Method for optimizing titanium alloy cogging forging process parameters based on uniformity evaluation

Abstract

The application relates to a method for optimizing titanium alloy cogging forging process parameters based on uniformity evaluation, a reasonable numerical simulation process scheme is designed through an orthogonal design test method, finite element simulation technology is used for numerical simulation, appropriate numerical simulation characteristic points are selected, actual cogging forging temperature values and strain values corresponding to the numerical simulation characteristic points are calculated from numerical simulation test results, an evaluation model for measuring actual cogging forging temperature distribution uniformity and strain distribution uniformity in a large-diameter titanium alloy cogging forging process is proposed, and the numerical values of the actual cogging forging temperature distribution uniformity evaluation model F' T and the strain distribution uniformity evaluation model F' ε under different cogging forging process conditions are calculated, so that the cogging forging process parameters of the large-diameter titanium alloy material are optimized, and the microstructure distribution of the large-diameter titanium alloy material is uniform.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy materials technology, and specifically to a method for optimizing the process parameters of titanium alloy billet forging. Background Technology

[0002] Titanium alloys possess advantages such as high strength, excellent corrosion resistance, and high heat resistance, making them widely used in aerospace, shipbuilding and marine engineering, weaponry, nuclear energy, metallurgy, transportation, and other fields. Titanium alloys are typically produced by forging ingots. However, due to the unavoidable internal defects such as porosity, voids, and inclusions in titanium alloy ingots, especially severe defects in large-diameter ingots, a multi-step forging technique is necessary to effectively break down the coarse as-cast structure, heal internal porosity and voids, and refine the as-cast structure to obtain homogeneous and dense large-diameter titanium alloy materials. Because titanium alloys have high deformation resistance and poor fluidity, the forging temperature range is relatively narrow. The forging process for large-diameter titanium alloy materials is very complex, influenced by numerous factors, and requires cross-phase forging deformation, resulting in severe deformation inhomogeneity. This leads to uneven microstructure distribution, affecting the performance of large-diameter titanium alloy materials.

[0003] Reference 1, "Yu Dejun, et al. Finite element simulation of titanium alloy billet forging process [J]. Chinese Journal of Nonferrous Metals, 2010, 20(S1): 500-504," reports a three-dimensional thermo-mechanical coupling simulation of the forging process of large-size TA15 titanium alloy ingots using the elastoplastic finite element method. The simulation analyzes the variation laws of temperature, stress, and strain under different conditions and proposes adjustments to the TA15 titanium alloy billet forging process design based on comprehensive discussion and analysis. However, this method only visually analyzes and compares the uniformity of stress and strain distribution during the forging process of titanium alloy bars, without determining reasonable forging process parameter values.

[0004] Reference 2, "Xu Junyang. Optimization of TC6 Titanium Alloy Die Forging Process Based on Microstructure Uniformity Control. Shenyang: Master's Thesis, Shenyang University of Technology, 2014; 47-56," reports the use of Deform-3D software to perform finite element simulation of the forging process of TC6 titanium alloy blades. Combined with a BP neural network model, the effects of deformation rate, deformation temperature, die temperature, and friction coefficient on the α phase content and α phase size were obtained. Based on the comparative analysis of microstructure distribution, reasonable forging process parameters were determined. The BP neural network model can obtain the α phase content and α phase size values ​​under different combinations of process parameters, but it cannot scientifically judge the distribution uniformity, thus it cannot guarantee that the selected combination of forging process parameters is the optimal combination. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for optimizing titanium alloy forging process parameters based on uniformity evaluation, which can intuitively reflect the uniformity of the actual forging temperature and strain distribution of titanium alloy through data, thereby optimizing the forging process parameters and obtaining titanium alloy material with uniform deformation after forging.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for optimizing titanium alloy billet forging process parameters based on uniformity evaluation, comprising the following steps:

[0007] Step 1: Using finite element simulation software, obtain the numerical simulation values ​​of the actual billet forging temperature and strain under different combinations of billet forging temperature, forging speed, and reduction, and calculate the actual billet forging temperature distribution uniformity and strain distribution uniformity.

