Current-assisted local performance regulation and control method for inertia friction welding head

Abstract

The invention discloses a current-assisted local performance regulation and control method for an inertia friction welding joint of a drum and a blisk component. The current-assisted local performance regulation and control method comprises the following steps: machining a joint at an inertia friction welding seam of the drum component into a small-section component by adopting a machining method; mounting the machined drum on an insulating and heat-insulating platform of a vacuum device; the electrode is installed on a clamping table, and the clamping force is adjusted; connecting a water cooling device to an electrode, and installing a temperature sensor at an inertia friction welding seam; the vacuum environment device is started, and the local heat treatment working environment is kept in a vacuum state; starting a power supply, enabling pulse current to flow through a welding joint part, and adjusting a current value to heat, preserve or cool an inertia friction welding joint; and by adjusting the current density and the action time, the change process of the microstructure of the material is observed by utilizing a temperature sensor, so that the local performance regulation and control of a welding seam at a certain welding joint part of the high-temperature alloy inertia friction welding blisk component are completed.

Description

Technical Field

[0001] The present invention relates to the field of manufacturing of aviation components, and particularly relates to a method for regulating the current-assisted local properties of inertia friction welding joints of drum barrels and integral bladed disks components. Background Art

[0002] Inertia friction welding technology is a solid-phase welding method that utilizes the frictional heat and plastic deformation heat between metals to form a metallurgical bond on the surfaces to be welded under pressure. Compared with fusion welding methods such as electron beam and laser, due to the dual action of thermo-mechanical coupling, the large plastic deformation generated during the inertia friction welding process results in a fine forged structure in the welding joint, and the mechanical properties of the joint are more excellent, making it more suitable for high-quality welding of heterogeneous materials. Therefore, inertia friction welding technology is widely used in the high-performance and high-quality manufacturing of core rotor components such as compressor drum barrels / integral bladed disks of aeroengines.

[0003] However, with the gradual increase in the thrust-to-weight ratio of aeroengines, the operating temperature of the compressor has increased significantly, and traditional superalloys have gradually been replaced by new superalloys with a higher volume fraction of strengthening phases, such as GH4151 and GH4065A, etc. However, due to the short welding process of inertia friction welding, the heating and cooling processes of the welding interface are usually completed within dozens of seconds, and the maximum temperature of the welding interface can usually reach above 1100 °C (lower than the melting point of the material and higher than the remelting temperature of the precipitation phase). Therefore, during the inertia friction welding process, under the coupled action of a high temperature field and a stress field, the strengthening phases in the superalloy will remelt into the matrix phase of the alloy, causing the material at the welding joint to form a metastable supersaturated solid solution. During the short cooling process, it is difficult for the strengthening phases to precipitate, resulting in a decrease in the effect of the precipitation strengthening mechanism in the alloy and a reduction in the mechanical properties of the joint. Currently, post-weld heat treatment is usually used to regulate the properties of the welding joint and to eliminate welding residual stress at the same time. However, since the superalloy material itself is not allowed to have the temperature of secondary aging after welding exceed the original aging temperature after solution and aging heat treatment, this results in the precipitation phase at the welding joint still being unable to precipitate and grow sufficiently, showing a certain difference from the high volume fraction and large size of the strengthening phases in the base material. Compared with the welding joint before heat treatment of inertia friction welding, the existing heat treatment methods have limited improvement in the properties such as high-temperature creep of the welding joint. Summary of the Invention

[0004] The object of the present invention is to overcome the deficiencies in the prior art. In view of the problem that the post-weld heat treatment temperature of the inertia friction welded drum and the integral blisk components of the new high-strengthened phase volume fraction superalloys for existing aero-engines is restricted by the parent material aging heat treatment system, which results in difficulty in a large amount of precipitation and growth of precipitated phases at the weld, thus leading to poor mechanical properties, a method for current-assisted local property regulation of the inertia friction welded joint of the drum component is proposed to break through the limitation of the parent material aging heat treatment temperature and achieve high-quality and high-performance manufacturing of key rotating components such as the compressor drum and integral blisk of the new superalloys for aero-engines.

[0005] A method for current-assisted local property regulation of the inertia friction welded joint of the drum and integral blisk components includes:

[0006] Step 1: Analyze the dimensions of the components using the sectional views of the drum and integral blisk components to determine the position of the inertia friction weld; and adopt the method of clamping electrodes at both ends of the specimen to measure the corresponding relationship between the material temperature field and the current density. By adjusting the current density and the action time, observe the change process of the material microstructure; based on the established mutual corresponding relationship of the current density, temperature, and microstructure characteristics, determine the width of the welded joint of the drum component; the cross-sectional dimensions of the determined welded joint can make the temperature field and current concentrate on the weld during the current treatment process without affecting the material structure and properties of the parent material of the integral blisk.

