Method for maintaining aero-engine casing through multi-physics field coupling

Abstract

The invention discloses a method for maintaining an aero-engine case through multi-physics field coupling. The method comprises the steps that the crack defect position of the case is determined; carrying out polishing treatment on the crack defect position of the cartridge receiver; ultrasonically cleaning the area where the polished crack defect position of the cartridge receiver is located; carrying out local electromagnetic coupling treatment on the crack defect position of the cartridge receiver; carrying out electron beam welding repair on the crack defect position of the cartridge receiver; carrying out flaw detection treatment on the repaired casing; and carrying out electromagnetic coupling treatment on the welding repair part of the cartridge receiver. According to the method, the electromagnetic coupling technology is adopted for treating the welding seam after the cartridge receiver is repaired, the control effect of the residual stress of the welding seam is remarkable, the whole electromagnetic coupling energy field treatment process does not need to be carried out in vacuum and other complex environments, and electromagnetic coupling treatment is efficient, clean and low in cost.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft engine casing maintenance, and in particular relates to a method for multi-physical field coupling maintenance of aircraft engine casings. Background Art

[0002] The casing, whose main material is titanium alloy, is called the "skeleton" of the aircraft engine and is the main load-bearing part of the aircraft engine. At the same time, the casing can provide a safe and stable working space for the core components of the aircraft engine, such as the combustion chamber and turbine. Its structure is complex and the working environment is harsh. The state of the casing parts has a significant impact on the service life, safety and stability of the aircraft engine. During the service life cycle, the casing material is often discarded and replaced due to matrix damage, weld crack failure, etc., which increases the operating cost of the aircraft. In order to reduce the number of aircraft engines that need to replace new casings due to maintenance failures and save operating costs, it is of great engineering practical significance to repair the casing. Among them, electron beam welding is widely used in the field of aircraft engine casing maintenance due to its advantages such as high welding speed, stable weld composition, large welding thickness range, wide material application range, small heat affected zone, and low welding deformation.

[0003] However, electron beam welding is accompanied by high welding energy and high welding speed, which will also cause the welds produced after electron beam welding repair to have large residual stress. Therefore, treatment is required before and after electron beam welding to reduce unfavorable factors such as excessive residual stress during welding repair. At present, the treatment method for the welds in casing repair is mainly aging heat treatment, which has the following main disadvantages:

[0004] 1. It has high energy consumption, long time effect, low energy utilization rate and great environmental pollution;

[0005] 2. The shape and size of the receiver are greatly restricted;

[0006] 3. Heat treatment is an integral treatment. During the aging heat treatment process, due to the complex structure of the casing, it is easy to be heated unevenly, resulting in a temperature gradient inside the parts, resulting in an incomplete weld crystal structure, the introduction of residual stress, and the reduction of mechanical properties such as strength, hardness, and toughness;

[0007] 4. It is easy to oxidize during the aging treatment process. If vacuum post-weld heat treatment is used, oxidation can be avoided, but the operation is complicated, the equipment requirements are high, and the treatment cost is high. Summary of the invention

[0008] The purpose of the present invention is to provide a method for repairing aircraft engine casings by multi-physical field coupling in view of the above-mentioned deficiencies in the prior art, so as to solve the problems of high cost, long aging and many restrictive conditions in traditional weld post-processing.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] A method for repairing an aircraft engine casing by multi-physics field coupling, comprising the following steps:

[0011] S1. Perform flaw detection on the casing to determine the location of the casing crack defect;

[0012] S2. Grind the crack defect position of the casing;

[0013] S3, the area where the crack defect of the casing is located after the grinding treatment is completed by ultrasonic cleaning;

[0014] S4, fixing the casing in the electromagnetic coupling device, setting electromagnetic coupling parameters, and performing local electromagnetic coupling processing on the crack defect position of the casing;

[0015] S5. Take out the casing from the electromagnetic coupling device and perform electron beam welding repair on the crack defect position of the casing;

[0016] S6, perform flaw detection on the repaired casing. If crack defects exist in the casing, return to S2; if crack defects do not exist in the casing, execute S7;

[0017] S7. Perform visual inspection on the casing welds;

[0018] S8. Fix the casing in the electromagnetic coupling device, set the electromagnetic coupling parameters, and perform electromagnetic coupling treatment on the welding repair part of the casing.