[0008] Step 2: Take the cross section of the titanium alloy material obtained under the different combined forging process conditions, and select multiple numerical simulation feature points on the cross section with the midpoint of the cross section as the starting point and the edge of the cross section as the ending point. Then calculate the actual forging temperature and strain value corresponding to the multiple numerical simulation feature points.

[0009] Step 3: Take the average actual forging temperature and strain values ​​on different directional lines, calculate the standard deviation of the actual forging temperature and strain on different directional lines, and thus establish an evaluation model for the uniformity of actual forging temperature and strain distribution during the titanium alloy forging process; substitute the uniformity values ​​of actual forging temperature distribution and strain distribution obtained in Step 1 into the evaluation model for the uniformity of actual forging temperature and strain distribution to calculate the numerical simulation values ​​of the uniformity of actual forging temperature and strain distribution.

[0010] Step 4: Substitute the actual billet forging temperature value of each numerical simulation feature point into the actual billet forging temperature distribution uniformity evaluation model to obtain the billet forging temperature distribution uniformity evaluation value corresponding to each numerical simulation feature point; the smaller the difference between the numerical simulation value of the actual billet forging temperature distribution uniformity evaluation model and the billet forging temperature distribution uniformity evaluation value, the more uniform the actual billet forging temperature distribution is during the titanium alloy billet forging process.

[0011] The forging strain value of each numerical simulation feature point is substituted into the forging strain distribution uniformity evaluation model to obtain the forging strain distribution uniformity evaluation value corresponding to each numerical simulation feature point. The smaller the difference between the numerical simulation value of the forging strain distribution uniformity evaluation model and the forging strain distribution uniformity evaluation value, the more uniform the strain distribution in the titanium alloy forging process.

[0012] By selecting the minimum or near-minimum evaluation values ​​for billet forging temperature and strain distribution uniformity, the optimal billet forging process parameters that achieve uniform actual billet forging temperature and strain distribution are obtained.

[0013] Furthermore, step one specifically includes:

[0014] 1) Using orthogonal design experimental method, numerical simulation process schemes for titanium alloy billet forging process were obtained by processing different combinations of billet forging processes.

[0015] 2) Using finite element simulation software, numerical simulation is performed on the numerical simulation process scheme to obtain the numerical simulation values ​​of the actual forging temperature and strain corresponding to each set of forging process conditions, and then the uniformity values ​​of the actual forging temperature distribution and strain distribution are calculated.

[0016] Furthermore, the forging temperature in the aforementioned billet forging process parameters is 840℃~870℃, and the forging speed is 30mm·s. -1 ~60mm·s -1 The compression amount is 100mm to 600mm.

[0017] Furthermore, the numerical simulation includes: establishing a geometric model of the titanium alloy billet forging process and mesh generation for the numerical simulation of the titanium alloy billet forging process in finite element simulation software.

[0018] Furthermore, the specific method for selecting multiple numerical simulation feature points on the cross-section of the titanium alloy material in step two is as follows:

[0019] Select the midpoint of the cross section of the titanium alloy material; with the midpoint as the starting point and the edge of the cross section of the titanium alloy material as the ending point, make at least one horizontal line, at least one vertical line, and at least one diagonal line between the horizontal and vertical lines, wherein the horizontal line is perpendicular to the vertical line; and uniformly select at least 8 feature points on the horizontal line, the vertical line, and the diagonal line, which are the selected numerical simulation feature points.

[0020] Furthermore, if the titanium alloy material has an octahedral or hexahedral structure, then the cross-section of the titanium alloy material is octagonal or hexagonal. In this case, the oblique line is at least one straight line that starts from the midpoint of the octagon or hexagon and ends at the vertex of the octagon or hexagon.

