Forging deformation range determination method for Ti17 alloy forged disc

Abstract

The invention provides a method for determining the forging deformation range of a Ti17 alloy forging disc, which comprises the following steps: carrying out numerical simulation according to the preset size and shape of the forging disc to obtain the distribution of equivalent strain of the forging disc; the Ti17 alloy bar is subjected to pre-forging, final forging and heat treatment, and a final forging piece of the forged disc piece is obtained; sampling different equivalent strain areas at different positions of the final forge piece to obtain a sample of the final forge piece, and carrying out mechanical property test and microscopic structure observation on the sample; determining the quantitative relationship between the equivalent strain of different positions of the final forging and the tested mechanical property and the qualitative relationship between the equivalent strain and the observed microscopic structure; according to the quantitative relation between the equivalent strain and the mechanical property and the qualitative relation between the equivalent strain and the microscopic structure, the equivalent strain range which is the deformation range suitable for forging of the integral forging disc piece made of the Ti17 alloy is determined.

Description

Technical Field

[0001] The present invention relates to the field of forging processes for engine disk parts, and particularly to a method for determining the forging deformation range of forged Ti17 alloy disks. Background Art

[0002] The large passenger aircraft engine is a typical high-bypass turbofan engine, and its development is to meet the power requirements of China's civil large aircraft. Compared with the large transport aircraft engine, the large passenger aircraft engine has higher requirements for longer life, higher reliability and economy. The high-pressure compressor disk is one of the key cold-end components of the large passenger aircraft engine, and according to airworthiness requirements, it should be able to be safely used under the condition of full decay while reaching the red-line temperature and red-line speed. Ti17 belongs to an α-rich near-β type titanium alloy, which has relatively high low-temperature strength, high toughness and high hardenability, and is used for large-section and high-load-bearing components such as fans and compressor disks. Its nominal phase transformation point is 890 °C, and the long-term use temperature can reach 427 °C. Compared with near-α titanium alloys, Ti17 does not have hold-time sensitivity when used in the low-temperature section.

[0003] With the increase in the bypass ratio of commercial engines, the engine performance, reliability and economy requirements increase. As the configuration size of parts increases and the structure becomes more complex, higher performance requirements are imposed on the compressor disk parts. Therefore, the performance requirements for forgings also increase. Summary of the Invention

[0004] Technical Problems to be Solved by the Invention

[0005] Forging large-size and complex-structured Ti17 compressor disks brings many problems: β forging requires a high billet heating temperature and has a narrow forging window; for complex-structured forgings, the deformation in each region is uneven, and deformation dead zones are likely to appear; in the microstructures at individual positions in the forging batch, the original β grains are recrystallized grains, which are coarse and equiaxed and do not meet the usage requirements; the mechanical properties of each region of the complex-structured disk vary greatly, and the consistency is poor.

[0006] In modern engine requirements, high reliability and stability are required for engine life-limiting parts, and both require the performance and microstructure consistency of forgings to be guaranteed. The forging process plays a crucial role in the consistency of forging performance.

[0007] The purpose of the present invention is to provide a method for determining the forging deformation range of Ti17 alloy forged disk parts. By establishing the relationship between the equivalent strain of numerical simulation, the measured mechanical properties, and the microstructure, an equivalent strain range of Ti17 that meets the design performance requirements of the compressor disk parts and is of high quality is obtained. At the same time, the quantitative relationship between the equivalent strain of the forging process numerical simulation and the mechanical properties is obtained. When mass-producing forgings or adjusting the process window, based on the characteristics of the microstructure of the test ring and the numerical values of the mechanical properties, a preliminary judgment on the performance of the forging body can be made without dissecting the forging, reducing time and economic costs. At the same time, it also guarantees the consistency of the forging performance.

