Method for determining pre-rotation holding time of wheel disc
By conducting tensile load holding tests and simulation calculations on the wheel disc specimens, the correspondence between load holding plastic strain and stress and time was established, which solved the problem that the pre-rotation load holding time of the wheel disc was difficult to determine in the existing technology, and realized rapid and accurate plastic deformation control, reducing test costs and cycle.
Patent Information
- Application Number
- CN202511118880.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-11
- Publication Date
- 2025-11-11
AI Technical Summary
The lack of a clear method in the existing technology to determine the amount of plastic deformation and the holding time during the pre-rotation and holding stage of the wheel leads to long test cycles, high costs, and difficulty in accurately controlling the plastic deformation after pre-rotation.
By conducting tensile holding tests on specimens at different stress levels, the correspondence between holding plastic strain and tensile stress and holding time was established. Combined with simulation calculations, the holding time of the wheel at the maximum pre-rotation speed was determined to ensure that the total plastic deformation meets the target value.
It enables rapid and accurate determination of the pre-rotation holding time of the wheel, precise control of plastic deformation, reduction of test cycle and cost, and improvement of the accuracy of the pre-rotation process.
Smart Images
Figure CN120927440A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of metal materials technology, and in particular to a method for determining the pre-rotation holding time of a wheel. Background Technology
[0002] Pre-rotation technology is a residual stress control technology for wheel disks that has been gradually developed in China in recent years. Its principle is to induce a certain degree of plastic deformation in the wheel disk through high-speed rotating centrifugal load, thereby releasing and regulating the distribution of residual stress inside the disk. This improves the dimensional stability of the wheel disk during machining and service, and extends its fatigue life. Pre-rotation technology is mainly applied to nickel-based high-temperature alloy and titanium alloy high-strength wheel disk materials, and is gradually being widely used in industries such as aero-engines and gas turbines.
[0003] The amount of plastic deformation (residual deformation) generated during pre-rotation is the core control point of the pre-rotation process. The magnitude of this plastic deformation determines the degree of residual stress release within the wheel, and also the changes in the wheel's internal microstructure and mechanical properties. The greater the plastic deformation generated during pre-rotation, the greater the degree of residual stress release within the wheel, and the greater the changes in the wheel material's microstructure and mechanical properties. Excessive plastic deformation may damage the wheel material's microstructure, leading to a decrease in some of its mechanical properties. Therefore, the amount of plastic deformation generated during pre-rotation must be strictly controlled to achieve good process results. In engineering, the amount of plastic deformation generated during wheel pre-rotation is usually explicitly required.
[0004] The pre-rotation process of the wheel includes three stages: acceleration, holding at maximum speed for a certain time, and deceleration. During the acceleration stage, the centrifugal force on the wheel gradually increases, leading to plastic deformation. During the holding stage, the amount of plastic deformation continues to increase with the holding time. Therefore, the plastic deformation generated during pre-rotation includes both the plastic deformation during the acceleration stage and the plastic deformation during the holding stage. To accurately control the total plastic deformation during pre-rotation, in addition to reasonably determining the maximum speed and accurately controlling the plastic deformation during the acceleration stage, it is also necessary to reasonably determine the holding time to accurately control the plastic deformation during the holding stage.
[0005] Currently, there is no clear method for determining the plastic deformation and holding time during the pre-rotation and load-holding stage in engineering. The amount of plastic deformation generated during the load-holding process cannot be accurately estimated, which can easily lead to deviations from the target value in the plastic deformation after the wheel's pre-rotation. In actual pre-rotation operations, multiple rounds of testing and verification are usually required to determine a reasonable holding time, resulting in long testing cycles and high costs. Existing literature and patent information mainly focus on methods and devices for controlling residual stress during rotation and testing methods for residual deformation during rotation, but do not address methods for quantifying plastic deformation during the pre-rotation and load-holding process. There is no research or record on how to reasonably determine the wheel's pre-rotation and load-holding time. Summary of the Invention
[0006] In view of the above analysis, the present invention aims to provide a method for determining the pre-rotation holding time of a wheel, in order to solve at least one of the problems of long test cycles and high costs caused by the need for multiple rounds of testing and verification to determine a reasonable holding time in the process of pre-rotation to release residual stress inside the wheel.
[0007] On one hand, embodiments of the present invention provide a method for determining the pre-rotation holding time of a wheel, the method comprising the following steps:
[0008] Step 1: Conduct tensile tests on the specimens at different stress levels. The tensile process includes three stages: tensile loading, holding under tensile stress, and unloading. Establish the correspondence between the plastic strain under tensile stress, tensile stress σ, and holding time t during the tensile holding stage: ε dc (t) = f(σ, t), where ε dc (t) represents the plastic strain of the specimen under tensile stress σ for time t.
