A method for integrated precision forming of large-size pure aluminum metal diaphragms

Abstract

The present invention relates to an integrated precision forming method for large-scale pure aluminum metal diaphragms, belonging to the field of precision forming. A spinning-turning composite integrated precision forming process is selected, and the product is clamped once by alternating spinning and turning processes, completing all surface and dimensional processing. After processing, processing stress is eliminated by heat treatment, thereby achieving precision forming of the metal diaphragm. The present invention can be widely used in the integrated forming of pure aluminum (aluminum alloy) metal diaphragms, achieving precision forming and uniform organization of large-scale pure aluminum metal diaphragms, and ensuring that they do not suffer from failures such as wrinkling, eccentricity, and cracking during the flipping process.

Description

Technical Field

[0001] The invention relates to an integrated precision forming processing method for a large-size pure aluminum metal diaphragm, belonging to the field of precision forming. Background Art

[0002] In order to reduce the safety and technical risks of high-pressure gas storage, a power system adopts a gas self-pressurization solution. During operation, gas is used to pressurize the gas cavity of the metal diaphragm tank, and the metal diaphragm flips and squeezes the liquid cavity to achieve the supply of propellant. Figure 2 The metal diaphragm shown is made of industrial pure aluminum 1050A material, and the diameter of the metal diaphragm reaches 718mm. In order to achieve effective turnover of the large diameter metal diaphragm, the thickness is controlled in 7 zones in the radius height direction, with a thickness range of 2mm to 3mm. The surface wall thickness accuracy is required to be ±0.05mm, the diameter tolerance of the large end flange is 0 to 0.1mm, and the wall thickness difference at the same latitude is not greater than 0.05mm. Figure 1 As shown. The low dimensional accuracy and uneven organization of the same latitude of the metal diaphragm during the precision forming process can easily lead to wrinkles in the metal diaphragm during the flipping process (such as Figure 2 As shown), eccentricity (as shown Figure 3 as shown) and cracking (as shown) Figure 4 As shown in the figure, failure faults such as those shown in the figure above will induce the metal diaphragm air cavity and liquid cavity to pass through the cavity, which is prone to serious explosion accidents during high-pressure gas operation. Therefore, it is urgent to study a new metal diaphragm precision forming processing method to ensure the normal operation of the power system. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: to overcome the shortcomings of the existing technology and provide an integrated precision forming processing method for large-sized pure aluminum material metal diaphragms, to achieve precision forming processing and uniform organization of large-sized pure aluminum material metal diaphragms, and to ensure that they do not suffer from failures such as wrinkling, eccentricity and cracking during the flipping process.

[0004] The technical solution of the present invention is:

[0005] A large-sized pure aluminum metal diaphragm integrated precision forming processing method, comprising:

[0006] A spinning die is designed, the spinning die comprising a spinning body, a first tail top, and a second tail top. The outer profile of the spinning body is consistent with the inner profile of the metal diaphragm to be processed. A hollow cavity is processed inside the spinning body, and the hollow cavity is connected to a vacuum pump. The metal diaphragm to be processed sequentially comprises a hemispherical section, a conical section, and a flanging section.

[0007] Clamp the spinning tire body, the first tail top, and the second tail top and align them; use a vacuum pump to evacuate the hollow cavity of the spinning tire body;

[0008] Clamping the blank sheet material so that it is located on the top of the spinning tire body, and using the first tail pusher to push the blank sheet material tightly onto the spinning tire body;

[0009] Perform multiple deep drawing and spinning on the blank sheet along the outer surface of the spinning tire body to ensure that the blank sheet after spinning fits the outer surface of the hemispherical section and cone section of the spinning tire body;

[0010] Correct the flanged part of the blank sheet after spinning so that the flanged part is partially attached to the tire;

[0011] Remove the first tail top, use the spinning forming die as the turning inner tube, and turn the outer allowance of the wall thickness of the hemisphere and cone section of the blank sheet to ensure that the thickness accuracy of the hemisphere and cone section of the processed parts meets the requirements;

