A method of superplastic forming of a split-flow two-way barrel

Abstract

The application discloses a kind of superplastic forming methods of shunt two-way cylinder, belong to lightweight structure design and superplastic forming field, solve the problem of poor lightweight of shunt two-way cylinder in prior art, high rejection rate of parts rework.The method includes placing shunt two-way cylinder blank in female die, male die is attached to female die and blank, and the die is pressed tightly;Shunt two-way cylinder blank, male die and female die are heated, so that the blank softens;Air is filled into shunt two-way cylinder blank, and shunt two-way cylinder blank is superplastic formed under the action of gas pressure, gradually adheres to male die and female die, and the superplastic forming of shunt two-way cylinder is completed.The application can be used for the superplastic forming of shunt two-way cylinder.

Description

Technical Field

[0001] This invention belongs to the field of lightweight structural design and superplastic forming, and in particular relates to a superplastic forming method for a split-flow two-way cylinder. Background Technology

[0002] Currently, the most common lightweight structures in superplastic forming are often flat multi-layer structures and rotating multi-layer structures. Superplastic forming structures are mainly used to form closed cavity reinforcing ribs and completely open cavity structures. The simplicity of the part structure determines and affects the difficulty of applying and promoting related technologies in the manufacturing industry.

[0003] The two-way splitter cylinder can be manufactured in the following two ways:

[0004] One approach involves using multi-segment skins or shells, locally employing cast or machined frames and ribs, and supplementing these with features such as front and rear end frames to form a part docking structure.

[0005] Another approach is to use integral casting or 3D printing of the blank, followed by machining.

[0006] However, such parts inevitably bring problems such as thicker walls and limited lightweighting. At the same time, the high precision requirements of the parts during product assembly lead to frequent rework and scrapping of parts, which seriously affects the manufacturing cycle and efficiency and increases the quality control cost of the parts. Summary of the Invention

[0007] Based on the above analysis, the present invention aims to provide a superplastic forming method for a split-flow two-way cylinder, which solves the problems of poor lightweighting and high rework and scrap rate of parts in the prior art.

[0008] The objective of this invention is mainly achieved through the following technical solutions:

[0009] This invention provides a superplastic forming method for a split-flow two-way cylinder, comprising the following steps:

[0010] Step 1: Provide a split-flow two-way cylinder blank and a matching punch and die. In the split-flow two-way cylinder blank, only the arc surface set along the axial direction of the fluid pipeline is made of curved plate, while the other parts are made of flat plate.

[0011] Step 2: Place the two-way cylinder blank into the cavity mold, install the punch onto the cavity mold and the blank, and press to close the mold;

[0012] Step 3: Heat the blank, punch, and die of the split-flow cylinder to soften the blank;

[0013] Step 4: Inflate the blank of the split-flow two-way cylinder with air. Under the action of gas pressure, the blank of the split-flow two-way cylinder undergoes superplastic forming and gradually fits onto the punch and die, completing the superplastic forming of the split-flow two-way cylinder and obtaining the split-flow two-way cylinder.

[0014] Furthermore, before the punch and die are pressed together to close the mold, the two-way cylinder blank is not pressurized with air.

[0015] Furthermore, the material of the diversion cylinder is TA15 plate; the heating temperature in step 3 is 850℃~950℃.

[0016] Furthermore, step 4 includes the following steps:

[0017] Step 41: Inflate the blank of the two-way splitter cylinder with an inflation pressure of 0.4 to 0.6 MPa, maintain the pressure for 8 to 12 minutes, and shape the arc surface set along the axial direction of the fluid pipeline;

[0018] Step 42: Increase the inflation pressure to 1.8-2.3 MPa, maintain the pressure for 18-20 minutes, and push the diverter cylinder blank to stretch upwards and downwards respectively;

[0019] Step 43: Increase the inflation pressure to 2.8-3.2 MPa and hold the pressure for 8-10 minutes to ensure that all corners of the split-flow two-way cylinder blank are completely fitted to the punch and die, thus completing the superplastic forming of the split-flow two-way cylinder and obtaining the split-flow two-way cylinder.

[0020] Furthermore, the material of the diversion cylinder is aluminum alloy sheet; the heating temperature in step 3 is 350℃~550℃.

[0021] Furthermore, step 4 includes the following steps:

[0022] Step 41: Inflate the blank of the two-way splitter cylinder with an inflation pressure of 1.0 to 1.2 MPa, maintain the pressure for 10 to 15 minutes, and shape the arc surface set along the axial direction of the fluid pipeline;

[0023] Step 42: Increase the inflation pressure to 3.0-3.5 MPa, maintain the pressure for 18-20 minutes, and push the diverter cylinder blank upwards and downwards respectively;

[0024] Step 43: Increase the inflation pressure to 5.5-6.0 MPa and hold the pressure for 15-20 minutes to ensure that all corners of the split-flow two-way cylinder blank are completely fitted to the punch and die, thus completing the superplastic forming of the split-flow two-way cylinder and obtaining the split-flow two-way cylinder.