[0019] Furthermore, the casing flaw detection process in S1 and S6 is fluorescent flaw detection, ultrasonic detection or X-ray detection.

[0020] Furthermore, in S2, the crack defect of the casing is polished, and the defect position is polished into a U shape, and the burrs at the defect position are eliminated.

[0021] Furthermore, the S4 specifically includes:

[0022] The casing is fixed on the workbench by a fixture, the fixture with the casing is placed in a working chamber composed of a multi-turn excitation coil, and an electrode is used to contact the casing;

[0023] Set the electromagnetic coupling parameters, start the electromagnetic coupling device, and apply electric and magnetic fields to the casing.

[0024] Furthermore, the electromagnetic coupling parameters include: voltage, magnetic field strength, electric pulse frequency, magnetic pulse time, number of electric pulses, number of electric pulse groups, number of magnetic pulses and number of magnetic pulse groups.

[0025] Furthermore, the electromagnetic coupling parameters are specifically:

[0026] The voltage U satisfies 0<U≤35V, and the magnetic field strength B satisfies 0<B≤1T;

[0027] The frequency of electric pulses was 50 Hz, the number of electric pulses in each group was 20, and the number of electric pulse groups was 15; the interval between each pulse of the pulsed electric field was 1 s;

[0028] The action time of a single magnetic pulse is 0.1 s, the interval between magnetic pulses is 8 s, the number of magnetic pulses is 20, and the number of magnetic pulse groups is 1.

[0029] Furthermore, in S7, the casing weld is subjected to appearance inspection, including inspection of the color, shape and surface quality of the weld.

[0030] Furthermore, the electromagnetic coupling parameters are set in S8, including:

[0031] The voltage U satisfies 0<U≤35V, and the magnetic field strength B satisfies 0<B≤1T;

[0032] The frequency of electric pulses was 50 Hz, the number of electric pulses in each group was 20, the number of electric pulse groups was 15, and the interval between each pulse of the pulsed electric field was 1 s;

[0033] The action time of a single magnetic pulse is 0.1 s, the interval between magnetic pulses is 8 s, the number of magnetic pulses is 20, and the number of magnetic pulse groups is 1.

[0034] The method for repairing an aircraft engine casing using a multi-physics coupling field provided by the present invention has the following beneficial effects:

[0035] 1. The present invention uses electromagnetic coupling technology to process the welds after the casing is repaired, and its residual stress regulation effect is remarkable.

[0036] 2. The electromagnetic coupling device of the present invention is easy to operate and has low requirements for the working environment. It only needs to place the repaired casing in the working chamber of the multi-turn excitation coil, fix the casing with a clamp, and then make the electrode in close contact with the welding seam of the casing. After the treatment is completed, the casing is taken out. The entire treatment process does not need to be carried out in a vacuum environment, which greatly reduces the treatment cost.

[0037] 3. The electromagnetic coupling treatment of the present invention is efficient, clean and low-cost. Experimental verification shows that the entire treatment process only takes 2-4 minutes, and is driven by electricity as the main energy source. The treatment process is pollution-free and low-cost.

[0038] 4. The electromagnetic coupling treatment of the present invention will not have a negative impact on the casing. Before and after the treatment process, the casing temperature remains almost unchanged, no obvious thermal effect will be caused, and no negative impacts such as new residual stress will be introduced.

[0039] 5. The present invention adopts electromagnetic coupling technology, the principle of which is to utilize the electroplastic effect generated when a pulse current passes through a metal, and the magnetoplasticity generated by a pulse magnetic field on a metal material, to repair defects in the crystal, regulate residual stress, and improve fatigue limit and fatigue life under the coupling effect of the two. Using electromagnetic coupling treatment instead of thermal aging treatment can reduce the residual stress amplitude, homogenize residual stress, increase weld fatigue life and fatigue strength, and thus improve the service life and overall performance of the repaired casing while ensuring the quality of the electron beam weld. The electromagnetic coupling treatment time is short, and the entire treatment process only takes 2-4 minutes. At the same time, the electron beam weld of the aviation casing can be locally treated, and only the repair position is subjected to electromagnetic coupling treatment, which will not have an adverse effect on other positions. At the same time, compared with the integrated thermal aging treatment method, it can greatly improve energy utilization. The electromagnetic coupling treatment technology can reduce the time cost and economic cost of aircraft casing maintenance.