[0021] Furthermore, the formula (1) for calculating the standard deviation of the actual billet forging temperature along different directional lines in step three is as follows:

[0022]

[0023] In the formula, F lT , , representing the standard deviation of the actual forging temperature in the l, m, and n directions, respectively; i represents the numerical simulation feature points in the l, m, and n directions (i = 1, 2, ..., 8); N represents the number of numerical simulation feature points; T i T represents the actual forging temperature value corresponding to the feature point in the numerical simulation; ave The average actual forging temperature value corresponding to all numerical simulation feature points in a certain direction;

[0024] Formula (2) for calculating the standard deviation of forging strain in different directions is as follows:

[0025]

[0026] In the formula, F l ε , ε represents the standard deviation of the forging strain in the l, m, and n directions, respectively; i represents the numerical simulation feature points in the l, m, and n directions (i = 1, 2, ..., 8); N represents the number of numerical simulation feature points; ε i ε represents the forging strain value corresponding to the feature point in the numerical simulation. ave The average forging strain value corresponding to all numerical simulation feature points in a certain direction;

[0027] Furthermore, an evaluation model F′ for the uniformity of actual billet forging temperature distribution was established. T for:

[0028]

[0029] In the formula, F′ T F is the function of the uniformity of temperature distribution during actual billet forging; l T , These represent the standard deviations of the actual billet forging temperature in the l, m, and n directions, respectively.

[0030] The established evaluation model F′ for the uniformity of forging strain distribution ε for:

[0031]

[0032] In the formula, F′ ε F is the function for uniformity of strain distribution during billet forging; l ε , These are the standard deviations of the forging strain in the three directions of l, m, and n, respectively.

[0033] Furthermore, the titanium alloy material is a Φ400mm Ti-1300, TC4, TC18, or Ti1023 titanium alloy bar.

[0034] Furthermore, the titanium alloy material is a Φ400mm Ti-1300 titanium alloy bar, obtained by forging at initial forging temperatures of 840℃, 850℃, 860℃, and 870℃, and forging speeds of 30mm·s⁻¹ and 40mm·s⁻¹, respectively. -1 50mm·s -1 60mm·s -1 Sample data of actual forging temperature and strain distribution under forging process conditions with forging reduction of 300mm, 400mm, 500mm and 600mm.

[0035] Furthermore, the titanium alloy material is a 400mm TC18 titanium alloy bar, and the forging temperatures are 840℃, 850℃, 860℃, and 870℃, and the forging speed is 30mm·s. -1 40mm·s -1 50mm·s -1 60mm·s -1 Sample data of actual forging temperature and strain distribution under forging process conditions with forging reduction of 100mm, 120mm, 150mm and 180mm.

[0036] The beneficial effects of this invention are as follows: This method simultaneously considers the influence of actual forging temperature and strain distribution on the uniformity of actual forging temperature and strain distribution during the forging process of large-diameter titanium alloys. It designs a reasonable numerical simulation process scheme through orthogonal design experimental methods, conducts numerical simulation using finite element simulation technology, selects appropriate numerical simulation feature points, and calculates the actual forging temperature and strain values ​​corresponding to the numerical simulation feature points from the numerical simulation experimental results. It proposes an evaluation model to measure the uniformity of actual forging temperature and strain distribution during the forging process of large-diameter titanium alloys, and calculates the evaluation model F′ for the uniformity of actual forging temperature distribution under different forging process conditions. T And strain distribution uniformity evaluation model F′ ε The values ​​are used to optimize the forging process parameters of large-diameter titanium alloy materials, thereby making the microstructure of large-diameter titanium alloy materials more uniform. Attached Figure Description

[0037] Figure 1 A geometric model for numerical simulation of the titanium alloy billet forging process;

[0038] Figure 2 Mesh diagram for numerical simulation of titanium alloy billet forging process;

[0039] Figure 3 Feature points were selected for numerical simulation of the titanium alloy billet forging process. Detailed Implementation

[0040] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0041] To achieve the above objectives, the present invention provides the following specific embodiments:

[0042] Example 1: A method for optimizing titanium alloy billet forging process parameters based on uniformity evaluation, comprising the following steps:

[0043] Step 1: Select a Φ400mm Ti-1300, TC4, TC18, or Ti1023 titanium alloy bar. Use finite element simulation software to obtain different initial forging temperatures ranging from 840℃ to 870℃ and an initial forging speed of 30mm / s. -1 ~60mm·s -1 Numerical simulation values ​​of actual forging temperature and strain under combined forging process conditions with a forging reduction of 100mm to 600mm were obtained. The specific steps for obtaining the numerical simulation values ​​are as follows:

[0044] 1) Using orthogonal design experimental method, numerical simulation process schemes for titanium alloy billet forging process were obtained by processing different combinations of billet forging processes.

