Tailor-welding spinning variable-wall-thickness forming method for large-size extension section of liquid rocket engine
By employing electron beam welding and multiple spinning processes, the problem of spinning large-size extension sections in liquid rocket engines was solved, enabling high-precision variable wall thickness forming of the high-temperature alloy GH3044 and reducing material ordering cycle and cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-31
- Publication Date
- 2026-04-14
AI Technical Summary
Existing technologies are difficult to effectively spin-form large-size extension sections for liquid rocket engines, especially since the high-temperature alloy GH3044 has poor spin-forming properties, and custom-made large-size plates have long lead times and high costs.
Flat blanks are prepared by electron beam welding, combined with preforming and multiple spinning processes, including vacuum solution treatment, to ensure weld strength and spinning quality. Variable wall thickness forming is achieved by adjusting the spinning gap and controlling parameters.
High-precision spinning forming was achieved, reducing the cycle and cost of custom materials, ensuring that the strength and flatness of the weld meet the requirements of the spinning process, and the product accuracy reaches a wall thickness tolerance of ±0.06mm at each point and a profile accuracy of ≤3mm.
Smart Images
Figure CN121848006A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of metal forming technology, and specifically relates to a method for welding and spinning variable wall thickness forming of large-size extension sections of liquid rocket engines. Background Technology
[0002] A certain liquid rocket engine, with high thrust, is made of GH3044, a high-temperature alloy rarely used in spinning. Its thrust chamber extension is an ultra-large GH3044 thin-walled precision component; the wall thickness at the small end is 1.5mm, much larger than the 0.65mm wall thickness at the large end; the diameter at the large end... Much larger than the diameter of the small end Axial distance 1485mm.
[0003] Currently, the extension section of this engine model is the largest variable wall thickness curved busbar extension section, and the spinning performance of GH3044 is not well understood, making spinning very difficult.
[0004] Because large-size GH3044 with a thickness of δ3.5mm requires custom production, the material ordering cycle is long and the cost is relatively high. Summary of the Invention
[0005] The technical problem solved by this application is to overcome the shortcomings of the prior art and provide a method for forming large-size extension sections of liquid rocket engines by welding and spinning with variable wall thickness. The method uses electron beam welding to obtain a flat blank of the required spinning size, ensuring that the strength of the weld and the flatness after welding meet the requirements of the spinning process. The method uses high-temperature alloy GH3044 and a targeted forming method (pre-forming + first cold spinning + second cold spinning) to spin into an ultra-large-size variable wall thickness curved generatrix extension section.
[0006] The technical solution provided in this application is as follows:
[0007] A method for welding and spinning variable wall thickness forming of large-size extension sections of liquid rocket engines, including:
[0008] S1: Cut the plate into two tangential circles, electron beam weld them into a whole circle to obtain a flat blank, and then perform vacuum solution treatment.
[0009] S2: The flat blank is drawn into a shallow dish-shaped blank through a pre-forming die and then vacuum solution treated.
[0010] S3: The shallow dish-shaped spinning blank is spun for the first time to obtain a spinning blank, which is then subjected to vacuum solution treatment.
[0011] S4: The blank is spun a second time to form a variable wall thickness extra-large curved generatrix extension section. The large end diameter of the extension section is not less than [missing information]. The axis length is not less than 1485mm.
[0012] In step 1, because the extension section of the high-temperature alloy GH3044 is too large, the width of its sheet material does not meet the process requirements. Therefore, the GH3044 sheet material is laser-cut into two tangential circles, with a diameter of... Electron beam welding is used to form a complete circle to obtain a flat blank, ensuring that the flatness of the flat blank is no more than 3mm.
[0013] In step 1, to prevent twisting and deformation after welding from affecting the quality of the spinning process, electron beam welding is used to splice the two tangential circles into a complete circle. Thorough welding is required during the splicing process. After welding, the weld quality is inspected by X-ray according to the Class I standard of GJB1718A-2005. Welding fixtures are used to prevent significant deformation after welding, and the flatness after welding must be guaranteed to be no more than 3mm.
