Design method of replaceable protective shell suitable for high-temperature alloy forging die
By constructing a comprehensive simulation model and area division, a replaceable protective shell suitable for high-temperature alloy forging dies is designed, which solves the problem of forging dies being easily damaged at high temperatures, improves the quality of forging parts and the life of forging dies, and reduces costs.
Patent Information
- Application Number
- CN202411357092.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-27
- Publication Date
- 2024-12-27
AI Technical Summary
High-temperature alloy forging dies are prone to collapse, cracks and surface wear during the manufacturing process, resulting in high cost, poor quality and short life. It is difficult for the existing technology to effectively solve these problems.
The replaceable protective shell design method is adopted to build a comprehensive simulation model, analyze stress, temperature field and wear, divide different areas, and design protective shells according to material selection, thickness and shape, to improve the heat resistance and service life of the forging die.
It effectively improves the quality of high-temperature alloy forgings, extends the service life of the forging die, reduces the production cost of the forging die, and optimizes heat transfer, stress and wear control through physical experiments, and improves the use effect of the protective shell.
Smart Images
Figure CN119203684A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of high-temperature alloy forging dies, and in particular to a design method for a replaceable protective shell suitable for a high-temperature alloy forging die. Background Art
[0002] Turbine discs, compressor discs and other high-temperature alloy disc forgings are important hot-end load-bearing components in gas turbine and aircraft engines, and are widely used in aerospace, national defense, energy industry, and shipbuilding industries. However, my country's current manufacturing and production capacity for high-temperature alloy forgings is seriously insufficient, and it faces problems such as high forging costs and poor quality. The most important limiting factor is the high-temperature alloy forging die manufacturing technology. Due to the high flow stress and narrow processing temperature range of high-temperature alloys, the forging die needs to withstand extremely high thermal loads, and is prone to collapse, cracks and failure. In addition, my country generally uses soft sleeve technology, which causes severe wear on the forging die surface, resulting in high forging die cost and low life.
[0003] In recent years, some optimization methods have emerged, such as: a manufacturing method for forging die design from the perspective of forging die structure design, which aims to select different materials for forging die manufacturing according to different working areas of the forging die; a metal protective shell forging die protection method, which aims to use a sheet metal part with the shape of a forging die cavity as a protection process for the forging die, fix a metal protective shell on the forging die before forging, and then directly carry out forging production. After a certain number of forgings, the protective shell fails and is removed, and the forging die is replaced with a new protective shell for continued use. These methods can save costs, reduce wear, and increase life to a certain extent.
[0004] Therefore, based on the metal protective shell forging die protection technology and according to the manufacturing concept of forging die partitioning, the present invention proposes a design method for a replaceable protective shell, aiming to improve the quality of high-temperature alloy forgings, extend the life of the forging die, and reduce the cost of the forging die. Summary of the invention
[0005] The present invention aims to provide a design method for a replaceable protective shell suitable for a high-temperature alloy forging die, thereby improving the quality of high-temperature alloy forgings, extending the life of the forging die, and reducing the cost of the forging die.
[0006] In order to achieve the above object, the present invention provides the following technical solutions:
[0007] A design method for a replaceable protective shell suitable for a high-temperature alloy forging die comprises the following steps:
[0008] S1. Construct a comprehensive simulation model of replaceable layers based on basic experiments;
[0009] S2, analyze the stress, temperature field and wear of the model and divide the replaceable layer into regions;
[0010] S3, refine according to the failure distribution of replaceable layers and the zoning of working areas;
[0011] S4. Design the protective case from three aspects: material selection, thickness design and shape design.
[0012] Furthermore, the protective shell is designed with material selection from different partitions.
[0013] Furthermore, the basic experiments in step S1 include heat transfer experiments, metal bending experiments, and replaceable layer friction and wear experiments, and the replaceable layer comprehensive simulation model includes a thermal-mechanical coupling finite element simulation model and a friction and wear finite element simulation model.
[0014] Furthermore, the area division in step S2 includes a substrate area and a working area.
[0015] Furthermore, in step S3, the working area is subdivided according to the temperature and stress changes in the model.
