A method for predicting the position change of internal defects of a titanium alloy forge piece in a forging process

Abstract

The application provides a method for predicting the position change of internal defects of a titanium alloy forging during a forging process, and relates to the technical field of titanium alloy material processing and preparation. First, a three-dimensional space rectangular coordinate system is established for a titanium alloy bar with implanted defects, the specific position of the defects is determined through ultrasonic detection, and the three-dimensional coordinates of the defects are constructed. Then, the titanium alloy bar with the defects is forged under different forging deformation amounts, the three-dimensional coordinates of the internal defects of the forging are determined through ultrasonic detection technology, the maximum absolute value of the three-dimensional coordinate change of the theoretical position and the actual position of the defects in the forging is taken as the defect position change amount during the forging process. Finally, the defect position change amount of the titanium alloy bar during the forging process is fitted with the forging deformation amount, a functional relationship between the defect position and the bar deformation amount during the forming process of the titanium alloy forging is established, the prediction of the internal defect position change of the titanium alloy forging is realized, and support is provided for the defect detection and control of high-performance titanium alloy forgings in the field of aviation and aerospace.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy material processing and preparation technology, specifically to a method for predicting the changes in the location of internal defects in titanium alloy forgings during the forging process. Background Technology

[0002] Titanium alloys possess high specific strength, low density, and excellent corrosion resistance, making them widely used in shipbuilding, petrochemicals, aerospace, and medical fields. In recent years, with the development of aerospace technologies, the requirements for materials have become increasingly stringent, especially for lightweight structural materials that can significantly reduce weight, where the strength and toughness matching requirements are becoming increasingly demanding. For semi-finished and finished titanium and titanium alloy products, ultrasonic testing is primarily used to inspect for defects. However, due to the elastic anisotropy of the α-phase and the high damping characteristics of the β-phase in titanium alloys, the accuracy of ultrasonic defect detection is very low, presenting significant limitations. Airworthiness regulations stipulate that "limited-life" parts must undergo appropriate damage tolerance assessments to determine whether potential failure due to defects in materials, manufacturing, or use will occur within the approved lifespan of the part.

[0003] Currently, there is no systematic and comprehensive database and analysis system in China for accumulating defects in titanium alloy life-limited components, which seriously affects and restricts the development of my country's civil aviation engine design, testing and verification, and airworthiness certification. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for predicting the changes in the location of internal defects in titanium alloy forgings during the forging process, thereby achieving the prediction of the changes in the location of defects in titanium alloy materials.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for predicting the changes in the location of internal defects in titanium alloy forgings during the forging process, comprising the following steps:

[0006] Step 1: Prefabricate titanium alloy bars containing multiple defects and establish a three-dimensional spatial coordinate system to determine the position coordinates of each defect;

[0007] Step 2: Forge the pre-made titanium alloy bar containing defects with different deformation amounts under different forging processes to obtain multiple titanium alloy forgings;

[0008] Step 3: Use ultrasonic testing to detect the location of defects in the titanium alloy forging, establish a three-dimensional spatial coordinate system, and record the actual position coordinates of each defect in the forging;

[0009] Step 4: Determine the theoretical coordinates of each defect in the forging based on the forging deformation and the position coordinates of defects in the bar stock;

[0010] Step 5: Take the maximum absolute value of the change in the three-dimensional coordinates of the theoretical and actual positions of defects in the titanium alloy forging as the change in defect position during the forging process of titanium alloy bars.

[0011] Step 6: Fit the change in defect location during the forging process of titanium alloy bars with the deformation during the forging process to obtain a functional relationship model between the change in defect location and the deformation of the bars during the processing of titanium alloy bars into forgings, so as to realize the prediction of the change in defect location in titanium alloy forgings.

[0012] Preferably, the functional relationship between the change in defect location and the deformation of the rod during the processing of the titanium alloy bar into a forging is shown in the following formula:

[0013] Max{(x1-x2),(y1-y2),(z1-z2)}=KF+B

[0014] Where x1, y1, and z1 are the actual coordinates of the defects in the forging, x2, y2, and z2 are the theoretical coordinates of the defects in the forging, F is the deformation during the bar forging process, and K and B are constants.

[0015] Preferably, in step 1, multiple defects are implanted at the center of the bar, at half the radius, and at a distance of 10mm from the edge. A three-dimensional spatial coordinate system is established with the center of the upper surface of the bar as the origin, and the position coordinates of each defect in the bar are determined.

[0016] Preferably, step 1 further utilizes ultrasonic detection to determine the location of the implanted defect in the rod, and corrects the determined defect location coordinates to determine the final defect location coordinates in the rod.

[0017] Preferably, in step 3, a three-dimensional spatial coordinate system is established with the center of the upper surface of the forging as the origin, and the position coordinates of each defect in the forging are determined.