[0045] 2) Using finite element simulation software, numerical simulation of the numerical simulation process scheme is performed to obtain the numerical simulation values ​​of the actual forging temperature and strain corresponding to each set of forging process parameters.

[0046] The numerical simulation includes: establishing a geometric model of the titanium alloy billet forging process and mesh generation for the numerical simulation of the titanium alloy billet forging process in finite element simulation software.

[0047] The uniformity values ​​of actual forging temperature distribution and strain distribution are calculated based on the numerical simulation values ​​of actual forging temperature and strain.

[0048] Step 2: Take the cross section of the titanium alloy material obtained under the different combined forging process conditions, and select multiple numerical simulation feature points on the cross section with the midpoint of the cross section as the starting point and the edge of the cross section as the ending point. Then calculate the actual forging temperature and strain value corresponding to the multiple numerical simulation feature points.

[0049] The specific method for selecting multiple numerical simulation feature points on the cross-section of the titanium alloy material is as follows: select the midpoint of the cross-section of the titanium alloy material; take the midpoint as the starting point and the edge of the cross-section of the titanium alloy material as the ending point, respectively create at least one horizontal line, at least one vertical line, and at least one diagonal line between the horizontal and vertical lines, wherein the horizontal line is perpendicular to the vertical line; and uniformly select at least 8 feature points on the horizontal line, the vertical line, and the diagonal line, which are the selected numerical simulation feature points.

[0050] If the titanium alloy material has an octahedral or hexahedral structure, then the cross-section of the titanium alloy bar is octagonal or hexagonal. In this case, the oblique line is at least one straight line that starts from the midpoint of the octagon or hexagon and ends at the vertex of the octagon or hexagon.

[0051] Step 3: Take the average actual billet forging temperature and strain values ​​on different directional lines, calculate the standard deviation of actual billet forging temperature and strain on different directional lines, and thus establish an evaluation model for the uniformity of actual billet forging temperature and strain distribution during the billet forging process.

[0052] The formula (1) for calculating the standard deviation of the actual forging temperature along different directional lines is as follows:

[0053]

[0054] In the formula, F l T , , representing the standard deviation of the actual forging temperature in the l, m, and n directions, respectively; i represents the numerical simulation feature points in the l, m, and n directions (i = 1, 2, ..., 8); N represents the number of numerical simulation feature points; T i T represents the actual forging temperature value corresponding to the feature point in the numerical simulation; ave The average actual forging temperature value corresponding to all numerical simulation feature points in a certain direction;

[0055] Formula (2) for calculating the standard deviation of forging strain in different directions is as follows:

[0056]

[0057] In the formula, F l ε , ε represents the standard deviation of the forging strain in the l, m, and n directions, respectively; i represents the numerical simulation feature points in the l, m, and n directions (i = 1, 2, ..., 8); N represents the number of numerical simulation feature points; ε i ε represents the forging strain value corresponding to the feature point in the numerical simulation. ave The average forging strain value corresponding to all numerical simulation feature points in a certain direction;

[0058] Furthermore, an evaluation model F′ for the uniformity of actual billet forging temperature distribution was established. T for:

[0059]

[0060] In the formula, F′ T F is the function of the uniformity of temperature distribution during actual billet forging; l T , These represent the standard deviations of the actual billet forging temperature in the l, m, and n directions, respectively.

[0061] The established evaluation model F′ for the uniformity of strain distribution in billet forging ε for:

[0062]

[0063] In the formula, F′ ε F is the function for uniformity of strain distribution during billet forging; l ε , These are the standard deviations of the forging strain in the three directions of l, m, and n, respectively.

[0064] And based on the established evaluation model F′ for the uniformity of actual billet forging temperature distribution T Evaluation model F′ for uniform strain distribution in billet forging ε Substitute the actual billet forging temperature distribution uniformity value and strain distribution uniformity value obtained in step one into the actual billet forging temperature and strain distribution uniformity evaluation model to calculate the numerical simulation value of the actual billet forging temperature and strain distribution uniformity evaluation model.

