Variable-section thin-wall titanium tube forming method and system based on fluid mechanics

Abstract

This article provides a variable-section thin-walled titanium tube forming method and system based on fluid mechanics. The method includes loading a thin-walled titanium tube blank into the cavity of the protective shell of the variable-section thin-walled titanium tube forming system, fixing one end of the thin-walled titanium tube blank on the slider and placing the other end in the stamping die, with the stamping die and the thin-walled titanium tube blank located on the same side of the slider; injecting a stamping fluid into the cavity through a high-pressure pump, so that the fluid pressure of the stamping fluid is transmitted to the thin-walled titanium tube blank and the slider through the stamping die; monitoring the fluid pressure on the slider to determine whether the stamping process is complete based on the fluid pressure; when the stamping process is complete, separating the thin-walled titanium tube blank from the slider and the stamping die to obtain a formed variable-section thin-walled titanium tube. This article uses computer equipment to monitor the fluid pressure on the slider to regulate the stamping process and achieve stamping forming of the titanium tube; and can take advantage of the uniform pressure distribution of the stamping fluid throughout the stamping die to improve the quality of the variable-section thin-walled titanium tube.

Description

Technical Field

[0001] This article relates to the technical field of pipe processing and manufacturing technology, especially a variable-section thin-walled titanium pipe forming method and system based on fluid mechanics. Background Art

[0002] Titanium is a metal with excellent properties and important strategic significance, known as the "space metal" and the "ocean metal." Compared with other structural materials, titanium alloys have the most important advantages of high specific strength and good thermal strength. Within the temperature range of 400°C to 500°C, the specific strength of titanium alloys exceeds that of most stainless steels and oxidation-resistant steels.

[0003] At present, titanium tubes with axially variable cross-sections are mainly manufactured by liquid extrusion. This method has the problems of high liquid pressure, high energy consumption, small deformation of the workpiece at one time, and sometimes multiple annealing is required to complete liquid extrusion or hydraulic bulging, resulting in low forming efficiency.

[0004] In view of this, this paper aims to provide a variable-section thin-walled titanium tube forming method and system based on fluid mechanics. Summary of the Invention

[0005] In view of the above problems in the prior art, the purpose of this article is to provide a variable-section thin-wall titanium tube forming method and system based on fluid mechanics to solve the problems in the prior art.

[0006] In order to solve the above technical problems, the specific technical solutions of this article are as follows:

[0007] On the one hand, this article provides a variable-section thin-wall titanium tube forming method based on fluid mechanics, comprising:

[0008] The thin-walled titanium tube blank is loaded into the cavity of the protective shell of the variable-section thin-walled titanium tube forming system, so that one end of the thin-walled titanium tube blank is fixed on the slider, and the other end of the thin-walled titanium tube blank is placed in the stamping die, and the stamping die and the thin-walled titanium tube blank are located on the same side of the slider;

[0009] Injecting punching fluid into the protective housing through a high-pressure pump, so that the fluid pressure exerted by the punching fluid is transmitted to the thin-walled titanium tube blank and the slider through the punching die;

[0010] monitoring the fluid pressure applied to the slider during the stamping process, so as to determine whether the stamping process is completed according to the fluid pressure applied to the slider;

[0011] When the stamping process is completed, the thin-walled titanium tube blank is separated from the slider and the stamping die to obtain a formed variable-section thin-walled titanium tube.

[0012] Specifically, monitoring the fluid pressure applied to the slider during the stamping process further includes:

[0013] Based on fluid mechanics, constructing a fluid pressure equation on the slider;

[0014]

[0015]

[0016]

[0017] Wherein, ρ is the fluid density of the punching fluid; Π is the shear stress; t is the punching time; is the gradient; (4) , Ψ (5) and Ψ (6) are the 4th, 5th and 6th order moments respectively; u is the velocity vector of the punching fluid; p is the stress tensor of the punching fluid; η is the viscosity coefficient of the punching fluid; q(κ) is the nonlinear dissipation factor; Δ is the additional normal stress; γ is the specific heat ratio; I is the unit matrix; η b is the volume viscosity coefficient; Q is the heat flow; c p is the constant pressure specific heat; T is the temperature of the stamping fluid; λ is the thermal conductivity coefficient of the stamping fluid; and the fluid pressure exerted on the slider during the stamping process is monitored based on the additional positive pressure obtained by solving the equation.

[0018] Furthermore, judging whether the stamping process is completed according to the fluid pressure applied to the slider includes:

[0019] Determining whether the fluid pressure applied to the slider reaches a preset pressure threshold and satisfies a preset time condition;

[0020] If so, it is determined that the stamping process is finished.

[0021] Before loading the thin-walled titanium tube blank into the variable-section thin-walled titanium tube forming system, the method further comprises:

[0022] According to the cross-sectional structural characteristics of the required variable-section thin-walled titanium tube, the appropriate stamping die and thin-walled titanium tube blank are selected.

[0023] Specifically, the variable-section thin-walled titanium tube forming system further includes a connecting rod and an extrusion head, the extrusion head is located at one end of the protective shell, the connecting rod sequentially passes through the stamping die, the thin-walled titanium tube blank and the slider and abuts against the extrusion head, and the connecting rod is used to limit the movement direction of the thin-walled titanium tube blank and the slider during the stamping process; before the thin-walled titanium tube blank is loaded into the variable-section thin-walled titanium tube forming system, the method further includes:

[0024] According to the required cross-sectional structural characteristics of the thin-walled titanium tube with variable cross-section, an appropriate connecting rod is selected.