[0025] Furthermore, step 43 is followed by the following steps:

[0026] Step 44: Continue to maintain pressure for 20-30 minutes, then release the air from the two-way splitter cylinder to reduce the air supply pressure to 0.004-0.006 MPa, and continue to supply air.

[0027] Furthermore, after completing the superplastic forming of the split-flow two-way cylinder, the following steps are also included:

[0028] The inner and outer surfaces of the splitter cylinder are sequentially subjected to alkaline annealing, acid washing, polishing, and grinding to obtain a splitter cylinder with smooth gas passages and outer surfaces.

[0029] Furthermore, the punch and die are made of metal with a higher expansion rate than the material of the split-through cylinder.

[0030] Furthermore, the punch includes an upper template and a core mold disposed on the upper template. The outer surface of the core mold is divided into a core mold reserved surface, a main outer forming surface, and a flow branching surface along the direction gradually away from the upper template. The core mold reserved surface is divided into a left bulging surface, a front guide surface, a right bulging surface, and a rear guide surface, which are connected in sequence to form a closed, ring-like surface. The inner surface of the die is divided into an upper stretching cavity, a main inner surface, and a lower bulging cavity arranged in sequence. The upper stretching cavity corresponds to the position of the core mold reserved surface, and the main inner surface corresponds to the position of the main outer forming surface.

[0031] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0032] The superplastic forming method for the diversion two-way cylinder provided by this invention can produce a diversion two-way cylinder structure with integrity and lightweight. Unlike the existing superplastic process for manufacturing internal and external shapes and the traditional process of segmented forming followed by welding and assembly, it has the characteristics of speed, low blank precision requirements, and low assembly cost. It can effectively shorten the quality control cycle and process, reduce the number of parts manufacturing processes and time consumption, reduce the cost of parts manufacturing and component assembly, stabilize the quality indicators of the diversion two-way cylinder structure, and is suitable for meeting the requirements of high efficiency, intelligence, and automation.

[0033] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0034] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0035] Figure 1 A schematic flowchart of the superplastic forming method for the diversion two-way cylinder provided in Embodiment 1 of the present invention is shown below;

[0036] Figure 2 This invention provides a schematic diagram of the blank structure in the superplastic forming method of the diversion two-way cylinder provided in Embodiment 1;

[0037] Figure 3 An exploded view of the blank in the superplastic forming method of the diversion two-way cylinder provided in Embodiment 1 of the present invention;

[0038] Figure 4 This invention provides a schematic diagram of the structure of the punch and die in the superplastic forming method of the split-flow two-way cylinder provided in Embodiment 1;

[0039] Figure 5 This invention provides a schematic diagram of the punch structure in the superplastic forming method of the split-flow two-way cylinder provided in Embodiment 1;

[0040] Figure 6 This invention provides a schematic diagram of the die structure in the superplastic forming method of the split-flow two-way cylinder provided in Embodiment 1;

[0041] Figure 7 This invention provides a schematic diagram of the assembly of the blank with the punch and die in the superplastic forming method of the diverter cylinder provided in Embodiment 1 of the present invention;

[0042] Figure 8 This is a schematic diagram of the structure of the diversion two-way cylinder obtained by the superplastic forming method of the diversion two-way cylinder provided in Embodiment 1 of the present invention.

[0043] Figure label:

[0044] 100-Diverter cylinder body; 200-Diverter cylinder body blank; 201-Left arc plate; 202-Left end cap; 203-Left bending plate; 204-Diverter crotch; 205-Right bending plate; 206-Right end cap; 207-Right arc plate; 208-Base plate; 209-Ventilation pipe; 300-Punch; 301-Upper template; 302-Main outer forming surface; 303-Left bulging surface; 304-Front front; 305-Diverter crotch forming surface; 400-Die; 401-Ventilation groove; 402-Upper stretching cavity; 403-Main inner forming surface; 404-Lower bulging cavity. Detailed Implementation

[0045] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of the present invention and, together with the embodiments of the present invention, serve to illustrate the principles of the present invention.