[0009] Step 2: Simulate and calculate the equivalent stress σ experienced by the wheel when it is loaded to the maximum pre-rotation speed. eff Plastic deformation of the outer diameter of the wheel during the loading stage D ac Based on the target value D of the total plastic deformation of the pre-rotating wheel's outer diameter. t Determine the target plastic deformation D of the wheel at the maximum pre-rotation speed under load. dc , where D dc =D t -D ac ;
[0010] Step 3: Based on the correspondence described in Step 1, determine whether to maintain the wheel at the maximum pre-rotation speed until the target plastic deformation D is reached. dc The time is the pre-rotation holding time of the wheel.
[0011] Furthermore, the temperature at which the tensile load test is performed on the specimen is the same as the temperature at which the wheel is pre-rotated, which is -150 to 700°C.
[0012] Furthermore, in step one, the specific steps of the tensile load test include:
[0013] (1) The sample is unloaded from the wheel to prepare the specimen for the tensile load test;
[0014] (2) The specimen is subjected to tensile load tests at different stress levels, and the strain of the specimen during the tensile process is measured using an extensometer.
[0015] Furthermore, in step (1), at least one specimen is prepared for tensile load testing under the same stress.
[0016] Furthermore, in step (2), the tensile load test uses at least three different levels of tensile load stress, all of which are greater than the yield strength of the specimen at the test temperature. The maximum value of the tensile load stress is greater than or equal to the equivalent stress at the maximum pre-rotation speed of the wheel.
[0017] Furthermore, in step one, after completing the tensile holding test, the change of the holding plastic strain of the specimen under different tensile holding stresses with the holding time is first determined, and then the correspondence between the holding plastic strain and the tensile holding stress and holding time is established.
[0018] Furthermore, the holding time is ≥10 min.
[0019] Furthermore, the specific steps of step two include:
[0020] S1. Simulate and calculate the distribution of residual stress inside the wheel before pre-rotation, and correct the simulation results of residual stress by combining the actual measured value of residual stress inside the wheel, and use the corrected value as the initial residual stress before pre-rotation of the wheel.
[0021] S2. Simulate and calculate the equivalent stress σ experienced by the wheel when it is loaded to the maximum pre-rotation speed. eff Plastic deformation of the outer diameter of the wheel during the loading stage D ac ;
[0022] S3. Based on the total plastic deformation target value D of the wheel meeting the acceptance criteria. t Determine the target plastic deformation D of the wheel at the maximum pre-rotation speed under load. dc , where D dc =D t -D ac .
[0023] Furthermore, the pre-rotation process includes three stages: pre-rotation loading, pre-rotation holding at maximum speed, and pre-rotation unloading.
[0024] Furthermore, in step three, the correspondence ε established in step one is used... dc (t) = f(σ, t), with the equivalent stress σ at the maximum pre-rotation speed of the wheel. eff As the load-bearing stress σ, according to the target plastic deformation amount D dc The pre-rotation holding time t of the wheel is calculated, wherein the holding time is ≥0s.
[0025] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:
[0026] 1. This invention establishes a quantitative correspondence between the plastic strain under load and the tensile stress and holding time of the specimen through tensile holding tests at the specimen level. Combined with simulation calculations, the target plastic deformation under load during the holding stage of the pre-rotation of the wheel is accurately obtained, thereby enabling the rapid determination of the holding time for pre-rotation of the wheel. Compared with the prior art, this invention not only provides a method for accurately determining the holding time of the pre-rotation of the wheel, but also solves the problems of long cycle and high cost in determining the holding time through trial and error experiments in the prior art.
[0027] 2. This invention combines tensile load testing of specimens with simulation calculations. While achieving rapid and accurate determination of the load holding time of the wheel pre-rotation, it can precisely control the plastic deformation generated by the wheel during the actual pre-rotation load holding process. This solves the problems in the prior art where the amount of plastic deformation generated during the pre-rotation load holding process cannot be accurately estimated, the plastic deformation after the wheel pre-rotation is prone to deviating from the target value, and the total plastic deformation after the wheel pre-rotation is not accurately controlled.
[0028] 3. The method of the present invention has universality and can be used for the pre-rotation of turbine disks, compressor disks and other disks of aero engines and gas turbines of different materials and shapes. It can overcome the problems of long test cycles and high test costs caused by trial and error tests.
[0029] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description
[0030] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.
[0031] Figure 1 This is a flowchart for determining the pre-rotation holding time of the wheel in this invention;
[0032] Figure 2 The strain curves of FGH96 alloy specimens under different stresses at room temperature are shown as a function of time.
[0033] Figure 3 The curves show the change of plastic strain under tensile stress over time when FGH96 alloy specimens are subjected to tensile stress at room temperature with different tensile stresses.
