Current-assisted local shape correction method for inertia friction welding head of rotor component

Abstract

The invention discloses a current-assisted local shape correction method for a welding joint of rotor component inertia friction welding. The method comprises the following steps: detecting a rotor component to determine the position of a welding seam and the width of the welding joint; processing the width of a welding joint of the rotor component at the inertial friction welding seam according to the determined position and width of the welding seam; one side of a shape correcting tool is fixedly arranged on the rotor component, electrodes are fixedly arranged on the other side of the shape correcting tool, the electrodes located on the two sides of the inertia friction welding seam are connected with the positive electrode and the negative electrode of a power source through wires correspondingly, and the power source, the electrodes and a welding connector form a conductive loop when powered on; installing a water cooling device on the shape correcting tool and the electrode; the working environment of the to-be-corrected rotor component, the correcting tool and the electrode is kept in a vacuum state; starting a power supply, enabling pulse current to flow through a welding joint part, adjusting a current value, and heating, preserving heat or cooling an inertia friction welding joint; and the shape correcting tool is started, so that the size precision of the welded part meets the design requirement.

Description

Technical Field

[0001] The present invention relates to the field of manufacturing of aviation components, and particularly relates to a method for current-assisted local straightening of inertia friction welding joints of rotor 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 surface to be welded under pressure. Compared with fusion welding methods such as electron beam and laser, due to the dual effects of thermo-mechanical coupling, the large plastic deformation generated during the inertia friction welding process makes the welded joint have a fine forged structure, and the mechanical properties of the joint are more excellent, making it more suitable for high-quality welding of heterogeneous materials.

[0003] Aero-engine rotor components are the core components that determine the performance of aero-engines. Their manufacturing precision directly affects the gas flow law of aero-engines, and thus affects other key indicators. Therefore, the requirements for the manufacturing precision of rotor components are very strict. Usually, the inertia friction welding size of aero-engine rotor components is above φ400mm, and the welding precision requirement is at the order of 0.1mm. However, during the inertia friction welding process, the material at the welded joint undergoes large plastic deformation with a high strain rate in an extremely short time, and its temperature also rapidly rises from room temperature to above 1000°C and then rapidly drops. Such a drastic change in the temperature field and stress-strain field within a short time usually results in a relatively high residual stress at the welded joint, which to a certain extent affects the welding precision; moreover, since the welding tonnage is usually in the hundreds of tons, this also poses strict requirements on the machining precision, overall structural stiffness of the welding fixture, and the manufacturing and control precision of the inertia friction welding machine. However, since the processing procedure of aero-engine rotor components usually requires first machining the complex structure of the rotor components and then performing the welding procedure, and some rotor components need to be welded in multiple passes, this directly leads to the deviation caused by welding being difficult to remedy and rework. When the deviation exceeds the standard, the parts can only be scrapped. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art. Aiming at the problem that the aero-engine inertia friction welded rotor components can only be scrapped after the parts exceed the tolerance after welding, a method for current-assisted local straightening of inertia friction welding joints of rotor components is proposed to achieve high-precision manufacturing of inertia friction welded rotor components.

[0005] The present invention discloses a method for current-assisted local straightening of inertia friction welding joints of rotor components, including:

[0006] Step 1: Detect the completed inertia friction welded rotor component to determine the position of the weld seam and the width of the welded joint;

[0007] Step 2: Use machining methods to machine the width of the welded joint of the rotor component at the inertia friction weld according to the weld position and width determined in Step 1; 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 3: Clamp and fix the processed rotor component on the insulating and heat-insulating platform of the vacuum environment device; fix one side of the straightening tooling on the clamping tables on both sides of the inertia friction weld 5 of the rotor component, and fix the other side of the straightening tooling with electrodes. The electrodes on both sides of the inertia friction weld are respectively 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 circuit; install a water-cooling device on the straightening tooling and the electrodes;