[0025] Furthermore, the variable-section thin-walled titanium tube forming system further includes a filling rod, which is used to fill the thin-walled titanium tube blank into the cavity of the protective shell and to remove the stamped variable-section thin-walled titanium tube from the cavity, and the end of the filling rod is connected to a positioning boss;

[0026] The end of the positioning boss connected to the connecting rod is provided with a first keyway, and the outer wall of the end of the connecting rod connected to the positioning boss is provided with a strong tooth. The first keyway and the strong tooth are adapted to limit the rotation of the connecting rod relative to the positioning boss.

[0027] A sealing cover is provided at one end of the protective shell; an opening is provided at the other end of the protective shell, and at least a portion of the extrusion head extends from the opening. The size of the opening is such that the extrusion head and the formed variable-section thin-walled titanium tube can only be removed from the sealing cover.

[0028] A shaft sleeve is provided on one side of the extrusion head located in the cavity, and a spline is provided on the inner wall of the shaft sleeve; the connecting rod rests against the shaft sleeve, and a second keyway matching the spline is provided on the outer wall of the connecting rod.

[0029] Furthermore, the slider is a tapered slider, and the diameter of the slider at one end close to the extrusion head is smaller than the diameter of the slider at one end close to the thin-walled titanium tube blank;

[0030] The inner diameter of the protective shell gradually decreases from an end close to the sealing cover to an end close to the extrusion head, and the high-pressure pump is arranged on a side of the protective shell close to the sealing cover.

[0031] On the other hand, this article provides a variable-section thin-wall titanium tube forming system based on fluid mechanics, the system comprising:

[0032] A protective shell with a cavity formed inside;

[0033] a high-pressure pump connected to the protective housing to inject a punching fluid into the cavity;

[0034] an extrusion head, located at one end of the protective shell;

[0035] A slider is used to fix the thin-walled titanium tube blank to drive the thin-walled titanium tube blank to move under the punching action of the punching fluid. The center of the slider is provided with an opening adapted to the connecting rod;

[0036] A stamping die is provided outside the thin-walled titanium tube blank and is located on the same side of the slider as the thin-walled titanium tube blank, and is used to stamp the thin-walled titanium tube blank under the stamping action of the stamping fluid;

[0037] A connecting rod, which passes through the stamping die, the thin-walled titanium tube blank and the slider in sequence and abuts against the extrusion head. The connecting rod is used to limit the movement direction of the thin-walled titanium tube blank and the slider during the stamping process. The connecting rod is a cylindrical connecting rod;

[0038] a flow rate sensor connected to the high-pressure pump and configured to obtain the flow rate of the punching fluid; and

[0039] A computer device, the computer device is connected to the high-pressure pump and the flow rate sensor, the computer device includes a memory, a processor and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, a variable-section thin-wall titanium tube forming method based on fluid mechanics as provided in the above technical solution is implemented.

[0040] Furthermore, the system further comprises:

[0041] The filling rod is used to fill the thin-walled titanium tube blank into the cavity and to take out the stamped variable-section thin-walled titanium tube from the cavity. The end of the filling rod is connected to a positioning boss, which matches the connecting rod.

[0042] By adopting the above-mentioned technical solution, the variable-section thin-walled titanium tube forming method and system based on fluid mechanics described in this article monitors the fluid pressure exerted on the slider through computer equipment, thereby regulating the stamping process and realizing the stamping forming of the titanium tube; at the same time, it can take advantage of the uniform pressure distribution of the stamping fluid in various parts of the stamping die to reduce the wall thickness difference, reduce or even eliminate the mechanical traces caused by other hardware processing methods, and improve the quality of the variable-section thin-walled titanium tube after casting.

[0043] In order to make the above and other purposes, features and advantages of this article more obvious and easy to understand, the following specifically cites preferred embodiments and provides detailed descriptions in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of this article or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of this article. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1A schematic structural diagram of a variable-section thin-walled titanium tube forming system based on fluid mechanics is shown in an embodiment of this invention;

[0046] Figure 2 A schematic structural diagram of a variable-section thin-walled titanium tube forming system based on fluid mechanics during a stamping process is shown in an embodiment of this invention;

[0047] Figure 3 A schematic diagram of the steps of a method for forming a thin-walled titanium tube with a variable cross-section based on fluid mechanics provided in an embodiment of this invention is shown;

[0048] Figure 4 A schematic structural diagram of a computer device provided in an embodiment of this invention is shown.

[0049] Description of the accompanying symbols:

[0050] 1. Protective shell;

[0051] 2. Slider;

[0052] 3. Thin-walled titanium tube blank;

[0053] 4. High-pressure pump;

[0054] 5. Connecting rod;

[0055] 6. Positioning boss

[0056] 7. Extrusion head;

[0057] 8. Stamping die;

[0058] 9. Loading rod;

[0059] 10. Cavity;

[0060] 402. Computer equipment;

[0061] 404, processor;

[0062] 406. Memory;

[0063] 408, driving mechanism;

[0064] 410, input / output module;

[0065] 412. Input devices;

[0066] 414. Output device;

[0067] 416. Presentation equipment;

[0068] 418. Graphical User Interface;

[0069] 420, network interface;

[0070] 422, communication link;

[0071] 424. Communication bus. DETAILED DESCRIPTION

[0072] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of this document. Obviously, the embodiments described are only part of the embodiments of this document, not all of the embodiments. Based on the embodiments of this document, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this document.