[0065] Step 4: Substitute the actual billet forging temperature value of each numerical simulation feature point into the actual billet forging temperature distribution uniformity evaluation model to obtain the billet forging temperature distribution uniformity evaluation value corresponding to each numerical simulation feature point; the smaller the difference between the numerical simulation value of the actual billet forging temperature distribution uniformity evaluation model and the billet forging temperature distribution uniformity evaluation value, the more uniform the actual billet forging temperature distribution is during the titanium alloy billet forging process.

[0066] The forging strain value of each numerical simulation feature point is substituted into the forging strain distribution uniformity evaluation model to obtain the forging strain distribution uniformity evaluation value corresponding to each numerical simulation feature point. The smaller the difference between the numerical simulation value of the forging strain distribution uniformity evaluation model and the forging strain distribution uniformity evaluation value, the more uniform the strain distribution in the titanium alloy forging process.

[0067] By selecting the minimum or near-minimum evaluation values ​​for billet forging temperature and strain distribution uniformity, the optimal billet forging process parameters that achieve uniform actual billet forging temperature and strain distribution are obtained.

[0068] Example 2 is the same as Example 1, except that:

[0069] (1) The titanium alloy material is a Φ400mm Ti-1300 titanium alloy bar, and the forging temperatures are 840℃, 850℃, 860℃, and 870℃, and the forging speed is 30mm·s. -1 40mm·s -1 50mm·s -1 60mm·s -1 Numerical simulations of actual forging temperature and strain under forging conditions with reductions of 300mm, 400mm, 500mm, and 600mm were obtained, and the uniformity values ​​of actual forging temperature distribution and strain distribution were calculated based on these simulation values.

[0070] Specifically, the experimental data were obtained through orthogonal design experimental methods. The orthogonal experimental tables designed using this method are shown in Tables 1 and 2. (Refer to...) Figure 1 A geometric model of the titanium alloy billet forging process was established, referring to... Figure 2 Mesh generation was completed for the numerical simulation of the titanium alloy billet forging process. The Deform-3D numerical simulation software was used for numerical simulation. The numerical simulation obtained 16 sets of actual billet forging temperature and strain values ​​under different billet forging process conditions. The actual billet forging temperature and strain uniformity values ​​were calculated using the numerical simulation values ​​of actual billet forging temperature and strain.

[0071] (2) Select 8 feature points in each of the three directions of the titanium alloy material cross section. The selection of feature points is as follows: Figure 3 As shown, the actual forging temperature and strain values ​​of the corresponding characteristic points under different forging process conditions are calculated. Since the initial blank is an octagonal blank, the M direction is the direction passing through the vertex of the octagonal blank, that is, the angle with the L direction is 22.5°. If it is a hexagonal blank, the angle can be changed accordingly. The origin is the center of the octagonal blank, which is equidistant from the eight sides. If it is a hexagonal blank, the distance to the six sides is equal, and the corresponding changes can be made accordingly.

[0072] (3) Using the feature points selected in step (2), establish an evaluation model for the uniformity of the actual forging temperature distribution and the uniformity of the strain distribution during the titanium alloy forging process.

[0073] (4) Using the evaluation model established in step (3), the actual uniformity of the forging temperature distribution and the uniformity of the strain distribution during the forging process of Ti-1300 titanium alloy were predicted. The results are compared in Table 1 and Table 2.

[0074] Table 1 Comparison of numerical simulation results and model prediction results for the uniformity of actual billet forging temperature distribution of Ti-1300 titanium alloy material

[0075]

[0076]

[0077] Table 2 Comparison of numerical simulation results and model prediction results of strain distribution uniformity during the initial forging of Ti-1300 titanium alloy.

[0078]

[0079]

[0080] (5) Using the evaluation model F′ for the uniformity of actual billet forging temperature distribution established in step (4) T And strain distribution uniformity evaluation model F′ ε The numerical simulation values ​​obtained by substituting the actual forging temperature distribution uniformity and strain distribution uniformity values ​​into the formula were used to obtain the evaluation model F′ for the actual forging temperature distribution uniformity of Ti-1300 titanium alloy under different forging processes. T Numerical and strain distribution uniformity evaluation model F′ ε The numerical simulation values ​​are shown in Table 3.

