A method for predicting the size change of internal defects in titanium alloy forgings during forging

Abstract

The present invention provides a method for predicting the size change of internal defects of titanium alloy forgings during forging, and relates to the technical field of titanium alloy material processing and preparation. First, a titanium alloy bar containing defects is prefabricated, and forged under different forging processes to obtain a plurality of titanium alloy forgings containing defects; then the position of the defects in each titanium alloy forging is determined; the forging containing defects is processed into a small sample block, and the small sample block is detected by industrial CT to determine the defect volume under different forging deformations; the difference between the original defect volume size and the defect volume size under different forging deformations is obtained as a defect size change variable during the titanium alloy bar forging process; the defect size change variable is fitted with the deformation amount during the bar forging process to obtain a functional relationship model between the defect size change amount and the bar forging deformation amount, so as to realize the prediction of the defect size change in the titanium alloy forging.

Description

Technical Field

[0001] The invention relates to the technical field of titanium alloy material processing and preparation, and in particular to a method for predicting the size change of internal defects of a titanium alloy forging during a forging process. Background Art

[0002] The airworthiness regulations stipulate that "life-limited" parts must undergo appropriate damage tolerance assessments to determine the approved life of the parts. Research on the accumulation mechanism of airworthiness material defect data is carried out, and a life-limited parts defect database framework is established. By establishing a structured, standardized, and procedural data system, it can effectively support the product development of aircraft engines and improve the sharing efficiency of data resources. It plays an important supporting role in the safety life assessment of life-limited parts and lays a solid foundation for the high-reliability application of new materials and new processes in engines. Titanium alloy bars containing defects are prepared by artificially implanting defects, and then the bars containing defects are forged. By predicting the change in the size of the defects during the forging process of the bars, a defect data method that matches my country's industrial level and technical characteristics is established to achieve effective accumulation of defect data in titanium alloys. Provide technical and theoretical support for the establishment of an autonomous airworthiness system that matches my country's industrial level and technical characteristics. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for predicting the size changes of internal defects of titanium alloy forgings during the forging process in view of the deficiencies of the above-mentioned prior art, so as to realize the prediction of the size changes of internal defects of titanium alloy forgings during the forging process.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for predicting the size change of internal defects of titanium alloy forgings during forging, comprising the following steps:

[0005] Step 1: Prefabricate a titanium alloy bar containing defects;

[0006] Step 2: Forging the titanium alloy bar containing defects under different forging processes to obtain a plurality of titanium alloy forgings containing defects;

[0007] Step 3: Using ultrasound to detect the location of defects in each titanium alloy forging;

[0008] Step 4: Process the defective forging into a small sample block so that the defect is located at the center of the small sample block. Use industrial CT to detect the small sample block, record the diameter and height of the defect under different forging deformation amounts, and then determine the defect volume under different forging deformation amounts;

[0009] Step 5: Calculate the difference between the original defect volume size and the defect volume size under different forging deformation amounts as the defect size change variable during the titanium alloy bar forging process;

[0010] Step 6: Fit the defect size change variable during the titanium alloy bar forging process with the deformation of the bar forging process to obtain a functional relationship model between the defect size change during the process of processing the titanium alloy bar into a forging and the bar forging deformation, thereby realizing the prediction of defect size changes in titanium alloy forgings.

[0011] Preferably, the functional relationship model between the defect size change and the rod deformation during the process of processing the titanium alloy rod into a forging is shown in the following formula:

[0012] Max{(V1-V2)}=A*X+B*X 2 +C*X 3 +D

[0013] Among them, V1 is the defect volume in the forging; V2 is the original volume of the defect in the bar; X is the forging deformation of the bar; A, B, C, and D are constants.

[0014] Preferably, the size of the titanium alloy rod prefabricated in step 1 is 100 mm in diameter and 160 mm in height, and the size of the built-in defect is 4 mm in diameter and 4 mm in height.

[0015] Preferably, in step 2, the titanium alloy bar with built-in defects is forged at forging temperatures of 910° C., 930° C., 950° C., 970° C., and deformations of 20%, 40%, 60%, and 80%.

[0016] Preferably, in step 4, the forging is machined into a sample block of 20 mm×20 mm×25 mm, and the defect is located at the center of the sample block.

