Method for determining the loading speed of superplastic forming of a nickel-based alloy disc and disc shaft
Patent Information
- Application Number
- CN202610987595.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-03
- Publication Date
- 2026-09-29
AI Technical Summary
现有研究虽已明确镍基合超塑性成形所需满足的微观组织前提（如细晶组织）及相应的应变速率窗口，但在具体的工艺实施层面，特别是对于盘/盘轴类构件的超塑性成形过程，其上模加载速度（即上模压下速度）的设定仍依赖现场工艺经验或基于总变形时间的粗略估算
本申请提供了一种镍基合金盘件与盘轴件超塑性成形加载速度确定方法，通过对镍基合金的原始锭坯进行开坯，得到镍基合金棒材，并对镍基合金棒材进行热模拟压缩实验，确定镍基合金棒材在不同变形条件下的应力-应变数据，进一步根据应力-应变数据对应的应变速率敏感指数，确定应变速率区间，根据应变速率与坯料填充模具的有效高度确定坯料填充模具的上模加载速度，使得盘件或盘轴件在成形过程中，应变速率始终维持在应变速率区间范围内，实现镍基高温合金盘件或盘轴件的超塑性成形，同时本申请能够精准控制镍基合金盘件或盘轴件超塑性成形的速度，提高盘件或盘轴件的性能均匀性和组织一致性，显著降低液压机吨位。
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Abstract
Description
Technical Field
[0001] This application relates to the field of materials heat treatment technology, and in particular to a method for determining the loading speed of superplastic forming of nickel-based alloy discs and disc shafts. Background Technology
[0002] Nickel-based superalloys (Ni-based alloys) have become the preferred material for key hot-end components such as turbine disks in modern aero-engines due to their excellent high-temperature strength, creep resistance, and fatigue resistance. With the continuous improvement of engine thrust-to-weight ratio, higher requirements are placed on the performance uniformity and microstructure consistency of turbine disk components. Although existing research has clarified the microstructural prerequisites (such as fine grain structure) and corresponding strain rate windows required for the superplastic forming of nickel-based alloys, at the specific process implementation level, especially for the superplastic forming process of disk / disk shaft components, the setting of the upper die loading speed (i.e., the upper die pressing speed) still relies on on-site process experience or a rough estimate based on the total deformation time. This speed curve design based on engineering experience lacks theoretical support and makes it difficult to ensure that the strain rate of each region within the blank can be maintained within the superplastic strain rate range throughout the entire deformation process. Once the strain rate deviates from the superplastic strain rate range, it may cause a surge in forming load and exacerbate die damage, thereby affecting the superplastic forming of disk / disk shaft components.
[0003] Therefore, based on the above problems, there is an urgent need to provide a method for determining the loading rate of superplastic forming of nickel-based alloy discs and disc shafts, which can maintain the strain rate of superplastic forming of nickel-based alloys by controlling the loading rate of the upper die, thereby improving the performance uniformity and microstructure consistency of discs and disc shafts. Summary of the Invention
[0004] The purpose of this application is to provide a method for determining the loading rate of superplastic forming of nickel-based alloy discs and disc shafts, which can maintain the strain rate of superplastic forming of nickel-based alloys by controlling the loading rate of the upper die, thereby improving the performance uniformity and microstructure consistency of nickel-based alloy parts.
[0005] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a method for determining the loading rate of superplastic forming of nickel-based alloy discs and disc shafts, including: The original nickel-based alloy ingot is cut into blanks to obtain nickel-based alloy bars; A thermal simulation compression test was conducted on the nickel-based alloy bar to determine the stress-strain data of the nickel-based alloy bar under different deformation conditions; Based on the strain rate sensitivity index corresponding to the stress-strain data, determine the strain rate range; and based on the strain rate range, determine the strain rate. Based on the superplastic deformation of the disc and the disc shaft, and considering the strain rate and the effective height of the blank filling mold, the upper mold loading speed of the blank filling mold is determined; the upper mold loading speed includes: the real-time loading speed of the upper mold and the initial loading speed of the upper mold.
