High-temperature superconducting high-intensity magnetic field homogenization heat treatment method and device for large-size titanium alloy ingot blank

Abstract

The invention discloses a high-temperature superconducting high-intensity magnetic field homogenization heat treatment method and device for a large-size titanium alloy ingot blank. The adopted device comprises a heating main body structure, a driving assembly, a temperature monitoring and control system and a cooling system. The heating main body structure comprises a supporting frame, an ingot blank rotating clamp, a superconducting coil and an adjustable magnetic core, and the ingot blank rotating clamp is connected with the driving assembly; a temperature monitoring assembly and a control system are arranged outside the ingot blank; the cooling system adopts a liquid nitrogen cooling mode to guarantee stable operation of the superconducting coil. Compared with a traditional titanium alloy heating method, the equipment efficiency can be improved by 82% through the homogenization heat treatment, the heating time is greatly shortened, and the production efficiency is improved. The axial temperature error of the titanium alloy ingot blank can be controlled within + / -3 DEG C, the structure property difference is effectively reduced, and the product quality is improved. The heating depth is increased through low-frequency heating, multiple temperature control modes are achieved in cooperation with a temperature monitoring and control system, and high industrial application value is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium alloys, and in particular relates to a high-temperature superconducting strong magnetic field homogenization heat treatment of a large-size titanium alloy ingot and a device thereof. Background Art

[0002] Titanium alloys are widely used in aerospace, shipbuilding, chemical industry and many other fields due to their advantages of low density, high specific strength and good corrosion resistance. In the processing of titanium alloys, heating is a key link, and its quality directly affects the subsequent processing performance and product quality.

[0003] In view of the process requirements of titanium alloys for precise temperature control in the two-phase region, traditional heat conduction heating is prone to uneven temperature field and thermal hysteresis due to the low thermal conductivity of the material. The thermal conductivity efficiency of titanium makes the traditional heating process cycle lengthy and will cause uneven composition inside large-sized titanium alloy forgings, making it difficult to accurately control the temperature during heat treatment. Currently, commonly used heating methods for titanium alloys include gas heating, resistance furnace heating, and traditional AC induction heating. However, these traditional heating methods have obvious technical defects, such as: Gas heating efficiency is low: it takes 10 hours to heat a D220mm TC4 titanium alloy ingot to 950°C, with an energy consumption of 3200kWh / ton; Poor temperature uniformity: When heated in a resistance furnace, the axial temperature difference of the ingot reaches ±25°C, resulting in grain boundary coarsening (grain size difference > 50μm); Inadequate induction heating depth: The skin depth of traditional AC induction heating (frequency 50Hz) is only 3.2mm, and the temperature difference on the core surface of a 200mm thick ingot exceeds 150℃.

[0004] In summary, with the development of industry, the requirements for the uniformity of the internal structure and heating efficiency of titanium alloys are increasing. The existing technology is difficult to meet these requirements. It is urgent to develop a homogenization heat treatment method for large-size titanium alloy ingots. Summary of the invention

[0005] In response to the above technical problems, the present invention aims to provide a high-temperature superconducting strong magnetic field homogenization heat treatment of large-size titanium alloy ingots and a device thereof, which achieves rapid, uniform and efficient heating of titanium alloys through DC electromagnetic induction heating and precise control of heating parameters, overcomes the drawbacks of traditional heating methods, improves the heating quality and production efficiency of titanium alloys, and meets the needs of industrial production for titanium alloy heating.

[0006] To achieve the above object, the technical solution of the present invention is: In one aspect, the present invention provides a high temperature superconducting strong magnetic field homogenization heat treatment method for a large-size titanium alloy ingot, comprising the following steps: Place a large-sized titanium alloy ingot blank in a direct current magnetic field, rotate the large-sized titanium alloy ingot blank to cut the magnetic lines of force in the direct current static magnetic field for electromagnetic induction heating, heat it to the target temperature using low frequency, and determine the heating time based on the target heating temperature of the titanium alloy ingot blank, the ingot blank size, as well as the set magnetic field strength and heating frequency. Establish a relationship model between the heating time and various parameters through experiments and simulation analysis to achieve precise control of the heating time. The heating time t (min) can be expressed as: Where: D: The diameter of the titanium alloy ingot blank (unit: mm), which needs to satisfy D≥150 mm. The titanium alloy ingot blank is usually in the shape of a cylindrical rod. ΔT=T 目标 −T 初始 (unit: °C). The initial temperature is usually room temperature, and room temperature is generally 20°C. B: The direct current static magnetic field strength (unit: T), which needs to satisfy B≥0.5 T. f: The low frequency heating frequency (unit: Hz), and the range is 4 Hz≤f≤8.3 Hz. k: The comprehensive correction coefficient, which is determined through experiments and simulation. The typical value is 0.0001792. The direct current static magnetic field is generated by a magnet made of high-temperature superconducting wire. For large-sized ingots or cases that require rapid heating, a higher magnetic field strength can be set. For occasions with extremely high requirements for temperature uniformity, the magnetic field strength can be appropriately adjusted to achieve the best effect.