[0040] 6. The first electromagnetic coupling of the present invention is intended to regulate the stress level of the area to be welded, homogenize the stress, and change the stress state (change in the direction of compressive stress). Because the stress state and stress magnitude of the area to be welded directly affect the quality of the weld after electron beam welding repair. Due to the high energy density of electron beam welding, the temperature rise and cooling rate of the welding area are different, and there is a large temperature gradient inside. This will cause the weld to be in a tensile stress state, reducing the fatigue performance and mechanical properties of the weld. The second electromagnetic coupling treatment is intended to treat the weld. Reduce the tensile stress level of the weld, change the stress state (change in the direction of compressive stress), repair the micro defects in the weld, improve the fatigue limit and mechanical properties of the weld, and thus improve the repair effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The present invention is a flow chart of the method for repairing an aircraft engine casing by multi-physics field coupling. DETAILED DESCRIPTION

[0042] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0043] Example 1

[0044] This embodiment provides a method for multi-physical field coupling repair of aircraft engine casing, which uses electromagnetic coupling technology to process the welds after the casing is repaired, and its residual stress regulation effect is significant. Figure 1 , which specifically includes the following:

[0045] Step S1, performing flaw detection on the casing to determine the location of crack defects in the casing;

[0046] This embodiment preferably uses non-destructive testing methods such as fluorescent testing, ultrasonic testing, and X-ray testing to detect the location of the casing crack defect, and then detect the type of the casing crack defect.

[0047] Step S2, grinding the crack defect position of the casing, which specifically includes the following contents:

[0048] The crack defect position of the casing is polished into a U-shape for easy welding, and burrs are removed to facilitate subsequent welding.

[0049] Step S3, using ultrasonic cleaning to clean the area where the crack defect of the casing is located after the grinding treatment, which specifically includes the following contents:

[0050] Ultrasonic cleaning is performed on the crack defect locations of the polished casing to ensure the cleanliness of the area to be repaired, avoid the introduction of impurities during the repair process, and reduce the repair effect of electron beam welding on the defects.

[0051] Step S4, fixing the casing in the electromagnetic coupling device, setting electromagnetic coupling parameters, and performing local electromagnetic coupling processing on the crack defect position of the casing, which specifically includes the following contents:

[0052] The casing is fixed on the workbench by a fixture, the fixture with the casing is placed in a working chamber composed of a multi-turn excitation coil, and an electrode is used to contact the casing;

[0053] Set the electromagnetic coupling parameters, start the electromagnetic coupling device, and apply electric and magnetic fields to the casing.

[0054] The electromagnetic coupling parameters of this embodiment include: voltage, magnetic field strength, electric pulse frequency, magnetic pulse time, number of electric pulses, number of electric pulse groups, number of magnetic pulses and number of magnetic pulse groups;

[0055] Among them, setting electromagnetic coupling parameters includes:

[0056] The voltage U satisfies 0<U≤35V, and the magnetic field strength B satisfies 0<B≤1T

[0057] The frequency of electric pulses was 50 Hz, the number of electric pulses in each group was 20, the number of electric pulse groups was 15, and the interval between each pulse of the pulsed electric field was 1 s;

[0058] The action time of a single magnetic pulse is 0.1 s, the interval between magnetic pulses is 8 s, the number of magnetic pulses is 20, and the number of magnetic pulse groups is 1.

[0059] Step S5, taking out the casing from the electromagnetic coupling device, and repairing the crack defect position of the casing by electron beam welding. The electron beam welding repair process parameters of this embodiment can be determined according to actual conditions, so they are not limited here.

[0060] Step S6, performing flaw detection on the repaired casing, if there is a crack defect in the casing, returning to S2, if there is no crack defect in the casing, executing S7;

[0061] Step S7: Perform appearance inspection on the casing weld, where the appearance inspection includes the color, shape, surface quality, etc. of the weld.

[0062] Step S8, fixing the casing in the electromagnetic coupling device, setting electromagnetic coupling parameters, and performing electromagnetic coupling treatment on the welding repaired part of the casing;

[0063] Among them, setting electromagnetic coupling parameters includes:

[0064] The voltage U satisfies 0<U≤35V, and the magnetic field strength B satisfies 0<B≤1T

[0065] The frequency of electric pulses was 50 Hz, the number of electric pulses in each group was 20, the number of electric pulse groups was 15, and the interval between each pulse of the pulsed electric field was 1 s;

[0066] The action time of a single magnetic pulse is 0.1 s, the interval between magnetic pulses is 8 s, the number of magnetic pulses is 20, and the number of magnetic pulse groups is 1.