[0006] According to the specific embodiments provided in this application, this application has the following technical effects: This application provides a method for determining the loading rate of superplastic forming of nickel-based alloy discs and disc shafts. The method involves preparing nickel-based alloy bars by cutting the original ingot blank, and conducting thermal simulation compression experiments on the bars to determine stress-strain data under different deformation conditions. Furthermore, based on the strain rate sensitivity index corresponding to the stress-strain data, a strain rate range is determined. The loading rate of the upper die of the blank filling die is then determined based on the strain rate and the effective height of the blank filling die. This ensures that the strain rate of the disc or disc shaft remains within the strain rate range during the forming process, achieving superplastic forming of nickel-based high-temperature alloy discs or disc shafts. Simultaneously, this application can precisely control the superplastic forming speed of nickel-based alloy discs or disc shafts, improving the performance uniformity and microstructure consistency of the discs or disc shafts, and significantly reducing the tonnage of the hydraulic press. Attached Figure Description
[0007] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0008] Figure 1 This is a schematic flowchart of a method for determining the superplastic forming loading speed of a nickel-based alloy disc and disc shaft in one embodiment of this application; Figure 2 This is a schematic diagram illustrating the positioning of the blank and the blank filling mold during mold assembly in one embodiment of this application; Figure 3 This is a schematic diagram showing the billet filling R1 in one embodiment of this application; Figure 4 This is a schematic diagram showing the billet filling R1 and the transition zone in one embodiment of this application; Figure 5 This is a schematic diagram illustrating the relationship between the real-time loading speed of the upper mold and the pressing stroke in one embodiment of this application; Figure 6 This is a schematic diagram of the forming of a blank disc in one embodiment of this application; Figure 7 This is a schematic diagram of the reverse extrusion steady-state extrusion process in one embodiment of this application. Detailed Implementation
[0009] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0010] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0011] In one exemplary embodiment, such as Figure 1 As shown, a method for determining the loading rate during superplastic forming of nickel-based alloy discs and disc shafts is provided, including the following S1 to S4. Wherein: S1: The original nickel-based alloy ingot is cut into blanks to obtain nickel-based alloy bars.
[0012] Specifically, a 2000t hydraulic press is used to perform hot extrusion on the original nickel-based alloy ingot to obtain fine-grained nickel-based alloy bars (also known as nickel-based high-temperature alloy bars). The hot extrusion process involves controlling the extrusion ratio and performing extrusion within the forging temperature range. The fine-grained structure requires a grain size smaller than a preset grain size threshold, which is 10μm. The microstructure of the nickel-based alloy bars in this application must meet the fine-grained structure requirements for superplastic forming.
[0013] S2: Conduct thermal simulation compression tests on nickel-based alloy bars to determine the stress-strain data of nickel-based alloy bars under different deformation conditions; Samples were cut from fine-grained nickel-based alloy bars, and thermal simulation compression tests were conducted on the nickel-based alloy bars using a thermal simulation compression testing machine (model Gleeble3500) to obtain stress-strain data under different deformation conditions (deformation temperature, initial strain rate, and deformation amount, etc.).
[0014] S3: Determine the strain rate range based on the strain rate sensitivity index corresponding to the stress-strain data; and determine the strain rate based on the strain rate range.
[0015] The strain rate sensitivity index (m value) is calculated based on the stress-strain data, and the initial strain rate with an m value in the range of 0.3 to 0.5 is taken as the strain rate range for superplastic deformation. The strain rate is determined based on the strain rate range.
[0016] S4: Based on the superplastic deformation of the disc and the disc shaft, and considering the strain rate and the effective height of the blank filling mold, determine the upper mold loading speed (i.e., the upper mold pressing speed) of the blank filling mold.
[0017] For the superplastic deformation of disc forging, the real-time loading speed of the upper die (i.e., the real-time pressing speed of the upper die) of the billet filling die is determined based on the strain rate and the effective height of the billet filling die. The calculation formula is as follows: ; in, For strain rate, To improve the real-time loading speed of the upper mold, The effective height for filling the mold with blank.