[0016] Furthermore, in step S3, the region is divided into a multiple failure region, a wear region, a plastic deformation region and an easy-to-break region.
[0017] Principle and beneficial effects of the technical solution: The method of the present invention first reveals the thermodynamic principle of the replaceable protective forging die, establishes a thermodynamic model, and integrates the thermomechanical coupling calculation model and wear model of forging with replaceable layers; then, through forging scale-down experiments, the material flow law and deformation behavior of the replaceable layer in the high-temperature alloy forging process are explored, the influence of the deformation of the replaceable layer on the forging is clarified, and a method for controlling the deformation of the replaceable layer to ensure the quality of the forging is proposed, and the manufacturing parameters and boundary condition design rules of the replaceable layer are obtained. The method of the present invention makes reasonable improvements on basic physical experiments, designs and innovates physical experiments for studying heat transfer, stress, friction and wear during forging, and proposes and establishes the use parameters and design rules for replaceable layer manufacturing based on the experiments, which can further improve the use effect of the metal protective shell, thereby improving the quality of forgings, extending the life of the forging die, and reducing the cost of the forging die. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 A process diagram of a method for protecting a metal protective shell forging die;
[0019] Figure 2 A flow chart of the protective shell design method of the present invention;
[0020] Figure 3 Schematic diagram of the basic experiment in step 1 of the present invention, a is a heat transfer experiment, b is a bending experiment, c is a friction coefficient experiment, and d is a wear experiment.
[0021] Figure 4 This is a forging experiment diagram of a cross-shaped disk member using a protective shell of the present invention;
[0022] Figure 5 The figure is a schematic diagram of the force applied to the shape of the protective shell of the present invention. DETAILED DESCRIPTION
[0023] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:
[0024] like Figure 1 The figure shows the metal protective shell forging die protection method mentioned in the background technology, which uses a sheet metal part with a forging die cavity shape as the protective shell of the forging die, fixes the metal protective shell on the forging die before forging, and then directly forges the production. After a certain number of forgings, the protective shell fails and is taken out, and the forging die is replaced with a new protective shell for continued use. The present invention proposes a process method for designing a protective shell.
[0025] like Figure 2 FIG. 1 is a flow chart of a design method of a replaceable protective shell suitable for a high-temperature alloy forging die according to the present invention, comprising the following steps:
[0026] 1. Constructing a comprehensive simulation model with replaceable layers based on basic experiments
[0027] Basic experiments such as Figure 3 As shown, including the use of Figure 3 The heat transfer model of the replaceable layer is constructed by the heat transfer experiment of the blank, replaceable layer, and forging die substrate shown in a). Figure 3 b) shows a metal bending experiment with replaceable layers to construct a replaceable layer stress model. The heat transfer model and the replaceable layer stress model jointly construct a thermal-mechanical coupling finite element model. Figure 3 c) and Figure 3 d) The metal friction and wear experiment with replaceable layers constructs a replaceable layer friction and wear finite element model, and the thermal-mechanical coupling model and the friction and wear finite element model are combined to obtain a comprehensive simulation model of the replaceable layer.
[0028] 2. Analyze the stress, temperature field and wear of the model and divide the replaceable layers into regions
[0029] The obtained replaceable layer model is subjected to distribution trend analysis of stress field and temperature field, including equivalent stress distribution and maximum stress distribution. The equivalent stress distribution characterizes the stress condition of each unit of the mold and replaceable layer, including shear force and principal stress, while the maximum stress can characterize the tensile and compressive stress condition of each part of the mold and replaceable layer. The wear of the mold and replaceable layer and the cumulative stress of the maximum stress section of the mold and replaceable layer are analyzed.
[0030] By combining the temperature and stress distribution in the finite element simulation, as well as the wear of the replaceable layer, we can obtain the different thermal load conditions and possible failure forms of different parts of the replaceable layer during its service, and divide the replaceable layer into regions based on this.