[0073] It should be noted that the terms "first," "second," and the like in the specification and claims herein and in the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product, or device comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or devices.

[0074] The embodiments of this article provide a variable-section thin-walled titanium tube forming method and system based on fluid mechanics, which can solve the problems in the prior art of titanium tube processing, such as high pressure and high energy consumption, small degree of deformation of the workpiece at one time, sometimes requiring multiple annealing to complete liquid extrusion or hydraulic bulging, and low forming efficiency. Figure 1 This is a schematic diagram of the structure of a variable-section thin-walled titanium tube forming system based on fluid mechanics provided in the embodiment of this article. Figure 1 As shown, the system includes:

[0075] A protective shell 1 is formed with a cavity 10 therein;

[0076] a high-pressure pump 4 connected to the protective housing 1 to inject punching fluid into the cavity 10;

[0077] An extrusion head 7 is located at one end of the protective shell 1;

[0078] The slider 2 is used to fix the thin-walled titanium tube blank 3 to drive the thin-walled titanium tube blank 3 to move under the punching action of the punching fluid. The center of the slider 2 is provided with an opening adapted to the connecting rod; the thin-walled titanium tube blank 3 is the raw material for casting the titanium tube, which will be punched and formed under the action of the punching fluid and the punching die 8.

[0079] A stamping die 8 is provided outside the thin-walled titanium tube blank 3 and is located on the same side of the slider 2 as the thin-walled titanium tube blank 3. The stamping die 8 is used to stamp and form the thin-walled titanium tube blank 3 under the stamping action of the stamping fluid;

[0080] The connecting rod 5 passes through the punching die 8, the thin-walled titanium tube blank 3, and the opening in the center of the slider 2 in sequence and abuts against the extrusion head 7. The connecting rod 5 is used to limit the movement direction of the thin-walled titanium tube blank 3 and the slider 2 during the punching process. The connecting rod 5 is a cylindrical connecting rod;

[0081] a flow rate sensor (not shown in the figure), connected to the high-pressure pump 4, for obtaining the flow rate of the punching fluid; and

[0082] A computer device is electrically connected to the high-pressure pump and the flow rate sensor, and is used to receive the flow rate detected by the flow rate sensor and establish a generalized fluid pressure equation received by the slider during the stamping process based on data such as the flow rate, and then determine whether the stamping process is completed based on the fluid pressure received by the slider during the stamping process obtained by solving the fluid pressure equation, and control the high-pressure pump to stop or work.

[0083] The embodiments of this specification provide a variable-section thin-walled titanium tube forming system based on fluid mechanics, which injects stamping liquid into the cavity of the protective shell through a high-pressure pump, monitors the flow rate of the stamping liquid through computer equipment, establishes a generalized fluid pressure equation on the slider and solves it to obtain the fluid pressure on the slider, thereby regulating the stamping process and realizing the stamping forming of the titanium tube; and the system provided by the embodiments of this specification can utilize the advantage of uniform pressure distribution of the stamping liquid at various locations of the stamping die, reduce wall thickness differences, reduce or even eliminate mechanical traces caused by other hardware processing methods, and improve the quality of the variable-section thin-walled titanium tube after casting.

[0084] In the embodiment of this specification, a sealing cap (not shown) is provided at the other end of the protective housing 1 away from the extrusion head 7. When loading the thin-walled titanium tube blank 3 or removing the stamped thin-walled titanium tube with a variable cross-section, the sealing cap is opened to facilitate loading or output operations; during the stamping process, the sealing cap remains closed.

[0085] like Figure 1 As shown, in the embodiment of this specification, the system further includes a loading rod 9, which is used to load the thin-walled titanium tube blank 3 into the cavity 10 of the protective shell 1 and to remove the stamped variable-section thin-walled titanium tube from the cavity 10. One end of the loading rod 9 is connected to a positioning boss 6, which matches the connecting rod 5.

[0086] A first keyway (not shown in the figure) is provided on the end of the positioning boss 6 connected to the connecting rod 5, and a tooth (not shown in the figure) is provided on the outer wall of the end of the connecting rod 5 connected to the positioning boss 6. The first keyway and the tooth are adapted to limit the rotation of the connecting rod 5 relative to the positioning boss 6, thereby facilitating the loading and removal operations of the thin-walled titanium tube blank 3.

[0087] Furthermore, an opening is provided at one end of the protective shell 1 away from the sealing cover, and a small portion of the extrusion head 7 extends out of the opening. The size of the opening allows the extrusion head 7 to be taken out only from the sealing cover.