[0034] Figure 4 The initial circumferential residual stress distribution before the disk pre-rotates in Example 1;
[0035] Figure 5 The equivalent stress distribution of the disk at the maximum pre-rotation speed in Example 1;
[0036] Figure 6 This is the curve showing the change of the outer diameter plastic deformation of the wheel as a function of the holding time during the pre-rotation maximum speed process in Example 1;
[0037] Figure label:
[0038] 1-Tension holding stress 1150MPa, 2-Tension holding stress 1200MPa, 3-Tension holding stress 1250MPa, 4-Tension holding stress 1300MPa, 5-Tension holding stress 1400MPa. Detailed Implementation
[0039] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.
[0040] The amount of plastic deformation generated by pre-rotation of the wheel not only determines the degree of release of residual stress inside the wheel, but also determines the changes in the microstructure and mechanical properties inside the wheel. Too little plastic deformation will result in the residual stress inside the wheel not being released well, while too much plastic deformation may damage the microstructure of the wheel material, leading to a decrease in some of its mechanical properties. Therefore, strictly controlling the amount of plastic deformation generated by pre-rotation of the wheel is of great significance for its engineering application.
[0041] The plastic deformation of the wheel originates from two pre-rotation stages: the loading stage and the holding stage. To accurately control the total plastic deformation during pre-rotation, in addition to determining the maximum rotation speed and accurately controlling the plastic deformation during the acceleration stage, it is also necessary to determine the holding time appropriately to accurately control the plastic deformation during the holding stage. Currently, there is no clear method for determining the pre-rotation holding time. In actual pre-rotation operations, it is usually necessary to conduct multiple rounds of tests and verifications to determine a reasonable holding time, which is time-consuming and costly.
[0042] Therefore, the present invention provides a method for determining the pre-rotation holding time of the wheel, the flowchart of which is as follows: Figure 1 As shown, the method includes:
[0043] Step 1: Conduct tensile tests on the specimens at different stress levels. The tensile process includes three stages: tensile loading, holding under tensile stress, and unloading. Establish the correspondence between the plastic strain under tensile stress, tensile stress σ, and holding time t during the tensile holding stage: ε dc (t) = f(σ, t), where ε dc (t) represents the plastic strain of the specimen under tensile stress σ for time t.
[0044] Step 2: Simulate and calculate the equivalent stress σ experienced by the wheel when it is loaded to the maximum pre-rotation speed. eff Plastic deformation of the outer diameter of the wheel during the loading stage D ac Based on the target value D of the total plastic deformation of the pre-rotating wheel's outer diameter. t Determine the target plastic deformation D of the wheel at the maximum pre-rotation speed under load. dc , where D dc =D t -D ac ;
[0045] Step 3: Based on the correspondence described in Step 1, determine whether to maintain the wheel at the maximum pre-rotation speed until the target plastic deformation D is reached. dc The time is the pre-rotation holding time of the wheel.
[0046] It should be noted that the plastic deformation generated by the wheel during pre-rotation (high-speed spin) is essentially the same as the plastic deformation of a standard tensile specimen. Both are irreversible strains dominated by dislocation slip. Both are caused by dislocation multiplication, slip, and pile-up, leading to irreversible lattice shear and forming true plastic strain. Therefore, during the pre-rotation of the wheel, the diameter of the disk expands, similar to the tensile process of the specimen material. Both are mechanical behaviors of the material under load, and this mechanical behavior is the same in the tensile process of the specimen material and the pre-rotation process of the wheel.
[0047] It should be noted that, in order to ensure that the changes in the material of the wheel under tensile stress during the tensile load test can truly reflect the changes in the wheel during the pre-rotation process, including the degree of release of internal residual stress and changes in internal microstructure and mechanical properties, the conditions for conducting the tensile load test on the material of the wheel in this invention are the same as the conditions for pre-rotating the wheel.
[0048] Specifically, in step one, the tensile test with different stress levels is carried out on the specimen. The tensile process includes three stages: tensile loading, tensile holding under tensile stress, and tensile unloading.
[0049] Furthermore, the specific steps of the tensile load test include:
[0050] (1) The sample is unloaded from the wheel to prepare the specimen for the tensile load test;
[0051] (2) The specimen is subjected to tensile load tests at different stress levels, and the strain of the specimen during the tensile process is measured using an extensometer.
[0052] Specifically, in step (1), the tensile specimen used for the tensile load test in this invention is processed from the wheel to ensure that the microstructure and mechanical properties of the tensile specimen are representative and completely consistent with the wheel.
[0053] It should be noted that, in order to ensure that the changes in the material of the wheel under tensile stress during the tensile load test can truly reflect the changes in the wheel during the pre-rotation process, the present invention requires that the temperature at which the sample is subjected to the tensile load test be consistent with the temperature at which the wheel is pre-rotated.
[0054] Specifically, in step (2), the temperature at which the tensile load test is performed on the specimen at different stress levels is the same as the temperature at which the wheel is pre-rotated, which is -150 to 700°C.
[0055] According to some preferred embodiments of the present invention, the temperature at which the wheel is pre-rotated can be any value within the range of -150 to 700°C, such as -150°C, -100°C, -50°C, 0°C, 50°C, 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, and 700°C.