[0014] In step S1, the conditions for electron beam welding are as follows: before welding, two arc-starting plates with a size of not less than 30×60mm are positioned at both ends of the weld. The arc-starting plate surface should fit the outer circle of the circular plate, the assembly gap should not be greater than 0.2mm, and the misalignment should not be greater than 0.15mm. Before welding, the surface of the joint is cleaned by pickling or mechanical cleaning. Before welding, a test weld is performed with a test plate of equal thickness. After confirming the penetration, the formal welding is carried out. After welding, non-destructive testing is required to ensure that there are no defects inside the weld.
[0015] In step S1, two tangential circles are fixed in a welding fixture for electron beam welding. The welding fixture includes a support assembly, a first fixing plate, a second fixing plate, and a third fixing plate. The surface of the support assembly is used to place the two tangential circles. The first fixing plate, the second fixing plate, and the third fixing plate are all located above the two tangential circles and are detachably connected to the support assembly at both ends. The first fixing plate and the second fixing plate are pressed on the larger tangential circle, and the third fixing plate is pressed on the smaller tangential circle. The second fixing plate and the third fixing plate are located on both sides of the splicing position of the two tangential circles.
[0016] In step 1, in order to eliminate welding stress, solution treatment is performed. The heat treatment regime is as follows: heat up to 950±10℃ within 90 minutes, hold for 26 to 30 minutes, then heat up to 1150±10℃ and hold for 14 to 16 minutes.
[0017] In step 2, the deep drawing test material is 1Cr18Ni9Ti. It serves two purposes: first, to adjust the blank holder force and deep drawing force so that the shallow dish-shaped parts drawn out do not wrinkle or wrinkle only slightly, thus ensuring the quality of the subsequent deep-drawn formal products; second, the deep drawing test material is also the test material for subsequent spinning, adjusting the spinning parameters for the formal products.
[0018] In step S2, the preforming mold includes a pressure ring, a positioning post, a female mold, an ejector pin, and a male mold. The positioning post is connected to the middle of the parting surface of the male mold and mates with the center hole of the flat blank. The pressure ring is sleeved on the outside of the male mold and is slidably connected to the male mold along the moving direction of the female mold.
[0019] In step S2, after the flat blank is drawn into a shallow dish shape by the pre-forming mold, the shallow dish-shaped blank is rotated 90° around its own axis and then stretched again by the pre-forming mold to correct the shape of the shallow dish-shaped blank, eliminate the wrinkling phenomenon at the large end, and obtain the shallow dish-shaped blank, which is then subjected to vacuum solution treatment.
[0020] In step S3, the first spinning process uses a single-spinning die, which includes a first tail top, a first positioning post, a first spinning die body, a first adapter plate, and a first push rod. The large end of the first spinning die body is fixed on the first adapter plate. A through hole is provided at the axial position of the first spinning die body. The first push rod is located in the through hole and can move along the axial direction of the first spinning die body. One end of the first push rod covers the small end of the first spinning die body. The first positioning post is coaxially fixedly connected to the end of the first push rod. A positioning hole that mates with the first positioning post is provided at the axial position of the first tail top, so that the first positioning post and the first tail top are coaxially connected. The shallow dish-shaped blank is located between the small end of the first spinning die body and the first tail top. The first positioning post passes through the central positioning hole of the shallow dish-shaped blank. After spinning, the first push rod is used to loosen the shallow dish-shaped blank from the first spinning die body.
[0021] In step S3, the initial allowance is determined based on the material of the shallow dish-shaped blank, and the initial spinning gap for each part is obtained. The initial spinning gap = theoretical wall thickness of the blank at each point - allowance. Based on the initial spinning gap, a 1Cr18Ni9Ti test material with the same shape as the shallow dish-shaped blank is first used for trial spinning. The spinning gap is continuously adjusted. When the wall thickness of the part is large, the spinning gap is smaller, and when the wall thickness is small, the spinning gap is larger. Instead of using one gap value for all parts, the wall thickness of the test material meets the requirements after trial spinning, and the adjusted spinning gap is obtained. Then, the shallow dish-shaped blank is spun using the adjusted spinning gap to obtain a first-spin blank. The 1Cr18Ni9Ti test material has the same shape as the shallow dish-shaped blank, and its specifications are within the allowable error range.