[0088] In some specific embodiments, the extrusion head 7 is truncated cone-shaped, and the opening is adapted to the slope of the outer wall of the extrusion head 7, so that the smaller end of the truncated cone-shaped extrusion head 7 can slightly extend from the opening, while the larger end remains within the opening or cavity 10. During the stamping process, the opening can limit the travel of the extrusion head 7, thereby limiting the travel of the slider 2. After the stamping is completed and the sealing cover is opened, the extrusion head 7 can be pushed toward the sealing cover, thereby facilitating the removal of the slider 2 and the formed variable-cross-section thin-walled titanium tube from the sealing cover, thereby improving the efficiency of removing the titanium tube.

[0089] Preferably, a first connecting portion (not shown in the figure) and a second connecting portion (not shown in the figure) are respectively provided on the inner wall of the opening and the outer wall of the extrusion head 7. The first connecting portion and the second connecting portion cooperate with each other so that during the stamping process, the extrusion head 7 cannot rotate relative to the protective shell 1.

[0090] The larger end of the extrusion head 7 (i.e., the end retained within the opening or cavity 10) is provided with a sleeve whose inner wall is provided with splines. The connecting rod 5 rests against the sleeve, and the outer wall of the end of the connecting rod 5 that rests against the sleeve is provided with a second keyway that matches the spline. During the stamping process, the spline and the second keyway cooperate to prevent the connecting rod 5 from rotating relative to the protective housing 1.

[0091] Furthermore, in the embodiment of this specification, the slider 2 is a truncated cone-shaped slider, and the diameter of the end of the slider 2 close to the extrusion head 7 is smaller than the diameter of the end close to the thin-walled titanium tube blank 3. Correspondingly, the inner diameter of the protective shell 1 gradually decreases from the end close to the sealing cover to the end close to the extrusion head 7 (that is, the size of the cavity 10 close to the sealing cover is larger than the size of the end close to the extrusion head 7). In addition, the high-pressure pump 4 is arranged on the side of the protective shell 1 close to the sealing cover, so that when the injected punching fluid flows in the cavity 10, it will flow from the larger end to the smaller end, so that the fluid pressure of the punching fluid exerts a fluid force on the thin-walled titanium tube blank 3 and the slider 2 from the side of the stamping die 8 as much as possible, which is beneficial to improving the stamping quality of the titanium tube. Under the action of the punching fluid, the slider 2 will drive the thin-walled titanium tube blank 3 and the stamping die 8 to move toward the side where the cavity gradually shrinks until the punching fluid abuts against the extrusion head 7.

[0092] During the stamping process, the slider 2 will continuously rest against the extrusion head 7 under the action of the stamping fluid, and the stamping die 8 will exert a stamping effect on the thin-walled titanium tube blank 3 under the action of the stamping fluid, so that the thin-walled titanium tube blank 3 is deformed and gradually filled in the interior of the stamping die 8. After the stamping is completed, the thin-walled titanium tube blank will have the internal shape of the stamping die 8 (i.e. Figure 2 shown).

[0093] Furthermore, the slider 2 is a tapered slider, and the diameter of the slider 2 near the thin-walled titanium tube blank 3 is larger than the diameter of the stamping die 8 near the slider 2 to ensure that the slider 2 firmly fixes the thin-walled titanium tube blank 3.

[0094] Furthermore, the cavity 10 is provided with a slide groove on the inner wall surface near the extrusion head 7. When the slider 2 together with the thin-walled titanium tube blank 3 is loaded into the cavity, it is necessary to align with the slide groove and move along the direction of the slide groove; during the stamping process, the slider 2 will not be able to rotate relative to the connecting rod 5 under the action of the slide groove, and will be relatively firmly pressed against the extrusion head 7.

[0095] Therefore, during the stamping process, the extrusion head 7, the slider 2 and the connecting rod 5 will not rotate relative to the protective shell 1, so as to ensure that the fluid force is stably applied to the thin-walled titanium tube blank 3.

[0096] Before using the variable-section thin-walled titanium tube forming method and system based on fluid mechanics provided in the embodiments of this specification to stamp a thin-walled titanium tube blank, the thin-walled titanium tube blank must first be loaded, as follows:

[0097] Step 1: Select an appropriate stamping die 8 and a thin-walled titanium tube blank 3 according to the cross-sectional structural characteristics of the required variable-section thin-walled titanium tube; load a small portion of the thin-walled titanium tube blank 3 into the stamping die 8, and fix the other end of the thin-walled titanium tube blank 3 to the slider 2.

[0098] Preferably, the outer diameter of the thin-walled titanium tube blank 3 should be slightly smaller than the inner diameter of the stamping die 8, which facilitates filling and reduces the gap between the stamping die 8 and the thin-walled titanium tube blank 3, so that the stamping fluid flowing between the stamping die 8 and the thin-walled titanium tube blank 3 is as small as possible, thereby reducing its offsetting effect on the stamping pressure of the stamping fluid outside the stamping die 8, thereby maximizing the fluid pressure acting on the stamping die 8.

[0099] Step 2: Select an appropriate connecting rod 5. Connect one end of the connecting rod 5 to the loading rod 9 via the positioning boss 6; pass the other end of the connecting rod 5 through the stamping die 8, the thin-walled titanium tube blank 3, and the central opening of the slider 2 in sequence to complete the loading preparation.