[0012] Control the second tail top to press the big end of the part tightly, and the second tail top serves as the big end flanging male mold;

[0013] The flanging is performed by deep drawing and spinning along the second tail top to form the inner surface of the flanging part;

[0014] Cut the outer margin of the flanged part of the part to make the wall thickness of the flanged part meet the requirements;

[0015] Turning is used to remove the axial allowance of the flanged part of the part so that the flanged part height meets the requirements;

[0016] The parts are annealed and heat-treated using an air resistance furnace and then air-cooled to room temperature to obtain a metal diaphragm.

[0017] Preferably, the first tail top is a columnar structure, and the contact portion between the first tail top and the spun tire body is arc-shaped and conforms to the spun tire body.

[0018] Preferably, the second tail top is a U-shaped structure, the inner wall profiles on both sides of the opening end of the U-shaped structure are consistent with the outer profile of the metal diaphragm cone section to be processed, and the outer wall profiles on both sides of the opening end of the U-shaped structure are consistent with the inner profile of the metal diaphragm flange part; the second tail top has a hole in the axial center, and the first tail top can retreat along the opening.

[0019] Preferably, a columnar limiting platform is designed at the bottom of the spinning tire body.

[0020] Preferably, the parts are subjected to annealing heat treatment, air-cooled to room temperature, and then tested for hardness and mechanical properties. Parts that meet the requirements are metal diaphragms.

[0021] Preferably, the blank sheet is subjected to multiple deep drawing and spinning along the outer surface of the spinning tire body to ensure that the blank sheet after spinning fits the outer surface of the hemispherical segment and the conical segment of the spinning tire body in the following manner:

[0022] A main spinning wheel is installed on the upper and lower sides of the spinning tire body. Driven by the machine tool, the two main spinning wheels perform multiple deep drawing and spinning on the blank sheet along the outer surface of the spinning tire body to ensure that the blank sheet after spinning fits with the outer surface of the hemispherical section and the conical section of the spinning tire body.

[0023] Preferably, the method for correcting the flanged portion of the blank sheet after spinning is as follows:

[0024] A corner clearing wheel is installed on one side of the spinning tire body. Driven by the machine tool, the corner clearing wheel corrects the flanged portion of the blank sheet after spinning, so that the flanged portion is partially attached to the tire.

[0025] Preferably, the method for implementing the one-time drawing, spinning and flanging along the second tail top is as follows:

[0026] A flanging wheel is installed on one side of the spinning tire body. Driven by the machine tool, the flanging wheel draws and spins the flanging along the second tail top once to form the inner surface of the flanging part.

[0027] Preferably, the material of the contact position between the first tail top and the blank sheet material is rubber.

[0028] Preferably, the spinning die material is Cr12MoV.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) Based on the realization of product precision processing, the present invention replaces the existing hydraulic forming and die forging schemes with a spinning scheme, which can reduce 2 sets of turning fixtures and 1 set of flanging dies, and achieve a material utilization rate of more than 95%.

[0031] (2) The present invention uses a spinning carcass to make a turning inner tube, so that the product can be clamped and formed in one step, and all parts size and surface processing work is completed, ensuring that the product will not have uneven wall thickness of parts at the same latitude due to repeated clamping and repeated positioning errors during turning. The product accuracy reaches a wall thickness tolerance of ±0.05mm at each point, and a surface contour of ≤0.3mm;

[0032] (3) The present invention achieves uniformity of product structure at the same latitude through spinning, and can also verify whether the material has defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the metal diaphragm structure;

[0034] Figure 2 Flip the fold diagram for the metal diaphragm;

[0035] Figure 3 This is the flip eccentric diagram of the metal diaphragm;

[0036] Figure 4 This is the flip cracking diagram of the metal diaphragm;

