Finite element simulation method for rolling forming of titanium alloy integral blade ring

Abstract

The invention relates to a titanium alloy integral blade ring rolling forming finite element simulation method which is based on Deform software. The method comprises the steps that firstly, a scheme is distributed according to a forge piece design drawing and forging deformation; 2, the. STL geometric model file is imported into finite element simulation software to be set; step 3, arranging a ring blank; step 4, setting a motion mode and motion parameters of each roller; 5, setting boundary conditions; step 6, operation program generation and solution calculation; 7, processing a simulation result; according to the method, the temperature field, the strain distribution, the forging defects and the like in the rolling process of the integral blade ring forging are predicted through finite element analog simulation, so that design and optimization of a forging forming process are assisted.

Description

Technical Field

[0001] The invention relates to the technical field of finite element simulation, and in particular to a finite element simulation method for titanium alloy integral blade ring rolling forming. Background Art

[0002] Improving the thrust-to-weight ratio is an important way to improve the overall performance of aircraft engines, and the use of lightweight, high-temperature resistant structural materials and lightweight structures are two important means to achieve this. However, as the potential of materials has been tapped to the limit, the use of lightweight structural design has become particularly important. Since the integral blade ring eliminates the blade connection device, it has a compact structure, small size, light weight and other advantages. Integral blade ring parts are generally prepared by rolling forming ring forgings + machining. In view of the special structure of the integral blade ring, its forgings are required to take into account the microstructure and mechanical properties required by the ring forgings and blade forgings. Therefore, compared with ordinary ring forgings, the integral blade ring forgings have more stringent requirements on the rolling forming process parameters such as deformation and stop forging temperature, and the integral blade ring forgings have a larger wall thickness, and the deformation temperature and deformation uniformity are not easy to control.

[0003] Finite element simulation technology can accurately predict the temperature field and strain field during the forging process. Liu Junjie et al. used Deform software to study the forging process parameters of cast AZ80A magnesium alloy gears, and combined with experimental verification and analysis, finally determined the optimal process parameters. Guo Jing et al. used Deform software to develop a flashless die forging process, which provides a technical solution to the current problems of excessive material cutting, insufficient filling, and poor performance in automotive differential housing forgings. Simufact Forming software is used in domestic and foreign literature to simulate and analyze the rolling process of ordinary casings / ring forgings, predict the temperature, strain and possible forging defects of the rolling process, and thus assist in structural design and process optimization. However, there has been no public literature report on the use of Deform software to carry out rolling forming simulation of integral blade ring forgings. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a finite element simulation method for titanium alloy integral blade ring rolling forming; the specific technical scheme is as follows:

[0005] A finite element simulation method for titanium alloy integral blade ring rolling forming is based on Deform software, and the specific implementation method is as follows:

[0006] Step 1: According to the forging design drawing and the forging deformation distribution plan, the UG software is used to draw the 3D geometric model of the initial ring blank. According to the geometric dimensions of the rolling equipment rolls, the 3D geometric models of the main roll, core roll, guide roll and tapered roll are drawn respectively and saved as .STL files;

[0007] Step 2: Import the above .STL geometric model file into the finite element simulation software, set the roll as a rigid body, the workpiece as a plastic body, and set the position between the workpiece and the main roll, core roll, guide roll and cone roll;

[0008] Step 3: Ring blank setting

[0009] Ring blank settings mainly include rolling temperature settings, meshing and material model establishment; mesh the workpiece through the software's own program. The principle is that after hiding the workpiece entity, the number of meshes divided can show the geometric shape and edge details of the ring; in order to ensure the accuracy of the simulation results, click Create new material to build a material model. The data includes stress data at different deformation temperatures and strain rates, and measured values ​​of Poisson's ratio, thermal expansion coefficient, thermal conductivity, specific heat capacity and elastic modulus at different deformation temperatures.

[0010] Step 4: Set the motion mode and motion parameters of each roller;

[0011] The main roller is set to self-rotate without displacement; the core roller moves in a radial feed motion with a feed speed V x According to the optimal deformation strain rate of titanium alloy, it is the set value. The core roller rotates passively due to the friction with the workpiece. The main function of the cone roller is to control the height of the ring. Its movement mode should include the axial downward pressure of the upper cone roller, self-rotation and retreat as the ring grows. The main function of the guide roller is to ensure the roundness of the ring. The determination of its movement parameters is relatively complicated. The instantaneous speed at a certain moment of rolling is calculated according to the following mathematical model: Assuming that D0, d0, B0, and H0 represent the initial outer diameter, inner diameter, wall thickness, and height of the ring blank, D t d t , B t , H t Indicates the instantaneous outer diameter, inner diameter, wall thickness and height of the ring blank at a certain moment. According to the principle of constant volume during rolling, we have:

[0012]

[0013] Instantaneous wall thickness B t =B0-V B t, then:

[0014] D t =B0H0(D0+d0) / 2B t H t +B t

[0015] Taking the derivative of the above formula, we can get the growth rate of the ring diameter:

[0016] V D=[B0H0(D0+d0) / 2]·[(V B H t +2V H B t ) / (H t 2 B t 2 )]-V B

[0017] When θ=60°, the instantaneous growth rate of the roller is V t =V D / 2; Input the real-time growth rate during rolling into the finite element simulation software to form V t -t curve;

[0018] Step 5: Set boundary conditions

[0019] The boundary conditions mainly include friction coefficient, heat transfer coefficient, simulation step length and simulation termination conditions; the friction type between the ring blank and the roller is set to shear friction;

[0020] The heat transfer coefficient between the ring blank and the air is set according to the different ambient temperatures; the heat radiation coefficient is set to 0.5-0.7, and the heat transfer coefficient between the ring blank and the roll is set according to the different preheating temperatures of the rolls;

[0021] The simulation unit step size is directly related to the confidence of the simulation results; the step size of the integral blade ring rolling simulation is calculated according to the following formula

[0022] Dstep=(0.036·D 环 ) / (D 主辊 ·ω 主动辊 )

[0023] The termination simulation condition is determined by using the Process Parameters process parameters to input the total rolling time and the Primary die is placement main die displacement input core roll displacement;

[0024] Step 6: Generate calculation program and solve calculation

[0025] Check whether the setting parameters are correct, generate and save the operation program, and then exit the pre-processing interface; complete the processor settings in the main interface of the software and solve the operation program;

[0026] Step 7: Simulation result processing

[0027] The simulation results are analyzed in the post-processing interface, and finally the simulation results of rolling load curve, stress field, strain field and temperature field are obtained.

[0028] The method for rolling forming and metallurgical quality assessment of GH4169 alloy integral blade ring forgings is preferably implemented as follows: in step three, for the titanium alloy integral blade ring, the rolling temperature range is Tβ-(20 to 40)°C.

[0029] The method for rolling forming and metallurgical quality assessment of GH4169 alloy integral blade ring forgings is preferably configured such that, in step three, the mesh type is a hexahedral mesh, and the number of meshes is guaranteed to be above 100,000.

[0030] The method for rolling forming and metallurgical quality assessment of GH4169 alloy integral blade ring forgings is preferably as follows: in step 4, the axial downward pressing speed V of the upper tapered roller is H =(H0-H t ) / t, self-rotation speed ω=V Z / R,V Z is the main roll speed set for the rolling mill, R is the contact area between the tapered roll and the ring, and the retreat speed is consistent with the growth rate of the ring billet diameter;

[0031] The method for rolling forming and metallurgical quality assessment of GH4169 alloy integral blade ring forgings is preferably configured as follows: in step five, the friction coefficient is set, wherein the friction coefficient between the main roller and the core roller and the ring blank is set to 0.5-0.7; the friction coefficient between the guide roller and the cone roller and the ring blank is set to 0.3; the heat transfer coefficient between the ring blank and the air is 0.01-0.03; and the heat transfer coefficient between the ring blank and the rolling roller is 7-11.

[0032] Compared with the prior art, the present invention has the following beneficial technical effects:

[0033] The technical solution of the present invention predicts the temperature field, strain distribution and forging defects during the rolling process of the integral blade ring forging through finite element simulation, thereby assisting in the design and optimization of the forging forming process, and solving the problem that the deformation temperature and deformation uniformity of the integral blade ring forging are difficult to control due to the large wall thickness, thereby shortening the process iteration cycle of such forgings and reducing R&D costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the flow chart of the rolling forming simulation technology for integral blade ring forgings;

[0035] Figure 2 Schematic diagram of the simulation geometry model.

[0036] In the figure: 1 main roller, 2 core roller, 3 guide roller, 4 tapered roller, 5 workpiece. DETAILED DESCRIPTION

[0037] The following is combined with Figure 1-2The present invention is described in detail, but the protection scope of the present invention is not limited by the accompanying drawings.