[0017] The method of the present invention first solves the problem that it is difficult to detect defects in titanium alloys in actual production, and the data obtained is difficult to support the research work on the accumulation of defect data in titanium alloys. A titanium alloy forging with defects is prepared by artificially implanting defects, and then the defects inside the forging are detected, and the size changes of the defects in the bar forging deformation are recorded, so as to establish a defect size change prediction method that matches my country's industrial level and technical characteristics, and realize the effective accumulation of defect data in titanium alloys. The method first records the size of the defects built into the bar, then forges the bar, records the size of the defects in the forging, analyzes the size changes of the defects during the processing, and establishes a model for predicting the size changes of defects inside titanium alloy forgings during the forging process. The core idea is that for the entire processing process of the material: the size of the defect in the bar → the deformation process of the bar → the size of the defect in the forging → the relationship between the defect size change and the deformation process → the size of the defect in the bar is traced according to the defect size in the forging and the forging process. The defects in the detection process are recorded and traced by the model, so as to accumulate the defect data, providing technical and theoretical support for the establishment of an autonomous airworthiness system that matches my country's industrial level and technical characteristics.

[0018] The beneficial effects of the above technical scheme are as follows: the present invention provides a method for predicting the change in the size of internal defects of titanium alloy forgings during the forging process, first recording the original size of the defect, then forging the titanium alloy bar containing defects under different forging deformation amounts and deformation conditions, and determining the approximate location of the internal defects by ultrasonic detection technology for the formed forgings, and then detecting the defect size in the forgings by CT, calculating the difference in the volume of the defect before and after deformation as the change in defect size; fitting the defect size change variable during the forging process of the titanium alloy bar with the forging deformation, and obtaining a model of the functional relationship between the defect size and the macroscopic deformation of the material during the processing of the titanium alloy bar into a forging, thereby realizing the prediction of the change in defect size. The method of the present invention can effectively establish a method for accumulating defect data in titanium alloy materials that is compatible with my country's industrial system, and provide technical and theoretical support for establishing an autonomous airworthiness system that matches my country's industrial level and technical characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A flow chart of a method for predicting the change in internal defect size of a titanium alloy forging during a forging process provided by an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of a sample block processing process provided by an embodiment of the present invention;

[0021] Figure 3 A CT inspection result diagram of defect size in a forging provided in an embodiment of the present invention;

[0022] Figure 4 A schematic diagram of a functional relationship model between the defect size change and the bar forging deformation provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0024] In this embodiment, a method for predicting the size change of internal defects of a titanium alloy forging during a forging process is provided. Figure 1 As shown, the following steps are included:

[0025] Step 1: Prefabricate a titanium alloy bar containing defects;

[0026] In this embodiment, the dimensions of the prefabricated titanium alloy rod are 100 mm in diameter and 160 mm in height, and a defect is implanted at the center of the rod, and the defect dimensions are 4 mm in diameter and 4 mm in height.

[0027] Step 2: Forging the titanium alloy bar containing defects under different forging processes to obtain a plurality of titanium alloy forgings containing defects;

[0028] In this embodiment, the titanium alloy bar with built-in defects is forged at forging temperatures of 910° C., 930° C., 950° C., and 970° C. and deformations of 20%, 40%, 60%, and 80%.

[0029] Step 3: Using ultrasound to detect the location of defects in each titanium alloy forging;

[0030] Step 4: Use machining to process the defective forging into a sample block of 20 mm × 20 mm × 25 mm, so that the defect is located at the center of the sample block, and use industrial CT to detect the sample block, record the diameter and height of the defect under different forging deformation amounts, and then determine the defect volume under different forging deformation amounts;

[0031] In this embodiment, ultrasonic testing is first used to roughly determine the approximate location of the defect in the forging, and then the forging is machined into a sample block of 20 mm × 20 mm × 25 mm. The machining process is as follows: Figure 2 As shown in the figure, the defect is located in the center of the sample block, and the surface roughness of the sample block is Ra<1.6. Then industrial CT is used for testing. The testing instrument is industrial CT non-destructive testing analysis system Y.CT Modular. The test is carried out in accordance with GBT / 12604.2-2005 non-destructive testing terminology radiography technology. The test results are as follows Figure 3As shown in Table 1, the defect diameter after deformation is 4.06 mm and the height is 3.60 mm. Finally, the volume change value corresponding to the defect in the titanium alloy forging is used as the defect size change variable during the forging process of the titanium alloy bar, as shown in Table 1.