[0007] Use the machining method to machine the width of the welded joint of the drum and integral blisk components at the inertia friction weld according to the width determined in the above steps; and the cross-sectional area of the processed welded joint is 40 - 60% smaller than the original cross-sectional area at the weld.

[0008] Step 2: Install the machined drum and integral blisk components on the insulating and heat-insulating platform of the vacuum device and fix the positions.

[0009] Step 3: Install the electrodes on the drum and integral blisk using the method of clamping electrodes at both ends of the specimen and adjust the clamping force; the other sides of the electrodes on both sides of the inertia friction weld are connected to the positive and negative poles of the power supply through wires, and when energized, the power supply, electrodes, and welded joint form a conductive circuit.

[0010] Step 4: Connect the water-cooling device to the electrodes and install a temperature sensor at the inertia friction weld; start the vacuum environment device to keep the local heat treatment working environment in a vacuum state, and control the vacuum degree at ≤1×10 -2 Pa;

[0011] Step 5: Turn on the power supply to allow pulsed current to flow through the welded joint area. Adjust the current value, and utilize the electrothermal effect of the metal to heat up, keep warm, or cool down the inertia friction welded joint; among them, the temperature change curves for heating up, cooling down, and keeping warm are formulated according to the material properties of the base material.

[0012] By adjusting the current density and action time, observe the change process of the material microstructure using a temperature sensor, thereby completing the local performance regulation of the weld seam at a certain welded joint area of the inertia friction welded drum component of the superalloy.

[0013] Further, after completing Step 5, after completing the local performance regulation of the weld seam at a certain welded joint area, gradually reduce the current value until it reaches zero, and then turn off the power supply; when the temperature at the inertia friction weld seam drops below the preset temperature, turn on the vacuum environment device, turn off the water cooling device, and remove the electrode.

[0014] Further, the welded joint after being processed in Step 1 refers to a reduced-diameter small cross-section that tapers towards the end of the welded joint, and the cross-section conforms to the current density-heat generation temperature relationship and the uniform transition of the thermal conductivity.

[0015] Even further, the cross-sectional area of the processed welded joint is determined according to the electrothermal relationship and thermal conductivity of the base materials of the drum and the integral blisk component.

[0016] Further, the electrode material in Step 2 is copper, and the power supply provides pulsed current for the local heat treatment of the inertia friction welded joint to achieve the regulation of the local structure and performance of the welded joint, and the range of its current value is between 1 A and 30000 A.

[0017] Further, the form in which the water cooling device is connected to the electrode is installed in an embedded or conforming manner on the surface of the electrode or distributed inside the electrode.

[0018] Further, in Step 5, the holding temperature range is between 780 °C and 1100 °C, and the holding time is between 30 min and 180 min.

[0019] The beneficial effects of the present invention include:

[0020] The method for current-assisted local performance regulation of the inertia friction welded joint of the drum and integral blisk component according to the present invention processes the welded joint of the drum component into a specific width, ensuring that the temperature field and current act concentratedly on the weld seam during the current treatment process without affecting the material structure and performance of the base material.

[0021] Moreover, the present invention adopts the current-assisted heat treatment technology. By utilizing the Joule heat effect and electro-induced phase transformation effect of metals, high-temperature heat treatment of local areas of the welded joint can be achieved. The temperature of the welded joint is monitored in real time by a temperature measuring element, and the magnitude of the current and the holding time are adjusted according to the microstructure evolution law of the new high-temperature alloy, so that the heat treatment temperature and time of the welded joint can be accurately controlled, thereby realizing the precise regulation of the microstructure and mechanical properties of the welded joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic cross-sectional view of the dual-stage inertia friction welded integral blisk before processing is shown;

[0023] Figure 2 A schematic cross-sectional view of the dual-stage inertia friction welded integral blisk and the electrode after the processing of Step 1 is shown; wherein, the welded joint of the integral blisk is processed into a small cross-section structure.

[0024] Wherein, 1: electrode, 2: dual-stage inertia friction welded integral blisk, 3: small cross-section structure of the welded joint, 4: inertia friction weld seam, 5: power supply. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The technical solutions of the present invention will be further described in detail below in conjunction with the drawings and specific embodiments. The specific embodiments described are only for explaining the present invention and are not intended to limit the present invention.