[0022] In step S3, before the first spinning, the wall thickness of the shallow dish-shaped blank is measured on at least four evenly distributed generatrices at intervals of 50-60mm. A total of 13 wall thickness values are measured on each generatrice, and a total of 52 wall thickness values are measured on the four generatrices. During the first spinning process, the spinning gap is adjusted according to the measured wall thickness. When the wall thickness of the part is large, the spinning gap is smaller, and when the wall thickness is small, the spinning gap is larger. Instead of using one gap value for all parts, this makes the wall thickness of the subsequent variable wall thickness flat blank after spinning closer to the theoretical value.
[0023] The adjustment value of the spinning gap is within ±0.06mm.
[0024] In step S3, during the first spinning process, the spinning speed is 10 mm / min, the spindle speed is 54-25 rpm, and the radius of the spinning wheel radius R is 8-10 mm.
[0025] In step 3, before the first spinning, after installing the shallow dish-shaped blank, the shallow dish-shaped blank is aligned, and the runout of the small end is ≤1mm.
[0026] In step S4, the initial retraction amount is determined based on the material of the first-spin blank, and the initial spinning gap of each part is obtained. The initial spinning gap = theoretical wall thickness of each part of the second-spin blank - retraction amount.
[0027] Based on the initial spinning gap, a 1Cr18Ni9Ti test material with the same shape as the first spinning blank is first tested and spun. The spinning gap is continuously adjusted until the wall thickness of the test material meets the requirements after the test spinning, and the adjusted spinning gap is obtained. The 1Cr18Ni9Ti test material has the same shape as the first spinning blank, and the specifications are within the allowable error range.
[0028] The blank is then spun again using the adjusted spinning gap. During the second spinning process, the spinning speed is 10 mm / min and the spindle speed is 54-25 rpm. The radius of the spinning wheel fillet is R8-R10 mm. This yields a variable wall thickness extension section of the ultra-large curved generatrix.
[0029] Before the second spinning, the actual wall thickness of the blank is measured at different locations on at least four generatrices. The spinning gap is adjusted according to the actual wall thickness. When the wall thickness of the part is large, the spinning gap is smaller, and when the wall thickness is small, the spinning gap is larger. Instead of using one gap value for all parts, this makes the wall thickness of the subsequent variable wall thickness flat blank after spinning closer to the theoretical value. The gap adjustment value is within ±0.06mm.
[0030] In step 3, the initial spinning gap is determined by subtracting the allowance of 0.45mm from the theoretical wall thickness at each point of the blank. A 1Cr18Ni9Ti test material is used to test spin the blank at the initial spinning gap. The wall thickness at each point of the test spin is measured and compared with the theoretical value. If the thickness is greater than the theoretical value, the spinning gap is reduced; if it is less than the theoretical value, the spinning gap is increased. This process continues until the wall thickness of the part meets the requirements after the test spin, thus obtaining the adjusted spinning gap. The adjusted spinning gap is then used to spin the GH3044 part. The 1Cr18Ni9Ti test material has the same shape and parameters as the GH3044 part.
[0031] In summary, this application includes at least the following beneficial technical effects:
[0032] (1) In this invention, the method of electron beam welding of flat blanks is used to obtain flat blanks with sufficient area size, without the need to specially purchase and order large-size plate blanks.
[0033] (2) In this invention, the design of welding fixtures for electron beam welding of flat blanks and the requirements for the shape and size after electron beam welding are provided to ensure that the requirements of subsequent spinning forming process are met and the quality of one-time forming can be ensured.
[0034] (3) The spinning forming method includes pre-drawing forming, one-time cold spinning of the wall thickness of the curved generatrix blank and two-time cold spinning of the wall thickness of the curved generatrix part. By controlling the parameters of each process, such as the wall thickness of the blank, spinning gap, and feed speed, the spinning process is stable, has good reproducibility, and the product accuracy reaches the wall thickness tolerance of ±0.06mm at each point and the profile of the surface ≤3mm.