[0009] Step 4: Start the vacuum environment device to keep the working environment of the rotor component to be straightened, the straightening tooling, and the electrodes in a vacuum state, and control the vacuum degree to be not greater than 1×10 -2 Pa; start the water-cooling device to ensure that the electrode temperature does not exceed 80°C;

[0010] Step 5: Start the power supply to allow pulsed current to flow through the welded joint area, adjust the current value, and use the electrothermal effect of the metal to heat up, keep warm, or cool down the inertia friction weld joint; among them, the temperature change curves for heating up, cooling down, and keeping warm are formulated according to the material properties;

[0011] Step 6: Start the straightening tooling to make the dimensional accuracy of the welded parts meet the design requirements, with the holding temperature range being 800°C to 1200°C and the holding time being between 15 min and 300 min;

[0012] Step 7: After reaching the preset holding time, when the straightening stress is reduced to below 5 MPa, gradually reduce the current value until it reaches zero, and then turn off the power supply; when the temperature of the welded joint drops below 150°C, open the vacuum environment device, turn off the water-cooling device, and take out the straightened parts, thus completing the local straightening work of the weld at a certain welded joint part of the superalloy inertia friction weld rotor component.

[0013] Further, Step 1 includes:

[0014] Use a dial indicator measurement method to detect the welding dimensions of the rotor component after inertia friction welding to determine the inertia friction weld position;

[0015] By using the method of clamping electrodes at both ends of the specimen, the corresponding relationship between the temperature field and current density of the material is measured, and by adjusting the current density and action time, the change process of the deformation behavior of the material is observed; based on the established corresponding relationship among the current density, temperature, and deformation behavior characteristics, the width of the welded joint of the drum component is determined; 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 structural dimensions of other positions.

[0016] Further, the electrode material is copper.

[0017] Further, in step six, the flow rate of the water cooling device is adjusted by the valve to keep the heat preservation temperature range at 800°C to 1200°C.

[0018] Further, after completing the local shape correction work of the weld at a certain welded joint part of the rotor component, repeat steps three to seven until the local shape correction work of the remaining welds on the rotor component is completed.

[0019] The beneficial effects of the present invention are as follows: Aiming at the deficiencies in the existing manufacturing process of inertial friction welded rotor components of aeroengines, it is proposed to utilize the Joule heat effect and electroplastic effect generated by passing current through metal to rapidly increase the temperature of the welded joint and improve the shape correction efficiency; by using the design method of the local small cross-section transition structure of the inertial friction welded joint and the The cooling structure design can increase the current density at the welded joint, making the shape correction temperature field more concentrated and without affecting influence on the initial performance of the base material of the part. By comprehensively utilizing the advantages of the current-assisted heating technology and the design of the cooling structure of the small cross-section transition structure, shape correction tooling, and electrodes of the welded joint, this patent has creativity and novelty in the field of high-efficiency and precise shape correction of inertial friction welded rotor components. Description of the Drawings

[0020] Figure 1 A schematic diagram showing the positions of the integral blisk, electrode, and tooling of the inertial friction welded joint of the rotor component after the processing in step two of the current-assisted local shape correction method for the inertial friction welded joint of the rotor component according to the present invention; wherein, the welded joint is processed into a small cross-section structure.

[0021] Among them, 1: electrode, 2: shape correction tooling; 3: integral blisk, 4: small cross-section structure, 5: inertial friction weld, 6: power supply. Detailed Description of the Invention

[0022] 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 used to explain the present invention and are not intended to limit the present invention.

[0023] Such as Figure 1As shown, a method for current-assisted local shape correction of the welded joint of a rotor component by inertia friction welding includes:

[0024] Step 1: Pretreatment:

[0025] S11: Determine the weld position. Use the dial indicator measurement method to detect the welding dimensions of the rotor component that has completed inertia friction welding, clarify the welding accuracy of the part in each direction, and at the same time determine the position of the inertia friction weld 5. This area has good openness and no interference, which is easy for welding and subsequent processing.

