also improve the heat treatment quality of the joint, reduce energy consumption, and optimize the production process. The implementation of this heating method provides a more reliable, economical and environmentally friendly auxiliary heating technology for the diffusion bonding of high-performance metal materials.

[0020] The specific embodiments of the present invention are as follows: like Figure 2-Figure 3 As shown, in this example, the diffusion bonding material is a rare earth magnesium alloy, and the processing target is a slot waveguide antenna thin-walled hollow structural member. The provided method for manufacturing a rare earth magnesium alloy slot waveguide antenna thin-walled hollow structural member by pulsed direct current and induced eddy current circulation assisted diffusion bonding includes the following steps: Step 1: Prepare a predetermined thin-walled hollow structural member 4 of a magnesium alloy slot waveguide antenna to be diffusely connected, and polish and clean the surface of the structural member; Use boron nitride spray to spray a layer of coating on the non-diffusion connection area of ​​the metal complex hollow structural parts as a solder stop, then blow dry with cold air, and then use 120#, 400#, 800#, 1500# sandpaper to polish the diffusion connection area of ​​the metal complex hollow structural parts step by step. Then, use mirror polishing paste and soft cloth or polishing wheel to polish the metal surface, gradually increase the polishing degree until the surface reaches a mirror effect. Then use phosphoric acid solution to wash off the surface grease and residual polishing paste, and finally put it in alcohol for ultrasonic cleaning, blow dry with cold air, and seal the cleaned parts for storage.

[0021] Step 2: placing the thin-walled hollow structural member 4 of the magnesium alloy slot waveguide antenna in the tooling mold 3 for molding, placing a combined support block in the hollow part of the structural member to prevent the collapse and failure of the structural member caused by the diffusion connection pressure, and placing the tooling mold 3 into a vacuum furnace; Step 3: Build a dual-source control system; A pressure head for diffusion connection is arranged on the upper and lower sides of the tooling die 3, and an electrode 1 clamped on the pressure head is arranged on the pressure head, and the electrode 1 is connected to a pulse power supply through a pressure head protection circuit, and an induction coil 2 is arranged around the tooling die 3, and the induction coil 2 is connected to an induction eddy current power supply through a coil protection circuit; like Figure 5 As shown, the pulse frequency of the pulse power supply and the modulation frequency of the induction eddy current power supply are set to be consistent, so that when the pulse power supply and the induction eddy current power supply are turned on, the induction eddy current power supply is powered on to supply heat during the duty period of the pulse power supply; Set the pulse power supply parameters to: The pulse frequency is 5~100Hz; The duty cycle is 20%~80%; Current density is 0.1~100A / mm 2 .

[0022] Set the parameters of the eddy current power supply to: Oscillation frequency is 1~500kHz; Modulation frequency is 5~100Hz; Induction current 0~150A.

[0023] Step 4: Set the diffusion bonding process parameters, pulsed DC electrode power supply parameters, and induced eddy current parameters. The vacuum furnace applies pressure to the mold through the pressure head, and diffusion bonding is performed under the specified parameters. After the diffusion time is over, the pressure is released and the mold is cooled with the furnace. The mold is removed after cooling to room temperature.

[0024] Before the diffusion connection temperature and pressure increase begins, evacuate the vacuum valve to a vacuum degree of 10 -3 Pa and below, then pass 15KPa argon gas into the furnace through the gas cylinder connected to the gas pipe, and then start to increase the temperature and pressure.