[0046] Two-way splitter cylinders are mainly used for airflow transport. In order to reduce gas flow resistance and ensure air intake efficiency, the walls of two-way splitter cylinders are usually flat or curved and do not have corner structures. However, existing superplastic forming is usually used for forming regular shapes such as flat surfaces or cylinders. For structures with too many curved surfaces and no corners (such as two-way splitter cylinders), the structure, design and manufacturing of the blank are very complex, resulting in poor feasibility of blank manufacturing for such structures. Superplastic forming of such structures is usually not possible.

[0047] Example 1

[0048] This embodiment provides a superplastic forming method for a split-flow two-way cylinder. See [link to documentation]. Figure 1 The superplastic forming method for preparing the diverterless two-way cylinder 100 includes the following steps:

[0049] Step 1: Provide a two-way splitter cylinder blank 200 and mating punches 300 and dies 400. In the two-way splitter cylinder blank 200, only the arc surface along the axial direction of the fluid pipeline is made of curved sheet metal; all other parts are made of flat sheet metal. See [link to relevant documentation]. Figures 2 to 7 ;

[0050] Step 2: Place the diverter cylinder blank 200 in the cavity mold 400, and install the punch 300 onto the cavity mold 400 and the diverter cylinder blank 200, and press them together to close the mold.

[0051] Step 3: Heat the two-way splitter cylinder blank 200, punch 300 and die 400 to soften the two-way splitter cylinder blank 200;

[0052] Step 4: Inflate the split-flow two-way cylinder blank 200 with gas (e.g., inert gas). Under the gas pressure, the split-flow two-way cylinder blank 200 undergoes superplastic forming, gradually conforming to the punch 300 and the die 400, completing the superplastic forming of the split-flow two-way cylinder 100, thus obtaining the split-flow two-way cylinder 100. See [link / reference] Figure 8 .

[0053] Compared with existing technologies, the superplastic forming method for the diversion two-way cylinder provided in this embodiment can produce a structure of the diversion two-way cylinder 100 with integrity and lightweight. It is different from the existing superplastic process for manufacturing internal and external shapes and the traditional process of segmented forming followed by welding and assembly. It has the characteristics of being fast, having low requirements for blank precision, and low assembly cost. It can effectively shorten the quality control cycle and process, reduce the number of parts manufacturing processes and time consumption, reduce the cost of parts manufacturing and component assembly, stabilize the quality indicators of the diversion two-way cylinder 100 structure, and is suitable for meeting the requirements of high efficiency, intelligence and automation.

[0054] For example, the structure of the above-mentioned diverter cylinder blank 200 is as follows:

[0055] The diversion two-way cylindrical blank 200 includes a left arc plate 201, a left end cap 202, a left curved plate 203, a diversion vent 204, a right curved plate 205, a right end cap 206, a right arc plate 207, and a bottom plate 208. The left arc plate 201 and the left curved plate 203 form one fluid passage of the diversion two-way cylindrical blank 200, and the right arc plate 207 and the right curved plate 205 form the other fluid passage of the diversion two-way cylindrical blank 200. The upper ends of the left arc plate 201 and the left curved plate 203 are both connected to the left end cap 202. The edge shape of the left end cap 202 is conformal to the shape formed by the upper ends of the left arc plate 201 and the left curved plate 203. The lower end of the left curved plate 203 is connected to one side of the diversion vent 204. The right arc plate... The upper ends of 207 and right curved plate 205 are both connected to right end cap 206. The edge shape of right end cap 206 is conformal to the shape formed by the upper ends of right curved plate 207 and right curved plate 205. The lower end of right curved plate 205 is connected to the other side of diversion septum 204. The lower end of diversion septum 204 is connected to the side of left curved plate 201 and right curved plate 207 respectively. The lower ends of left curved plate 201 and right curved plate 207 are both connected to bottom plate 208, thereby forming an internally sealed diversion two-way cylinder blank 200.

[0056] By analyzing the wall structure of the diversion two-way cylinder 100, it is simplified and disassembled. The complex curved surface of the diversion two-way cylinder 100 is decomposed into a left arc plate 201, a left curved plate 203, a diversion slit 204, a right curved plate 205, and a right arc plate 207, making the diversion two-way cylinder blank 200 feasible to manufacture. In addition, by setting the bottom plate 208 and the left end cap 202, the left arc plate 201, the left end cap 202, the left curved plate 203, the diversion slit 204, the right curved plate 205, the right end cap 206, the right arc plate 207, and the bottom plate 208 form an internally sealed diversion two-way cylinder blank 200, thereby enabling the superplastic forming of the diversion two-way cylinder 100.

[0057] Furthermore, the left arc plate 201, left bending plate 203, right bending plate 205 and right arc plate 207 of the diversion two-way cylinder blank 200 with this structure can generate an upward lifting driving force on the diversion crotch 204 area during the forming process, thereby enabling the diversion crotch 204 to be attached to the punch 300.