[0067] Before and after electron beam welding repair. The structure of the base material has not changed, and the composition of the weld is similar to that of the base material. After experimental verification, this group of parameters has the best effect on the residual stress control of the titanium alloy casing. Therefore, the electromagnetic coupling processing parameters before and after electron beam welding repair are the same.

[0068] The electromagnetic coupling parameters of this embodiment include: voltage, magnetic field strength, electric pulse frequency, magnetic pulse time, number of electric pulses, number of electric pulse groups, number of magnetic pulses and number of magnetic pulse groups;

[0069] This embodiment performs electromagnetic coupling treatment on the weld repair part of the casing, which can improve the stress state of the electron beam weld. At the same time, under the coupling effect of the electric field and the magnetic field, the microscopic defects in the weld are repaired, the fatigue life of the weld is increased, and the service life and overall performance of the repaired casing are improved.

[0070] Example 2

[0071] Based on Example 1, this embodiment provides a specific application scenario of a method for repairing an aircraft engine casing by multi-physical field coupling, which specifically includes the following steps:

[0072] Step A1: Perform flaw detection on the casing to determine the location of the casing crack defect.

[0073] Step A2: Grinding the crack defect position of the casing.

[0074] Step A3, using ultrasonic cleaning to complete the area where the crack defect position of the casing is located after the grinding treatment, which specifically includes the following contents: ultrasonic cleaning is performed on the crack defect position of the casing after grinding to ensure the cleanliness of the area to be repaired, avoid introducing impurities during the repair process, and reduce the repair effect of electron beam welding on the defect.

[0075] Step A4: fix the casing in the electromagnetic coupling device, set the electromagnetic coupling parameters, and perform local electromagnetic coupling treatment on the crack defect position of the casing, which specifically includes the following contents:

[0076] The casing is fixed on the workbench by a fixture, the fixture with the casing is placed in a working chamber composed of a multi-turn excitation coil, and an electrode is used to contact the casing;

[0077] The electromagnetic coupling parameters are set, the electromagnetic coupling device is started, and the electric field and magnetic field are applied to the casing.

[0078] In the flaw detection process of step A1, a crack defect is detected, so the electromagnetic coupling parameters of this embodiment are set as:

[0079] The voltage is 1V, the electric pulse frequency is 50Hz, the number of electric pulses in each group is 20 times, and the number of electric pulse groups is 15 groups; the interval between each pulse of the pulse electric field is 1s;

[0080] The magnetic field intensity is 1.0 T, the action time of a single magnetic pulse is 0.1 s, the magnetic pulse interval is 8 s, the number of magnetic pulses is 20 times, and the number of magnetic pulse groups is 1 group.

[0081] Step A5, taking out the casing from the electromagnetic coupling device, and repairing the crack defect position of the casing by electron beam welding.

[0082] Step A6, performing flaw detection on the repaired casing. If crack defects exist in the casing, return to step A2; if crack defects do not exist in the casing, execute A7;

[0083] Step A7: Perform appearance inspection on the casing weld, which includes the color, shape, surface quality, etc. of the weld.

[0084] Step A8, fixing the casing in the electromagnetic coupling device, setting electromagnetic coupling parameters, and performing electromagnetic coupling treatment on the welding repair part of the casing, which specifically includes the following contents:

[0085] Set the electromagnetic coupling processing parameters, namely the pulse electric field parameters and pulse magnetic field parameters, including voltage, magnetic field strength, electric pulse frequency, magnetic pulse time, number of pulses, and number of pulse groups, which are:

[0086] The voltage is 1V, the electric pulse frequency is 50Hz, the number of electric pulses in each group is 20 times, and the number of electric pulse groups is 15 groups; the interval between each pulse of the pulse electric field is 1s;

[0087] The magnetic field intensity is 1.0T, the action time of a single magnetic pulse is 0.1s, the interval between magnetic pulses is 8s, the number of magnetic pulses is 20, and the number of magnetic pulse groups is 1;

[0088] The electromagnetic coupling treatment equipment is started, an electric field and a magnetic field are applied to the weld area, the electrode and the excitation coil are moved, and the sample treated by the electromagnetic coupling is taken out.