[0037] Figure 5 Schematic diagram of the integrated spinning-turning forming process of the metal diaphragm, where (a) is a schematic diagram of the local forming of the top, (b) is a schematic diagram of the deep drawing and spinning forming of the hemisphere and cone section, (c) is a schematic diagram of the local angle clearing forming of the large end U-shaped flanging, (d) is a schematic diagram of the wall thickness allowance turning of the hemisphere, cone section and local U-shaped flanging, (e) is a schematic diagram of the flanging forming of the U-shaped flanging, (f) is a schematic diagram of the outer wall thickness allowance turning of the U-shaped part, and (g) is a schematic diagram of the axial allowance turning of the U-shaped flanging;

[0038] Figure 6 This is a real picture of the metal after forming;

[0039] Figure 7 Schematic diagram of the metal diaphragm segmentation. DETAILED DESCRIPTION

[0040] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0041] The present invention relates to an integrated precision forming method for a large-scale pure aluminum metal diaphragm. A certain power system adopts a gas self-pressurization scheme, and the design of the metal diaphragm storage tank volume reaches 175L. The metal diaphragm includes a hemispherical section, a conical section, and a flange section in sequence, presenting a nearly hemispherical structure. Industrial pure aluminum 1050A material is selected, and the metal diaphragm diameter reaches 718mm. To achieve effective flipping of the large-diameter metal diaphragm, it is divided into 7 zones with unequal thickness control in the radius height direction, with a thickness range of 2mm to 3mm. The surface wall thickness accuracy requirement is ±0.05mm, the diameter tolerance of the large end flange is 0 to 0.1mm, and the wall thickness difference at the same latitude is no more than 0.05mm. This metal diaphragm is a key technology in the development of power systems, and its processing quality assurance is the key to determining flight missions. The present invention adopts a spinning-turning composite integrated precision forming process method, and through the alternating forming method of spinning and turning, the product can be clamped in one go, and all surface and dimensional processing is completed. After processing, heat treatment is performed to eliminate processing stress, thereby achieving precision forming of the metal diaphragm. The present invention can be widely applied to the integrated forming process of pure aluminum (aluminum alloy) metal diaphragms.

[0042] The present invention provides a precision forming method for a large-sized pure aluminum metal diaphragm, comprising the following steps:

[0043] (1) Control the state and mechanical properties of pure aluminum raw materials and the specifications and dimensions of pure aluminum blanks to obtain blank sheets;

[0044] (2) Designing a spinning mold, wherein the spinning mold includes a spinning tire body, a first tail top and a second tail top, wherein the outer profile of the spinning tire body is consistent with the inner profile of the metal diaphragm to be processed, and a hollow cavity is processed inside the spinning tire body, and the hollow cavity is connected to a vacuum pump; Figure 7 As shown, the metal diaphragm to be processed includes a hemispherical section, a cone section and a flange section in sequence. The first tail top is a columnar structure, and the contact portion between the first tail top and the spun tire body is arc-shaped and co-shaped with the spun tire body. The second tail top is a U-shaped structure, and the inner wall profiles on both sides of the opening end of the U-shaped structure are consistent with the outer profile of the cone section of the metal diaphragm to be processed, and the outer wall profiles on both sides of the opening end of the U-shaped structure are consistent with the inner profile of the flange part of the metal diaphragm; the second tail top has an opening in the axial center, and the first tail top can retreat along the opening. A columnar limit platform is designed at the bottom of the spun tire body.

[0045] (3) Clamping the spun tire body, the first tail top, and the second tail top and aligning them; using a vacuum pump to evacuate the hollow cavity of the spun tire body; clamping the blank sheet so that it is located at the top of the spun tire body, and using the first tail top to press the blank sheet against the spun tire body.