[0058] Among them, the left end cap 202, the right end cap 206 and the bottom plate 208 are flat parts.

[0059] The cross-sectional shape of the left curved plate 203 is U-shaped, including a first left chamfer plate, a first left flat plate, a second left chamfer plate, a second left flat plate, a third left chamfer plate, a third left flat plate, and a fourth left chamfer plate connected in sequence. The first left flat plate is fixedly connected to one side of the left curved plate 201 through the first left chamfer plate, and the third left flat plate is fixedly connected to the other side of the left curved plate 201 through the fourth left chamfer plate, thereby forming one of the fluid passages of the two-way cylindrical blank 200. The first left chamfer plate, the second left chamfer plate, the third left chamfer plate, and the fourth left chamfer plate are all located at the chamfer.

[0060] The right curved plate 205 has a concave cross-sectional shape and includes a first right chamfer plate, a first right flat plate, a second right chamfer plate, a second right flat plate, a third right chamfer plate, a third right flat plate, and a fourth right chamfer plate connected in sequence. The first right flat plate is fixedly connected to one side of the right arc plate 207 through the first right chamfer plate, and the third right flat plate is fixedly connected to the other side of the right arc plate 207 through the fourth right chamfer plate, thereby forming another fluid passage of the diversion two-way cylindrical blank 200. The first right chamfer plate, the second right chamfer plate, the third right chamfer plate, and the fourth right chamfer plate are all located at the chamfer.

[0061] The flow divider 204 includes a first chamfered chamfered plate, a first trapezoidal transition plate, a second chamfered chamfered plate, a first chamfered plate, a third chamfered chamfered plate, a second trapezoidal transition plate, and a fourth chamfered chamfered plate connected in sequence.

[0062] Accordingly, based on the above-described structure, the connection relationships between the left curved plate 203, right curved plate 205, and diversion vent 204 are as follows:

[0063] The lower end of the first left chamfer plate is connected to one side of the first crotch chamfer plate, the upper end of the first left chamfer plate is connected to the left end cap 202, the lower end of the first right chamfer plate is connected to the other side of the first crotch chamfer plate, and the upper end of the first right chamfer plate is connected to the right end cap 206.

[0064] The lower end of the first left plate is connected to one side of the first trapezoidal transition plate, the upper end of the first left plate is connected to the left end cap 202, the lower end of the first right plate is connected to the other side of the first trapezoidal transition plate, and the upper end of the first right plate is connected to the right end cap 206.

[0065] The lower end of the second left chamfer plate is connected to one side of the second crotch chamfer plate, the upper end of the second left chamfer plate is connected to the left end cap 202, the lower end of the second right chamfer plate is connected to the other side of the second crotch chamfer plate, and the upper end of the second right chamfer plate is connected to the right end cap 206.

[0066] The lower end of the second left plate is connected to one side of the first crotch plate, the upper end of the second left plate is connected to the left end cap 202, the lower end of the second right plate is connected to the other side of the first crotch plate, and the upper end of the second right plate is connected to the right end cap 206.

[0067] The lower end of the third left chamfer plate is connected to one side of the third crotch chamfer plate, the upper end of the third left chamfer plate is connected to the left end cap 202, the lower end of the third right chamfer plate is connected to the other side of the third crotch chamfer plate, and the upper end of the third right chamfer plate is connected to the right end cap 206.

[0068] The lower end of the third left plate is connected to one side of the second trapezoidal transition plate, the upper end of the third left plate is connected to the left end cap 202, the lower end of the third right plate is connected to the other side of the second trapezoidal transition plate, and the upper end of the third right plate is connected to the right end cap 206.

[0069] The lower end of the fourth left chamfer plate is connected to one side of the fourth crotch chamfer plate, the upper end of the fourth left chamfer plate is connected to the left end cap 202, the lower end of the fourth right chamfer plate is connected to the other side of the fourth crotch chamfer plate, and the upper end of the fourth right chamfer plate is connected to the right end cap 206.

[0070] The diversion two-way cylindrical blank 200 with the above-described structure, based on the function, structure, and forming difficulties of the diversion two-way cylindrical blank 100, requires the material of the part to undergo tensile deformation in the diversion crotch and transition rounded corner areas of the diversion two-way cylindrical blank 100. Therefore, a trapezoidal transition area is designed at the diversion crotch 204 position, and obtuse-angled transition plates (e.g., first left chamfer plate, second left chamfer plate, third left chamfer plate, fourth left chamfer plate, first right chamfer plate, second right chamfer plate, third right chamfer plate, fourth right chamfer plate, first crotch chamfer plate, second crotch chamfer plate, third crotch chamfer plate, and fourth crotch chamfer plate) are designed in the diversion crotch and transition rounded corner areas of the diversion two-way cylindrical blank 100 to achieve the purpose of preventing the diversion two-way cylindrical blank 200 from cracking during forming. This shape can control the deformation mode to be mainly tensile deformation, with shear deformation approximately zero.