[0018] This invention first addresses the difficulty in detecting defects in titanium alloys during actual production, and the resulting data is insufficient to support research on the accumulation of defect data in titanium alloys. It prepares titanium alloy forgings containing internal defects by artificially implanting defects. Subsequently, the defects within the defective bars and forgings are detected, and the positional changes of the defects during bar deformation are recorded. This establishes a method for predicting the positional changes of defects in titanium alloy materials that is compatible with my country's industrial level and technological characteristics, enabling the effective accumulation of defect data in titanium alloys. The method first records the position of defects within the bar, then forges the bar, recording the position of defects in the forging. The changes in defects during processing are analyzed to establish a method for predicting the positional changes of defects in titanium alloy materials. Its core idea is to address the entire material processing process: defect position in the bar → bar deformation process → defect position in the forging → relationship between defect position change and deformation process → connection between defect position change and the bar → tracing the position of defects in the bar based on the defect position in the forging. By recording and tracing the defects found during the testing process, defect data can be accumulated, providing technical and theoretical support for establishing an independent airworthiness system that matches my country's industrial level and technological characteristics.

[0019] The beneficial effects of adopting the above technical solution are as follows: This invention provides a method for predicting the change in the position of internal defects in titanium alloy forgings during the forging process. First, a three-dimensional rectangular coordinate system is established for the artificially implanted defect titanium alloy bar. By combining this with ultrasonic testing technology, the three-dimensional coordinates of the defect are constructed. Then, the titanium alloy bar containing the defect is forged under different forging deformation amounts. The three-dimensional coordinates of the internal defect in the formed forging are determined by ultrasonic testing technology. The maximum absolute value of the change in the three-dimensional coordinates of the theoretical and actual positions of the defects in the titanium alloy forging is used as the variable for the change in the defect position during the forging process. Using the deformation amount as a variable in the forging process, the variable for the change in the defect during the forging process is fitted with the forging deformation amount to obtain the relationship between the defect position and the macroscopic deformation function of the material during the processing of the titanium alloy bar into a forging. This can effectively establish a method for accumulating defect data in titanium alloy materials that is compatible with my country's industrial system, providing technical and theoretical support for establishing an independent airworthiness system that matches my country's industrial level and technological characteristics. Attached Figure Description

[0020] Figure 1 A flowchart illustrating a method for predicting the location changes of internal defects in titanium alloy forgings during the forging process, provided by an embodiment of the present invention;

[0021] Figure 2This is a schematic diagram of the location of defects in a titanium alloy bar provided in an embodiment of the present invention, wherein (a) is the bar before forging, (b) is a top view of the position coordinates of the defects in the bar, (c) is a front view of the position coordinates of the defects in the bar, and (d) is a left view of the position coordinates of the defects in the bar.

[0022] Figure 3 A schematic diagram of the ultrasonic testing results of the defect location in the forging provided in an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the position change of defects in a forging under 40% deformation provided in an embodiment of the present invention, wherein (a) is a forging under 40% deformation, (b) is a top view of the position coordinates of the defects in the forging, (c) is a front view of the position coordinates of the defects in the forging, and (d) is a left view of the position coordinates of the defects in the forging.

[0024] Figure 5 The graph showing the functional relationship between the defect location change and the forging deformation of titanium alloy is provided for the embodiments of the present invention. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0026] In this embodiment, a method for predicting the location changes of internal defects in titanium alloy forgings during the forging process is described, such as... Figure 1 As shown, it includes the following steps:

[0027] Step 1: Prefabricate titanium alloy bars containing multiple defects and establish a three-dimensional spatial coordinate system to determine the position coordinates of each defect;

[0028] This embodiment first prefabricates a TC4 titanium alloy rod containing internal defects. The rod has a diameter of 100mm and a height of 160mm. The location of the defects within the rod is as follows: Figure 2 As shown, nine defects were implanted at the center, half the radius, and 10mm from the edge. A three-dimensional rectangular coordinate system was established with the center of the circle on the upper surface of the bar as the origin to determine the position coordinates of each defect, such as the position coordinates of defect #1 being (40, 0, 80). Then, contact ultrasound was used to detect the defect positions and correct their coordinates.

[0029] Step 2: Forge the pre-made titanium alloy bar containing defects under different forging processes with different deformation amounts to obtain multiple titanium alloy forgings, with each deformation amount corresponding to one forging.

[0030] In this embodiment, four titanium alloy forgings were obtained by forging TC4 titanium alloy bars containing defects under forging processes with deformation amounts of 20%, 40%, 60%, and 80%.