[0056] It should be noted that, in order to induce localized plastic deformation of the wheel material under tensile stress and thereby alter the distribution of residual stress within the material, the present invention requires limiting the stress used in the tensile load test.
[0057] Specifically, in step (2), the stress required for the tensile test of the specimen needs to be higher than the yield strength of the material at the test temperature.
[0058] According to some preferred embodiments of the present invention, when using the method of the present invention to confirm the holding time of a wheel with material grade FGH96 at room temperature (25°C), the tensile stress used in the tensile test of the wheel material is greater than the yield strength of FGH96 material at room temperature (1140MPa). For example, it can be at least one of 1150MPa, 1200MPa, 1250MPa, 1300MPa, 1400MPa, 1450MPa, and 1500MPa. However, the tensile stress cannot be too high, and the decrease in the creep performance of the wheel after pre-rotation and the failure of the wheel due to cracking must also be considered.
[0059] It should be noted that, due to the different requirements of the wheel's performance in real-world engineering applications or the limitations of the pre-rotation process device for the wheel in reality, the maximum rotational speed for pre-rotating the wheel may vary. Therefore, multiple stresses can be taken for the tensile load test on the wheel material to correspond to the equivalent stress generated at the maximum rotational speed during the pre-rotation process of the wheel.
[0060] Specifically, in step (2), at least three different stress levels of tensile stress are used in the tensile stress test of the same material of the wheel at the same temperature. The maximum value of the tensile stress of different magnitudes used should be greater than or equal to the equivalent stress at the maximum pre-rotation speed of the wheel.
[0061] According to some preferred embodiments of the present invention, when confirming the holding time of the FGH96 material wheel at room temperature (25°C) using the scheme of the present invention, tensile holding stresses greater than the yield strength of FGH96 material at room temperature (1140MPa) can be used to conduct tensile holding tests on the wheel material respectively.
[0062] Specifically, in step (2), during the tensile load test, an extensometer is used to measure the strain of the specimen under a certain tensile stress during the tensile loading and tensile load process, which mainly includes tensile plastic strain and tensile elastic strain.
[0063] According to some preferred embodiments of the present invention, during tensile load tests on FGH96 material for wheel discs at room temperature with stresses of 1150 MPa, 1200 MPa, 1250 MPa, 1300 MPa, and 1400 MPa, the tensile strain versus time curves are as follows: Figure 2 As shown.
[0064] It should be noted that, in order to ensure that the material of the wheel can fully release residual stress and avoid the adverse effects on the material performance that may be caused by excessively long holding time, the present invention controls the tensile holding time of the material under tensile holding stress.
[0065] Specifically, in step (2), during the tensile stress test, the material for the wheel is subjected to tensile stress for 10-60 minutes. If the tensile stress is too short, the residual stress of the specimen cannot be fully released, which may result in the plastic deformation after tensile stress not meeting the requirements. If the tensile stress is too long, the plastic deformation of the material will not change significantly after reaching a certain level, but it will have an adverse effect on other properties of the specimen, such as creep properties, and may even lead to material fracture failure, and is not economical or practical.
[0066] According to some preferred embodiments of the present invention, the tensile holding time for the material for the wheel disc under tensile holding stress can be any value within the range of 10-60 minutes, such as 10 minutes, 12 minutes, 15 minutes, 18 minutes, 20 minutes, 23 minutes, 25 minutes, 28 minutes, 30 minutes, 32 minutes, 35 minutes, 38 minutes, 40 minutes, 42 minutes, 45 minutes, 47 minutes, 50 minutes, 53 minutes, 55 minutes, 58 minutes, and 60 minutes.
[0067] It should be noted that during the tensile holding load test on the specimen, the change of the plastic strain of the specimen over time is recorded under different tensile holding load stresses to establish the correspondence between the holding load plastic strain and the tensile holding load stress and holding time.
[0068] Specifically, in step one, during the tensile hold-load test of the specimen, the change of the hold-load plastic strain of the specimen under different tensile hold-load stresses with the hold-load time is first determined, and then the correspondence between the hold-load plastic strain and the tensile hold-load stress σ and the hold-load time t is established: ε dc (t)=f(σ、t), where εdc(t) is the plastic strain of the specimen under tensile stress σ for time t.
[0069] According to some preferred embodiments of the present invention, under room temperature conditions, the plastic strain of FGH96 material for wheel bearings under tensile stresses of 1150 MPa, 1200 MPa, 1250 MPa, 1300 MPa, and 1400 MPa, respectively, varies with time as shown in the curves. Figure 3 As shown, from Figure 3 It can be seen that under various tensile stresses, the plastic strain of the specimen gradually increases with the extension of the holding time during the loading process, but the rate of increase of the plastic strain gradually decreases with the extension of time; and according to Figure 3 Based on the curve data, establish the correspondence between the plastic strain under load, tensile stress, and holding time of the specimen ε dc (t) = f(σ, t).