[0035] (4) In this invention, the forming of the extension section relies entirely on the spinning forming parameters, without the need for subsequent cutting of the wall thickness. The cutting is only designed for the machining allowance at both ends, which solves the problem of the wall thickness exceeding the tolerance caused by cutting and reduces the processing risk. Attached Figure Description
[0036] Figure 1 This is a schematic diagram of the preform mold structure;
[0037] Figure 2 This is a schematic diagram of a rotary mold structure;
[0038] Figure 3 This is a schematic diagram of a two-spindle mold structure;
[0039] Figure 4 They are two tangent-chord circles;
[0040] Figure 5 Drawing of shallow dish-shaped blank part;
[0041] Figure 6 Drawing of a blank part;
[0042] Figure 7 Drawing of a two-turn blank part;
[0043] Figure 8 Electron beam welding fixture.
[0044] Explanation of reference numerals in the attached diagram: 1. Pressure ring; 2. Positioning pin; 3. Female mold; 4. Ejector pin; 5. Male mold; 6. First tail ejector; 7. First positioning pin; 8. First spinning die; 9. First adapter plate; 10. First ejector pin; 11. Second tail ejector; 12. Second positioning pin; 13. Second spinning die; 14. Second adapter plate; 15. Second ejector pin;
[0045] 16. Supporting component; 17. First fixing plate; 18. Second fixing plate; 19. Third fixing plate. Detailed Implementation
[0046] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.
[0047] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.
[0048] This invention provides a method for welding and spinning variable wall thickness forming of large-size extension sections of liquid rocket engines, comprising the following steps:
[0049] Step 1: Due to the excessively large dimensions of the extended section of the high-temperature alloy GH3044, the width of the sheet metal does not meet the process requirements. Therefore, the GH3044 sheet metal is laser-cut into two tangential circles, as follows: Figure 4 As shown, electron beam welding is used to form a complete circle to obtain a flat blank. The conditions for electron beam welding are as follows: Before welding, two 30×60mm arc-starting plates are positioned at both ends of the weld. The arc-starting plate surface should fit snugly against the outer circle of the circular plate, with an assembly gap of no more than 0.2mm and a misalignment of no more than 0.15mm. Before welding, the surface of the joint is cleaned by pickling. Before welding, a test weld is performed using a test plate of equal thickness to confirm penetration before formal welding. After welding, non-destructive testing is required to ensure that there are no defects inside the weld. Then, vacuum solution treatment is performed. The conditions for vacuum solution treatment are: heating to 950±10℃ within 90 minutes, holding at that temperature for 26 to 30 minutes, then heating to 1150±10℃ and holding at that temperature for 14 to 16 minutes.
[0050] like Figure 8 As shown, during electron beam welding, a welding fixture is used to fix two tangential circles. The welding fixture includes a support assembly, a first fixing plate, a second fixing plate, and a third fixing plate. The surface of the support assembly is used to place the two tangential circles. The first fixing plate, the second fixing plate, and the third fixing plate are all located above the two tangential circles and are detachably connected to the support assembly at both ends. The first fixing plate and the second fixing plate are pressed on the larger tangential circle, and the third fixing plate is pressed on the smaller tangential circle. The second fixing plate and the third fixing plate are located on both sides of the splicing position of the two tangential circles.
[0051] Step 2: Using 1Cr18Ni9Ti as the test material, deep drawing is performed through a pre-forming die. Then, the variable wall thickness flat blank is deep drawn into a shallow dish-shaped spinning blank through the pre-forming die, followed by vacuum solution treatment. Specifically, this includes:
[0052] First, the test material is deep-drawn into a shallow dish shape using a pre-forming die, during which the blank holder force and forming force parameters are determined. Then, using the blank holder force and forming force parameters determined by the test material, the variable wall thickness flat blank is deep-drawn into a shallow dish-shaped spinning blank using a pre-forming die. The shallow dish-shaped blank is rotated 90° around its own axis and then stretched again using a pre-forming die to correct the shape of the shallow dish-shaped blank and eliminate wrinkling at the large end. Both the shallow dish-shaped test material and the shallow dish-shaped blank undergo vacuum solution treatment. The conditions for vacuum solution treatment are: heating to 950±10℃ within 90 minutes, holding at that temperature for 26 to 30 minutes, then heating to 1150±10℃ and holding at that temperature for 14 to 16 minutes.