[0007] In an embodiment of the present invention, the low frequency heating frequency is 4 - 8.3 Hz, and the rotation speed of the large-sized titanium alloy ingot blank is 240 - 500 rpm / min. Low frequency heating can increase the heating depth, reduce the skin effect, and make the internal heating of the ingot blank more uniform. In actual operation, the heating frequency is precisely adjusted according to the diameter of the ingot blank and the required heating rate. For example, for a larger diameter ingot blank, the frequency is appropriately reduced to increase the heat penetration depth; for a smaller diameter ingot blank, the frequency can be appropriately increased to accelerate the heating rate.

[0008] In an embodiment of the present invention, when the magnetic field strength is 0.5 T and the heating frequency is 5 Hz, when the electromagnetic induction heating target temperature of a Ti-6Al-4V ingot blank with a diameter of 200 mm and a length of 1250 mm is 950°C, the heating time is 25 min, and the required temperature and tissue homogenization can be achieved. After stopping heating, stop the rotation of the titanium alloy ingot blank within 20 s after shutdown.

[0009] In an embodiment of the present invention, the diameter D of the large-sized titanium alloy ingot blank ≥150 mm.

[0010] In an embodiment of the present invention, after the electromagnetic induction heating is completed, the ingot billet is cooled to room temperature in the furnace, or is subjected to corresponding treatment according to the requirements of subsequent processing technologies. For example, if forging processing is required, the ingot billet can be directly transferred to forging equipment for forging; or if specific microstructure and properties are desired, heat preservation treatment can be carried out. The heat preservation time is determined according to process requirements, generally 5 - 60 min, and then cooling is carried out. The cooling method can be selected from air cooling, water cooling, oil cooling, etc. to meet different process requirements.

[0011] In a second aspect, the present invention also provides a high-temperature superconducting strong magnetic field homogenization heat treatment device for large-sized titanium alloy ingot billets, which is used to implement the high-temperature superconducting strong magnetic field homogenization heat treatment method for large-sized titanium alloy ingot billets as described above, and includes: a high-temperature furnace, a cooling system, a temperature monitoring component, and a controller; The interior of the high-temperature furnace includes: A support frame, which is arranged inside the high-temperature furnace; A rotating driving shaft, which is rotatably installed on the support frame; A rotating driven shaft, which is rotatably installed on the support frame, and the central axis of the rotating driving shaft coincides with the central axis of the rotating driven shaft; An ingot billet rotating fixture, which includes a first ingot billet rotating fixture and a second ingot billet rotating fixture. The first ingot billet rotating fixture and the second ingot billet rotating fixture are respectively installed on the rotating driving shaft and the rotating driven shaft; A large-sized titanium alloy ingot billet, and both ends of the large-sized titanium alloy ingot billet in the axial direction are respectively clamped between the first ingot billet rotating fixture and the second ingot billet rotating fixture; A driving component, which is in transmission connection with the rotating driving shaft, and the driving component drives the rotating driving shaft to rotate; A south pole of a high-temperature superconducting magnet, and there is one such south pole of the high-temperature superconducting magnet; North Pole of the high-temperature superconducting magnet. There is one North Pole of the high-temperature superconducting magnet. The North Pole and the South Pole of the high-temperature superconducting magnet are respectively located on both sides of the radial direction of the titanium alloy ingot. Adjust the distance between the North Pole and the South Pole of the high-temperature superconducting magnet to adjust the magnetic induction intensity and distribution. Both the North and South Poles of the high-temperature superconducting magnet include a magnetic core and a superconducting coil. The superconducting coil is wound around the magnetic core. The magnetic core includes multiple movable magnetic core blocks, which can adjust the distance between the magnetic cores of the North Pole and the South Pole of the high-temperature superconducting magnet as a whole, and can also adjust the distance between some of the relative magnetic cores to adjust the air gap width between the North Pole and the South Pole of the high-temperature superconducting magnet. Therefore, in the present invention, by adjusting the position of the magnetic core, the distance between the North Pole and the South Pole of the high-temperature superconducting magnet is regulated, thereby controlling the magnetic field intensity and distribution. Controlling the position of the magnetic core can, on the one hand, adapt to titanium alloy ingots of different sizes, and on the other hand, adjust the magnetic field distribution to achieve precise control of the axial temperature distribution of the titanium alloy ingot. The magnetic core material is selected from materials with good magnetic conductivity, such as silicon steel sheets with high magnetic permeability, to suppress the skin effect, reduce eddy current losses, and increase the eddy current penetration depth. The cooling system is used to cool the superconducting coil so that the operating temperature of the superconducting coil is strictly lower than the critical temperature of its material. The temperature monitoring component, the driving component, the DC induction heating device are electrically connected to the controller. The temperature monitoring component is used to monitor the surface and internal temperatures of the large-sized titanium alloy ingot.