[0071] In order to improve the fit between the flow divider 204 and the punch 300, a baffle is provided on the flow divider 204. The baffle divides the space inside the flow divider cylinder blank 200 into two forming cavities, and air is injected into the two forming cavities respectively, thereby improving the fit between the flow divider 204 and the punch 300, as well as the smooth transition quality and stability of the flow divider 204 forming.

[0072] It should be noted that before the punch 300 and die 400 are pressed together, the splitter cylinder blank 200 is not pressurized with air, which can prevent the air pressure from causing deformation of the splitter cylinder blank 200.

[0073] Specifically, for TA15 sheet material, the heating temperature in step 3 above is 850℃~950℃.

[0074] Step 4 above includes the following steps:

[0075] Step 41: Inflate the two-way cylinder blank 200 with an inflation pressure of 0.4-0.6MPa, maintain the pressure for 8-12 minutes, and shape the arc surface of the fluid pipeline axially set.

[0076] Step 42: Increase the inflation pressure to 1.8-2.3 MPa, hold the pressure for 18-20 minutes, and push the left end cap 202 and the right end cap 206 to drive the left arc plate 201, the left curved plate 203, the right curved plate 205 and the right arc plate 207 to stretch upward and downward respectively;

[0077] Step 43: Increase the inflation pressure to 2.8-3.2 MPa and hold the pressure for 8-10 minutes, so that each corner of the diversion two-way cylinder blank 200 is completely attached to the punch 300 and the die 400, completing the superplastic forming of the diversion two-way cylinder 100, and obtaining the diversion two-way cylinder 100.

[0078] For aluminum alloy sheets, the heating temperature in step 3 above is 350℃~550℃.

[0079] Step 4 above includes the following steps:

[0080] Step 41: Inflate the two-way cylinder blank 200 with an inflation pressure of 1.0 to 1.2 MPa, maintain the pressure for 10 to 15 minutes, and shape the arc surface of the fluid pipeline axially set.

[0081] Step 42: Increase the inflation pressure to 3.0-3.5MPa, maintain the pressure for 18-20 minutes, and push the left end cap 202 and the right end cap 206 to drive the left arc plate 201, the left curved plate 203, the right curved plate 205 and the right arc plate 207 to stretch upward and downward respectively;

[0082] Step 43: Increase the inflation pressure to 5.5-6.0 MPa and hold the pressure for 15-20 minutes, so that all corners of the diversion two-way cylinder blank 200 are completely attached to the punch 300 and the die 400, completing the superplastic forming of the diversion two-way cylinder 100, and obtaining the diversion two-way cylinder 100.

[0083] To prevent oxidation of the diversion tube 100 due to the high internal temperature after superplastic forming, the following steps are included after step 43:

[0084] Step 44: Continue to maintain the pressure for 20-30 minutes, then release the gas from the diversion two-way cylinder 100, reduce the gas supply pressure to 0.004-0.006 MPa, and continue to supply gas to ensure the purity of the gas inside the diversion two-way cylinder 100.

[0085] It should be noted that after the superplastic forming of the diversion two-way cylinder 100 is completed, the process also includes a step of removing excess material. Specifically, the removal of excess material includes the following steps:

[0086] Cut the upper and lower ends of the left end cap 202, right end cap 206 and bottom plate 208 to remove excess material, so as to achieve the upper and lower ventilation of the diversion two-way cylinder 100.

[0087] To ensure the cleanliness of the inside and outside of the obtained diversion two-way cylinder 100, the following steps are included after removing the excess material:

[0088] The inner and outer surfaces of the diverter cylinder 100 are sequentially subjected to alkaline annealing, acid washing, polishing and grinding to obtain a diverter cylinder 100 with smooth gas passage and outer surface.

[0089] For the fabrication of the diversion two-way cylinder blank 200, the following steps are included before step 1 above:

[0090] Step A: Construct the left arc plate 201, left end cap 202, left curved plate 203, diversion slit 204, right curved plate 205, right end cap 206, right arc plate 207, and bottom plate 208 respectively;

[0091] Step B: Perform sealing butt welding (e.g., electron beam welding, laser welding, brazing or argon arc welding) on ​​the left arc plate 201, left end cap 202, left bend plate 203, diversion septum 204, right bend plate 205, right end cap 206, right arc plate 207 and bottom plate 208 to obtain diversion two-way cylinder blank 200.