[0008] Technical solution for solving the technical problem

[0009] According to one aspect of the present invention, there is provided a method for determining the forging deformation range of Ti17 alloy forged disk parts, characterized by comprising the following steps:

[0010] S1. Perform numerical simulation according to the preset size and shape of the forged disk part to obtain the distribution of the equivalent strain of the forged disk part;

[0011] S2. Perform pre-forging, finish-forging, and heat treatment on the Ti17 alloy bar to obtain the finish-forged part of the forged disk part;

[0012] S3. Take samples from different equivalent strain regions at different positions of the finish-forged part as the finish-forged part to obtain samples of the finish-forged part, and perform mechanical property tests and microstructure observations on the samples;

[0013] S4. Determine the quantitative relationship between the equivalent strain at different positions of the finish-forged part and the measured mechanical properties, and the qualitative relationship with the observed microstructure; and

[0014] S5. Determine the equivalent strain range that is the suitable forging deformation range of the overall forged disk part using the Ti17 alloy according to the quantitative relationship between the equivalent strain and the mechanical properties, and the qualitative relationship between the equivalent strain and the microstructure.

[0015] Thus, since the present invention obtains the equivalent strain through numerical simulation based on dimensions and shapes, the equivalent strain of the present invention can also be said to be obtained by considering different directions (helical direction, chordal direction, and radial direction). In addition, since the forging process parameters and procedures used in actual production are adopted for the Ti17 alloy bar, the obtained forgings are real forgings that can be actually used, rather than specimen parts for experimental tests, etc. Additionally, by determining the quantitative relationship between the equivalent strain at different positions of the final forging and the mechanical properties of the final forging, as well as the qualitative relationship with the microstructure of the final forging, the suitable forging deformation range, i.e., the range of the equivalent strain, of the integral forged disk made of the Ti17 alloy is determined, so as to directly guide the production of the integral forged disk of the Ti17 alloy. When mass-producing forgings or adjusting the process window, based on the characteristics of the microstructure of the test ring and the numerical values of the mechanical properties, a preliminary judgment on the properties of the forging body can be made without dissecting the forging, reducing time and economic costs. At the same time, it also guarantees the consistency of the forging properties.

[0016] In addition, according to an embodiment of one aspect of the present invention, preferably in step S5, the range of the equivalent strain is from 0.7 to 1.8.

[0017] According to an embodiment of one aspect of the present invention, preferably in step S5, the range of the equivalent strain is from 0.7 to 1.

[0018] According to an embodiment of one aspect of the present invention, preferably in step S5, the range of the equivalent strain is from 1.6 to 1.8.

[0019] Thus, forging of the forging body within the range of the equivalent strain from 0.7 to 1.8 can meet the design requirements and material standard requirements. At the same time, when the forging body is within the range of the equivalent strain from 0.7 to 1 and from 1.6 to 1.8, better forging properties and microstructures can be obtained.

[0020] According to any one of the above embodiments of one aspect of the present invention, preferably the forged disk is a single-stage integral blisk.

[0021] And preferably the single-stage integral blisk adopts specifications.

[0022] And preferably the mechanical properties of the single-stage integral blisk and the equivalent strain satisfy the following relationship, y = 147x 2 - 377x + 1388

[0023] where y is the tensile strength of the single-stage integral blisk and x is the equivalent strain.

[0024] According to any one of the above embodiments of one aspect of the present invention, preferably the forged disk is a two-stage integral blisk.

[0025] And preferably, the double-stage integral blisk adopts specifications.

[0026] And preferably, the mechanical properties of the double-stage integral blisk and the equivalent strain satisfy the following relationship: y = 42x 2 - 125x + 1260

[0027] where y is the tensile strength of the double-stage integral blisk and x is the equivalent strain.

[0028] Thus, by fitting the data of the equivalent strain and the tensile strength of the single-stage integral blisk and the double-stage integral blisk with different forging processes, a quantitative relationship between the equivalent strain and the mechanical properties is obtained, so as to be able to directly guide the selection of the Ti17 disk structure and the forging process.