[0012] The controller uses a programmable logic controller (PLC) or an industrial computer, etc. as the core of the controller, receives the temperature signal transmitted by the temperature monitoring device, and automatically adjusts the current intensity of the superconducting coil, the heating frequency, and the rotation speed of the driving component through a preset control algorithm to achieve precise control of the heating process. Preferably, the controller also has a human-machine interface, and the operator can set heating parameters, view information such as the temperature change curve during the heating process, etc. through the interface.

[0013] In a preferred embodiment of the present invention, the superconducting coil is wound by high-temperature superconducting wire (such as REBCO coated conductor) to generate a strong DC magnetic field. The number of turns, wire diameter, and winding method of the superconducting coil are designed according to the equipment power and heating requirements to ensure that a magnetic field with sufficient intensity and uniformity can be generated.

[0014] In a preferred embodiment of the present invention, the cooling medium of the cooling system is liquid nitrogen. The cooling system includes a cryogenic pump, a vacuum-insulated pipeline, a liquid nitrogen storage tank, and a mass flow meter. The liquid nitrogen storage tank is equipped with a vaporizer for regulating the temperature and pressure of the liquid nitrogen. The mass flow meter is used to accurately control the flow rate of the liquid nitrogen. The cryogenic pump, the liquid nitrogen storage tank, and the vacuum-insulated pipeline are connected. The mass flow meter is installed on the vacuum-insulated pipeline. High-purity liquid nitrogen is used for cooling. The boiling point of liquid nitrogen is constantly -196°C (77 K). When cooling, the liquid nitrogen flow rate is 5 - 15 L / min (dynamically adjusted according to the coil heat load), and accurate control is achieved by using a mass flow meter. The conveying pressure is usually 0.5 - 2 bar (gauge pressure) to avoid a sudden increase in pressure caused by the vaporization of liquid nitrogen. To ensure the normal operating temperature of the superconducting coil, it must be strictly lower than the critical temperature of its material, which is -196°C to -163°C, to improve the stability and service life of the equipment.

[0015] In a preferred embodiment of the present invention, the temperature monitoring component includes an infrared thermometer and a thermocouple. The infrared thermometer is used to monitor the surface temperature of the titanium alloy ingot blank in real time and has the characteristics of non-contact and fast response. The thermocouple is used to monitor the internal temperature of the titanium alloy ingot blank and accurately measure the internal temperature. The combination of the two can comprehensively and accurately obtain the temperature information of the ingot blank.

[0016] In a preferred embodiment of the present invention, the driving component includes a driving motor and a transmission unit. The driving motor is connected to the transmission unit, and the transmission unit is connected to the rotating main shaft. A driving motor with an appropriate power is selected, such as a 630 kW driving motor system, to drive the rotation of the titanium alloy ingot blank. The rotation speed of the motor can be accurately adjusted according to the heating frequency, and the rotation speed range is 240 - 500 rpm to meet different heating requirements. The transmission device uses methods such as belt drive, gear drive, or chain drive to transmit the power of the driving motor to the ingot blank rotating device, ensuring that the ingot blank can rotate stably and uniformly. The design of the transmission device should ensure high transmission efficiency and good stability, reducing energy loss and vibration.

[0017] Due to the adoption of the above technical solutions, the present invention has the following advantages and positive effects compared with the prior art: 1. For the process requirement of precise temperature control in the two-phase region of titanium alloy, the electromagnetic induction heating of the present invention directly stimulates the internal eddy current thermal effect of the material through electromagnetic coupling, combines the regulation of the electromagnetic field frequency to optimize the depth of energy deposition, can establish a uniform temperature field in milliseconds and maintain precise temperature control. By dynamically adjusting the electromagnetic parameters, on the premise of ensuring the full completion of phase transformation, the abnormal growth of grains is effectively inhibited, and the fine-grained tissue characteristics are maintained. With the closed-loop control system of the DC electromagnetic field, the equipment efficiency can reach more than 82%, nearly doubling the efficiency compared with the traditional AC induction heating equipment. The present invention also can effectively control the magnetic field distribution through the optimized magnetic core structure and low-frequency heating method, so that the axial temperature uniformity error of the titanium alloy ingot can be controlled within ±3°C. It not only realizes the high uniformity of the alloy microstructure and the isotropy of mechanical properties, but also significantly improves the energy utilization efficiency, greatly shortens the heat treatment cycle and reduces the heating time compared with the traditional process.