[0081] Table 3 Numerical simulation values ​​of the uniformity of actual forging temperature and strain distribution in Ti-1300 titanium alloy materials.

[0082]

[0083]

[0084] (6) Evaluation model F′ of the actual forging temperature distribution uniformity during the forging process of Φ400mm Ti-1300 titanium alloy under different combinations of forging processes calculated in Table 3. T And strain distribution uniformity evaluation model F′ ε The actual forging process parameters for a relatively uniform initial forging temperature distribution are: forging temperature 840℃, forging speed 30mm·s. -1The forging process parameters for a billet with a reduction of 300mm and relatively uniform strain distribution are: forging temperature 850℃ and forging speed 50mm·s. -1 The reduction is 600mm.

[0085] Taking into account the uniformity of actual forging temperature distribution and strain distribution, the forging process parameters are: forging temperature 850℃, forging speed 40mm·s-1, and reduction 300mm.

[0086] This invention achieves the improvement of deformation non-uniformity in the forging process of Φ400mm titanium alloy by comprehensively considering the uniformity of the forging strain distribution and the uniformity of the actual forging temperature distribution, selecting the optimal forging process parameters corresponding to the relatively uniform actual forging temperature and strain distribution.

[0087] Example 3 is the same as Example 1, except that:

[0088] (1) The titanium alloy material is a 400mm TC18 titanium alloy bar, and the forging temperatures are 840℃, 850℃, 860℃, and 870℃, and the forging speed is 30mm·s. -1 40mm·s -1 50mm·s -1 60mm·s -1 Numerical simulations of actual forging temperature and strain under forging process conditions with forging reductions of 100mm, 120mm, 150mm, and 180mm were obtained, and the uniformity values ​​of actual forging temperature distribution and strain distribution were calculated based on these simulation values.

[0089] Specifically, the experimental data were obtained through orthogonal design experimental methods. The orthogonal experimental tables designed using these methods are shown in Tables 1 and 2. (Refer to...) Figure 1 A geometric model of the titanium alloy billet forging process was established, referring to... Figure 2 Mesh generation was completed for the numerical simulation of the titanium alloy billet forging process. The Deform-3D numerical simulation software was used for numerical simulation. The numerical simulation obtained 16 sets of actual billet forging temperature and strain values ​​under different billet forging process conditions. The actual billet forging temperature and strain uniformity values ​​were calculated using the numerical simulation values ​​of actual billet forging temperature and strain.

[0090] (2) Select 8 feature points in each of the three directions of the titanium alloy material cross section. The selection of feature points is as follows: Figure 3As shown, the actual forging temperature and strain values ​​of the corresponding characteristic points under different forging process conditions are calculated. Since the initial blank is an octagonal blank, the M direction is the direction passing through the vertex of the octagonal blank, that is, the angle with the L direction is 22.5°. If it is a hexagonal blank, the angle can be changed accordingly. The origin is the center of the octagonal blank, which is equidistant from the eight sides. If it is a hexagonal blank, the distance to the six sides is equal, and the corresponding changes can be made accordingly.

[0091] (3) Using the feature points selected in step (2), establish an evaluation model for the uniformity of the actual forging temperature distribution and the uniformity of the strain distribution during the titanium alloy forging process.

[0092] (4) Using the evaluation model established in step (3), the actual uniformity of the forging temperature distribution and the uniformity of the strain distribution during the forging process of TC18 titanium alloy were predicted. The results are compared in Tables 4 and 5.

[0093] Table 4 Comparison of numerical simulation results and model prediction results for the uniformity of actual billet forging temperature distribution in TC18 titanium alloy material.

[0094]

[0095]

[0096] Table 5 Comparison of numerical simulation results and model prediction results for the uniformity of strain distribution during the initial forging of TC18 titanium alloy.