[0029] Invention Effect

[0030] According to the present invention, it is possible to obtain a high-quality Ti17 equivalent strain range that meets the design performance requirements of the compressor disk by establishing the relationship between the numerically simulated equivalent strain and the measured mechanical properties and the microstructure. At the same time, a quantitative relationship between the numerically simulated equivalent strain and the mechanical properties of the forging process can be obtained. When mass-producing forgings or adjusting the process window, the properties of the forging body can be preliminarily judged according to the characteristics of the microstructure of the test ring and the numerical values of the mechanical properties, without dissecting the forging, reducing the time and economic costs. At the same time, it can also ensure the consistency of the forging properties. Brief Description of the Drawings

[0031] By describing the exemplary embodiments of the present disclosure in conjunction with the drawings, the present disclosure can be better understood. In the drawings:

[0032] Figure 1 is a flowchart of a method for determining the forging deformation range of a Ti17 alloy forging disk according to the present invention.

[0033] Figure 2 is a blank dissection diagram of a single-stage integral blisk and a double-stage integral blisk according to the present invention.

[0034] Figure 3 is the relationship between the tensile strength at different positions of a single-stage integral blisk and a double-stage integral blisk and the numerically simulated equivalent strain according to the present invention.

[0035] Figure 4 is the quantitative relationship between the tensile strength of a single-stage integral blisk and a double-stage integral blisk and the numerically simulated equivalent strain according to the present invention.

[0036] Figure 5 is the microstructure of a single-stage integral blisk under different equivalent strains according to the present invention. Specific Embodiment

[0037] Next, a preferred embodiment of the method for determining the forging deformation range of the forged Ti17 alloy disk is described with reference to the accompanying drawings.

[0038] Figure 1 is a flowchart of the method for determining the forging deformation range of the forged Ti17 alloy disk. As Figure 1 shown, the method for determining the forging deformation range of the forged Ti17 alloy disk includes the following steps.

[0039] S1. Perform numerical simulation according to the preset dimensions and shape of the forged disk to obtain the distribution of the equivalent strain of the forged disk. The preset dimensions and shape can be the dimensions and shape of a large-sized integral forged disk (integral part) for actual production pre-designed by a computer, such as a single-stage integral blisk, a two-stage integral blisk, etc. And, since the equivalent strain is obtained by numerical simulation based on the dimensions and shape, the equivalent strain of the present invention can also be said to be obtained by considering different directions (rotation direction, chord direction, and radial direction).

[0040] S2. Perform pre-forging, finish-forging, and heat treatment on the Ti17 alloy bar to obtain the finish-forged part of the forged disk. Here, since the forging process parameters and process used in actual production are adopted for the Ti17 alloy bar, the forged part obtained is a real forged part that can be actually used, rather than a specimen for experimental testing, etc. In addition, due to integral forging, the number of processes can be reduced, and the cost and production cycle can be lowered.

[0041] S3. Sample different equivalent strain regions at different positions of the finish-forged part as the finish-forged part to obtain samples of the finish-forged part, and perform mechanical property tests and microscopic structure observations on the samples.

[0042] S4. Determine the quantitative relationship between the equivalent strain at different positions of the finish-forged part and the measured mechanical properties, and the qualitative relationship with the observed microscopic structure.

[0043] S5. Determine the equivalent strain range that is the suitable forging deformation range of the integral forged disk using the Ti17 alloy according to the quantitative relationship between the equivalent strain and the mechanical properties, and the qualitative relationship between the equivalent strain and the microscopic structure.

[0044] By determining the quantitative relationship between the equivalent strain at different positions of the final forging and the mechanical properties of the final forging, as well as the qualitative relationship with the microstructure of the final forging, the appropriate forging deformation range, i.e., the range of the equivalent strain, for the integral forged disk made of the Ti17 alloy is determined, so as to directly guide the production of the integral forged disk of the Ti17 alloy. When mass-producing forgings or adjusting the process window, based on the characteristics of the microstructure of the test ring and the numerical values of the mechanical properties, a preliminary judgment on the properties of the forging body can be made without dissecting the forging, reducing time and economic costs. At the same time, it also guarantees the consistency of the forging properties.

[0045] Next, with reference to the attached Figures 2 - 5 , taking the forged disks as single-stage integral blisks and double-stage integral blisks as examples, their forging methods, mechanical properties and microstructures will be described respectively.