[0018] 2. During the rotation of the ingot, each part is heated evenly, reducing the temperature difference, avoiding the difference in tissue properties caused by uneven heating, and improving the product quality. When heating experiments are carried out on a Ti-6Al-4V ingot with a diameter of 220 mm and a length of 1250 mm, using the device and method of the homogenization heat treatment method of the present invention, the temperature difference between different parts of the ingot is extremely small, and the tissue uniformity is good. The low-frequency heating reduces the skin effect, and the heating depth increases significantly. Experiments show that the heating depth of the present invention is several times that of the traditional medium-high frequency AC induction heating, which can ensure that the inside of the large-size titanium alloy ingot can also be fully and evenly heated. The advanced temperature monitoring and controller can accurately monitor and adjust the ingot temperature in real time. According to different process requirements, it can realize the control of uniform temperature distribution, reduce the residual stress during forging; it can also realize the control of gradient temperature distribution, meet the needs of manufacturing functionally gradient materials, and improve the process adaptability of the equipment and the diversity of products.

[0019] 3. The homogenization heat treatment method provided by the present invention is applicable to large-size titanium alloy ingots with a diameter D≥150 mm. High-temperature superconducting magnets are used to achieve a DC static magnetic field of more than 0.5 T, and a low-frequency heating method is adopted. The ingot is heated evenly, avoiding tissue non-uniformity and performance instability caused by temperature non-uniformity, and is suitable for mass processing of large-size titanium alloy ingots under industrial conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of the high-temperature superconducting strong magnetic field homogenization heat treatment device for large-size titanium alloy ingots in the present invention; Description of the reference numerals in the drawings: 1 - Rotating drive shaft; 2 - First ingot blank rotating fixture; 3 - South pole of the high-temperature superconducting magnet; 4 - Cylindrical titanium alloy ingot blank; 5 - Rotating driven shaft; 6 - Second ingot blank rotating fixture; 7 - North pole of the high-temperature superconducting magnet; 701 - Superconducting coil; 702 - Magnetic core; 8 - Controller; 9 - Thermocouple; Detailed implementation manners

[0021] The present invention will be elaborated in detail through specific implementation cases below. These implementation cases will provide a more intuitive understanding reference for those skilled in the art, but do not constitute any limitation to the protection scope of the present invention. It should be noted that those of ordinary skill in the art can make various forms of modifications or supplements to specific implementation scenarios without departing from the core design concept of the present invention, and such improvements should be included in the scope of the rights of the present invention.

[0022] In addition, it should be clear that the technical features involved in the various implementation manners of the present invention can be freely combined on the premise that there is no technical conflict between them.

[0023] The directional descriptions (such as upper, lower, left, right, front, rear, etc. azimuth indications) involved in the embodiments are only used to explain the relative position relationship and motion state between components in a specific posture shown in the drawings. When the specific posture changes, the corresponding directional indications will also be adjusted accordingly.

[0024] During the heat treatment process, alloying elements tend to aggregate at grain boundaries, thereby forming coarse intermetallic compounds. If the heating process parameters are set unreasonably, the heating degrees of different parts of the ingot blank are different, and the coarse intermetallic compounds at the grain boundaries cannot be fully dissolved, and it takes a long time to heat to the required temperature. In addition, the large-sized titanium alloy ingot blank itself has poor heat transfer characteristics, resulting in uneven temperature distribution. This makes it impossible for alloying elements to diffuse evenly, and there will also be differences in the dissolution and transformation processes of the second phase. Therefore, the present invention provides a high-temperature superconducting strong magnetic field homogenization heat treatment method for large-sized titanium alloy ingot blanks, especially suitable for titanium alloy ingot blanks with a diameter D≥150 mm. By using electromagnetic induction heating, the internal eddy current heat effect of the material is directly excited through electromagnetic coupling, and the depth optimization of energy deposition is realized by combining the electromagnetic field frequency regulation. A uniform temperature field can be established in milliseconds and precise temperature control can be maintained. By dynamically adjusting the electromagnetic parameters, on the premise of ensuring the full completion of phase transformation, the abnormal growth of grains is effectively inhibited, and the fine grain tissue characteristics are maintained. With the closed-loop control system of the direct current electromagnetic field, not only the high uniformity of the alloy microstructure and the isotropy of mechanical properties are achieved, but also the energy utilization efficiency is significantly improved, and the heat treatment cycle is greatly shortened compared with the traditional process, and the heating time is reduced.