[0038] The present invention proposes a simulation method for the rolling process of titanium alloy integral blade ring forgings based on Deform software and the principle of superplastic forming. The specific implementation steps are as follows:

[0039] Step 1: According to the forging design drawing and the forging deformation distribution plan, the UG software is used to draw the 3D geometric model of the initial ring blank. According to the geometric dimensions of the rolling equipment rolls, the 3D geometric models of the main roll, core roll, guide roll and tapered roll are drawn respectively and saved as .STL files;

[0040] Steps: Import the above .STL geometric model file into the finite element simulation software, set the roll as a rigid body, the workpiece as a plastic body, and set the position between the workpiece and the main roll, core roll, guide roll and cone roll, such as Figure 2 As shown;

[0041] Step 3: Ring blank setting

[0042] The ring blank setting mainly includes rolling temperature setting, meshing and material model establishment. For titanium alloy integral blade rings, the rolling temperature range is Tβ-(20~40)℃. The workpiece is meshed through the software's own program. The mesh type uses hexahedral meshes and the number of meshes must be guaranteed to be above 100,000. The principle is that after the workpiece entity is hidden, the number of divided grids can show the geometric shape and edge details of the ring. In order to ensure the accuracy of the simulation results, click Create new material to build a material model. The data includes stress data at different deformation temperatures and strain rates, and the measured values ​​of Poisson's ratio, thermal expansion coefficient, thermal conductivity, specific heat capacity and elastic modulus at different deformation temperatures.

[0043] Step 4: Set the movement mode and movement parameters of each roller. The main roller 1 is set to self-rotate without displacement; the movement of the core roller 2 is radial feed movement, and the feed speed V x According to the optimal deformation strain rate of titanium alloy, it is set as the value. The core roller 2 rotates passively due to the friction with the workpiece 5. The main function of the cone roller 4 is to control the height of the ring. Its movement mode should include axial downward pressure of the upper cone roller, self-rotation and retreat as the ring grows. Its downward pressure speed V H =(H0-H t ) / t, self-rotation speed ω=V Z / R,V Z is the main roll speed set for the rolling mill, R is the contact area between the tapered roll and the ring, and the retreat speed is consistent with the growth rate of the ring billet diameter;

[0044] The main function of the guide roller 3 is to ensure the roundness of the ring. The determination of its motion parameters is relatively complex. The instantaneous speed at a certain moment of rolling is calculated according to the following mathematical model: Assume that D0, d0, B0, and H0 represent the initial outer diameter, inner diameter, wall thickness, and height of the ring blank, and D t d t , B t , H t Indicates the instantaneous outer diameter, inner diameter, wall thickness and height of the ring blank at a certain moment. According to the principle of constant volume during rolling, we have:

[0045]

[0046] Instantaneous wall thickness B t =B0-V B t, then:

[0047] D t =B0H0(D0+d0) / 2B t H t +B t

[0048] Taking the derivative of the above formula, we can get the growth rate of the ring diameter:

[0049] V D =[B0H0(D0+d0) / 2]·[(V B H t +2V H B t ) / (H t 2 B t 2 )]-V B

[0050] When θ=60°, the instantaneous growth rate of the roller is V t =V D / 2. Input the real-time growth rate during rolling into the finite element simulation software to form V t -t curve.

[0051] Step 5: Set boundary conditions

[0052] The boundary conditions mainly include friction coefficient, heat transfer coefficient, simulation step length and termination simulation conditions. The friction type between the ring blank and the roller is set to shear friction, where the friction coefficient between the main roller and the core roller and the ring blank can be set to 0.5-0.7, and the friction coefficient between the guide roller and the cone roller and the ring blank is set to 0.3; the heat transfer coefficient between the ring blank and the air can be set to 0.01-0.03 according to the ambient temperature, the heat radiation coefficient can be set to 0.5-0.7, and the heat transfer coefficient between the ring blank and the roller can be set to 7-11 according to the preheating temperature of the roller.

[0053] The simulation unit step size is directly related to the confidence of the simulation results. The step size of the integral blade ring rolling simulation can be calculated according to the following formula:

[0054] D step =(0.036·D 环 ) / (D 主辊 ·ω 主动辊 )

[0055] The termination conditions of the simulation are determined by inputting the total rolling time through Process Parameters and the core roll displacement through Primary dieisplacement.

[0056] Step 6: Generate the operation program and solve the calculation. Check whether the setting parameters are correct, generate and save the operation program, and then exit the pre-processing interface. Complete the processor settings in the main interface of the software and solve the operation program.

[0057] Step 7: Simulation result processing

[0058] The simulation results are analyzed in the post-processing interface, and finally the simulation results such as rolling load curve, stress field, strain field, temperature field, etc. are obtained.