[0046] Example 1: Single-stage integral blisk

[0047] First, design a single-stage integral blisk actually used in an aircraft (such as Figure 2 the contour shown by the double-dot dash line in (a)), and numerically simulate the size and shape of the designed single-stage integral blisk through a numerical simulation model, etc., so as to obtain the distribution of the numerically simulated equivalent strain of the designed single-stage integral blisk. Among them, the numerically simulated equivalent strain is the equivalent strain described in the present invention.

[0048] Next, forge the single-stage integral blisk. Specifically, ① use α + β state Ti17 bar of a certain specification, upset the cake after holding at 40 °C below the phase transformation point for at least 175 min, and air cool after forging; ② forge in one heat after holding at 30 °C above the phase transformation point for at least 70 min, and air cool after forging; ③ solution treatment: 800 ± 10 °C, and hold for 240 min, water cool, transfer time ≤ 45 s; aging: 630 ± 6 °C, hold for 480 min, air cool.

[0049] Next, sample different positions, i.e., different equivalent strain regions, of the forging of the single-stage integral blisk obtained through the above forging to obtain samples of the forging of the single-stage integral blisk, and conduct mechanical property tests and microstructure observations on the above samples.

[0050] Specifically, Figure 3 shows the relationship between the tensile strength at different positions of the single-stage integral blisk and the double-stage integral blisk involved in the present invention and the numerically simulated equivalent strain. Figure 4 shows the quantitative relationship between the tensile strength of the single-stage integral blisk and the double-stage integral blisk involved in the present invention and the numerically simulated equivalent strain. Figure 5It is the microstructure of the single-stage blisk involved in the present invention under different equivalent strains. Here, the single-stage blisk is taken as an example for specific illustration, and the two-stage blisk will be elaborated later.

[0051] Figure 3 In it, the diamond solid pattern represents the single-stage blisk, the circular solid pattern represents the two-stage blisk, the horizontal axis represents the equivalent strain, and the vertical axis represents the strength (MPa). In addition, as Figure 3 shown, the tensile strength at different equivalent strains of the single-stage blisk is shown, and at the same time, the tensile strength at different positions under the same equivalent strain is also shown. For example, when the equivalent strain is 1.6, the tensile strengths at three different positions are measured respectively. As Figure 3 shown, the tensile strength of the single-stage blisk decreases with the increase of the equivalent strain within the equivalent deformation range of the forging, and reaches the lowest point at the equivalent strain of 1.2 and then increases. Thus, by fitting the above various numerical simulation equivalent strains and tensile strengths in the computer, the quantitative relationship between the numerical simulation equivalent strain and the tensile strength as shown in Figure 4 can be obtained as Equation (1).

[0052] y = 147x 2 -377x + 1388 ······ (1)

[0053] In addition, the microstructure of the sampling sample of the single-stage blisk is as Figure 4 shown. (a) When the numerical simulation equivalent strain is 0.875, the original β grains are elongated crystals, showing flat and long shapes, and the acicular α lamellae are woven in a certain direction. (b) When the numerical simulation equivalent strain is 1, the original β grains are elongated crystals, showing flat and long shapes, and the acicular α lamellae are woven in a certain direction. (c) When the numerical simulation equivalent strain is 1.2, the aspect ratio of the original β grains decreases, and the shape becomes flat and round. (d) When the numerical simulation equivalent strain is 1.4, the shape of the original β grains is similar to that at the equivalent strain of 1.2, the aspect ratio decreases, and the shape becomes flat and round, but the weaving condition of the acicular α lamellae is better. (e) When the numerical simulation equivalent strain is 1.6, the original β grains are elongated crystals, showing flat and long shapes, and the acicular α lamellae are woven in a certain direction. (f) When the numerical simulation equivalent strain is 1.8, the original β grains are elongated crystals, showing flat and long shapes, and the weaving condition of the acicular α lamellae is better.