[0092] For example, in step A above, the flat parts, namely the left end cap 202, the right end cap 206 and the base plate 208, can be processed by laser cutting, water jet cutting, wire cutting, disc shearing, hand-held disc shears or hand shears.

[0093] In step A above, the flow divider 204, left curved plate 203, and right curved plate 205 can be processed using bending machines, flipping machines, thermoforming, or electro-plastic forming methods to achieve the processing of four bends and two trapezoidal ends. The end rounded corners can be processed into approximately straight rounded corners. After forming, the plane outside the rounded corner area is sheared off and fitted to the corresponding parts of the left curved plate 201 and right curved plate 207 to achieve approximately aligned welding of the plane and curved surfaces. During welding, a protective atmosphere is used to protect the metal material properties at the weld joint; for example, carbon dioxide or nitrogen is used for 20 steel, while argon is used for aluminum alloys, titanium alloys, and stainless steel.

[0094] In step A above, for the fabrication of the left curved plate 203 and the right curved plate 205, in order to improve processing efficiency, the two are designed to be integrated and formed as a whole during the fabrication process. The specific forming method can be progressive bending or roll bending. Since the cross-section is variable, the forming method can refer to Chinese patent application CN201351145.8 A saddle-shaped curved surface forming device and a saddle-shaped curved surface workpiece forming method or CN310557313.2 A titanium alloy skin cold bending forming method.

[0095] It should be noted that in this embodiment, the segmentation of each part of the diversion two-way cylinder blank 200 is mainly carried out by cold forming, especially the cold forming of titanium alloy.

[0096] This embodiment includes, but is not limited to, re-dividing the various parts to adapt to other forming methods. For example, the middle flow divider and the left bending plate 203 and right bending plate 205 are designed as a single unit and processed by thermoforming. Alternatively, the left arc plate 201 and the left bending plate 203 are treated as a single cylindrical blank, and the flat surface after bending at the end of the left bending plate 203 is eliminated and replaced with a curved surface. After welding, the parts are formed under heating or room temperature conditions.

[0097] To increase the allowance of the parts, the upper ends of the left arc plate 201, right arc plate 207, left bent plate 203, and right bent plate 205 are 0-10mm higher than the theoretical edge of the splitter cylinder 100, and the lower ends of the left arc plate 201 and right arc plate 207 are 0-10mm lower than the theoretical edge of the splitter cylinder 100. On the one hand, this allows for sufficient optimization margins for subsequent functional extension parts. On the other hand, it optimizes the base of upper and lower stretching, increases the circumferential deformation, helps improve the forming accuracy of the rounded transition zone of the splitter 204, increases the circumference, improves the smoothness of the material under air pressure deformation, reduces the risk of shear force generation, and improves the safety and stability of the SPF.

[0098] For the punch 300 and the die 400, they are made of metals with a higher expansion rate than the material of the diversion two-way cylinder 100. For example, the mold of the titanium alloy diversion two-way cylinder 100 is made of Ni7N, and the mold of the aluminum alloy diversion two-way cylinder 100 is made of materials such as stainless steel or high carbon steel.

[0099] Specifically, the structure of the punch 300 includes an upper template 301 and a core mold mounted on the upper template 301. The outer surface of the core mold is divided into a core mold reserved surface, a main outer forming surface 302, and a flow-dividing crotch surface 305, gradually moving away from the upper template 301. The core mold reserved surface is further divided into a left bulging surface 303, a front guide surface 304, a right bulging surface, and a rear guide surface, which are connected in sequence to form a closed, ring-like surface. Among them, the left bulging surface 303 and the right bulging surface are upward stretching parts. They close with the upper stretching cavity of the die 400 to form an upper deformation stretching area, which can provide the drive for the upward lifting of the flow-dividing two-way cylindrical blank 200, and also provide circumferential stretching operation space for the rounded corner transition area during the final mold fitting process.

[0100] In order to further improve the fit between the flow divider 204 and the punch 300, the design model of the aforementioned core mold flow divider is consistent with that of the flow divider cylinder 100, and its height should be in contact with the upper surface of the flow divider 204 of the flow divider cylinder blank 200 without pressing it.

[0101] It should be noted that during the mold closing process of the punch 300 and the die 400, the gap between the front guide face 304 and the rear guide face and the die 400 does not exceed 0.02mm. This is because the front guide face 304 and the rear guide face are in the last closing stroke after the punch 300 and the die 400 are aligned, and the two have a guiding function, which facilitates the matching and precise docking of the surfaces of the punch 300 and the die 400.