[0100] Preferably, the length of the connecting rod 5 should be adapted to the length of the cavity (i.e., the distance between the sealing cover and the sleeve of the extrusion head 7), and the outer diameter of the connecting rod 5 should be adapted to the inner diameter of the thin-walled titanium tube blank 3. Furthermore, a sealing structure (not shown in the figure) can be provided at the junction of the connecting rod 5 and the stamping die 8, so that the amount of stamping liquid between the connecting rod 5 and the thin-walled titanium tube blank 3, and in the space enclosed by the connecting rod 5, the thin-walled titanium tube blank 3, and the stamping die 8 is as small as possible, thereby improving the stamping effect on the thin-walled titanium tube blank 3 and improving the stamping forming effect.

[0101] Step 3: Open the sealing cover, and extend the connecting rod 5 and the slider 2, thin-walled titanium tube blank 3 and stamping die 8 sleeved on the outside of the connecting rod 5 into the interior of the protective shell 1 through the filling rod 9 and the positioning boss 6, so that the end of the connecting rod 5 rests on the shaft sleeve of the extrusion head 7.

[0102] Step 4: withdraw the filling rod 9 and the positioning boss 6 connected to its end, close the sealing cover so that the two ends of the connecting rod 5 are respectively against the shaft sleeve and the sealing cover. At this point, the filling operation is completed and the stamping process can be carried out.

[0103] When the stamping is completed, the shape of the thin-walled titanium tube blank 3 is the same as the internal shape of the stamping die 8 (such as Figure 2 The removal operation of the formed thin-walled titanium tube with variable cross-section is as follows:

[0104] Step 1: Open the sealing cover and discharge the punching liquid in the cavity 10 of the protective housing 1;

[0105] Step 2: Connect the loading rod 9 to the connecting rod 5 through the positioning boss 6 to extract the connecting rod 5 and the variable-section thin-walled titanium tube sleeved on the outside of the connecting rod 5; at the same time, push the extrusion head 7 toward the sealing cover to facilitate the removal of the variable-section thin-walled titanium tube.

[0106] Step 3: Pull the variable-section thin-walled titanium tube, the stamping die 8 and the slider 2 away from the connecting rod 5 , and separate the variable-section thin-walled titanium tube from the stamping die 8 and the slider 2 .

[0107] The embodiment of this specification also provides a method for forming a thin-walled titanium tube with a variable cross-section based on fluid mechanics. Figure 3 It is a schematic diagram of the steps of a variable cross-section thin-walled titanium tube forming method based on fluid mechanics provided in the embodiment of this article. It should be noted that this specification provides the method operation steps as described in the embodiment or flow chart, but it may include more or fewer operation steps based on conventional or non-creative labor. The order of steps listed in the embodiment is only one way of executing the steps among many, and does not represent the only execution order. When the actual system or device product is executed, it can be executed in the order or in parallel according to the method shown in the embodiment or the accompanying drawings. Specifically, Figure 3 As shown, the method may include:

[0108] S310: Load the thin-walled titanium tube blank into the cavity of the protective shell of the variable-section thin-walled titanium tube forming system, so that one end of the thin-walled titanium tube blank is fixed on the slider, and the other end of the thin-walled titanium tube blank is placed in the stamping die; the stamping die and the thin-walled titanium tube blank are located on the same side of the slider.

[0109] S320: Injecting punching fluid into the protective shell through a high-pressure pump, so that the fluid pressure applied by the punching fluid is transmitted to the thin-walled titanium tube blank and the slider through the punching die.

[0110] S330: monitoring the fluid pressure applied to the slider during the stamping process, so as to determine whether the stamping process is completed based on the fluid pressure applied to the slider.

[0111] S340: When the stamping process is completed, the thin-walled titanium tube blank is separated from the slider and the stamping die to obtain a formed variable-section thin-walled titanium tube.

[0112] Specifically, the method for loading the thin-walled titanium tube blank and the method for removing the formed variable-section thin-walled titanium tube have been described in detail in the previous system section and will not be repeated here.

[0113] The embodiments of this specification provide a variable-section thin-walled titanium tube forming method based on fluid mechanics, which uses stamping liquid to achieve stamping of the titanium tube. It can fully utilize the advantage of the uniform pressure distribution of the stamping liquid in various parts of the stamping die, reduce wall thickness differences, reduce or even eliminate mechanical traces caused by other hardware processing methods, and is beneficial to improving the quality of the variable-section thin-walled titanium tube after casting.

[0114] Furthermore, in the embodiment of this specification, in step S330, monitoring the fluid pressure applied to the slider during the stamping process can be achieved by the following method:

[0115] Based on fluid mechanics, constructing a fluid pressure equation on the slider;

[0116]

[0117]

[0118]

[0119] Wherein, ρ is the fluid density of the punching fluid; Π is the shear stress; t is the punching time; is the gradient; (4) , Ψ (5) and Ψ (6) are the 4th, 5th and 6th order moments respectively; u is the velocity vector of the punching fluid; p is the stress tensor of the punching fluid; η is the viscosity coefficient of the punching fluid; q(κ) is the nonlinear dissipation factor; Δ is the additional normal stress; γ is the specific heat ratio; I is the unit matrix; η b is the volume viscosity coefficient; Q is the heat flow; c p is the constant pressure specific heat; T is the temperature of the stamping fluid; λ is the thermal conductivity coefficient of the stamping fluid; and the fluid pressure exerted on the slider during the stamping process is monitored based on the additional positive pressure obtained by solving the equation.