[0025] The following further elaborates in detail on a high-temperature superconducting strong magnetic field homogenization heat treatment and its device for a large-sized titanium alloy ingot blank proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer.

[0026] Example 1 Refer to Figure 1 , this embodiment provides a high-temperature superconducting strong magnetic field homogenization heat treatment device for a large-sized titanium alloy ingot blank, including: a high-temperature furnace, a cooling system, a temperature monitoring component, and a controller 8. The high-temperature furnace is made of materials with good heat insulation performance to reduce heat dissipation and improve energy utilization efficiency.

[0027] Inside the high-temperature furnace includes: A support frame, arranged inside the high-temperature furnace; A rotating drive shaft 1, the rotating drive shaft 1 is rotatably installed on the support frame; A rotating driven shaft 5, the rotating driven shaft 5 is rotatably installed on the support frame, and the central axis of the rotating drive shaft 1 coincides with the central axis of the rotating driven shaft 5; An ingot blank rotating fixture, the ingot blank rotating fixture includes a first ingot blank rotating fixture 2 and a second ingot blank rotating fixture 6, and the first ingot blank rotating fixture 2 and the second ingot blank rotating fixture 6 are respectively installed on the rotating drive shaft 1 and the rotating driven shaft 5; A large-sized titanium alloy ingot blank 4, both ends in the axial direction of the large-sized titanium alloy ingot blank 4 are clamped between the first ingot blank rotating fixture 2 and the second ingot blank rotating fixture 6; A driving component, the driving component is in transmission connection with the rotating drive shaft 1, and the driving component drives the rotating drive shaft 1 to rotate; The south pole 3 of the high-temperature superconducting magnet, there is one south pole 3 of the high-temperature superconducting magnet; North Pole 7 of the high-temperature superconducting magnet. There is one North Pole 7 of the high-temperature superconducting magnet. The North Pole 7 of the high-temperature superconducting magnet and the South Pole 3 of the high-temperature superconducting magnet are respectively arranged on both sides of the radial direction of the titanium alloy ingot blank 4. Adjust the distance L between the North Pole 7 of the high-temperature superconducting magnet and the South Pole 3 of the high-temperature superconducting magnet to adjust the magnetic induction intensity and distribution. Both the South Pole 3 of the high-temperature superconducting magnet and the North Pole 7 of the high-temperature superconducting magnet include a magnetic core 701 and a superconducting coil 702. The superconducting coil 702 is wound around the magnetic core 701. The magnetic core includes a plurality of movable magnetic core blocks, and the distance between the magnetic core 701 of the North Pole 7 of the high-temperature superconducting magnet and the magnetic core 701 of the South Pole 3 of the high-temperature superconducting magnet can be adjusted as a whole, and the distance between some relative magnetic cores 701 can also be adjusted. For example, for the axial two ends and the middle of the titanium alloy ingot blank 4, the distance between the magnetic core 701 of the North Pole 7 of the high-temperature superconducting magnet and the magnetic core 701 of the South Pole 3 of the high-temperature superconducting magnet at the axial two end parts is less than the distance between the magnetic core 701 of the North Pole 7 of the high-temperature superconducting magnet and the magnetic core 701 of the South Pole 3 of the high-temperature superconducting magnet in the axial middle part. The air gap width between the North Pole 7 of the high-temperature superconducting magnet and the South Pole 3 of the high-temperature superconducting magnet is adjusted in two ways. Therefore, in the present invention, by adjusting the position of the magnetic core 701, the distance between the North Pole of the high-temperature superconducting magnet and the South Pole 3 of the high-temperature superconducting magnet is regulated, thereby controlling the magnetic field intensity and distribution. By controlling the position of the magnetic core 701, on the one hand, it can be adapted to different sizes of titanium alloy ingot blanks 4, and on the other hand, the magnetic field distribution is adjusted to achieve precise control of the axial temperature distribution of the titanium alloy ingot blank. The magnetic core 701 is made of a material with good magnetic conductivity, such as silicon steel sheets with high magnetic permeability, to suppress the skin effect, reduce eddy current losses, and increase the eddy current penetration depth. The cooling system is used to cool the superconducting coil 702 to make the operating temperature of the superconducting coil 702 strictly lower than the critical temperature of its material. The temperature monitoring component, the driving component, the DC induction heating device of the superconducting coil 702 are electrically connected to the controller 8. The temperature monitoring component is used to monitor the surface and internal temperatures of the large-sized titanium alloy ingot blank 4.