[0097]

[0098]

[0099] (5) Using the evaluation model F′ for the uniformity of actual billet forging temperature distribution established in step (4) T And strain distribution uniformity evaluation model F′ ε The numerical simulation values ​​obtained by substituting the actual blanking forging temperature distribution uniformity and strain distribution uniformity values ​​obtained in step (1) into the formula are obtained, that is, the numerical simulation values ​​of the actual blanking forging temperature distribution uniformity and strain distribution uniformity of Ti-1300 titanium alloy material under different combined blanking forging processes are obtained.

[0100] (6) According to the different combinations of forging process parameters calculated in Tables 4 and 5, the forging process parameter combination with a relatively uniform actual forging temperature distribution during the forging of Φ400mm TC18 titanium alloy material is as follows: forging temperature 860℃, forging speed 50mm·s. -1 The forging process parameters for a billet with a reduction of 100mm and relatively uniform strain distribution are: forging temperature 850℃ and forging speed 50mm·s.-1 The reduction is 180mm.

[0101] Taking into account the uniformity of actual forging temperature distribution and strain distribution, the forging process parameters are: forging temperature 850℃, forging speed 40mm·s-1, and reduction 100mm.

[0102] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for optimizing titanium alloy billet forging process parameters based on uniformity evaluation, characterized in that, Includes the following steps: Step 1: Using finite element simulation software, obtain the numerical simulation values ​​of the actual billet forging temperature and strain under different combinations of billet forging temperature, forging speed, and reduction, and calculate the actual billet forging temperature distribution uniformity and strain distribution uniformity. Step 2: Take the cross section of the titanium alloy material obtained under the different combined forging process conditions, and select multiple numerical simulation feature points on the cross section with the midpoint of the cross section as the starting point and the edge of the cross section as the ending point. Then calculate the actual forging temperature and strain value corresponding to the multiple numerical simulation feature points. Step 3: Take the average actual forging temperature and strain values ​​on different directional lines, calculate the standard deviation of the actual forging temperature and strain on different directional lines, and thus establish an evaluation model for the uniformity of actual forging temperature and strain distribution during the titanium alloy forging process; substitute the uniformity values ​​of actual forging temperature distribution and strain distribution obtained in Step 1 into the evaluation model for the uniformity of actual forging temperature and strain distribution to calculate the numerical simulation values ​​of the uniformity of actual forging temperature and strain distribution. Among them, the formula (1) for calculating the standard deviation of the actual forging temperature on different directional lines is: ， （1） In the formula, , , , representing the standard deviation of the actual forging temperature in the l, m, and n directions respectively; i represents the numerical simulation feature points in the l, m, and n directions i=1,2,…,8; N represents the number of numerical simulation feature points; The actual forging temperature value corresponding to the feature point in the numerical simulation; The average actual forging temperature value corresponding to all numerical simulation feature points in a certain direction; Formula (2) for calculating the standard deviation of forging strain in different directions is as follows: ， （2） In the formula, , , , representing the standard deviation of forging strain in the three directions of l, m, and n respectively; i represents the numerical simulation feature points in the three directions of l, m, and n, i=1,2,…,8; N represents the number of numerical simulation feature points; The forging strain value corresponding to the feature point in the numerical simulation; The average forging strain value corresponding to all numerical simulation feature points in a certain direction; Furthermore, an evaluation model for the uniformity of actual billet forging temperature distribution was established. for: ， （3） In the formula, This is a function representing the uniformity of temperature distribution during actual billet forging. , , These represent the standard deviations of the actual billet forging temperature in the l, m, and n directions, respectively. Established evaluation model for uniformity of forging strain distribution for: ， (4) In the formula, For the uniformity of strain distribution during billet forging; , , These are the standard deviations of the forging strain in the three directions of l, m, and n, respectively. Step 4: Substitute the actual billet forging temperature value of each numerical simulation feature point into the actual billet forging temperature distribution uniformity evaluation model to obtain the billet forging temperature distribution uniformity evaluation value corresponding to each numerical simulation feature point; the smaller the difference between the numerical simulation value of the actual billet forging temperature distribution uniformity evaluation model and the billet forging temperature distribution uniformity evaluation value, the more uniform the actual billet forging temperature distribution is during the titanium alloy billet forging process. The forging strain value of each numerical simulation feature point is substituted into the forging strain distribution uniformity evaluation model to obtain the forging strain distribution uniformity evaluation value corresponding to each numerical simulation feature point. The smaller the difference between the numerical simulation value of the forging strain distribution uniformity evaluation model and the forging strain distribution uniformity evaluation value, the more uniform the strain distribution in the titanium alloy forging process. By selecting the minimum or near-minimum evaluation values ​​for billet forging temperature and strain distribution uniformity, the optimal billet forging process parameters that achieve uniform actual billet forging temperature and strain distribution are obtained.