[0026] S12: Determine the width of the welded joint at the weld. Adopt the method of clamping electrodes at both ends of the specimen to fixedly set the electrodes. 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, electrodes, and welded joint form a conductive circuit. Measure the corresponding relationship between the material temperature field and the current density, and observe the change process of the material deformation behavior by adjusting the current density and the action time. Based on the established mutual corresponding relationship of the current density, temperature, and deformation behavior characteristics, determine the width of the welded joint of the drum component to ensure that the temperature field and current act concentratedly at the weld during the current treatment process, so that the deformation is controlled in the joint area and does not affect the structural dimensions of other positions.

[0027] Step 2: Machine the rotor: According to the electro-thermal relationship of the integral blisk superalloy material and the heat conduction and dissipation performance of the superalloy, design the shape and size of the inertia friction welded joint of the integral blisk by calculation, and use the milling method to machine the inertia friction weld 5 determined in S11 in step 1 into a small cross-section structure 4 with a uniform transition at the blisk near the blade. The small cross-section structure 4 refers to a reduced-diameter small cross-section that tapers towards the end of the welded joint, as Figure 1 shown; the cross-sectional area of the small cross-section structure 4 is 40 - 60% smaller than the original cross-sectional area, and the size of the small cross-section is determined according to S12 in step 1.

[0028] Step 3: Install relevant equipment

[0029] S301: Clamp and fix the machined integral blisk 3 on the insulating and heat-insulating platform of the vacuum environment device by using a general-purpose fixture. 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.

[0030] S302: Fix one side of the sizing tooling 2 on the clamping tables on both sides of the inertia friction welding seam 5 of the integral blisk 3 by mechanical clamping; fix the electrode 1 on the other side of the sizing tooling 2 also by mechanical clamping. The electrodes 1 located on both sides of the inertia friction welding seam 5 are respectively connected to the positive and negative poles of the power supply through wires. When powered on, the power supply 6, the electrodes 1 and the welded joint form an electrical conduction loop. The material of the electrode is copper, and the power supply provides pulsed current for the local heat treatment of the inertia friction welded joint to realize the regulation of the local structure and properties of the welded joint, and the current value ranges from 1 A to 30,000 A. When installing the electrode, pay attention to adjusting the clamping force of the electrode 1 to prevent arcing during the power-on process. The sizing tooling 2 adopts an existing sizing tooling, and the present invention does not limit it, as long as it can achieve sizing.

[0031] S303: Install the water cooling device on the sizing tooling 2 and the electrode 1. The form in which the water cooling device is connected to the sizing tooling 2 and the electrode 1 is embedded or attached to the surface of the electrode and the sizing tooling 2 or distributed inside the electrode. 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 cooling liquid. Moreover, install a thermocouple temperature sensor at the inertia friction welding seam 5 (or on the sizing tooling). The temperature sensor is connected to the processor through a wire, and the processor receives the data from the temperature sensor for the user to monitor the temperature of the sizing tooling.

[0032] Step Four: Start the vacuum environment device to keep the working environment of the blisk 3 to be sized, the sizing tooling 2 and the electrode 1 in a vacuum state, and the vacuum degree is controlled to be not greater than 1×10 -2 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 electrode temperature does not exceed 80 °C.

[0033] Step Five: Start the power supply to make the pulsed current flow through the welded joint part, gradually increase the current value, and use the electrothermal effect of the metal to raise the temperature at the welded seam 4 of the rotor component, and keep the joint temperature at 850 °C after heat preservation. Among them, the temperature change curves of 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 inertia friction welding seam 5;

[0034] Step Six: Start the sizing tooling to make the dimensional accuracy of the welded parts meet the design requirements. The heat preservation temperature range is between 800 °C and 1200 °C, and the heat preservation time is between 15 min and 300 min; adjust the flow rate through the valve of the water cooling device to keep the heat preservation temperature range between 800 °C and 1200 °C.