[0025] The combined heating rate of pulsed DC heating and induction eddy current heating is 100°C / min~200°C / min, and the temperature rise is stopped after reaching 400°C~600°C. After the temperature reaches the diffusion temperature, the pressure head electrode is controlled by the console to rise to 1~10MPa pressure in 1min and then the pressure rise is stopped. After reaching the temperature and pressure, the dual-source control parameters are stabilized and kept warm for 1~4h. After the heat and pressure are finished, the furnace is opened and the parts are taken out after cooling to room temperature. Example

[0026] like Figure 4 As shown, in this example, the diffusion bonding material is stainless steel, and the processing target is a multi-layer microchannel hollow structure. The provided method for manufacturing a stainless steel multi-layer microchannel hollow structure by pulsed direct current and induced eddy current circulation assisted diffusion bonding includes the following steps: Step 1: Prepare a predetermined stainless steel single-layer microchannel hollow structural member 5 to be diffusion-connected, and polish and clean the surface of the structural member; Use boron nitride spray to spray a layer of coating on the non-diffusion connection area of ​​the metal complex hollow structural parts as a solder stop, then blow dry with cold air, and then use 120#, 400#, 800#, 1500# sandpaper to polish the diffusion connection area of ​​the metal complex hollow structural parts step by step. Then, use mirror polishing paste and soft cloth or polishing wheel to polish the metal surface, gradually increase the polishing degree until the surface reaches a mirror effect. Then use stainless steel pickling liquid to soak and wash away the surface grease and residual polishing paste, and finally put it in alcohol for ultrasonic cleaning, blow dry with cold air, and seal the cleaned parts for storage.

[0027] Step 2: stack the stainless steel microchannel hollow structural component substrate 6 in the mold, place the stainless steel microchannel hollow structural component substrate 5 on the top layer of the structural component, and place the mold into a vacuum furnace; Step 3: Build a dual-source control system; A pressure head for diffusion connection is arranged on the upper and lower sides of the tooling die 3, and an electrode 1 clamped on the pressure head is arranged on the pressure head, and the electrode 1 is connected to a pulse power supply through a pressure head protection circuit, and an induction coil 2 is arranged around the tooling die 3, and the induction coil 2 is connected to an induction eddy current power supply through a coil protection circuit; like Figure 5 As shown, the pulse frequency of the pulse power supply and the modulation frequency of the induction eddy current power supply are set to be consistent, so that when the pulse power supply and the induction eddy current power supply are turned on, the induction eddy current power supply is powered on to supply heat during the duty period of the pulse power supply; Set the pulse power supply parameters to: The power supply frequency is 5~100Hz; The duty cycle is 20%~80%; Current density is 0.1~100A / mm 2 .

[0028] Set the parameters of the eddy current power supply to: Oscillation frequency is 1~500kHz; Modulation frequency is 5~100Hz; The induced current is 0~150A.

[0029] Step 4: Set the diffusion bonding process parameters, pulsed DC electrode power supply parameters, and induced eddy current parameters. The vacuum furnace applies pressure to the mold through the pressure head, and diffusion bonding is performed under the specified parameters. After the diffusion time is over, the pressure is released and the mold is cooled with the furnace. The mold is removed after cooling to room temperature.

[0030] Before the diffusion connection temperature and pressure increase begins, evacuate the vacuum valve to a vacuum degree of 10 -3 Pa and below, and then start to increase the temperature and pressure.

[0031] The combined heating rate of pulsed DC heating and induction eddy current heating is 100°C / min~200°C / min, and the temperature rise is stopped after reaching 900°C~1200°C. After the temperature reaches the diffusion temperature, the pressure head electrode is controlled by the console to rise to 1~10MPa pressure in 1min and then the pressure rise is stopped. After reaching the temperature and pressure, the dual-source control parameters are stabilized and kept warm for 1~4h. After the heat and pressure are finished, the furnace is opened and the parts are taken out after cooling to room temperature.