[0054] Thus, through the above relationship between the equivalent strain and the tensile strength of the single-stage blisk, as well as the relationship between different equivalent strains and the microstructure, it can be evaluated that the forging of the forging body within the range of the numerical simulation equivalent strain from 0.7 to 1.8 meets the design requirements and the material standard requirements. However, in order to pursue better forging performance and microstructure, within the equivalent strain ranges of 0.7 to 1 and 1.6 to 1.8, the mechanical properties of the forging are higher, and the original β grains of the microstructure are flat and long, the aspect ratio is greater than 2, and the weaving condition of the acicular α lamellae is good.

[0055] Example 2: Two-stage blisk

[0056] Similar to the single-stage blisk in the above Example 1, first, a two-stage blisk actually used for an aircraft is designed (such as the contour shown by the double-dot dash line in (b) of Figure 2 ), and the size and shape of the designed two-stage blisk are numerically simulated through a numerical simulation model, etc., so as to obtain the distribution of the numerically simulated equivalent strain of the designed two-stage blisk. Among them, the numerically simulated equivalent strain is the equivalent strain described in the present invention.

[0057] Next, forging of the two-stage blisk is carried out. Specifically, ① Use α + β state Ti17 bar of specification, pre-forge for 1 heat after holding at 30 °C below the phase transformation point for 240 min, and air-cool after forging; ② Die-forge for 1 heat after holding at 30 °C above the phase transformation point for 140 min, and air-cool after forging; ③ Solution treatment: 800 ± 10 °C, and hold for 240 min, water-cool, transfer time ≤ 45 s; Aging: 630 ± 6 °C, hold for 480 min, air-cool.

[0058] Next, samples of the two-stage blisk are taken from different positions, that is, different equivalent strain regions, of the two-stage blisk obtained through the above forging to obtain samples of the two-stage blisk, and mechanical property tests and microscopic structure observations are carried out on the above samples.

[0059] Specifically, Figure 3 In, the circular solid pattern represents the two-stage blisk, showing the tensile strength at different equivalent strains of the two-stage blisk, and also showing the tensile strength at different positions under the same equivalent strain. As Figure 3 shown, the tensile strength of the two-stage blisk decreases as the equivalent strain increases within the equivalent deformation range of the forging until the equivalent strain reaches 1.4. Thus, by fitting the above various numerically simulated equivalent strains and tensile strengths in the computer, the quantitative relationship between the numerically simulated equivalent strain and the tensile strength as shown in Figure 4 can be obtained as Equation (2).

[0060] y = 42x 2 -125x + 1260 ······ (2)

[0061] In addition, the microscopic structure of the sampled samples of the two-stage blisk is the same as that of Figure 4The microstructures of the sampling samples of the single-stage integral blisk shown are the same. That is, when the numerical simulation equivalent strain is 0.875 and 1, the original β grains are elongated crystals, being flat, long, and the needle-like α lamellae are woven with a certain directionality. When the numerical simulation equivalent strain is 1.2, the aspect ratio of the original β grains decreases, and the morphology becomes flat and round. When the numerical simulation equivalent strain is 1.4, the morphology of the original β grains is similar to that at the equivalent strain of 1.2, the aspect ratio decreases, and the morphology becomes flat and round, but the needle-like α lamellae are woven better. When the numerical simulation equivalent strain is 1.6, the original β grains are elongated crystals, being flat, long, and the needle-like α lamellae are woven with a certain directionality. When the numerical simulation equivalent strain is 1.8, the original β grains are elongated crystals, being flat, long, and the needle-like α lamellae are woven better.

[0062] Thus, through the relationship between the above equivalent strain and tensile strength of the two-stage integral blisk, as well as the relationship between different equivalent strains and microstructures, it can be evaluated that the forging of the forging body within the range of the numerical simulation equivalent strain from 0.7 to 1.8 meets the design requirements and material standard requirements. However, in order to pursue better forging properties and microstructures, within the equivalent strain ranges of 0.7 to 1 and 1.6 to 1.8, the mechanical properties of the forging are higher, and the original β grains of the microstructure are flat and long, with an aspect ratio greater than 2, and the needle-like α lamellae are woven well.