[0035] Step 7: After reaching the preset heat preservation time, when the straightening stress decreases to below 5 MPa, gradually reduce the current value until it reaches zero, and then turn off the power supply; when the temperature of the welded joint drops below 150 °C, turn on the vacuum environment device, turn off the water cooling device, and take out the straightened part, thereby completing the local straightening of the weld at a certain welded joint of the high-temperature alloy inertia friction welded rotor component.

[0036] Then repeat Steps 3 to 7 until the local straightening of the remaining welds on the overall blisk is completed.

[0037] 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 of the present invention and the scope protected by the claims, and all of them fall within the protection scope of the present invention.

Claims

1. A method for local shape correction of rotor component inertia friction welding joints assisted by current, characterized in that: include: Step 1: Inspect the rotor parts that have completed inertia friction welding to determine the position of the weld and the width of the weld joint; Step 2: using a mechanical processing method to process the width of the weld joint of the rotor component at the inertia friction welding weld according to the weld position and width determined in step 1; and the cross-sectional area of ​​the weld joint after processing is 40-60% smaller than the original cross-sectional area at the weld; Step 3: clamping and fixing the processed rotor component on an insulating and heat-insulating platform of a vacuum environment device; fixing one side of a shape correction tool (2) on a clamping platform on both sides of the inertia friction welding weld (5) of the rotor component, and fixing electrodes (1) on the other side of the shape correction tool (2); the electrodes (1) located on both sides of the inertia friction welding weld (5) are respectively connected to the positive and negative electrodes of a power source through wires, and when power is turned on, the power source, the electrodes and the welding joint form a conductive loop; installing a water cooling device on the shape correction tool (2) and the electrodes (1); Step 4: Start the vacuum environment device to keep the working environment of the rotor component to be calibrated, the calibrating tool (2) and the electrode (1) in a vacuum state, and control the vacuum degree to no more than 1×10 -2 Pa; start the water cooling device to ensure that the electrode temperature does not exceed 80°C; Step 5: Start the power supply to 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; Step 6: Start the shape correction tool (2) to make the dimensional accuracy of the welded parts meet the design requirements, the holding temperature range is 800° C. to 1200° C., and the holding time is between 15 min and 300 min; Step 7: After reaching the preset insulation time, when the shaping stress is reduced to below 5MPa, gradually reduce the current value until the value returns to zero, and then turn off the power supply; when the temperature of the weld joint drops below 150°C, open the vacuum environment device, turn off the water cooling device, and take out the shaping parts, thereby completing the local shaping work of the weld at a certain welding joint of the high-temperature alloy inertia friction welding rotor component.

2. The current-assisted local shape correction method for the inertia friction welding joint of a rotor component according to claim 1 is characterized in that: The step 1 specifically includes: Using a meter measurement method to detect the welding dimensions of the rotor component that has completed inertia friction welding, and determine the position of the inertia friction welding weld (5); The method of clamping electrodes at both ends of the sample is adopted to measure the corresponding relationship between the temperature field of the material and the current density, and the change process of the deformation behavior of the material is observed by adjusting the current density and the action time; based on the established mutual correspondence between the current density, temperature, and deformation behavior characteristics, the width of the welding joint of the drum component is determined; the determined cross-sectional size of the welding joint can make the temperature field and the current in the current treatment process concentrate on the weld, without affecting the structural dimensions of other positions.

3. The current-assisted local shape correction method for the inertia friction welding joint of a rotor component according to claim 1, characterized in that: The electrode is made of copper.

4. The current-assisted local shape correction method for inertia friction welding joints of rotor components according to claim 1, characterized in that: In step six, the flow rate of the water cooling device is adjusted by using a valve to maintain the insulation temperature range between 800°C and 1200°C.

5. The current-assisted local shape correction method for inertia friction welding joints of rotor components according to claim 1, characterized in that: After completing the local shaping work of the weld at a certain welding joint of the rotor component, repeat steps 3 to 7 until the local shaping work of the remaining welds on the rotor component is completed.

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