2. The method for optimizing titanium alloy billet forging process parameters based on uniformity evaluation as described in claim 1, characterized in that, The first step is as follows: An orthogonal design experiment method was used to obtain a numerical simulation process scheme for the titanium alloy billet forging process by processing different combinations of billet forging processes. Finite element simulation software was used to perform numerical simulation on the numerical simulation process scheme to obtain the numerical simulation values ​​of the actual forging temperature and strain corresponding to each set of forging process conditions, and then the uniformity values ​​of the actual forging temperature distribution and strain distribution were calculated.

3. The method for optimizing titanium alloy billet forging process parameters based on uniformity evaluation as described in claim 2, characterized in that, The forging temperature in the forging process parameters is 840℃~870℃, and the forging speed is 30 mm·s. -1 ~60mm·s -1 The compression amount is 100 mm to 600 mm.

4. The method for optimizing titanium alloy billet forging process parameters based on uniformity evaluation as described in claim 2, characterized in that, The numerical simulation includes: establishing a geometric model of the titanium alloy billet forging process and mesh generation for the numerical simulation of the titanium alloy billet forging process in finite element simulation software.

5. The method for optimizing titanium alloy billet forging process parameters based on uniformity evaluation as described in claim 1, characterized in that, The specific method for selecting multiple numerical simulation feature points on the cross-section of the titanium alloy material in step two is as follows: Select the midpoint of the cross section of the titanium alloy material; with the midpoint as the starting point and the edge of the cross section of the titanium alloy material as the ending point, make at least one horizontal line, at least one vertical line, and at least one diagonal line between the horizontal and vertical lines, wherein the horizontal line is perpendicular to the vertical line; and uniformly select at least 8 feature points on the horizontal line, the vertical line, and the diagonal line, which are the selected numerical simulation feature points.

6. The method for optimizing titanium alloy billet forging process parameters based on uniformity evaluation as described in claim 5, characterized in that, If the titanium alloy material has an octahedral or hexahedral structure, then the cross-section of the titanium alloy material is octagonal or hexagonal. In this case, the oblique line is at least one straight line that starts from the midpoint of the octagon or hexagon and ends at the vertex of the octagon or hexagon.

7. The preferred method for titanium alloy billet forging process parameters based on uniformity evaluation as described in any one of claims 1-6, characterized in that, The titanium alloy material is a Φ400mm Ti-1300, TC4, TC18, or Ti1023 titanium alloy bar.

8. The method for optimizing titanium alloy billet forging process parameters based on uniformity evaluation as described in claim 7, characterized in that, The titanium alloy material is a Φ400mm Ti-1300 titanium alloy bar, obtained by forging at initial forging temperatures of 840℃, 850℃, 860℃, and 870℃, and forging speeds of 30mm·s⁻¹ and 40mm·s⁻¹, respectively. -1 50mm·s -1 60mm·s -1 Sample data of actual forging temperature and strain distribution under forging process conditions with forging reduction of 300mm, 400mm, 500mm and 600mm.

9. The preferred method for titanium alloy billet forging process parameters based on uniformity evaluation as described in claim 7, characterized in that, The titanium alloy material is a 400mm TC18 titanium alloy bar, and the forging temperatures obtained are 840℃, 850℃, 860℃, and 870℃, and the forging speed is 30mm·s. -1 40mm·s -1 50mm·s -1 60mm·s -1 Sample data of actual forging temperature and strain distribution under forging process conditions with forging reduction of 100mm, 120mm, 150mm and 180mm.

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