[0102] To facilitate the subsequent removal of excess material, the height of the reserved surface of the core mold is 50-100mm.

[0103] Specifically, the inner surface of the die 400 is divided into an upper stretching cavity 402, a main inner surface 403, and a lower bulging cavity 404 arranged sequentially. The upper stretching cavity 402 corresponds to the position of the reserved surface of the core mold, and the main inner surface 403 corresponds to the position of the main outer forming surface 302.

[0104] It is understandable that in order to accommodate the vent pipe 209, the aforementioned die 400 needs to have a vent groove 401. After the vent pipe 209 passes through the vent groove 401, it connects with the interior of the diverter cylinder blank 200, thereby achieving inflation.

[0105] To ensure smooth inflation and deflation, the aforementioned venting groove 401 is formed on the reserved surface of the core mold, and the distance from the upper end of the reserved surface of the core mold is 8 to 12 mm. For example, the cross-sectional shape of the venting groove 401 can be rectangular or circular to ensure that the venting pipe 209 is not flattened in the venting groove 401, thus ensuring smooth inflation and deflation.

[0106] It should be noted that, in order to allow the two-way cylinder blank 200 to be smoothly loaded into or unloaded from the punch 300 and the die 400, the cross-section of the punch 300 and the die 400 is designed with a larger opening and a smaller bottom.

[0107] However, from the perspective of fit, the cross-sectional area of ​​the lower bulging cavity 404 is larger than that of the main inner surface 403. In other words, there is a widened area on the inner surface of the die 400. Thus, during the inflation process, the deformation of the blank at the position of the lower bulging cavity 404 increases, which can further stretch the blank at the position of the main inner surface 403 and improve the fit between the main inner surface 403 and the blank. Since the lower bulging cavity 404 is a widened area, the blank cannot be directly loaded into or unloaded from the punch 300 and the die 400. Therefore, the die 400 needs to be a split type.

[0108] For example, the height of the lower bulging cavity 404 is 100-200mm, which leaves enough room for optimization of subsequent functional extension parts and can also increase the circumferential deformation of the lower cavity, which helps to improve the forming accuracy of the flow divider crotch rounded transition zone. The principle is that the circumference increases, which improves the smoothness of the material under air pressure deformation, reduces the risk of shear force generation, and improves the safety and stability of SPF.

[0109] The coordinated assembly between the two-way cylindrical blank 200 and the punch 300 and die 400, i.e., step 2, includes the following steps:

[0110] Step 21: Align the punch 300 and install it into the die 400, and place it in the thermoforming press. The punch 300 is fixed on the upper platform, and the die 400 is fixed on the lower platform.

[0111] Step 22: Control the upper platform of the thermoforming press to move up, open the mold, and expose the outer surface of the punch 300 and the inner surface of the die 400;

[0112] Step 23: Position the left end cap 202, left curved plate 203, flow divider, right curved plate 205, right end cap 206, and right arc plate 207, and place them into the cavity mold 400. Adjust the blank dimensions according to the distance between the flow divider surface 305 of the punch 300 and the inner bottom surface of the cavity mold 400. This can be done by grinding the parts to reduce the height, or by placing a plate or block on the inner bottom surface to increase the height. Raise the blank by 5mm according to the position of the vent groove 401, and mark the pipe interface positioning point at the installation position of the vent pipe 209. Adjust the upper end height of the blank to be higher than the lower edge line of the upper stretching cavity 402; this can also be done by placing a plate or block on the inner bottom surface to increase the height.

[0113] Step 24: Remove all parts from the blank, drill vent holes at the pipe interface positioning points, install vent pipe 209 and weld it completely.

[0114] Step 25: Completely weld the joints of each part (e.g., left arc plate 201, left bend plate 203, diversion septum, right bend plate 205 and right arc plate 207). During welding, a protective atmosphere is used to protect the metal material properties of the weld. For example, carbon dioxide or nitrogen is used for carbon steel, and argon is used for aluminum alloy, titanium alloy and stainless steel.

[0115] Step 26: Position and weld the left end cap 202, right end cap 206, and base plate 208 at both ends, with venting protection during the process. Through the above blank preparation process, two internally and externally connected sealed cavities are formed. After welding, to replace the gas inside the cylinder, place the blank horizontally with one of the two vent pipes 209 facing upwards and the other downwards. Connect argon gas to the lower vent pipe 209 and slowly replace the gas, gradually filling the cylinder. According to the density difference, slowly expel the air from the upper vent pipe 209. The detection method is to light a match and bring it close to the upper pipe; if the flame goes out, the upper pipe has been emptied of air. Seal the pipe and insert it into the concave mold 400.