[0032] There are many specific implementation ways of the present invention. The above is only the preferred implementation mode of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principle of the present invention. These improvements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a complex hollow structure by using pulsed direct current and induced eddy current cycle loading assisted diffusion connection, characterized in that: The following steps are involved: Step 1: Prepare a predetermined metal complex hollow structure to be diffusion-bonded, and polish and clean the surface of the metal complex hollow structure; Step 2: placing the metal complex hollow structural part in the tooling mold (3) for molding, and placing the tooling mold (3) in a vacuum furnace; Step 3: Build a dual-source control system; A pressure head for performing diffusion connection is arranged on the upper and lower sides of the tooling mold (3), and an electrode (1) clamped on the pressure head is arranged on the pressure head, the electrode (1) is connected to a pulse power supply via a pressure head protection circuit, an induction coil (2) is arranged around the tooling mold (3), and the induction coil (2) is connected to an induction eddy current power supply via a coil protection circuit; The power-on frequencies of the pulse power supply and the induction eddy current power supply are set to be consistent, so that when the pulse power supply and the induction eddy current power supply are turned on, the induction eddy current power supply is powered on to provide heat during the duty period of the pulse power supply; Step 4: Set the diffusion bonding process parameters, pulsed DC electrode power supply parameters, and induced eddy current parameters. The vacuum furnace applies pressure to the mold through the pressure head, and diffusion bonding is performed under the specified parameters. After the diffusion time is over, the pressure is released and the mold is cooled with the furnace. The mold is removed after cooling to room temperature.

2. The method for preparing a complex hollow structure by using pulsed direct current and induced eddy current cycle loading assisted diffusion connection according to claim 1, characterized in that: The specific pretreatment of metal complex hollow structural parts in step 1 is: Use boron nitride spray to spray a layer of coating on the non-diffusion connection area of ​​the metal complex hollow structural parts as a solder stop, then blow dry with cold air, and then use 120#, 400#, 800#, 1500# sandpaper to polish the diffusion connection area of ​​the metal complex hollow structural parts step by step, then use mirror polishing paste and soft cloth or polishing wheel to polish the metal surface, gradually increase the polishing degree until the surface reaches a mirror effect. Then use different immersion liquids for different metal materials to wash off the surface grease and residual polishing paste, and finally put them in alcohol for ultrasonic cleaning, blow dry with cold air, and seal the cleaned parts for storage.

3. The method for preparing a complex hollow structure by using pulsed direct current and induced eddy current cycle loading assisted diffusion connection according to claim 1, characterized in that: In step 3, set the pulse power supply parameters as follows: pulse frequency 5~100Hz; duty cycle 20%~80%; current density 0.1~100A / mm 2 ; The parameters of the induction eddy current power supply are set as follows: oscillation frequency is 1~500kHz; modulation frequency is 5~100Hz; induction current is 0~150A.

4. The method for preparing a complex hollow structure by using pulsed direct current and induced eddy current cycle loading assisted diffusion connection according to claim 1, characterized in that: In step 4, before the diffusion connection temperature and pressure increase, the vacuum valve is used to evacuate the vacuum to 10 -3 Pa and below, then the temperature and pressure begin to rise; For magnesium alloy, after vacuuming, 15KPa argon gas is passed into the furnace through a gas cylinder connected to a gas pipe; The combined heating rate of pulsed DC heating and induction eddy current heating is 100°C / min~200°C / min, and the heating is stopped after the temperature reaches the specified temperature of diffusion bonding; For steel, the specified temperature range for diffusion bonding is 900°C to 1200°C; For aluminum alloys, the specified temperature range for diffusion bonding is 400°C to 600°C; For titanium alloys, the specified temperature range for diffusion bonding is 750°C to 1000°C; For rare earth magnesium alloys, the specified temperature range for diffusion bonding is 400°C to 600°C; After the temperature reaches the specified temperature for diffusion bonding, the control electrode (1) applies pressure to the tooling die (3), and after 1 minute, the pressure is raised to 1-10 MPa and then the pressure is stopped; After reaching the temperature and pressure, stabilize the dual-source control parameters and keep warm for 1 to 4 hours. After the heat preservation and pressure maintenance are completed, the furnace is opened and the parts are taken out as the furnace cools to room temperature to obtain the finished product.

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