[0063] The above lists the suitable forging ranges of the single-stage integral blisk and the two-stage integral blisk of the Ti17 alloy, that is, the range of equivalent strain. It can be seen that when the numerical simulation equivalent strain is lower than 1.2, obvious rules are presented in the forging body, showing a trend of decreasing strength with the increase of equivalent strain. Lower deformation can deform the original β grains without recrystallization and rapid growth. As the deformation increases, the original β grains grow and spheroidize, which will cause a corresponding decrease in strength. When the deformation exceeds 1.6, the original β grains are flattened and refined in weaving, and the strength will increase accordingly.

[0064] It should be understood that the above description is illustrative rather than restrictive. For example, the above embodiments (and / or aspects thereof) can be used in combination with each other. In addition, many modifications can be made without departing from the scope of the present invention to adapt a particular situation or material to the teachings of the various embodiments of the present invention. Although the size and type of the materials described herein are used to define the parameters of the various embodiments of the present invention, the various embodiments are not meant to be restrictive, but are exemplary embodiments. In light of the above description, many other embodiments will be apparent to those skilled in the art. Therefore, the scope of the various embodiments of the present invention should be determined with reference to the appended claims and the full scope of the equivalent forms claimed thereby.

Claims

1. A method for determining the forging deformation range of a forged Ti17 alloy disk component, characterized in that, it includes the following steps: S1. Perform numerical simulation according to the preset size and shape of the forged disk component to obtain the distribution of the equivalent strain of the forged disk component; S2. Perform pre-forging, final forging and heat treatment on the Ti17 alloy bar to obtain the final forging of the forged disk component; S3. Sample different equivalent strain regions at different positions of the final forging as the sample of the final forging, and conduct mechanical property tests and microstructural observations on the sample; S4. Determine the quantitative relationship between the equivalent strain at different positions of the final forging and the measured mechanical properties, and the qualitative relationship with the observed microstructure; and S5. According to the quantitative relationship between the equivalent strain and the mechanical properties, and the qualitative relationship between the equivalent strain and the microstructure, determine the equivalent strain range that is the suitable forging deformation range of the overall forged disk component using the Ti17 alloy.

2. The method for determining the forging deformation range of a forged Ti17 alloy disk component according to claim 1, characterized in that, in step S5, the range of the equivalent strain is from 0.7 to 1.

8.

3. The method for determining the forging deformation range of a forged Ti17 alloy disk component according to claim 2, characterized in that, in step S5, the range of the equivalent strain is from 0.7 to 1.

4. The method for determining the forging deformation range of a forged Ti17 alloy disk component according to claim 2, characterized in that, in step S5, the range of the equivalent strain is from 1.6 to 1.

8.

5. The method for determining the forging deformation range of a forged Ti17 alloy disk component according to any one of claims 1 to 4, characterized in that, the forged disk component is a single-stage integral blisk.

6. The method for determining the forging deformation range of a forged Ti17 alloy disk component according to claim 5, characterized in that, The single-stage integral blisk adopts specifications.

7. The method for determining the forging deformation range of a forged Ti17 alloy disk component according to claim 5, characterized in that, the mechanical properties of the single-stage integral blisk and the equivalent strain satisfy the following relationship, y = 147x 2 -377x + 1388 wherein, y is the tensile strength of the single-stage integral blisk, and x is the equivalent strain.

8. The method for determining the forging deformation range of a forged Ti17 alloy disk component according to any one of claims 1 to 4, characterized in that, the forged disk component is a two-stage integral blisk.

9. The method for determining the forging deformation range of a forged Ti17 alloy disk component according to claim 8, characterized in that, The double-stage integral blisk adopts specifications.

10. The method for determining the forging deformation range of a forged Ti17 alloy disk component according to claim 8, characterized in that, the mechanical properties of the two-stage integral blisk and the equivalent strain satisfy the following relationship, y = 42x 2 -125x + 1260 wherein, y is the tensile strength of the two-stage integral blisk, and x is the equivalent strain.

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