[0120] That is, in the above-constructed fluid pressure equation, the additional normal stress Δ can be understood as the fluid pressure of the stamping fluid exerted on the slider. Furthermore, judging whether the stamping process is completed based on the fluid pressure exerted on the slider may include:

[0121] Determining whether the fluid pressure applied to the slider reaches a preset pressure threshold and satisfies a preset time condition;

[0122] If so, it is determined that the stamping process is finished.

[0123] For example, a curve of the additional normal stress Δ versus stamping time t can be plotted, and the completion of the stamping process can be determined based on the value and change trend of the additional normal stress Δ:

[0124] As the amount of punching fluid injected into the cavity 10 gradually increases, the fluid pressure (additional normal stress Δ) acting on the slider 2 will also gradually increase. When the punching fluid fills the cavity 10 of the protective housing 1, the punching fluid can be continued to be injected into the cavity for a short period of time. At this time, the liquid pressure of the punching fluid in the cavity 10 will further increase, causing the fluid pressure acting on the punching die 8 to also increase. When the fluid pressure on the slider reaches a preset pressure threshold and the punching time meets the preset time condition, the punching process can be determined to be complete.

[0125] The following describes the process for solving the additional normal stress Δ based on the fluid pressure equation. This process can then be used to determine whether the fluid pressure acting on the slider has reached a preset pressure threshold. In practice, solving for the additional normal stress Δ can be performed using a computer, ensuring both high computational efficiency and more accurate results.

[0126] In order to simplify and reduce the difficulty of solving the equation, the time partial derivative of the non-conserved quantity in the equation can be ignored, that is, the time partial derivative on the left side of the equation can be ignored to obtain a set of steady evolution equations. This is because, in the specific monitoring process, from the perspective of the evolution time scale of the non-conserved quantity, the conserved quantity can be regarded as a constant. Moreover, when iteratively solving the non-conserved quantity, the conserved quantity in the equation can be regarded as a constant; at the same time,

[0127] Item and Items can be ignored.

[0128] In the fluid pressure equation,

[0129] represents the gradient of vector u;

[0130] represents the divergence of vector u;

[0131] represents the second-order partial derivative, i.e. the Hamiltonian operator;

[0132] During the simplification process, define:

[0133] And let k = cR, c is a constant coefficient.

[0134] Since the constant coefficient c is introduced, the negative sign can be substituted into c in the process of simplifying the fluid pressure equation, so the "-" signs on the right sides of the three equations can all be replaced with "+" signs.

[0135] Furthermore, the Rayleigh-Onsager dissipation function is introduced to reduce the above equations into one equation, and we get:

[0136]

[0137] in, is the dissipation function; c is a constant coefficient;

[0138]

[0139] Wherein, the superscript ^ indicates dimensionless; f b is the ratio of volume viscosity to shear viscosity; the subscript 0 represents the initial value in the NS equation, that is, represents the dimensionless initial value of shear stress, represents the initial value of the dimensionless heat flow, It represents the initial value of dimensionless additional normal stress. Unless otherwise specified, the symbols in the following formulas are the same as those mentioned above.

[0140] Furthermore, by iteratively solving the above formula, we can obtain the following after the nth iteration:

[0141]

[0142] is the dissipation function after the nth iteration; is the dimensionless shear stress after the nth iteration; is the dimensionless additional normal stress after the nth iteration; is the dimensionless heat flow after the nth iteration;

[0143] And after the n+1th iteration:

[0144]

[0145]

[0146]

[0147]

[0148] in, is the dissipation function after the n+1th iteration; is the dimensionless shear stress after the n+1th iteration; is the dimensionless additional normal stress after the n+1th iteration; is the dimensionless heat flux after the n+1th iteration.

[0149] Therefore, the precalculation is performed according to the linear NSF constitutive model:

[0150] That is, the initial values ​​of shear stress, additional normal stress and heat flow are obtained (subscript 0).

[0151] Then, the initial values ​​of shear stress, additional normal stress and heat flow are substituted into the iteration to obtain the values ​​of shear stress, additional normal stress and heat flow after one calculation (subscript 1).

[0152]

[0153]

[0154]

[0155] Then, the first calculated values ​​of shear stress, additional normal stress and heat flow (subscript 1) are substituted into the iteration to obtain the values ​​of shear stress, additional normal stress and heat flow after all iterations.

[0156] According to the structure of two adjacent iterations and the preset convergence conditions, determine whether the iteration is completed:

[0157] Specifically, in the embodiment of this specification, the convergence condition is When the convergence condition is met, it means that the difference between the dissipation functions at two adjacent instants is extremely small. At this time, the iteration stops and the final shear stress, additional normal stress and heat flow values ​​are obtained.

[0158] It should be noted that in the embodiments of this specification, the flow rate of the stamping fluid and the speed at which the slider moves to the side where the space gradually decreases are primarily regulated based on the actual calculated additional normal stress to achieve control of the stamping process. Since the pressure within the cavity can be adjusted by the movement of the slider after the high-pressure pump injects the stamping fluid into the cavity, in other feasible embodiments, the slider's speed can also be used to characterize and monitor the fluid pressure applied to the slider during the stamping process.