[0018] For the superplastic deformation of the disc shaft component under reverse extrusion, based on the strain rate and the size of the billet filling die, and based on the steady-state extrusion process, the initial loading speed of the upper die of the billet filling die (i.e., the initial pressing speed of the upper die) is determined, and the calculation formula is as follows: ; in, The initial loading speed of the upper mold. The diameter of the lower die. The diameter of the upper mold. denoted as strain rate.
[0019] In an exemplary embodiment, taking the die forging of a solid cylindrical billet as an example, the friction between the billet and the upper and lower dies is not considered, that is, the bulging that does not occur during the upsetting process, and the two sides of the billet remain in a vertical state during the upsetting deformation.
[0020] The original nickel-based alloy ingot was prepared by hot extrusion. The extrusion ratio was controlled and the extrusion was carried out within the forging temperature range to obtain fine-grained nickel-based superalloy extruded bars (nickel-based alloy bars). The average grain size of the microstructure of the nickel-based alloy bars was less than 10 μm, which meets the fine-grained microstructure requirements for superplastic forming.
[0021] Samples were cut from fine-grained nickel-based alloy bars, and thermally simulated compression experiments were conducted. Based on stress-strain data obtained under different deformation conditions, the corresponding strain rate sensitivity index (m value) was calculated; the initial strain rate with an m value in the range of 0.3 to 0.5 was considered as the strain rate range of superplastic deformation, and the strain rate was determined.
[0022] The real-time loading speed of the upper die is determined based on the relationship between the effective height and strain rate at different stages of the blank filling die (hereinafter referred to as the die). This ensures that the strain rate of the disc remains within the superplastic strain rate range during the forming process, thereby achieving superplastic forming of the nickel-based superalloy disc. The relationship between the effective height and the strain rate is as follows: ; in, For strain rate, To improve the real-time loading speed of the upper mold, This refers to the effective height during the upper die pressing process.
[0023] Specifically, when loading begins, the positioning of the blank and the mold is as follows: Figure 2 As shown, the billet is currently in region R1, and the effective height of the billet is equal to the height of the billet itself. When the upper die presses down, the billet begins to fill R1. The billet forming belongs to the upsetting deformation type, and the effective height of the billet is the real-time height of the billet. For example... Figure 3 As shown, when the upper die's lower stroke is When the right side of the billet reaches point A, it is considered that the billet has filled R1. At this time, the height of the billet is... , diameter is Based on the principle that the volume remains constant during the plastic deformation of materials, the initial height of the billet can be obtained. Initial diameter of billet billet height and billet diameter The relationship between them: .
[0024] Then the upper mold presses down the stroke for: .
[0025] like Figure 4 As shown, when the upper die continues to press down, the blank begins to fill the transition area, and the effective height at this time is the height of the right side of the blank; when the upper die presses down for a certain period of time... When the right side of the billet reaches point B, it is considered that the billet has filled the transition zone. At this time, the height of the right side of the billet is... The diameter of the upper end face is The diameter of the lower end face is Based on the principle that the volume remains constant during the plastic deformation of materials, we can obtain... , , , , The height difference between the two platforms of the lower mold and the upper mold The relationship between them: .
[0026] Then the upper mold presses the lower stroke for: .
[0027] As the upper die continues to press down, the billet begins to fill R2 until the disc forging is completed. At this point, the effective height of the billet is still the real-time height on the right side of the billet.
[0028] For the above-mentioned disc forging process, the effective height of the billet is divided into three stages, with a fixed strain rate of . Based on the relationship between strain rate and effective height during compression, the velocity curve of the upper die segment is obtained, and the upper die velocity is also divided into three stages.
[0029] Stage 1 (Blank Filling R1): The formula for calculating the real-time loading speed of the upper die during the blank forming process is as follows: , ; in, This refers to the real-time downward pressure stroke of the upper mold.
[0030] Phase Two (Blank Filling Transition Zone): The formula for calculating the real-time loading speed of the upper die during the blank forming process is as follows: ; ; ; ; ; in, This refers to the effective height during the upper die pressing process. The angle between the lower mold and the horizontal direction in the transition area. This is the combination of coefficients of the linear terms in Cardano's formula. This is an intermediate quantity used to determine the condition of the roots of the equation.