[0070] According to some preferred embodiments of the present invention, a formula is used to fit the relationship between the plastic strain, tensile stress, and holding time of the above-mentioned FGH96 material for wheel disks at room temperature, resulting in the following formula:
[0071] In equation (1), ε dc To maintain the plastic strain under load, σ is the tensile stress, t is the holding time, and m, A, and n are constants: A = 1.8077 × 10⁻⁶ -12 m = -0.356, n = 2.33.
[0072] It should be noted that the relationship ε between the plastic strain under load, tensile stress, and holding time obtained in step one is as follows: dc (t) = f(σ, t). If the target plastic deformation amount that the wheel needs to achieve in the pre-rotation stage can be obtained, then at a certain maximum pre-rotation speed, the holding time of the wheel pre-rotation can be accurately calculated according to the above correspondence.
[0073] It should be noted that during the pre-rotation process, in order to avoid excessive impact on the wheel due to excessively high rotation speed, it is necessary to load from a lower rotation speed to the maximum pre-rotation speed required to release residual stress. During the loading stage of the pre-rotation, the tensile strain generated by the wheel is elastic strain or a combination of elastic and plastic strain (plastic deformation will occur when the pre-rotation speed is loaded to a value greater than the yield strength of the wheel material). When the maximum pre-rotation speed is reached, in order to fully release the residual stress inside the wheel, it is necessary to maintain the load at the maximum pre-rotation speed for a period of time to control the total amount of plastic deformation after the pre-rotation of the wheel. Therefore, determining the duration of the pre-rotation holding stage is crucial for the actual pre-rotation operation.
[0074] Specifically, in step two, the present invention uses simulation calculation to obtain the equivalent stress σ experienced by the wheel when it is loaded to the maximum pre-rotation speed. eff Plastic deformation D during loading ac Then, according to the total plastic deformation D that the wheel needs to meet the standard during acceptance, t To determine the target plastic deformation D that the wheel needs to achieve during the load-holding process at the maximum pre-rotation speed. dc , where D dc =D t -D ac .
[0075] According to some preferred embodiments of the present invention, step two specifically includes the following steps:
[0076] S1. Simulate and calculate the distribution of residual stress inside the wheel before pre-rotation, and correct the simulation results of residual stress by combining the actual measured value of residual stress inside the wheel, and use the corrected value as the initial residual stress before pre-rotation of the wheel.
[0077] S2. Simulate and calculate the equivalent stress σ experienced by the wheel when it is loaded to the maximum pre-rotation speed. eff and the amount of plastic deformation D during loading ac ;
[0078] S3. Based on the total plastic deformation D of the wheel meeting the acceptance criteria. t Determine the target plastic deformation D of the wheel at the maximum pre-rotation speed under load. dc , where D dc =D t -D ac .
[0079] More preferably, in steps S1 and S2, the residual stress testing method used in this invention can be a commonly used residual stress testing method in engineering, including X-ray method, blind hole method, and profile method, and the simulation software used for the simulation calculation can be finite element analysis software such as Abaqus and Ansys.
[0080] It should be noted that, after the target plastic deformation D of the wheel needs to be achieved under load at the maximum pre-rotation speed, determined by simulation calculations and acceptance criteria, is... dc Then, the correspondence ε determined in step one is used. dc (t) = f(σ, t), with the equivalent stress σ at the maximum pre-rotation speed of the wheel. eff As the load-bearing stress σ, according to the target plastic deformation amount D dc , where D dc =∫ r ε dc dr, where r is the radius of the wheel, calculates the holding time t for pre-rotating the wheel, where the holding time is ≥0s.
[0081] It should be noted that during the actual pre-rotation of the wheel, when the selected maximum speed is reached, if the plastic deformation of the wheel is less than the total plastic deformation that meets the acceptance standard, it is necessary to maintain the load at the maximum pre-rotation speed for a period of time; when the selected maximum speed has not yet been reached, if the plastic deformation of the wheel already meets the total plastic deformation that meets the acceptance standard, the aforementioned holding stage is not required, i.e., the holding time is equal to 0 seconds.
[0082] According to some preferred embodiments of the present invention, the holding time during the pre-rotation process of the wheel can be 0s, 25s, 90s, 270s, 10min, 12min, 15min, 18min, 20min, 23min, 25min, 28min, 30min, 32min, 35min, 38min, 40min, 42min, 45min, 47min, 50min, 53min, 55min, 58min, or 60min.
[0083] Compared with existing technologies, this invention establishes a quantitative correspondence between the plastic strain under load and the maximum stress and holding time of the specimen through tensile holding tests at the specimen level. Combined with simulation calculations, the target plastic deformation under load during the holding stage of the pre-rotation of the wheel is accurately obtained, thereby enabling the rapid determination of the holding time for pre-rotation of the wheel. Compared with existing technologies, this invention not only provides a clear method for determining the holding time of pre-rotation of the wheel, but also solves the problems of long cycle and high cost in determining the holding time through trial and error experiments in existing technologies.