[0031] Step 3: Use ultrasonic testing to detect the location of defects in the titanium alloy forging, establish a three-dimensional spatial coordinate system, and record the actual position coordinates of each defect in the forging;

[0032] For each formed titanium alloy forging, the location of defects was determined using ultrasonic testing technology. The ultrasonic testing results are as follows: Figure 3 As shown, a three-dimensional coordinate system is established using the center of the upper surface of the forging or another location as the origin, to determine the position coordinates of each defect in the forging.

[0033] Step 4: Determine the theoretical coordinates of each defect in the forging based on the forging deformation and the position coordinates of defects in the bar stock;

[0034] Step 5: Take the maximum absolute value of the change in the three-dimensional coordinates of the theoretical and actual positions of defects in the titanium alloy forging as the change in defect position during the forging process of titanium alloy bars.

[0035] In this embodiment, when the deformation is 40%, the defect locations detected by ultrasound in the forging after bar forging are as follows: Figure 4 As shown in Table 1, the changes in the coordinates of defects in the forging are as follows: the defect at radius 1 / 2 changes position more than the defects at other locations, with a maximum change of 14 mm.

[0036] Table 1. Changes in defect location after 40% deformation during forging

[0037]

[0038] Step 6: Fit the change in defect location during the forging process of titanium alloy bars with the deformation during the forging process to obtain a functional relationship model between the change in defect location and the deformation of the bars during the processing of titanium alloy bars into forgings, so as to realize the prediction of the change in defect location in titanium alloy forgings.

[0039] The maximum absolute value of the three-dimensional coordinate change corresponding to the theoretical and actual positions of defects in titanium alloy forgings is set as Max{(x1-x2),(y1-y2),(z1-z2)}. Using the bar deformation as a variable in the bar forging process, the change in defect position coordinates during the forging of TC4 titanium alloy bars is fitted with the bar deformation to obtain the following result: Figure 5 The functional relationship between the defect location and the deformation of the titanium alloy bar during the machining of the titanium alloy bar into a forging is shown in the following formula:

[0040] Max{(x1-x2),(y1-y2),(z1-z2)}=KF+B

[0041] Where x1, y1, and z1 are the actual coordinates of the defects in the forging, x2, y2, and z2 are the theoretical coordinates of the defects in the forging, F is the deformation during the bar forging process, and K and B are constants.

[0042] The three regions where the defect is located in the bar are the center, half radius, and edge. Since the position of the defect changes to different degrees during the forging process, the K and B constants in the function relationship are different when calculating the defect at the center, half radius, and edge using the above function relationship model.

[0043] When the deformation of the titanium alloy bar is known, the maximum value of the defect position change can be calculated by the method of predicting the change of defect position in the titanium alloy material according to the present invention, thereby tracing the position of the defect in the unforged titanium alloy bar and predicting the distribution position of the defect in the forging.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the claims of the present invention.

Claims

1. A method for predicting the location changes of internal defects in titanium alloy forgings during the forging process, characterized in that: Includes the following steps: Step 1: Prefabricate titanium alloy bars containing multiple defects and establish a three-dimensional spatial coordinate system to determine the position coordinates of each defect; Multiple defects were implanted at the center of the bar, at half the radius, and at a distance of 10 mm from the edge. A three-dimensional spatial coordinate system was established with the center of the upper surface of the bar as the origin to determine the position coordinates of each defect in the bar. The location of the defect implanted in the bar is detected by ultrasonic testing, and the coordinates of the determined defect location are corrected to determine the final coordinates of the defect location in the bar. Step 2: Forge the pre-made titanium alloy bar containing defects with different deformation amounts under different forging processes to obtain multiple titanium alloy forgings; Step 3: Use ultrasonic testing to detect the location of defects in the titanium alloy forging, establish a three-dimensional spatial coordinate system, and record the actual position coordinates of each defect in the forging; Step 4: Determine the theoretical coordinates of each defect in the forging based on the forging deformation and the position coordinates of defects in the bar stock; Step 5: Take the maximum absolute value of the change in the three-dimensional coordinates of the theoretical and actual positions of defects in the titanium alloy forging as the change in defect position during the forging process of titanium alloy bars. Step 6: Fit the change in defect location during the forging process of titanium alloy bars with the deformation during the forging process to obtain a functional relationship model between the change in defect location and the deformation of the bars during the process of processing titanium alloy bars into forgings, so as to realize the prediction of the change in defect location in titanium alloy forgings. The functional relationship between the change in defect location and the deformation of the rod during the machining of the titanium alloy bar into a forging is shown in the following formula: ； in, These are the actual coordinates of the defects in the forging. Let F be the theoretical coordinates of the defect in the forging, F be the deformation during the bar forging process, and K and B be constants.

2. The method for predicting the location change of internal defects in titanium alloy forgings during the forging process according to claim 1, characterized in that: Step 3 establishes a three-dimensional spatial coordinate system with the center of the upper surface of the forging as the origin, and determines the position coordinates of each defect in the forging.

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