[0031] Therefore, it can be seen that in stage two, the loading speed of the upper mold and the stroke of the upper mold are not simply linearly related, which is detrimental to the execution and control of the control system in engineering practice. To improve the feasibility of the process, this embodiment modifies the relationship between the upper mold stroke and the speed of the upper mold in stage two. and The two corresponding velocity state points are linearly connected, and this connecting line segment is used as the upper mold velocity loading curve for stage two.
[0032] Stage 3 (Blank Filling R2): The formula for calculating the real-time loading speed of the upper die during the blank forming process is as follows: , .
[0033] In summary, the relationship between the upper die loading speed and the pressing stroke is obtained, as follows: Figure 5 As shown.
[0034] Not all disc forgings go through the three stages described above. For some blanks with a small height-to-diameter ratio, such as... Figure 6 As shown, it is assumed that the billet skips R1 and directly enters the transition zone at the beginning. Similarly, based on the principle of constant volume in the plastic forming process, the billet begins to enter R2 when the real-time loading speed of the upper die is calculated. Then, the real-time loading speed of the upper die is determined by the relationship between the effective height and the strain rate at different stages, so that the strain rate of the disc is within the range of the superplastic strain rate during the forming process, thereby realizing the superplastic forming of the nickel-based high-temperature alloy disc.
[0035] In an exemplary embodiment, for the reverse extrusion superplastic deformation of the disc shaft component, a hot extrusion process is used to open the original nickel-based alloy ingot. The extrusion ratio is controlled, and extrusion is carried out within the forging temperature range to obtain a fine-grained nickel-based superalloy extruded bar (nickel-based alloy bar); the average grain size of the microstructure of the nickel-based alloy bar is less than 10 μm, which meets the fine-grained microstructure requirements for superplastic forming.
[0036] Samples were cut from fine-grained nickel-based alloy bars, and thermally simulated compression experiments were conducted. Based on stress-strain data obtained under different deformation conditions, the corresponding strain rate sensitivity index (m value) was calculated. The initial strain rate with an m value in the range of 0.3 to 0.5 was considered as the strain rate range for superplastic deformation, and the strain rate was determined.
[0037] For the superplastic deformation of disc shaft components via reverse extrusion, based on the strain rate and the dimensions of the blank filling die, and considering the steady-state extrusion process, the initial loading speed of the upper die of the blank filling die is determined. This ensures that the strain rate of the disc shaft component remains within this superplastic strain rate range during the forming process, achieving superplastic forming of the nickel-based superalloy disc shaft component. The relationship between the initial loading speed of the upper die and the strain rate is as follows: ; in, The initial loading speed of the upper mold. The diameter of the lower die. The diameter of the upper mold. denoted as strain rate.
[0038] like Figure 7 As shown, according to the law of constant volume in metal plastic forming, the volume displaced by the initial compression of the upper die per unit time is equal to the volume extruded through the annular gap between the upper and lower dies. Therefore, the average speed of the annular gap extrusion can be obtained. With upper mold diameter Lower die diameter and the initial loading speed of the upper mold The relationship is calculated using the following formula: .
[0039] In the stable extrusion process of reverse extrusion, the main deformation zone mainly occurs in the annular gap between the upper and lower dies. In cylindrical coordinates, the velocity field of the main deformation zone can be approximately described as follows: the radial velocity is zero. ), circumferential velocity is zero ( ), axial velocity The velocity varies in the radial direction, that is... The equivalent strain rate can be obtained from the formula for calculating the equivalent strain rate of the main deformation zone. The formula is as follows: ; in, The axial strain rate is... Distance along the axis For circumferential strain rate, This is the distance from the axis. Radial strain rate, The radial-circumferential shear strain rate. The radial-axial shear strain rate. The circumferential-axial shear strain rate is given.
[0040] ; in, The equivalent rate of change, .
[0041] In the reverse extrusion process, the strain rate of uniform deformation along the z-axis is relatively small, while shear deformation plays a dominant role. Then the equivalent rate of change It can be considered as close as: .