[0032] Table 1 Changes in defect size after forging under different forging processes

[0033]

[0034]

[0035] Step 5: Calculate the difference between the original defect volume size and the defect volume size under different forging deformation amounts as the defect size change variable during the titanium alloy bar forging process;

[0036] Step 6: Fit the defect size change variable during the titanium alloy bar forging process with the deformation of the bar forging process to obtain a functional relationship model between the defect size change during the process of processing the titanium alloy bar into a forging and the bar forging deformation, thereby realizing the prediction of defect size changes in titanium alloy forgings.

[0037] In this embodiment, the functional relationship model between the defect size change and the bar deformation during the process of processing the titanium alloy bar into a forging is shown in the following formula:

[0038] Max{(V1-V2)}=A*X+B*X 2 +C*X 3 +D

[0039] Among them, V1 is the defect volume in the forging; V2 is the original volume of the defect in the bar; X is the forging deformation of the bar; A, B, C, and D are constants, which are determined by fitting the defect size change variables during the forging process of the titanium alloy bar and the deformation of the bar during the forging process.

[0040] In this embodiment, the deformation of the rod is used as a variable in the rod forging process, and the defect size change variable in the titanium alloy rod forging process is fitted with the forging deformation to obtain a model of the functional relationship between the defect size change and the macroscopic deformation of the material in the process of processing the titanium alloy rod into a forging, such as Figure 4 When the deformation of the titanium alloy bar is known, the model can be used to predict the change in defect size, so that after the defect is found in the forging, the size of the defect in the bar can be traced back according to the defect size in the forging, and then the characteristics of the defect can be determined.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. However, these modifications or replacements 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 size change of internal defects of titanium alloy forgings during forging, characterized in that: The following steps are involved: Step 1: Prefabricate a titanium alloy bar containing defects; Step 2: Forging the titanium alloy bar containing defects under different forging processes to obtain a plurality of titanium alloy forgings containing defects; Step 3: Using ultrasound to detect the location of defects in each titanium alloy forging; Step 4: Process the defective forging into a small sample block so that the defect is located at the center of the small sample block. Use industrial CT to detect the small sample block, record the diameter and height of the defect under different forging deformation amounts, and then determine the defect volume under different forging deformation amounts; Step 5: Calculate the difference between the original defect volume size and the defect volume size under different forging deformation amounts as the defect size change variable during the titanium alloy bar forging process; Step 6: Fit the defect size change variable during the titanium alloy bar forging process with the deformation of the bar forging process to obtain a functional relationship model between the defect size change during the titanium alloy bar forging process and the bar forging deformation, thereby realizing the prediction of defect size change in titanium alloy forgings; The functional relationship model between the defect size change and the bar deformation during the titanium alloy bar is processed into a forging is shown in the following formula: Max{(V1-V2)}= A*X +B* X 2 +C* X 3 +D Among them, V1 is the defect volume in the forging; V2 is the original volume of the defect in the bar; X is the forging deformation of the bar; A, B, C, and D are constants.

2. The method for predicting the size change of internal defects of a titanium alloy forging during forging according to claim 1, characterized in that: The size of the titanium alloy rod prefabricated in step 1 is 100 mm in diameter and 160 mm in height, and the size of the built-in defect is 4 mm in diameter and 4 mm in height.

3. The method for predicting the size change of internal defects of a titanium alloy forging during forging according to claim 2, characterized in that: In the step 2, the titanium alloy bar with built-in defects is forged at forging temperatures of 910° C., 930° C., 950° C., and 970° C. and deformations of 20%, 40%, 60%, and 80%.

4. The method for predicting the size change of internal defects of a titanium alloy forging during forging according to claim 3, characterized in that: In step 4, the forging is machined into a sample block of 20 mm×20 mm×25 mm, and the defect is located at the center of the sample block.

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