[0084] This invention combines tensile load testing of specimens with simulation calculations. While achieving rapid and accurate determination of the load holding time of the wheel pre-rotation, it can precisely control the plastic deformation of the wheel during the actual pre-rotation load holding process. This solves the problems in the prior art where the amount of plastic deformation generated during the wheel pre-rotation load holding process cannot be accurately estimated, the plastic deformation after wheel pre-rotation is prone to deviating from the target value, and the total plastic deformation after pre-rotation is not accurately controlled.
[0085] The method of this invention is universal and can be used for the pre-rotation of turbine disks and compressor disks of aero engines and gas turbines of different materials and shapes. It can overcome the problems of long test cycles and high test costs caused by trial and error tests.
[0086] Based on the target value D of the total plastic deformation of the outer diameter of the wheel after pre-rotation. t The method of this invention determines the holding time t at the maximum pre-rotation speed. In practical applications, under the same pre-rotation conditions (temperature, maximum pre-rotation speed, etc.), after holding the disk at the maximum pre-rotation speed for the specified time t, the actual value D of the total plastic deformation of the disk's outer diameter is obtained. t ', through D t 'With target value D t The deviation between the two values is used to evaluate the reliability of the method of the present invention, denoted by R, where R = (D t '-D t ) / D t ×100%.
[0087] During the research process, the inventors discovered that by combining the tensile load test and simulation calculation of the specimen according to the technical solution of the present invention, it is possible not only to quickly and accurately determine the load holding time of the wheel pre-rotation, but also to precisely control the plastic deformation of the wheel generated during the actual pre-rotation load holding process, wherein R is ±10%.
[0088] The technical solution of the present invention will be further explained and illustrated below using examples and comparative examples.
[0089] In this embodiment of the invention, the wheel is made of FGH96 material, with an outer diameter of 600 mm, an inner diameter of 50 mm, and a height of 160 mm. Pre-rotation is performed at room temperature. At room temperature, the yield strength of the FGH96 material used in the wheel is 1140 MPa. The target value D for the total plastic deformation of the wheel's outer diameter after pre-rotation is... t It is 0.3mm.
[0090] Example 1
[0091] At room temperature, determine the holding time when the wheel is pre-rotated at its maximum speed of 14000 r / min during the pre-rotation process.
[0092] Step 1: Conduct a tensile test on the specimen to establish the relationship between the plastic strain under load and the tensile stress σ and the holding time t. This includes the following steps:
[0093] (1) Load and unload the wheel blank to prepare a specimen for tensile load test;
[0094] (2) Under room temperature conditions, the specimens obtained in step (1) were subjected to tensile tests under different stresses. The tensile tests included three stages: tensile loading, tensile holding stress, and tensile unloading. In this embodiment, the five tensile holding stresses were 1150 MPa, 1200 MPa, 1250 MPa, 1300 MPa, and 1400 MPa, respectively. When the tensile load was reached to the set tensile holding stress, the holding stress was carried out for 10 minutes. The strain changes over time during the tensile loading and holding stages were measured using an extensometer. The measured curves are shown below. Figure 2 As shown;
[0095] (3) Record the changes in plastic strain of the specimen over time during the holding period under different tensile stress levels. The resulting curves are shown in the figure. Figure 3 As shown, from Figure 3 It can be seen that under different tensile stresses, the plastic strain of the specimen gradually increases with the increase of the holding time during the loading process; according to Figure 3 Based on the curve data, establish the correspondence between the plastic strain under load, tensile stress, and holding time of the specimen ε dc(t)=f(σ、t); After fitting, we get: Under room temperature conditions, the relationship between the plastic strain and tensile stress of the disk using FGH96 material and the holding time satisfies formula (1). In equation (1), ε dc To maintain the plastic strain under load, σ is the tensile stress, t is the holding time, and m, A, and n are constants: A = 1.8077 × 10⁻⁶ -12 m = -0.356, n = 2.33;
[0096] Step 2: Determine the target plastic deformation of the wheel during the pre-rotation and load holding phase, including the following steps:
[0097] S1: Simulate the distribution of residual stress inside the wheel before pre-rotation, and correct the simulation results based on the actual measured residual stress values of the wheel. Use the corrected values as the initial residual stress before pre-rotation. In this embodiment, Abaqus finite element analysis software is used to simulate the distribution of residual stress inside the wheel before pre-rotation. The maximum circumferential residual stress inside the nickel-based high-temperature alloy wheel blank, measured using the contour method, is 606 MPa. After correction, the simulated initial circumferential residual stress distribution inside the wheel is as follows: Figure 4 As shown;
[0098] S2: Simulation calculation of the equivalent stress σ experienced by the wheel when loaded to the maximum pre-rotation speed. eff And the plastic deformation Dac during the loading stage; in this embodiment, the maximum rotational speed of the wheel during pre-rotation is 14000 r / min, and the equivalent stress distribution of the wheel when it is loaded to the maximum rotational speed of 14000 r / min is as follows. Figure 5 As shown, the maximum equivalent stress value σ eff The plastic deformation D of the wheel is 1202 MPa when it is loaded to the maximum speed of 14000 r / min. ac It is 0.23mm;
[0099] S3: Total plastic deformation D required to be achieved according to the pre-rotation process of the wheel. t The target plastic deformation D during the pre-rotation and load holding stage was calculated. dc In this embodiment, the total plastic deformation D of the outer diameter of the wheel required to be achieved during the pre-rotation process is... t The plastic deformation D during the loading stage is 0.3 mm. ac The target value D of the plastic deformation during the load-holding stage is calculated to be 0.23 mm. dc It is 0.07mm (D) dc =D t -D ac =0.3mm - 0.23mm = 0.07mm);
[0100] Step 3: Based on the equivalent stress σ at the maximum pre-rotation speed eff Based on the specimen-level "holding plastic strain - tensile holding stress - holding time" relationship established in step one, the holding plastic deformation under different holding times during pre-rotation is calculated. In this embodiment, at the maximum pre-rotation speed of 14000 r / min, the curve of the wheel's plastic deformation over time during the pre-rotation holding process is as follows: Figure 6 As shown, from Figure 6 It can be seen that when the holding time reaches 90s, the plastic deformation of the wheel during the pre-rotation holding process reaches the target holding plastic deformation amount of 0.07mm. Therefore, the holding time of the wheel at the maximum pre-rotation speed is 90s.
[0101] The wheel described in this embodiment was pre-rotated at room temperature with a maximum speed of 14000 r / min and a maximum speed holding time of 90 s. The total plastic deformation D of the outer diameter of the wheel after pre-rotation was obtained by actual testing. t The value is 0.31 mm, which is 3.3% of the target value of 0.3 mm for total pre-rotation plastic deformation, with an accuracy R of 3.3%.
[0102] Example 2
[0103] Using the same method as in Example 1, the holding time at the maximum pre-rotation speed of 13900 r / min during the pre-rotation of the wheel was determined at room temperature. The difference is:
[0104] In step S2 of step two, the maximum equivalent stress value σ is obtained through simulation calculation when the wheel is loaded to the maximum speed of 13900 r / min in this embodiment. eff The plastic deformation D of the wheel is 1191 MPa when it is loaded to the maximum speed of 13900 r / min. ac It is 0.21mm;
[0105] In step S3 of step two: the total plastic deformation D of the outer diameter of the wheel required to be achieved according to the pre-rotation process. t The plastic deformation D during the loading stage is 0.3 mm. ac The target value D for plastic deformation during the load-holding stage is calculated to be 0.21 mm. dc It is 0.09mm (D) dc =D t -D ac =0.3mm - 0.21mm = 0.09mm);
[0106] Step 3: Based on the equivalent stress σ at the maximum pre-rotation speed effBased on the specimen-level "holding plastic strain - tensile holding stress - holding time" relationship established in step one, the holding plastic deformation under different holding times during pre-rotation is calculated. In this embodiment, at the maximum pre-rotation speed of 13900 r / min, the curve of the change of the wheel's plastic deformation with time during the pre-rotation holding process is as follows: Figure 6 As shown, from Figure 6 It can be seen that when the holding time reaches 270s, the plastic deformation of the wheel during the pre-rotation holding process reaches the target holding plastic deformation amount of 0.09mm. Therefore, the holding time of the wheel at the maximum pre-rotation speed is 270s.
[0107] The wheel described in this embodiment was pre-rotated at room temperature with a maximum speed of 13900 r / min and a maximum speed holding time of 270 s. The total plastic deformation D of the outer diameter of the wheel after pre-rotation was obtained by actual testing. t The value is 0.27 mm, which is -10.0% of the target value of 0.3 mm for total pre-rotation plastic deformation.