[0028] The controller 8 uses a programmable logic controller (PLC) or an industrial computer, etc. as the core of the controller 8, receives the temperature signal transmitted by the temperature monitoring device, and automatically adjusts the current intensity, heating frequency of the superconducting coil 702, and the rotation speed of the driving component through a preset control algorithm to achieve precise control of the heating process. Preferably, the controller 8 also has a human-machine interface, and the operator can set heating parameters, view information such as the temperature change curve during the heating process, etc. through the interface.

[0029] In some preferred embodiments, the superconducting coil 702 is wound by high-temperature superconducting wire (such as REBCO coated conductor) and is used to generate a strong DC magnetic field. The number of turns, wire diameter, and winding method of the superconducting coil 702 are designed according to the equipment power and heating requirements to ensure that a magnetic field with sufficient intensity and uniformity can be generated.

[0030] In some preferred embodiments, the cooling medium of the cooling system is liquid nitrogen. The medium of the cooling system can also be cooling water, which is not limited here. The cooling system includes a cryogenic pump, a vacuum adiabatic pipeline, a liquid nitrogen storage tank, and a mass flow meter. The liquid nitrogen storage tank is equipped with a vaporizer for regulating the temperature and pressure of liquid nitrogen, and the mass flow meter is used to accurately control the flow rate of liquid nitrogen; the cryogenic pump, the liquid nitrogen storage tank are connected to the vacuum adiabatic pipeline, and the mass flow meter is installed on the vacuum adiabatic pipeline. High-purity liquid nitrogen is used for cooling. The boiling point of liquid nitrogen is constant at -196°C (77 K). During cooling, the liquid nitrogen flow rate is 5 - 15 L / min (dynamically adjusted according to the coil heat load), and accurate control is achieved using a mass flow meter. The conveying pressure is usually 0.5 - 2 bar (gauge pressure) to avoid a sudden increase in pressure caused by the vaporization of liquid nitrogen. To ensure the normal operating temperature of the superconducting coil 702 must be strictly lower than the critical temperature of its material, which is -196°C to -163°C, to improve the stability and service life of the equipment.

[0031] In some preferred embodiments, the temperature monitoring component includes an infrared thermometer and a thermocouple 9. The infrared thermometer is used to monitor the surface temperature of the titanium alloy ingot blank 4 in real time and has the characteristics of non-contact and fast response; the thermocouple 9 is embedded at a specific position inside the ingot blank and is used to monitor the internal temperature of the titanium alloy ingot blank 4 in real time and accurately measure the internal temperature. The combination of the two can comprehensively and accurately obtain the temperature information of the ingot blank.

[0032] In a preferred embodiment of the present invention, the driving component includes a driving motor and a transmission unit. The driving motor is connected to the transmission unit, and the transmission unit is connected to the rotating main shaft 1. A driving motor with a suitable power is selected, such as a 630 kW driving motor system, to drive the rotation of the titanium alloy ingot blank. The rotation speed of the motor can be accurately adjusted according to the heating frequency, and the speed range is 240 - 500 rpm to meet different heating requirements. The transmission device uses belt drive, gear drive, or chain drive, etc., to transmit the power of the driving motor to the ingot blank rotating device to ensure that the ingot blank can rotate stably and uniformly. The design of the transmission device should ensure high transmission efficiency and good stability, reducing energy loss and vibration.

[0033] After the device in this embodiment is started, the drive motor is started. A large current is formed in the high-temperature superconducting wire to generate a magnetic field, and a DC static magnetic field is formed between the south pole 3 of the opposing high-temperature superconducting magnet and the north pole 7 of the opposing high-temperature superconducting magnet. The cylindrical titanium alloy ingot 4 is in the magnetic field.

[0034] The drive motor drives the rotation of the rotating drive shaft 1, driving the first ingot rotating fixture 2 to realize the rotation of the cylindrical titanium alloy ingot 4. The second ingot rotating fixture 6 and the rotating driven shaft 5 are the driven ends, maintaining stable rotation. The large-sized cylindrical titanium alloy ingot 4 rotates to cut the magnetic field lines, realizing induction heating.

[0035] The infrared thermometer measures the surface temperature of the ingot, which is non-contact and has a fast response. The thermocouple 9 is inserted into a specific position inside the titanium alloy ingot 4 to accurately measure the internal temperature. The controller 8 uses a programmable logic controller 8 (PLC) as the core of the control system and has a human-machine interface. During the operation of the equipment, liquid nitrogen is used to cool the superconducting coil 702 to ensure that the normal operating temperature of the superconducting coil 702 must be strictly lower than the critical temperature of its material, -196°C to -163°C, to improve the stability and service life of the equipment.