[0159] Furthermore, in the embodiment of this specification, in step S310, before loading the thin-walled titanium tube blank into the variable-section thin-walled titanium tube forming system, the method further includes:

[0160] According to the cross-sectional structural characteristics of the required variable-section thin-walled titanium tube, the appropriate stamping die and thin-walled titanium tube blank are selected.

[0161] For example, Figure 1 and Figure 2 As shown, the required variable cross-section thin-walled titanium tube includes connected variable cross-section sections (i.e., the outer diameter of this section of titanium tube gradually decreases) and non-variable cross-section sections (i.e., the outer diameter of this section of titanium tube does not change, and the outer diameter is equal to the maximum outer diameter of the variable cross-section section). On this basis, the stamping die is selected, and the selected thin-walled titanium tube blank can be a cylindrical blank with an outer diameter equal to the inner diameter of the non-variable cross-section section (such as Figure 1 shown).

[0162] Furthermore, in an embodiment of this specification, the variable-section thin-walled titanium tube forming system further includes a connecting rod and an extrusion head, the extrusion head being located at one end of the protective housing, the connecting rod sequentially passing through the stamping die, the thin-walled titanium tube blank, and the slider and resting against the extrusion head, the connecting rod being used to limit the movement direction of the thin-walled titanium tube blank and the slider during the stamping process. In step S310: before loading the thin-walled titanium tube blank into the variable-section thin-walled titanium tube forming system, the method further includes:

[0163] According to the required cross-sectional structural characteristics of the thin-walled titanium tube with variable cross-section, an appropriate connecting rod is selected.

[0164] For example, in the embodiment of this specification, the inner diameter of the required variable-section thin-walled titanium tube remains unchanged, and to match it, the connecting rod can be a cylindrical long rod with an outer diameter equal to the inner diameter of the required variable-section thin-walled titanium tube.

[0165] The variable-section thin-walled titanium tube forming system also includes a filling rod, which is used to load the thin-walled titanium tube blank into the cavity of the protective shell and to remove the stamped variable-section thin-walled titanium tube from the cavity. The end of the filling rod is connected to a positioning boss, which matches the connecting rod.

[0166] The embodiment of this specification also provides a variable-section thin-wall titanium tube forming device based on fluid mechanics, the device comprising:

[0167] Establish a module for establishing the fluid pressure equation of the slider during the stamping process;

[0168] a calculation module, configured to calculate the fluid pressure of the slider during the stamping process according to the fluid pressure equation;

[0169] The judging module is used to judge whether the stamping process is completed according to the calculated fluid pressure. When the stamping process is completed, the stamping fluid flow rate of the high-pressure pump is controlled to zero, and the formed variable-section thin-walled titanium tube is taken out.

[0170] The beneficial effects achieved by the device provided in the embodiments of this specification are consistent with the beneficial effects achieved by the above-mentioned method and will not be repeated here.

[0171] like Figure 4As shown, a computer device provided in an embodiment of this invention is provided. The variable-section thin-wall titanium tube forming device based on fluid mechanics in this specification can be a computer device in this embodiment, which performs the above-mentioned method of this invention. The computer device 402 may include one or more processors 404, such as one or more central processing units (CPUs), each of which can implement one or more hardware threads. The computer device 402 may also include any memory 406, which is used to store any type of information such as code, settings, data, etc. For example, without limitation, the memory 406 may include any one or more combinations of the following: any type of RAM, any type of ROM, flash memory device, hard disk, optical disk, etc. More generally, any memory can use any technology to store information. Furthermore, any memory can provide volatile or non-volatile retention of information. Furthermore, any memory can represent a fixed or removable component of the computer device 402. In one embodiment, when the processor 404 executes the associated instructions stored in any memory or combination of memories, the computer device 402 can perform any operation of the associated instructions. The computer device 402 also includes one or more drive mechanisms 408 for interacting with any memory, such as a hard disk drive mechanism, an optical disk drive mechanism, and the like.

[0172] The computer device 402 may also include an input / output module 410 (I / O) for receiving various inputs (via input devices 412) and for providing various outputs (via output devices 414). A specific output mechanism may include a presentation device 416 and an associated graphical user interface (GUI) 418. In other embodiments, the input / output module 410 (I / O), input devices 412, and output devices 414 may not be included, and the computer device 402 may simply be a computer device in a network. The computer device 402 may also include one or more network interfaces 420 for exchanging data with other devices via one or more communication links 422. One or more communication buses 424 couple the components described above together.

[0173] The communication link 422 may be implemented in any manner, for example, via a local area network, a wide area network (e.g., the Internet), a point-to-point connection, etc., or any combination thereof. The communication link 422 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0174] Corresponding to Figure 3 The embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which executes the steps of the above method when executed by a processor.

[0175] The embodiment of the present invention also provides a computer readable instruction, wherein when the processor executes the instruction, the program causes the processor to execute the following Figure 3 The method shown.

[0176] The embodiment of the present invention further provides a computer program product, comprising at least one instruction or at least one program segment, wherein the at least one instruction or the at least one program segment is loaded and executed by a processor to implement the following Figure 3 The method shown.

[0177] It should be understood that in the various embodiments of this document, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this document.