[0053] Among them, such as Figure 1 As shown, the preforming die includes a blank holder ring 1, a positioning post 2, a female die 3, an ejector pin 4, and a male die 5. The female die is located on one side of the male die and is movable along the direction of approaching or moving away from the male die. The positioning post is connected to the middle of the parting surface of the male die and mates with the center hole of the flat blank. The blank holder ring is sleeved on the outside of the male die and is slidably connected to the male die along the moving direction of the female die. During deep drawing, the flat blank has a center hole through which the positioning post passes and is placed on the male die. The ejector pin lifts the blank holder ring and the part, and the female die descends to press on the blank holder ring. The main cylinder pressure is 500 tons, and the blank holder force is 350 tons to form the part. After forming, the female die is raised, the blank holder ring lifts the part, and the part is rotated 90°. The deep drawing process is repeated once to correct wrinkles and deformation at the large end of the part. A pre-formed shallow dish-shaped blank is obtained, as shown. Figure 5 As shown.
[0054] Step 3: The shallow dish-shaped blank is first spun to obtain a spun blank, which is then vacuum solution treated.
[0055] Specifically, it includes:
[0056] The initial allowance is determined based on the material of the shallow saucer-shaped blank, and the initial spinning gap for each part is obtained. The initial spinning gap = theoretical wall thickness of the blank at each part - allowance. Based on the initial spinning gap, a 1Cr18Ni9Ti test material with the same shape as the shallow saucer-shaped blank is first installed on the first spinning mold for trial spinning. The spinning gap is continuously adjusted until the wall thickness of the test material meets the requirements after trial spinning, and the adjusted spinning gap is obtained. After installing the shallow saucer-shaped blank, the shallow saucer-shaped blank is aligned until the runout at the small end is ≤1mm. Then, the shallow saucer-shaped blank is spun using the adjusted spinning gap to obtain the first spinning blank. During this spinning process, the spinning speed is 10 mm / min, the spindle speed is 54-25 rpm, and the radius R of the spinning wheel is 8-10mm. The conditions for vacuum solution treatment are as follows: heat to 950±10℃ within 90 minutes, hold for 26–30 minutes, then heat to 1150±10℃ and hold for 14–16 minutes.
[0057] Before the first spinning, the actual wall thickness of the shallow dish-shaped blank is measured at multiple different locations on at least four generatrices. During the first spinning process, the spinning gap is adjusted according to the actual wall thickness. When the wall thickness of the part is large, the spinning gap is smaller, and when the wall thickness is small, the spinning gap is larger. Instead of applying one gap value to all parts, this makes the wall thickness of the subsequent variable wall thickness flat blanks closer to the theoretical value after spinning. The adjustment value of the spinning gap is within ±0.06mm.
[0058] Among them, such as Figure 2 As shown, a spinning die includes a first tail ejector 6, a first positioning post 7, a first spinning die body 8, a first adapter plate 9, and a first ejector rod 10. The large end of the first spinning die body 8 is fixed on the first adapter plate 9. A through hole is provided at the axial position of the first spinning die body 8. The first ejector rod 10 is located in the through hole and can move along the axial direction of the first spinning die body 8. One end of the first ejector rod 10 covers the small end of the first spinning die body 8. The first positioning post 7 is coaxially fixedly connected to the end of the first ejector rod 10. The first tail ejector 6 is located at the axial position of the first tail ejector 6. A positioning hole is provided to mate with the first positioning post 7, so that the first positioning post 7 and the first tail tip 6 are coaxially connected. The small end of the first spinning die 8 is coaxially connected to the first tail tip 6 through the first positioning post 7. The preformed blank is located between the small end of the first spinning die 8 and the first tail tip 6. It is fixed to the outside of the first spinning die 8 by the pressure of the first positioning post 7 passing through the center positioning hole of the preformed blank and the first tail tip 6. After spinning, the part is loosened from the first spinning die 8 by the first push rod 10 and the part is removed. A spinning blank is obtained, such as... Figure 6 As shown.