[0116] Step 27: Lower the upper platform of the thermoforming press, close the parting surfaces of the punch 300 and the die 400, and press the whole mold together.

[0117] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A superplastic forming method for a split-flow two-way cylindrical body, characterized in that, Includes the following steps: Step 1: Provide a two-way splitter cylinder blank and a matching punch and die. In the two-way splitter cylinder blank, only the arc surface set along the axial direction of the fluid pipeline is made of curved plate, and the other parts are made of flat plate. Step 2: Place the two-way cylinder blank into the cavity mold, install the punch onto the cavity mold and the blank, and press to close the mold; Step 3: Heat the blank, punch, and die of the split-flow cylinder to soften the blank; Step 4: Inflate the blank of the split-flow two-way cylinder with air. Under the action of gas pressure, the blank of the split-flow two-way cylinder undergoes superplastic forming and gradually fits onto the punch and die, thus completing the superplastic forming of the split-flow two-way cylinder and obtaining the split-flow two-way cylinder. The punch includes an upper template and a core mold disposed on the upper template. The outer surface of the core mold is divided into a core mold reserved surface, a main outer forming surface and a flow branching surface along the direction gradually away from the upper template. The core mold reserved surface is divided into a left expansion surface, a front guide surface, a right expansion surface and a rear guide surface, which are connected in sequence to form a closed annular surface. The inner surface of the die is divided into an upper stretching cavity, a main inner surface, and a lower bulging cavity arranged sequentially. The upper stretching cavity corresponds to the position of the reserved surface of the core mold, and the main inner surface corresponds to the position of the main outer forming surface.

2. The superplastic forming method for a split-flow two-way cylinder according to claim 1, characterized in that, Before the punch and die are pressed together, the blank of the diverter cylinder is not pressurized with air.

3. The superplastic forming method for a split-flow two-way cylindrical body according to claim 1, characterized in that, The material of the diversion two-way cylinder is TA15 plate; The heating temperature in step 3 is 850℃~950℃.

4. The superplastic forming method for the diversion two-way cylinder according to claim 3, characterized in that, Step 4 includes the following steps: Step 41: Inflate the blank of the two-way splitter cylinder with an inflation pressure of 0.4~0.6MPa, maintain the pressure for 8~12min, and shape the arc surface set along the axial direction of the fluid pipeline; Step 42: Increase the inflation pressure to 1.8~2.3MPa, hold the pressure for 18~20min, and push the diverter cylinder blank to stretch upwards and downwards respectively; Step 43: Increase the inflation pressure to 2.8~3.2MPa and hold the pressure for 8~10 minutes to ensure that all corners of the split-flow two-way cylinder blank are completely fitted to the punch and die, thus completing the superplastic forming of the split-flow two-way cylinder and obtaining the split-flow two-way cylinder.

5. The superplastic forming method for a split-flow two-way cylindrical body according to claim 1, characterized in that, The material of the diversion two-way cylinder is aluminum alloy plate; The heating temperature in step 3 is 350℃~550℃.

6. The superplastic forming method for a split-flow two-way cylinder according to claim 5, characterized in that, Step 4 includes the following steps: Step 41: Inflate the blank of the two-way splitter cylinder with an inflation pressure of 1.0~1.2MPa, maintain the pressure for 10~15min, and shape the arc surface set along the axial direction of the fluid pipeline; Step 42: Increase the inflation pressure to 3.0~3.5MPa, hold the pressure for 18~20min, and push the diverter cylinder blank to stretch upwards and downwards respectively; Step 43: Increase the inflation pressure to 5.5~6.0MPa and hold the pressure for 15~20min to ensure that all corners of the split-flow two-way cylinder blank are completely fitted to the punch and die, thus completing the superplastic forming of the split-flow two-way cylinder and obtaining the split-flow two-way cylinder.

7. The superplastic forming method for a split-flow two-way cylinder according to claim 4 or 6, characterized in that, Following step 43, the following steps are also included: Step 44: Continue to maintain the pressure for 20~30 minutes, then release the air from the two-way splitter cylinder to reduce the air supply pressure to 0.004~0.006MPa, and continue to supply air.

8. The superplastic forming method for a split-flow two-way cylinder according to any one of claims 1 to 6, characterized in that, After the superplastic forming of the diversion two-way cylinder is completed, the following steps are also included: The inner and outer surfaces of the splitter cylinder are sequentially subjected to alkaline annealing, acid washing, polishing, and grinding to obtain a splitter cylinder with smooth gas passages and outer surfaces.

9. The superplastic forming method for a split-flow two-way cylinder according to any one of claims 1 to 6, characterized in that, The punch and die are made of metal with a higher expansion rate than the material of the diversion two-way cylinder.

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