[0046] (4) Multi-pass deep drawing and spinning of the metal diaphragm hemisphere and cone section, optimizing the spinning path and spinning gap, optimizing the spinning forming parameters, and achieving complete fit between the inner surface of the metal diaphragm hemisphere and cone section and the mold;

[0047] A main spinning wheel is installed on the upper and lower sides of the spinning tire body. Driven by the machine tool, the two main spinning wheels perform multiple deep drawing and spinning on the blank sheet along the outer surface of the spinning tire body to ensure that the blank sheet after spinning fits with the outer surface of the hemispherical section and the conical section of the spinning tire body.

[0048] (5) Replace the rotary wheel and install a corner cleaning rotary wheel on one side of the spinning tire body. The corner cleaning rotary wheel corrects the flanged part of the blank sheet after spinning under the drive of the machine tool, so that the flanged part is partially attached to the tire.

[0049] (6) Remove the first tail top and use the spinning forming mold as the inner tube to cut the outer thickness of the metal diaphragm hemisphere and cone section to ensure the thickness accuracy of the metal diaphragm hemisphere and cone section.

[0050] (7) The second tail top is used to support the large end of the part as the male mold for the large end flanging. A flanging wheel is installed on one side of the spinning tire body. The flanging wheel is driven by the machine tool to draw and spin the flanging along the second tail top once to form the inner surface of the flanging part.

[0051] (8) Cut the outer margin of the flanged part to make the wall thickness of the flanged part meet the requirements of the drawing;

[0052] (9) Turn and remove the axial allowance of the flange part of the part so that the height of the flange part meets the technical requirements of the drawing;

[0053] (10) Use air resistance furnace equipment to anneal the metal diaphragm and air cool it to room temperature to eliminate processing stress. At the same time, perform hardness and mechanical property tests. The part that meets the requirements is the metal diaphragm.

[0054] Example:

[0055] like Figure 1 As shown in the figure, this is a schematic diagram of the metal diaphragm structure. The metal diaphragm is divided into 7 zones in the radial height direction for control. The thickness accuracy requirements of each zone are specific: Zone I 2.0±0.05mm, Zone II 2.2±0.05mm, Zone III 2.4±0.05mm, Zone IV 2.6±0.05mm, Zone V 2.75±0.05mm, Zone VI 2.9±0.05mm, Zone VII 3.0±0.05mm, and the thickness difference at the same latitude is no more than 0.05mm.

[0056] The specific implementation is carried out according to the following process steps:

[0057] Step 1: Control the raw material state, mechanical performance indicators and blank blanking size: the metal diaphragm material is 1050A, the material state is H24 (incomplete annealing state), the material tensile strength is 75-100 MPa, the material yield strength is 30-40 MPa, and the material elongation is ≥45%; control the blank blanking size δ5×Φ860mm.

[0058] Step 2, such as Figure 5 As shown in (a), a spinning mold is designed. The mold material is Cr12MoV, the surface hardness is HRC55~60, the surface roughness is not greater than 1.6, the mold surface is consistent with the inner surface of the hemispherical section and the inner surface of the cone section of the metal diaphragm, the second tail top surface is consistent with the outer surface of the cone section of the part and the inner surface of the flanging part, and the material of the contact position between the first tail top and the part is a rubber surface.

[0059] Step 3, such as Figure 5 As shown in (a), the spun tire body and tail top are clamped and aligned, and the radial runout of the spun tire body is ≤0.01mm, and the axial runout is ≤0.01mm.

[0060] Step 4, such as Figure 5 As shown in (a), the blank sheet is clamped, the vacuum pump of the equipment is started, and the hollow cavity position of the spinning mold is evacuated to a negative pressure, and the vacuum degree reaches 10-2Pa.

[0061] Step 5, such as Figure 5 As shown in (a), the first tail pusher 1 presses the blank sheet with a force of 3 tons. The top of the part is locally hydraulically formed using the first tail pusher surface. The outer cylindrical flattening tool is moved to turn and trim the outer edge end face of the blank until it is completely exposed to light. The spindle speed is 200 rpm.