[0042] Within the deformation zone, the axial velocity From the lower right end of the upper mold ( The speed changes rapidly from 0 to the exit area. )speed The radial velocity gradient can be approximated as the average gradient. Substituting this into the formula, we obtain the average equivalent strain rate during the back-extrusion process. The calculation formula is as follows: .
[0043] During the reverse extrusion process, the relationship between the initial loading speed of the upper die and the strain rate is as follows: .
[0044] in, The initial loading speed of the upper mold. The diameter of the lower die. The diameter of the upper mold. denoted as strain rate.
[0045] This application determines the upper die loading speed curve based on the relationship between the distance between the upper and lower dies and the strain rate when the billet fills different areas of the mold cavity. This ensures that the strain rate of the disc and disc shaft parts is within the superplastic strain rate range during the forming process, providing a reference for the design of loading speed curves for superplastic forming of nickel-based high-temperature alloy discs and disc shaft parts. This application can also be applied to the superplastic isothermal forging of discs with more complex cross-sections, while significantly reducing the tonnage of the hydraulic press and maintaining a uniform and fine grain structure during the superplastic isothermal forging process.
[0046] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0047] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A method for determining the loading rate of superplastic forming of nickel-based alloy discs and disc shafts, characterized in that, The method includes: The original nickel-based alloy ingot is cut into blanks to obtain nickel-based alloy bars; A thermal simulation compression test was conducted on the nickel-based alloy bar to determine the stress-strain data of the nickel-based alloy bar under different deformation conditions; Based on the strain rate sensitivity index corresponding to the stress-strain data, determine the strain rate range; and based on the strain rate range, determine the strain rate. Based on the superplastic deformation of the disc and the disc shaft, and considering the strain rate and the effective height of the blank filling mold, the upper mold loading speed of the blank filling mold is determined; the upper mold loading speed includes: the real-time loading speed of the upper mold and the initial loading speed of the upper mold.
2. The method for determining the superplastic forming loading rate of nickel-based alloy discs and disc shafts according to claim 1, characterized in that, The process of cutting the original nickel-based alloy ingot into nickel-based alloy bars specifically includes: The original nickel-based alloy billet is opened by hot extrusion process to obtain fine-grained nickel-based alloy rods; the grain size of the fine-grained material is smaller than the preset grain size threshold.
3. The method for determining the superplastic forming loading rate of nickel-based alloy discs and disc shafts according to claim 2, characterized in that, The preset grain size threshold is 10 μm.
4. The method for determining the superplastic forming loading rate of nickel-based alloy discs and disc shafts according to claim 1, characterized in that, A thermal simulation compression experiment was conducted on nickel-based alloy bars using a thermal simulation compressor.
5. The method for determining the superplastic forming loading rate of nickel-based alloy discs and disc shafts according to claim 1, characterized in that, The determination of the upper mold loading speed of the billet filling mold based on the superplastic deformation of the disc and disc shaft components, and considering the strain rate and the effective height of the billet filling mold, specifically includes: For superplastic deformation of disc forging, the real-time loading speed of the upper die of the billet filling die is determined based on the strain rate and the effective height of the billet filling die. For the superplastic deformation of the disc shaft component, the initial loading speed of the upper die of the billet filling die is determined based on the strain rate and the size of the billet filling die.
6. The method for determining the superplastic forming loading rate of nickel-based alloy discs and disc shafts according to claim 5, characterized in that, For the superplastic deformation of disc forging, the real-time loading speed of the upper die of the billet filling die is determined based on the strain rate and the effective height of the billet filling die, specifically including: Using formula Determine the real-time loading speed of the upper mold of the blank filling mold; in, For strain rate, To improve the real-time loading speed of the upper mold, The effective height for filling the mold with blank.
7. The method for determining the superplastic forming loading rate of nickel-based alloy discs and disc shafts according to claim 5, characterized in that, For the reverse extrusion superplastic deformation of the disc shaft component, the initial loading speed of the upper die of the billet filling mold is determined based on the strain rate and the size of the billet filling mold, specifically including: Using formula Determine the initial loading speed of the upper mold of the blank filling mold; in, The initial loading speed of the upper mold. The diameter of the lower die. The diameter of the upper mold. denoted as strain rate.