[0089] Electromagnetic coupling treatment of the weld can improve the stress state of the receiver welding repair site. At the same time, under the coupling of electric and magnetic fields, it can repair microscopic defects in the weld, increase the fatigue life of the weld, and improve the service life and overall performance of the repaired receiver.

[0090] In order to verify the correctness of the method of the present invention, the present invention conducted a test, and the test showed that compared with the untreated sample, the residual compressive stress at the test point of the treated sample increased and the residual tensile stress decreased. The average residual compressive stress increased by 34.62%, and the average residual tensile stress decreased by 18.9%.

[0091] Although the specific implementation of the invention is described in detail in conjunction with the drawings, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. A method for repairing an aircraft engine casing by coupling multiple physical fields, characterized in that: The following steps are involved: S1. Perform flaw detection on the casing to determine the location of the casing crack defect; S2. Grind the crack defect position of the casing; S3, the area where the crack defect of the casing is located after the grinding treatment is completed by ultrasonic cleaning; S4, fixing the casing in the electromagnetic coupling device, setting electromagnetic coupling parameters, and performing local electromagnetic coupling processing on the crack defect position of the casing; S5. Take out the casing from the electromagnetic coupling device and perform electron beam welding repair on the crack defect position of the casing; S6, perform flaw detection on the repaired casing. If crack defects exist in the casing, return to S2; if crack defects do not exist in the casing, execute S7; S7. Perform visual inspection on the casing welds; S8. Fix the casing in the electromagnetic coupling device, set the electromagnetic coupling parameters, and perform electromagnetic coupling treatment on the welding repair part of the casing.

2. The method for repairing an aircraft engine casing by multi-physics field coupling according to claim 1, characterized in that: The casing flaw detection process in S1 and S6 is fluorescent flaw detection, ultrasonic detection or X-ray detection.

3. The method for repairing an aircraft engine casing by multi-physics field coupling according to claim 1, characterized in that: In the step S2, the crack defect of the casing is polished, the defect position is polished into a U shape, and the burrs at the defect position are eliminated.

4. The method for repairing an aircraft engine casing by multi-physics field coupling according to claim 1, characterized in that: The S4 specifically includes: The casing is fixed on the workbench by a fixture, the fixture with the casing is placed in a working chamber composed of a multi-turn excitation coil, and an electrode is used to contact the casing; Set the electromagnetic coupling parameters, start the electromagnetic coupling device, and apply electric and magnetic fields to the casing.

5. The method for repairing an aircraft engine casing by multi-physics field coupling according to claim 4 is characterized in that: The electromagnetic coupling parameters include: voltage, magnetic field strength, electric pulse frequency, magnetic pulse time, number of electric pulses, number of electric pulse groups, number of magnetic pulses and number of magnetic pulse groups.

6. The method for repairing an aircraft engine casing by multi-physics field coupling according to claim 5, characterized in that: The specific electromagnetic coupling parameters are: The voltage U satisfies 0<U≤35V, and the magnetic field strength B satisfies 0<B≤1T; The frequency of electric pulses was 50 Hz, the number of electric pulses in each group was 20, and the number of electric pulse groups was 15; the interval between each pulse of the pulsed electric field was 1 s; The action time of a single magnetic pulse is 0.1 s, the interval between magnetic pulses is 8 s, the number of magnetic pulses is 20, and the number of magnetic pulse groups is 1.

7. The method for repairing an aircraft engine casing by multi-physics field coupling according to claim 1, characterized in that: In the S7, the casing weld is visually inspected, including the color, shape and surface quality of the weld.

8. The method for repairing an aircraft engine casing by multi-physics field coupling according to claim 1, characterized in that: The electromagnetic coupling parameters are set in S8, including: The voltage U satisfies 0<U≤35V, and the magnetic field strength B satisfies 0<B≤1T; The frequency of electric pulses was 50 Hz, the number of electric pulses in each group was 20, the number of electric pulse groups was 15, and the interval between each pulse of the pulsed electric field was 1 s; The action time of a single magnetic pulse is 0.1 s, the interval between magnetic pulses is 8 s, the number of magnetic pulses is 20, and the number of magnetic pulse groups is 1.

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