[0036] After heating is completed, the current is turned off and the drive motor is stopped, thus ending the heating process.

[0037] Embodiment 2 This embodiment provides a high-temperature superconducting strong magnetic field homogenization heat treatment method for a large-sized titanium alloy ingot 4, using the device provided in Embodiment 1, including the following steps: Step 1: Select a Ti-6Al-4V titanium alloy ingot with a diameter of 220 mm and a length of 1250 mm. Polish and clean its surface to remove oil stains and oxide scales, and fix the two ends in the axial direction on two ingot rotating fixtures respectively.

[0038] Step 2: Place the ingot in the high-temperature furnace body of the high-temperature superconducting direct current induction heating device, adjust the position of the ingot so that it is located at the center of the magnetic field and has a uniform gap with the coil. Select a suitable superconducting coil 702 and magnetic core structure, set the cooling system to ensure that the temperature of the cooling medium is 20°C and the flow rate is 20 L / min. Set the magnetic field strength to 0.7 T and the heating frequency to 5 Hz (corresponding to an ingot rotation speed of 300 rpm / min). According to the formula Calculation shows that the expected heating time is 25 min and the target heating temperature is 950°C.

[0039] Step 3: Start the heating device, drive the motor to rotate the ingot, and energize the superconducting coil 702 to generate a magnetic field. During the heating process, the temperature monitoring component monitors the ingot temperature in real time, and the control system fine-tunes the heating parameters based on temperature feedback. When the external and internal temperatures of the ingot are close to the target temperature, the heating power is gradually reduced to ensure that the ingot reaches 950°C accurately.

[0040] Step 4: After the ingot reaches the target temperature, it is transferred to the forging equipment for forging. The forging process is smooth, the ingot is deformed evenly, the product quality after forging is good, and all performance indicators meet the requirements.

[0041] Compared with the prior art, the present invention has significant advantages in heating efficiency and temperature uniformity. Taking D220×1250mm titanium alloy ingot 4 as an example, the traditional gas heating furnace takes 600 minutes to rise to 950°C; conventional AC induction heating (50Hz / 3000rpm) takes 180 minutes and the temperature difference between the surface and the core exceeds 130°C. However, the low-frequency induction heating (0.5T / 500rpm) of the present invention only takes 25 minutes to complete the heating, with a surface temperature of 952°C and a core temperature of 949°C, a temperature difference of ≤3°C, and an axial temperature uniformity error controlled within ±3°C. Compared with traditional heating methods, the efficiency is increased by 82%, and the temperature difference between the surface and the core is only 3°C, which fully meets the requirements of TC4 alloy plastic forming for a temperature gradient of ≤28.5°C. This method effectively suppresses the skin effect through the coupling of low-frequency strong magnetic field (4-8.3Hz) and low-speed rotation, increases the eddy current penetration depth by 3-5 times, and shortens the heating time by 40%-60% for every 0.5T increase in magnetic field intensity. It has both high efficiency and uniform temperature, and is particularly suitable for industrial homogenization heat treatment of D150-600mm large-size titanium alloy ingots 4. Low-frequency heating increases the heating depth, and cooperates with temperature monitoring and control systems to achieve multiple temperature control modes, significantly improving process adaptability and product diversity, and has high industrial application value.

[0042] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the protection scope of the present invention.

Claims

1. A method for heat treatment of homogenization of high-temperature superconductivity strong magnetic field for large-sized titanium alloy ingots, characterized in that, It includes the following steps: Place a large-sized titanium alloy ingot blank in a DC magnetic field, rotate the large-sized titanium alloy ingot blank to cut the magnetic field lines in the DC static magnetic field for electromagnetic induction heating, and use low-frequency heating to heat it to the target temperature. The heating time t (min) is expressed as: Where: D: The diameter of the titanium alloy ingot blank (unit: mm), and it is required that D≥150 mm; ΔT=T 目标 −T 初始 (unit: °C); B: The DC static magnetic field intensity (unit: T), and it is required that B≥0.5 T; f: The low-frequency heating frequency (unit: Hz), and the range is 4 Hz≤f≤8.3 Hz; k: The comprehensive correction coefficient, and the typical value is 0.0001792; The DC static magnetic field is generated by a magnet made of high-temperature superconducting wire.

2. The high-temperature superconducting strong magnetic field homogenization heat treatment method for large-sized titanium alloy ingots according to claim 1, characterized in that, The rotation speed of the large-sized titanium alloy ingot blank is 240 - 500 rpm / min.