[0178] It should also be understood that in the embodiments herein, the term "and / or" merely describes an association between associated objects, indicating that three possible relationships exist. For example, "A and / or B" could represent: A alone, A and B simultaneously, or B alone. Furthermore, the character " / " in this document generally indicates an "or" relationship between the associated objects.

[0179] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the composition and steps of each example according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this document.

[0180] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0181] In the several embodiments provided herein, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices, or units, or can be an electrical, mechanical, or other form of connection.

[0182] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments herein.

[0183] In addition, the functional units in the various embodiments herein may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0184] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this article is essentially or the part that contributes to the existing technology, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of this article. The aforementioned storage medium includes: various media that can store program code, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0185] This article uses specific embodiments to illustrate the principles and implementation methods of this article. The description of the above embodiments is only used to help understand the methods and core ideas of this article. At the same time, for those skilled in the art, based on the ideas of this article, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation to this article.

Claims

1. A method for forming a thin-walled titanium tube with a variable cross-section based on fluid mechanics, characterized in that: include: The thin-walled titanium tube blank is loaded into the cavity of the protective shell of the variable-section thin-walled titanium tube forming system, so that one end of the thin-walled titanium tube blank is fixed on the slider, and the other end of the thin-walled titanium tube blank is placed in the stamping die, and the stamping die and the thin-walled titanium tube blank are located on the same side of the slider; Injecting punching fluid into the protective housing through a high-pressure pump, so that the fluid pressure exerted by the punching fluid is transmitted to the thin-walled titanium tube blank and the slider through the punching die; monitoring the fluid pressure applied to the slider during the stamping process, so as to determine whether the stamping process is completed according to the fluid pressure applied to the slider; When the stamping process is completed, the thin-walled titanium tube blank is separated from the slider and the stamping die to obtain a formed variable-section thin-walled titanium tube; Monitoring the fluid pressure applied to the slider during the stamping process further includes: Based on fluid mechanics, constructing a fluid pressure equation on the slider; Wherein, ρ is the fluid density of the punching fluid; Π is the shear stress; t is the punching time; is the gradient; (4) , Ψ (5) and Ψ (6) are the 4th, 5th and 6th order moments respectively; u is the velocity vector of the punching fluid; p is the stress tensor of the punching fluid; η is the viscosity coefficient of the punching fluid; q(κ) is the nonlinear dissipation factor; Δ is the additional normal stress; γ is the specific heat ratio; I is the unit matrix; η b is the volume viscosity coefficient; Q is the heat flow; c p is the specific heat at constant pressure; T is the temperature of the stamping fluid; λ is the thermal conductivity coefficient of the stamping fluid; The fluid pressure to which the slider is subjected during the stamping process is monitored based on the additional positive pressure obtained by solving the equation.

2. The method according to claim 1, characterized in that Determining whether the stamping process is completed according to the fluid pressure applied to the slider further includes: Determining whether the fluid pressure applied to the slider reaches a preset pressure threshold and satisfies a preset time condition; If so, it is determined that the stamping process is finished.

3. The method according to claim 1, characterized in that Before loading the thin-walled titanium tube blank into the variable-section thin-walled titanium tube forming system, the method further comprises: According to the cross-sectional structural characteristics of the required variable-section thin-walled titanium tube, the appropriate stamping die and thin-walled titanium tube blank are selected.

4. The method according to claim 3, characterized in that The variable-section thin-walled titanium tube forming system further includes a connecting rod and an extrusion head. The extrusion head is located at one end of the protective shell. The connecting rod sequentially passes through the stamping die, the thin-walled titanium tube blank, and the slider and abuts against the extrusion head. The connecting rod is used to limit the movement direction of the thin-walled titanium tube blank and the slider during the stamping process. Before loading the thin-walled titanium tube blank into the variable-section thin-walled titanium tube forming system, the method further comprises: According to the required cross-sectional structural characteristics of the thin-walled titanium tube with variable cross-section, an appropriate connecting rod is selected.

5. The method according to claim 4, characterized in that The variable-section thin-walled titanium tube forming system further includes a loading rod, which is used to load the thin-walled titanium tube blank into the cavity of the protective shell and to remove the stamped variable-section thin-walled titanium tube from the cavity, and the end of the loading rod is connected to a positioning boss; A first keyway is provided at one end of the positioning boss connected to the connecting rod, and a key tooth is provided on the outer wall of one end of the connecting rod connected to the positioning boss. The first keyway and the key tooth are adapted to limit the rotation of the connecting rod relative to the positioning boss.

6. The method according to claim 5, characterized in that A sealing cover is provided at one end of the protective shell; an opening is provided at the other end of the protective shell, and at least a portion of the extrusion head extends from the opening. The size of the opening is such that the extrusion head and the formed variable-section thin-walled titanium tube can only be removed from the sealing cover. A shaft sleeve is provided on one side of the extrusion head located in the cavity, and a spline is provided on the inner wall of the shaft sleeve; a second keyway matching the spline is provided on the outer wall of the connecting rod.

7. The method according to claim 6, characterized in that The slider is a tapered slider, and the diameter of the slider at one end close to the extrusion head is smaller than the diameter of the slider at one end close to the thin-walled titanium tube blank; The inner diameter of the protective shell gradually decreases from an end close to the sealing cover to an end close to the extrusion head, and the high-pressure pump is arranged on a side of the protective shell close to the sealing cover.

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