[0059] Step 4: The blank is spun a second time to form a variable wall thickness extra-large curved generatrix extension section. The large end diameter of the extension section is... The axis length is 1485mm. Specifically, it includes:
[0060] The initial allowance is determined based on the material of the first-spin blank, and the initial spinning gap of each part is obtained. The initial spinning gap = theoretical wall thickness of each part of the second-spin blank - allowance.
[0061] Based on the initial spinning gap, a 1Cr18Ni9Ti test material with the same shape as the first spinning blank is first tested and spun. The spinning gap is continuously adjusted until the wall thickness of the test material meets the requirements after the test spinning, and the adjusted spinning gap is obtained.
[0062] The blank is then spun again using the adjusted spinning gap. During the second spinning process, the spinning speed is 10 mm / min and the spindle speed is 54-25 rpm. The radius of the spinning wheel radius R is 8-10 mm. This yields a variable wall thickness extension section of the ultra-large curved generatrix.
[0063] Before the second spinning, the actual wall thickness of the blank is measured at different locations on at least four evenly distributed generatrices. A wall thickness value is measured every 10-20mm on each generatrice. The spinning gap is adjusted according to the actual wall thickness. When the wall thickness of the part is large, the spinning gap is smaller, and when the wall thickness is small, the spinning gap is larger. Instead of using one gap value for all parts, this makes the wall thickness of the subsequent variable wall thickness flat blank after spinning closer to the theoretical value. The gap adjustment value is within ±0.06mm.
[0064] The structure of the second-turn mold is the same as that of the first-turn mold, only the dimensions differ. For example... Figure 3 As shown, the two-spinning die includes a second tail jack 11, a second positioning pin 12, a second spinning die 13, a second adapter plate 14, and a second push rod 15. The large end of the second spinning die 13 is fixed to the second adapter plate 14, and the small end is coaxially connected to the second tail jack 11 via the second positioning pin 12. A spin-formed blank is located between the small end of the second spinning die 13 and the second tail jack 11. It is fixed to the outside of the second spinning die 13 by the pressure of the second positioning pin 12 passing through the center positioning hole of the spin-formed blank and the second tail jack 11. After spinning, the second push rod 15 is used to loosen the part from the second spinning die 13, and the part is removed. A two-spinning blank is obtained, as shown... Figure 7 As shown.
[0065] In this invention, the extension section obtained by the above-mentioned method for forming ultra-large size welded and spun variable wall thickness extension section of liquid rocket engine GH3044 has a product accuracy of wall thickness tolerance at each point of ±0.06mm and surface profile ≤3mm.
[0066] In this invention, for a thickness of 3.5mm, two tangentially tangent circles with a diameter of 1400mm are laser-cut and then electron-beam welded into a complete circle; the wall thickness of the small-end curved surface of the blank after the first spinning process is... The wall thickness of the large end curved surface is After secondary spinning, the wall thickness of the curved generatrix variable wall thickness part is 1.5±0.06mm at the small end and 0.65±0.06mm at the large end.
[0067] Example:
[0068] Example 1
[0069] (1) High-temperature alloy tangent circle, electron beam welding becomes The conditions for electron beam welding are as follows: Before welding, two arc-starting plates with dimensions not less than δ3.5×30×60mm are positioned at both ends of the weld. The arc-starting plate surface should fit snugly against the outer circle of the circular plate, with an assembly gap of 0.1mm and a misalignment of 0.1mm. Before welding, the surface of the joint is cleaned by pickling. Before welding, a test weld is performed using a test plate of equal thickness to confirm penetration before formal welding. After welding, X-ray inspection is performed to ensure no defects are found inside the weld. Simultaneously, 1Cr18Ni9Ti stainless steel test material is cut, with the same dimensions and shape as the high-temperature alloy. The high-temperature alloy undergoes solution heat treatment. The solution heat treatment regime is as follows: within 90 minutes, the temperature is raised to 950±10℃, held for 26–30 minutes, then raised to 1150±10℃, and held for 14–16 minutes. 1Cr18Ni9Ti stainless steel undergoes solution treatment.