[0031] For the analysis of stress field, determining the standard for dividing the area is the most important issue. Different materials have different yield strengths and their ability to withstand pressure is also different. Therefore, it is necessary to analyze in combination with the performance parameters of the material. The principle of selecting the material of the matrix is to try to choose a material with lower value under the premise of meeting the use conditions. Therefore, a matrix material with lower value is pre-selected first, and the relationship between the yield strength and temperature of this material is determined according to the mechanical characteristic curve of the material. s (T), and considering the effect of stress superposition, the formula for the accumulation of the replaceable layer force σ can be obtained by fitting the stress accumulation curve at the maximum cumulative stress point on the surface of the replaceable layer cavity: n By simulating stress analysis, the stress distribution of the replaceable layer σ(T) can be obtained. Then σ(T)≤σ s (T)-σ n The area is defined as the base area, and the working area and the base area can be divided. Then the working area is subdivided.
[0032] 3. Refinement based on the distribution of replaceable layer failures and work area zoning
[0033] The main failure modes in hot forging are wear, thermal fatigue, plastic deformation and fracture.
[0034] The temperature change of a certain point in the replaceable protective shell during a forging working cycle is defined as ΔTi, then ΔTi=2Tia=Timax-Timin, where Tia is the temperature amplitude of a certain point.
[0035] Multiple failure zone: This area is located on the surface of the replaceable layer. It has the highest service temperature and the largest temperature fluctuation in the mold parts. There are many failure problems that are prone to occur, such as low-cycle fatigue caused by temperature fluctuations, plastic deformation caused by high temperature softening, angle collapse, and severe wear, etc., and it is also subject to strong unidirectional compressive stress. Multiple failure zone division standard: The part with ΔTi>10℃ is defined as the multiple failure zone.
[0036] Wear zone: This area is located on the surface of the replaceable layer, and is in direct contact with the blank or will be in direct contact with the mold during the service life of the mold; the highest temperature and temperature fluctuation during the service process are second only to the multiple failure zone; the main failure form is wear. Wear zone classification standards: 1. The area with a depth of ≥1mm from the surface of the replaceable layer cavity (the part size tolerance range is -0.5~+2mm, and the maximum allowable wear of the lower mold is 1mm) or 10℃>ΔTi>5℃.
[0037] Plastic deformation zone: located in the center of the replaceable layer, not in direct contact with the blank; affected by temperature and force during service, but with small temperature fluctuations; no wear and thermal fatigue will occur, and the main failure form becomes plastic deformation. Plastic deformation zone division standard: 5℃>ΔTi>0℃.
[0038] Easy-to-break zone: It appears at the bottom corner or groove of the replaceable layer cavity where there is a large stress concentration; the main failure form is cracks. Since the cracks of the hot forging die are mainly thermal fatigue cracks, the location of the easy-to-break zone is generally located in the surface layer, and there will be a certain overlap with the wear zone and multiple failure zone. The division standard of the easy-to-break zone is: σ Ti >σ b , where σ b High temperature tensile strength of the material selected for the wear zone or multiple failure zone.
[0039] 4. Material selection, thickness design and shape design according to the divided areas
[0040] 4.1 Material selection
[0041] The main criterion for material selection is high failure resistance, and prevention of failure is the main criterion; the batch size of the product is the decision-making factor for material selection, and economy and ease of production management are important factors.
[0042] Material selection for multiple failure zones: Multiple failure zones have the longest contact time with the blank. This zone is the most prone to failure. All four failure modes may occur. Among them, thermal fatigue, deformation and thermal wear are more serious. Therefore, this zone requires the material to have a higher thermal yield strength, good tempering resistance and red hardness; and considering the lifespan, under the condition of no failure, the wear calculation model is used to substitute the material parameters for calculation and select the appropriate material.
[0043] Material selection in the wear zone: The main wear in the wear zone is thermal abrasion. In order to reduce this thermal abrasion, the material selection should have high thermal yield strength, good tempering stability and good ductility. The high-temperature mechanical properties of the material are screened through the established model, and the maximum temperature, maximum stress, and maximum temperature fluctuation of the wear zone are checked. When the above conditions are met, the wear performance and thermal fatigue resistance are focused on.