[0062] Step 6, such as Figure 5As shown in (b), install the rotary wheels (a pair of main rotary wheels for shaping, a rotary wheel for cleaning corners, and a rotary wheel for flanging) and tools (carbide tools for turning the wall thickness of the hemispherical part, tools for turning the outer side of the flanging part, tools for leveling the outer edge of the part, and tools for removing the axial allowance of the flanging part), start the machine tool, adjust the rotary wheel seat, and perform tool setting (tool setting for the main rotary wheel, tool setting for cleaning corners, tool setting for external cylindrical turning tools, and tool setting for the gap between the mold and the main rotary wheel).

[0063] Step 7, such as Figure 5 As shown in (b), two main rollers perform multiple deep drawing and spinning of the hemispherical and conical surface of the part and the flange to be flanging to ensure that the hemispherical and conical surface of the blank are completely attached to the tire after spinning. Drawing oil is used as the lubricant, and lubrication is ensured in time during the spinning process. The spindle speed is 400 rpm, the roller feed is 25 mm / min, and the main roller corner radius is R10.

[0064] Step 8, such as Figure 5 As shown in (c), the corner cleaning wheel is used to trim the radius of the flanging part until the outer side of the flanging R is attached to the tire, and the corner cleaning wheel is used to round the corner R4.

[0065] Step 9, such as Figure 5 As shown in (d), the first tail top is removed, and the outer margin of the hemisphere and cone section of the part is removed by turning to the wall thickness requirement. The engine oil is cooled during the turning process to prevent the tool from getting stuck. The spindle speed is 500 rpm, and the surface roughness after fine turning is not greater than 3.2.

[0066] Step 10, such as Figure 5 As shown in (e), the second tail pusher 2 presses the big end of the part, and the flanging wheel turns the big end edge with a tightening force of 2 tons.

[0067] Step 11, such as Figure 5 As shown in (f), after the turning tool is aligned on the outside of the flanging part, the outer allowance of the flanging part of the part is fine-turned.

[0068] Step 12, such as Figure 5 As shown in (g), the axial allowance of the flanging part is removed by turning, the negative pressure device of the spinning tire body is removed, and the tire center hole pressurization and tire removal parts are removed.

[0069] Step 13, Annealing and Stress Relief Heat Treatment: Before loading into the furnace, pickle the part surface. Use an air resistance furnace to ensure temperature uniformity and that the instrumentation system is within the test cycle. Lay the part flat, large end down, on the aluminum plate of the furnace, ensuring that the flash does not extend beyond the effective range of the furnace. Heat treatment is performed at a holding temperature of 410°C for 40-45 minutes, followed by air cooling to room temperature. After cooling to room temperature, hardness and mechanical properties are tested. Parts that meet the requirements are considered metal diaphragms.

[0070] The metal diaphragm products produced by this solution have undergone rollover tests and flight tests. Figure 6 shown.

[0071] The present invention aims at the precision forming of large-sized pure aluminum material metal diaphragms. By adopting a spinning-turning composite integrated precision forming process method, the precision forming processing and uniform structure of large-sized pure aluminum material metal diaphragms can be achieved, ensuring that they do not suffer from failures such as wrinkling, eccentricity and cracking during the flipping process.