Claims

1. A finite element simulation method for titanium alloy integral blade ring rolling forming, characterized in that: This method is based on Deform software, and the specific implementation is as follows: Step 1: According to the forging design drawing and the forging deformation distribution plan, the UG software is used to draw the 3D geometric model of the initial ring blank. According to the geometric dimensions of the rolling equipment rolls, the 3D geometric models of the main roll, core roll, guide roll and tapered roll are drawn respectively and saved as .STL files; Step 2: Import the above .STL geometric model file into the finite element simulation software, set the roll as a rigid body, the workpiece as a plastic body, and set the position between the workpiece and the main roll, core roll, guide roll and cone roll; Step 3: Ring blank setting Ring blank settings mainly include rolling temperature settings, meshing and material model establishment; mesh the workpiece through the software's own program. The principle is that after hiding the workpiece entity, the number of meshes divided can show the geometric shape and edge details of the ring; in order to ensure the accuracy of the simulation results, click Create new material to build a material model. The data includes stress data at different deformation temperatures and strain rates, and measured values ​​of Poisson's ratio, thermal expansion coefficient, thermal conductivity, specific heat capacity and elastic modulus at different deformation temperatures. Step 4: Set the motion mode and motion parameters of each roller; The main roller is set to self-rotate without displacement; the core roller moves in a radial feed motion with a feed speed V x According to the optimal deformation strain rate of titanium alloy, it is the set value. The core roller rotates passively due to the friction with the workpiece. The main function of the cone roller is to control the height of the ring. Its movement mode should include the axial downward pressure of the upper cone roller, self-rotation and retreat as the ring grows. The main function of the guide roller is to ensure the roundness of the ring. The determination of its movement parameters is relatively complicated. The instantaneous speed at a certain moment of rolling is calculated according to the following mathematical model: Assuming that D0, d0, B0, and H0 represent the initial outer diameter, inner diameter, wall thickness, and height of the ring blank, D t d t , B t , H t Indicates the instantaneous outer diameter, inner diameter, wall thickness and height of the ring blank at a certain moment. According to the principle of constant volume during rolling, we have: Instantaneous wall thickness B t =B0-V B t, then: D t =B0H0(D0+d0) / 2B t H t +B t Taking the derivative of the above formula, we can get the growth rate of the ring diameter: IN D =[B0H0(D0+d0) / 2]·[(V B H t +2V H B t ) / (H t 2 B t 2 )]-IN B When θ=60°, the instantaneous growth rate of the roller is V t =V D / 2; Input the real-time growth rate during rolling into the finite element simulation software to form V t -t curve; Step 5: Set boundary conditions The boundary conditions mainly include friction coefficient, heat transfer coefficient, simulation step length and simulation termination conditions; Set the friction type between the ring blank and the roller to shear friction; The heat transfer coefficient between the ring blank and the air is set according to the different ambient temperatures; the heat radiation coefficient is set to 0.5-0.7, and the heat transfer coefficient between the ring blank and the roll is set according to the different preheating temperatures of the rolls; The simulation unit step size is directly related to the confidence of the simulation results; the step size of the integral blade ring rolling simulation is calculated according to the following formula Dstep=(0.036·D 环 ) / (D 主辊 ·oh 主动辊 ) The termination simulation condition is determined by using the Process Parameters process parameters to input the total rolling time and the Primary die is placement main die displacement input core roll displacement; Step 6: Generate calculation program and solve calculation Check whether the setting parameters are correct, generate and save the operation program, and then exit the pre-processing interface; complete the processor settings in the main interface of the software and solve the operation program; Step 7: Simulation result processing The simulation results are analyzed in the post-processing interface, and finally the simulation results of rolling load curve, stress field, strain field and temperature field are obtained.

2. A GH4169 alloy integral blade ring forging rolling forming and forging metallurgical quality assessment method according to claim 1, characterized in that: In step three, for the titanium alloy integral blade ring, the rolling temperature range is Tβ-(20~40)℃.

3. The method for rolling forming and metallurgical quality assessment of GH4169 alloy integral blade ring forgings according to claim 1, characterized in that: In step 3, the mesh type adopts a hexahedral mesh, and the number of meshes must be guaranteed to be more than 100,000.

4. A GH4169 alloy integral blade ring forging rolling forming and forging metallurgical quality assessment method according to claim 1, characterized in that: In step 4, the axial downward pressing speed V of the upper tapered roller is H =(H0-H t ) / t, self-rotation speed ω=V Z / R,V Z is the main roll speed set for the rolling mill, R is the contact area between the tapered roll and the ring, and the retreat speed is consistent with the growth rate of the ring billet diameter.

5. The method for rolling forming and metallurgical quality assessment of GH4169 alloy integral blade ring forgings according to claim 1, characterized in that: In step five, the friction coefficient is set, wherein the friction coefficient between the main roller and the core roller and the ring blank is set to 0.5-0.7; the friction coefficient between the guide roller and the cone roller and the ring blank is set to 0.3; the heat transfer coefficient between the ring blank and the air is 0.01-0.03; and the heat transfer coefficient between the ring blank and the rolling roller is 7-11.

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