[0026] As Figure 1-2 shown, a method for current-assisted local property regulation of an inertia friction welded joint of a drum and integral blisk component includes:

[0027] Step 1: Process the specimen

[0028] S101: Using the cross-sectional view of the integral blisk, analyze the dimensions of the integral blisk part, and determine the position of the inertia friction weld seam 4; then, by the method of clamping the electrodes at both ends of the specimen, the electrodes are fixedly arranged, and the other sides of the electrodes on both sides of the welded joint are connected to the positive and negative poles of the power supply through wires. When energized, the power supply, the electrodes, and the welded joint form a conductive loop. Measure the corresponding relationship between the material temperature field and the current density, and observe the change process of the material microstructure. Based on the established mutual corresponding relationship of current density, temperature, and microstructure characteristics, determine the width of the welded joint of the drum component to ensure that the temperature field and current act concentratedly on the weld seam during the current treatment process without affecting the material structure and properties of the base material.

[0029] S102: According to the electrothermal relationship of GH4151 superalloy and its own thermal conductivity, milling is performed on the inertia friction weld seam at 4 places to process it into a small cross-section structure with a uniform transition that conforms to the current density - heat generation temperature relationship and thermal conductivity. The small cross-section structure refers to a reduced-diameter small cross-section that tapers towards the end of the welded joint. The cross-sectional area of the small cross-section structure is 40 - 60% smaller than the original cross-sectional area, and the size of the small cross-section is determined according to the electrothermal relationship and thermal conductivity of the base material of the integral blisk 2, which can increase the local current density and cause the temperature to rise rapidly. Moreover, in the present invention, the welded joint of the drum member is processed into a specific width to ensure that during the current treatment process, the temperature field and current concentration act on the weld seam without affecting the material structure and properties of the base material.

[0030] Step 2: Install the integral blisk with the inertia friction welded joint structure processed on the insulation and heat insulation platform of the vacuum environment device, and use a general-purpose tooling fixture to mechanically fix it on the insulation and heat insulation platform. The vacuum environment device provides a vacuum environment for the entire current-assisted heat treatment process to avoid adverse reactions such as oxidation on the surface of the specimen during the local current treatment process.

[0031] Step 3: As Figure 2 shown, on the clamping platforms on both sides of the inertia friction weld seam 4 of the integral blisk 2, electrodes 1 are fixedly arranged by the method of clamping the electrodes at both ends of the specimen. The other sides of the electrodes on both sides of the inertia friction weld seam 4 are connected to the positive and negative poles of the power supply through wires. When energized, the power supply, electrodes, and welded joint form an electrical conduction loop. The material of the electrodes is copper, and the power supply provides pulsed current for the local heat treatment of the inertia friction welded joint to achieve the regulation of the local structure and properties of the welded joint, and the range of its current value is 1A - 30000A. When installing the electrodes, pay attention to adjusting the clamping force of the electrodes 1 to prevent arcing during the energization process.

[0032] Step 4: Connect the water cooling device to the electrodes 1. The form of connecting the water cooling device to the electrodes 1 is inlayed or attached to the surface of the electrodes or distributed inside the electrodes. The cooling medium of the water cooling device is a water cooling medium; the water cooling device includes an S-shaped cooling pipe and a water cooling tank, and the water cooling tank stores the coolant. Moreover, a thermocouple temperature sensor is installed at the inertia friction weld seam 4.

[0033] Step 5: Start the vacuum environment device to keep the local heat treatment working environment in a vacuum state. Since the base materials of the blade and the disk are heterogeneous titanium alloys of TC4 / TC17, the vacuum degree is controlled at ≤1×10 -3 Pa to prevent adverse phenomena such as surface oxidation from occurring at the welded joint due to heating. Start the water cooling device to ensure that the temperature of the electrodes does not exceed 80°C.

[0034] Step 6: Turn on the power supply to allow pulsed current to flow through the welded joint area, gradually increase the current value, and utilize the electrothermal effect of the metal to raise the temperature of the inertia friction welded joint. According to the characteristics of the inertia friction welded joint of GH4151 superalloy, keep the joint temperature at 850 °C for heat preservation for 90 min. Among them, the temperature change curves for heating, cooling, and heat preservation are formulated according to the material properties, and the temperature of the local heat treatment is monitored in real time by the thermocouple temperature sensor located at the weld 4. Measure the corresponding relationship between the material temperature field and the current density, and observe the change process of the material microstructure by adjusting the current density and the action time.

[0035] Step 7: The temperature sensor is electrically connected to the processor through a wire, and the processor receives the data from the temperature sensor for the user to monitor the local heat treatment temperature.

[0036] Since the base materials of the blade and the disk are heterogeneous titanium alloys of TC4 / TC17, secondary local heat treatment is carried out by adjusting the pulsed current value; by reducing the pulsed current value, the temperature is lowered to 630 °C - 650 °C, and the heat preservation time is controlled within 60 min - 90 min.