[0044] Material selection for plastic deformation zone: This area occupies most of the working area and is located inside. The main failure form is plastic deformation. Therefore, the main material selection criterion is the metal's ability to resist deformation at high temperatures. The main measurement indicators are yield strength σ and high-temperature hardness. The material life of the plastic deformation zone needs to be considered after multiple forging experiments, because there will be residual stress in each working cycle, and multiple stress residuals are superimposed to produce plastic deformation. The maximum stress and position of the plastic deformation zone are found through the established model. Through multiple forging experiments, the superposition curve and its calculation formula at the maximum stress are obtained by nonlinear fitting. The required number of products are substituted to calculate the residual stress accumulation. When selecting materials, their yield strength should be greater than the sum of the maximum stress value and the residual stress accumulation, and they should also have good toughness.
[0045] Material selection for easy-to-break zones: The location of easy-to-break zones should be determined in combination with the material properties of the wear-resistant zone and the stress distribution of the mold. Whether easy-to-break zones need to be set should be determined based on the maximum principal stress in the model and the tensile strength of the material selected for the wear-resistant zone at the maximum temperature.
[0046] 4.2 Thickness design
[0047] Carry out multiple forging experiments and design the thickness according to the heat transfer performance of the material in the forging experiments and the impact on the heat affected zone.
[0048] like Figure 4 The figure shows the morphological changes of the metal protective shell of a cross-shaped disk after different forging times. From the shape of the cavity, it can be seen that the deformation is consistent with the forging cavity after the first forging, and there is no obvious change in shape after 40 forgings. Figure 4 It can be seen that the deformation of the protective shell is mainly concentrated in the convex corner position. As the number of forgings increases, the deformation decreases rapidly. It can be seen that with the increase in the number of forgings, the deformation difficulty of the protective shell in the convex corner area increases. The thickness reduction occurs in a fixed area. As the number of forgings increases, the reduction in the thickness of the protective shell decreases. Therefore, the thickness can be designed at different points according to the thickness change curve at different points.
[0049] 4.3 Shape Design
[0050] The shape design is based on the deformation performance of the protective shell, and the cross section at a certain moment during the forging process is used as the shape of the protective shell to prevent folding. Figure 5 The figure shows the force diagram of the protective shell cross section. The calculation formula for the folding trigger of the metal protective shell is:
[0051]
[0052] F=σ n ·(μ bc -μ cd )·l·b
[0053] ≈k fb ·(μ bc -μ cd )·l·b
[0054] Where μ is the friction coefficient; 1 is the contact length between the metal protective shell and the blank; b is the contact width between the metal protective shell and the blank; k fb is the flow stress of the blank; σ n is the normal stress. The shape of the protective shell is designed according to this formula.
[0055] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the technical solution of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.
Claims
1. A design method for a replaceable protective shell suitable for a high-temperature alloy forging die, characterized in that: The following steps are involved: S1. Construct a comprehensive simulation model of replaceable layers based on basic experiments; S2, analyze the stress, temperature field and wear of the model and divide the replaceable layer into regions; S3, refine according to the failure distribution of replaceable layers and the zoning of working areas; S4. Design the protective case from three aspects: material selection, thickness design and shape design.
2. The design method of a replaceable protective shell suitable for a high-temperature alloy forging die according to claim 1, characterized in that: The protective shell is designed with material selection from different partitions.
3. The design method of a replaceable protective shell suitable for a high-temperature alloy forging die according to claim 1, characterized in that: The basic experiments in step S1 include heat transfer experiments, metal bending experiments, and replaceable layer friction and wear experiments. The replaceable layer comprehensive simulation model includes a thermal-mechanical coupling finite element simulation model and a friction and wear finite element simulation model.
4. The design method of a replaceable protective shell suitable for a high-temperature alloy forging die according to claim 1, characterized in that: The area division in step S2 includes a base area and a working area.
5. The design method of a replaceable protective shell suitable for a high-temperature alloy forging die according to claim 1, characterized in that: The working area subdivision in step S3 is differentiated according to the temperature and stress changes in the model.
6. The design method of a replaceable protective shell suitable for a high-temperature alloy forging die according to claim 4 is characterized in that: In step S3, the regions are divided into multiple failure regions, wear regions, plastic deformation regions and easy fracture regions.