[0072] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A large-scale pure aluminum material metal diaphragm integrated precision forming processing method, characterized in that: include: A spinning die is designed, the spinning die comprising a spinning body, a first tail top, and a second tail top. The outer profile of the spinning body is consistent with the inner profile of the metal diaphragm to be processed. A hollow cavity is processed inside the spinning body, and the hollow cavity is connected to a vacuum pump. The metal diaphragm to be processed sequentially comprises a hemispherical section, a conical section, and a flanging section. Clamp the spinning tire body, the first tail top, and the second tail top and align them; use a vacuum pump to evacuate the hollow cavity of the spinning tire body; Clamping the blank sheet material so that it is located on the top of the spinning tire body, and using the first tail pusher to push the blank sheet material tightly onto the spinning tire body; Perform multiple deep drawing and spinning on the blank sheet along the outer surface of the spinning tire body to ensure that the blank sheet after spinning fits the outer surface of the hemispherical section and cone section of the spinning tire body; Correct the flanged part of the blank sheet after spinning so that the flanged part is partially attached to the tire; Remove the first tail top, use the spinning forming die as the turning inner tube, and turn the outer allowance of the wall thickness of the hemisphere and cone section of the blank sheet to ensure that the thickness accuracy of the hemisphere and cone section of the processed parts meets the requirements; Control the second tail top to press the big end of the part tightly, and the second tail top serves as the big end flanging male mold; The flanging is performed by deep drawing and spinning along the second tail top to form the inner surface of the flanging part; Cut the outer margin of the flanged part of the part to make the wall thickness of the flanged part meet the requirements; Turning is used to remove the axial allowance of the flanged part of the part so that the flanged part height meets the requirements; The parts are subjected to annealing heat treatment using an air resistance furnace and then air-cooled to room temperature to obtain a metal diaphragm; The first tail top is a columnar structure, and the contact portion between the first tail top and the spun tire body is arc-shaped and conforms to the spun tire body; The second tail top is a U-shaped structure, and the inner wall surfaces on both sides of the opening end of the U-shaped structure are consistent with the outer surface of the metal diaphragm cone section to be processed, and the outer wall surfaces on both sides of the opening end of the U-shaped structure are consistent with the inner surface of the metal diaphragm flange part; the second tail top has an opening in the axial center, and the first tail top can retreat along the opening.

2. The method for integrated precision forming of a large-sized pure aluminum metal diaphragm according to claim 1, characterized in that: The bottom of the spinning tire body is designed with a columnar limiting platform.

3. The method for integrated precision forming of a large-sized pure aluminum metal diaphragm according to claim 1, characterized in that: The parts are annealed and heat treated, then air-cooled to room temperature. The hardness and mechanical properties are then tested, and the parts that meet the requirements are metal diaphragms.

4. The method for integrated precision forming of a large-sized pure aluminum metal diaphragm according to claim 1, characterized in that: The blank sheet is subjected to multiple deep drawing and spinning along the outer surface of the spinning tire body to ensure that the blank sheet after spinning fits the outer surface of the hemispherical section and the conical section of the spinning tire body in the following way: A main spinning wheel is installed on the upper and lower sides of the spinning tire body. Driven by the machine tool, the two main spinning wheels perform multiple deep drawing and spinning on the blank sheet along the outer surface of the spinning tire body to ensure that the blank sheet after spinning fits with the outer surface of the hemispherical section and the conical section of the spinning tire body.

5. The method for integrated precision forming of a large-sized pure aluminum metal diaphragm according to claim 1, characterized in that: The method for correcting the flanged portion of the blank after spinning is as follows: A corner clearing wheel is installed on one side of the spinning tire body. Driven by the machine tool, the corner clearing wheel corrects the flanged portion of the blank sheet after spinning, so that the flanged portion is partially attached to the tire.

6. The method for integrated precision forming of a large-sized pure aluminum metal diaphragm according to claim 1, characterized in that: The method of realizing the one-step drawing, spinning and flanging along the second tail top is as follows: A flanging wheel is installed on one side of the spinning tire body. Driven by the machine tool, the flanging wheel draws and spins the flanging along the second tail top once to form the inner surface of the flanging part.

7. The method for integrated precision forming of a large-sized pure aluminum metal diaphragm according to claim 1, characterized in that: The material of the contact position between the first tail top and the blank sheet material is rubber.

8. A large-scale pure aluminum material metal diaphragm integrated precision forming processing method according to any one of claims 1 to 7, characterized in that: The material of the spinning die is Cr12MoV.

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