[0037] Step 8: After completing the local treatment of the weld at a certain welded joint area of the integral blisk component of the superalloy inertia friction welding, gradually reduce the current value until it reaches zero, and then turn off the power supply; when the temperature at the weld 4 of the GH4151 superalloy inertia friction weld drops below 150 °C, turn on the vacuum environment device, turn off the water cooling device, remove the electrode, and the local performance regulation of the first welded joint on the integral blisk ends;

[0038] Then repeat Steps 3 to 8 until the local performance regulation of the welds at the remaining welded joint areas on the integral blisk is completed.

[0039] Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the spirit and scope protected by the claims of the present invention, and all of them fall within the protection scope of the present invention.

Claims

1. A method for controlling the local performance of an inertia friction welding joint with current assistance, characterized in that: The control method is used for drum and blisk components, and includes: Step 1: Analyze the dimensions of the drum and the integral blade disc components using the cross-sectional view of the components to determine the position of the inertia friction welding weld (4); and use the method of clamping electrodes at both ends of the sample to measure the corresponding relationship between the material temperature field and the current density, and observe the change process of the material microstructure by adjusting the current density and the action time; determine the width of the weld joint of the drum component based on the established mutual correspondence between the current density, temperature, and microstructure characteristics; the determined cross-sectional dimensions of the weld joint can make the temperature field and the current act on the weld in the current treatment process in a concentrated manner; The width of the weld joint of the drum and the integral blade disk component at the inertia friction welding weld (4) is processed by a mechanical processing method according to the determined width, and the cross-sectional area of ​​the processed weld joint is 40-60% smaller than the original cross-sectional area at the weld; Step 2: Install the machined drum on the insulating and heat-insulating platform of the vacuum device and fix the position; Step 3: The electrodes are mounted on the drum and the integral blade disk by clamping the electrodes at both ends of the sample, and the clamping force is adjusted; the other side of the electrodes on both sides of the inertia friction welding weld (4) is connected to the positive and negative electrodes of the power supply through wires, and when power is turned on, the power supply, the electrodes and the welding joint form a conductive loop; Step 4: Connect the water cooling device to the electrode (1) and install a temperature sensor at the inertia friction welding weld (4); start the vacuum environment device to keep the local heat treatment working environment in a vacuum state, and control the vacuum degree to ≤1×10 -2 Pa; Step 5: Start the power supply, make the pulse current flow through the welding joint, adjust the current value, and use the electrothermal effect of the metal to heat up, keep warm or cool down the inertia friction welding joint; wherein, the temperature change curves of heating up, cooling down and keeping warm are formulated according to the material properties of the base material; By adjusting the current density and action time and using a temperature sensor to observe the change process of the material's microstructure, the local performance control of the weld at a certain welding joint of the high-temperature alloy inertia friction welding drum and the integral blade disk component can be completed.

2. The method for controlling the local performance of an inertia friction welding joint with current assistance according to claim 1, characterized in that: After completing step five, after completing the local performance regulation of the weld at a certain welding joint, gradually reduce the current value until the value returns to zero, and then turn off the power supply; when the temperature at the inertia friction welding weld (4) drops below the preset temperature, open the vacuum environment device, turn off the water cooling device, and remove the electrode.

3. The current-assisted local performance control method of an inertia friction welding joint according to claim 1, characterized in that: The weld joint processed in step 1 refers to a small cross section with a gradually reduced diameter toward the end of the weld joint, and a cross section that conforms to the current density-heat generation temperature relationship and a uniform transition of thermal conductivity.

4. The current-assisted local performance control method of an inertia friction welding joint according to claim 3 is characterized in that: The cross-sectional area of ​​the welded joint after the treatment is determined according to the electrothermal relationship and thermal conductivity of the base material of the drum component.

5. The current-assisted local performance control method of an inertia friction welding joint according to claim 1, characterized in that: In step 2, the electrode material is copper, and the power supply provides pulse current for local heat treatment of the inertia friction welding joint to achieve local organization and performance regulation of the welding joint, and the current value ranges from 1A to 30000A.

6. The current-assisted local performance control method of an inertia friction welding joint according to claim 1, characterized in that: The water cooling device is connected to the electrode (1) in an embedded or fitted manner and is installed on the surface of the electrode or is distributed inside the electrode.

7. The method for controlling the local performance of an inertia friction welding joint with current assistance according to claim 3, characterized in that: In step five, the insulation temperature ranges from 780° C. to 1100° C., and the insulation time ranges from 30 min to 180 min.

Images