3. The high-temperature superconducting strong magnetic field homogenization heat treatment method for large-sized titanium alloy ingots according to claim 1, characterized in that When the target temperature of electromagnetic induction heating of the large-sized titanium alloy ingot blank is 950°C, the heating time is 25 min.

4. The high-temperature superconducting strong magnetic field homogenization heat treatment method for large-size titanium alloy ingots according to claim 1, wherein The diameter D of the large-sized titanium alloy ingot blank is D≥220 mm.

5. The high-temperature superconducting strong magnetic field homogenizing heat treatment method for large-sized titanium alloy ingots according to claim 1, wherein After the electromagnetic induction heating is completed, the ingot blank is cooled to room temperature in the furnace, or taken out and cooled, or corresponding treatment is carried out according to the requirements of subsequent processing technology.

6. A high-temperature superconducting strong magnetic field homogenization heat treatment device for large-sized titanium alloy ingots, which is used to implement the high-temperature superconducting strong magnetic field homogenization heat treatment method for large-sized titanium alloy ingots described in any one of claims 1-5, and is characterized in that, It includes: A high-temperature furnace, a cooling system, a temperature monitoring component, and a controller; Inside the high-temperature furnace includes: A support frame, which is arranged inside the high-temperature furnace; A rotating driving shaft, and the rotating driving shaft is rotatably installed on the support frame; A rotating driven shaft, and the rotating driven shaft is rotatably installed on the support frame. The central axis of the rotating driving shaft coincides with the central axis of the rotating driven shaft; An ingot blank rotating fixture, and the ingot blank rotating fixture includes a first ingot blank rotating fixture and a second ingot blank rotating fixture. The first ingot blank rotating fixture and the second ingot blank rotating fixture are respectively installed on the rotating driving shaft and the rotating driven shaft; A large-sized titanium alloy ingot blank, and both ends of the large-sized titanium alloy ingot blank in the axial direction are clamped between the first ingot blank rotating fixture and the second ingot blank rotating fixture; A driving component, and the driving component is in transmission connection with the rotating driving shaft, and the driving component drives the rotating driving shaft to rotate; There is one south pole of the high-temperature superconducting magnet; There is one north pole of the high-temperature superconducting magnet. The north pole of the high-temperature superconducting magnet and the south pole of the high-temperature superconducting magnet are respectively arranged on both sides of the radial direction of the titanium alloy ingot. Adjust the distance between the north pole of the high-temperature superconducting magnet and the south pole of the high-temperature superconducting magnet to adjust the magnetic induction intensity and distribution; The cooling system is used to cool the superconducting coils of the south pole of the high-temperature superconducting magnet and the north pole of the high-temperature superconducting magnet, so that the working temperature of the superconducting coils is strictly lower than the critical temperature of its material; The temperature monitoring component, the driving component, the DC induction heating device are electrically connected to the controller, and the temperature monitoring component is used to monitor the surface and internal temperature of the large-sized titanium alloy ingot blank.

7. The high-temperature superconducting strong magnetic field homogenization heat treatment device for large-sized titanium alloy ingots according to claim 6, characterized in that, The cooling medium of the cooling system is liquid nitrogen. The cooling system includes a cryogenic pump, a vacuum-insulated pipeline, a liquid nitrogen storage tank, and a mass flowmeter. The liquid nitrogen storage tank is equipped with a vaporizer for regulating the temperature and pressure of liquid nitrogen, and the mass flowmeter is used to accurately control the flow rate of liquid nitrogen. The cryogenic pump, the liquid nitrogen storage tank are connected to the vacuum-insulated pipeline, and the mass flowmeter is installed on the vacuum-insulated pipeline.

8. The high-temperature superconducting strong magnetic field homogenization heat treatment device for large-size titanium alloy ingots according to claim 6, wherein, The temperature monitoring component includes an infrared thermometer and a thermocouple. The infrared thermometer is used to monitor the surface temperature of the titanium alloy ingot blank in real time, and the thermocouple is used to monitor the internal temperature of the titanium alloy ingot blank in real time.

9. The high-temperature superconducting strong magnetic field homogenization heat treatment device for large-sized titanium alloy ingots according to claim 6, characterized in that, The controller further includes a human-machine interaction interface.

10. The high-temperature superconducting strong magnetic field homogenization heat treatment device for large-sized titanium alloy ingots according to claim 6, characterized in that The driving component includes a driving motor and a transmission unit. The driving motor is connected to the transmission unit, and the transmission unit is connected to the rotating drive shaft.

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