[0108] Example 3
[0109] Using the same method as in Example 1, the holding time at the maximum pre-rotation speed of 14100 r / min during the pre-rotation of the wheel was determined at room temperature. The difference is:
[0110] In step S2 of step two, the maximum equivalent stress value σ is obtained through simulation calculation when the wheel is loaded to the maximum speed of 14100 r / min in this embodiment. eff The plastic deformation D of the wheel is 1215 MPa when it is loaded to the maximum speed of 14100 r / min. ac It is 0.26mm;
[0111] In step S3 of step two: the total plastic deformation D of the outer diameter of the wheel required to be achieved according to the pre-rotation process. t The plastic deformation D during the loading stage is 0.3 mm. ac The target value D for plastic deformation during the load-holding stage is calculated to be 0.26 mm. dc 0.04mm (D) dc =D t -D ac =0.3mm - 0.26mm = 0.04mm);
[0112] Step 3: Based on the equivalent stress σ at the maximum pre-rotation speed effBased on the specimen-level "holding plastic strain - tensile holding stress - holding time" relationship established in step one, the holding plastic deformation under different holding times during pre-rotation is calculated. In this embodiment, at the maximum pre-rotation speed of 14100 r / min, the curve of the wheel's plastic deformation over time during the pre-rotation holding process is as follows: Figure 6 As shown, from Figure 6 It can be seen that when the holding time reaches 25s, the plastic deformation of the wheel during the pre-rotation holding process reaches the target holding plastic deformation amount of 0.04mm. Therefore, the holding time of the wheel at the maximum pre-rotation speed is 25s.
[0113] The wheel described in this embodiment was pre-rotated at room temperature with a maximum speed of 14100 r / min and a maximum speed holding time of 25 s. The total plastic deformation D of the outer diameter of the wheel after pre-rotation was obtained by actual testing. t The value is 0.33 mm, which is 10.0% of the target value of 0.3 mm for total pre-rotation plastic deformation.
[0114] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for determining the pre-rotation holding time of a wheel, characterized in that, The method includes the following steps: Step 1: Conduct tensile tests on the specimens at different stress levels. The tensile process includes three stages: tensile loading, holding under tensile stress, and unloading. Establish the correspondence between the plastic strain under tensile stress, tensile stress σ, and holding time t during the tensile holding stage: ε dc (t) = f(σ, t), where ε dc (t) represents the plastic strain of the specimen under tensile stress σ for time t. Step 2: Simulate and calculate the equivalent stress σ experienced by the wheel when it is loaded to the maximum pre-rotation speed. eff Plastic deformation of the outer diameter of the wheel during the loading stage D ac Based on the target value D of the total plastic deformation of the pre-rotating wheel's outer diameter. t Determine the target plastic deformation D of the wheel at the maximum pre-rotation speed under load. dc , where D dc =D t -D ac ; Step 3: Based on the correspondence described in Step 1, determine whether to maintain the wheel at the maximum pre-rotation speed until the target plastic deformation D is reached. dc The time is the pre-rotation holding time of the wheel.
2. The method according to claim 1, characterized in that, The temperature at which the tensile load test is performed on the specimen is the same as the temperature at which the wheel is pre-rotated, which is -150 to 700°C.
3. The method according to claim 1, characterized in that, In step one, the specific steps of the tensile load test include: (1) The sample is unloaded from the wheel to prepare the specimen for the tensile load test; (2) The specimen is subjected to tensile load tests at different stress levels, and the strain of the specimen is measured using an extensometer during the tensile load test.
4. The method according to claim 3, characterized in that, In step (1), at least one specimen is prepared for tensile load test under the same stress.
5. The method according to claim 3, characterized in that, In step (2), the tensile load test uses at least three different levels of tensile load stress, all of which are greater than the yield strength of the specimen at the test temperature. The maximum value of the tensile load stress is greater than or equal to the equivalent stress at the maximum pre-rotation speed of the wheel.
6. The method according to claim 1, characterized in that, In step one, after completing the tensile holding test, the change of the holding plastic strain of the specimen under different tensile holding stresses with the holding time is first determined, and then the correspondence between the holding plastic strain and the tensile holding stress and holding time is established.
7. The method according to claim 6, characterized in that, The load holding time is ≥10 min.
8. The method according to claim 1, characterized in that, Step two includes the following steps: S1. Simulate and calculate the distribution of residual stress inside the wheel before pre-rotation, and correct the simulation results of residual stress by combining the actual measured value of residual stress inside the wheel, and use the corrected value as the initial residual stress before pre-rotation of the wheel. S2. Simulate and calculate the equivalent stress σ experienced by the wheel when it is loaded to the maximum pre-rotation speed. eff Plastic deformation of the outer diameter of the wheel during the loading stage D ac ; S3. Based on the total plastic deformation target value D of the wheel meeting the acceptance criteria. t Determine the target plastic deformation D of the wheel under the maximum pre-rotation speed. dc , where D dc =D t -D ac .
9. The method according to claim 8, characterized in that, The pre-rotation process includes three stages: pre-rotation loading, pre-rotation holding at maximum speed, and pre-rotation unloading. The total plastic deformation includes plastic deformation during the pre-rotation loading stage and plastic deformation during the pre-rotation holding stage.
10. The method according to claim 1, characterized in that, In step three, the correspondence ε established in step one is used... dc (t) = f(σ, t), with the equivalent stress σ at the maximum pre-rotation speed of the wheel. eff As the load-bearing stress σ, according to the target plastic deformation amount D dc The pre-rotation holding time t of the wheel is calculated, wherein the holding time is ≥0s.