[0070] (2) Pre-forming, i.e., deep drawing, is performed on an 800-ton hydraulic press with a main cylinder pressure of 500 tons and a blank holder force of 350 tons. Then rotate 90 degrees and repeat the above stretching process, using the same pressure to straighten and eliminate the large-end wrinkling quadrant. Perform solution heat treatment, with the following conditions: heat to 950±10℃ within 90 minutes, hold for 26 to 30 minutes, then heat to 1150±10℃ and hold for 14 to 16 minutes.
[0071] (3) Install a spinning jig on a 60-ton spinning press and adjust it. The radial runout of the large and small ends of the spinning jig should be ≤0.06mm. Compile a spinning program and create a 24-point spinning gap along the axial direction. The principle for selecting the 24 points is that the theoretical wall thickness difference between two points is 0.03-0.05mm. The spinning gap is the distance between the R angle of the spinning roller and the spinning jig. The spinning gap is the wall thickness of the part at this point minus the allowance. After the program is completed, use a feeler gauge to measure and confirm the spinning gap point by point. After the part is installed, it is spun into a curved generatrix variable wall thickness blank. First, use stainless steel 1Cr18Ni9Ti test material for trial spinning. Adjust the spinning gap according to the wall thickness of the test part until the wall thickness of the test part meets the process requirements, and then spin the high-temperature alloy part. Solution treatment of high-temperature alloy parts: The solution heat treatment process is as follows: heat to 950±10℃ within 90 minutes, hold for 26-30 minutes, then heat to 1150±10℃ and hold for 14-16 minutes. Solution treatment of 1Cr18Ni9Ti stainless steel.
[0072] (4) Install the two spinning jigs on the 60-ton spinning press and adjust them. The radial runout of the large and small ends of the spinning jigs should be ≤0.06mm. Compile the spinning program and create a 24-point spinning gap along the axial direction. The principle for selecting the 24 points is that the theoretical wall thickness difference between two points is 0.03-0.05mm. The spinning gap is the distance between the R angle of the spinning roller and the spinning jig. The spinning gap is the wall thickness of the part at this point minus the allowance. After the program is completed, use a feeler gauge to measure and confirm the spinning gap point by point. After the part is installed, it is spun into a blank with a curved generatrix and variable wall thickness. First, use stainless steel 1C18Ni9Ti as a test material for spinning. Adjust the spinning gap according to the wall thickness of the test part until the wall thickness of the test part meets the process requirements. Then spin the high-temperature alloy 3044 part. The large and small ends of the part are machined to the final size.
[0073] In this embodiment, the thickness of the flat blank is 3.45–3.55 mm.
[0074] After electron beam welding, the weld seam, after grinding, should have a thickness no less than the thickness of the substrate material. The flatness after electron beam welding should be no greater than 3mm.
[0075] After the first spinning process, the wall thickness of the small end flat surface of the blank with variable wall thickness is 3.5mm, and the wall thickness of the small end curved surface is... The small end diameter is 337mm; the large end curved surface wall thickness is... The effective diameter of the large end is 1176mm; the effective length of the blank is 754.5mm.
[0076] After the second spinning, the small end flat wall thickness of the part with variable wall thickness is 3.5mm, the small end curved surface wall thickness is 1.5±0.06mm, and the small end diameter is 337mm; the large end curved surface wall thickness is 0.65±0.06mm, and the large end effective diameter is 1176mm; the effective length of the part is 1476.5mm.
[0077] The product's precision reaches a wall thickness tolerance of ±0.06mm at each point, and a surface profile tolerance of ≤3mm.
[0078] The present application has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present application. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present application without departing from the spirit and scope of the present application, and all such modifications and improvements fall within the scope of the present application. The scope of protection of the present application is determined by the appended claims.
[0079] The contents not described in detail in this application specification are common knowledge to those skilled in the art.
Claims
1. A method for welding and spinning variable wall thickness forming of large-size extension sections of liquid rocket engines, characterized in that, include: S1: Cut the plate into two tangential circles, electron beam weld them into a whole circle to obtain a flat blank, and then perform vacuum solution treatment. S2: The flat blank is drawn into a shallow dish-shaped blank through a pre-forming die and then vacuum solution treated. S3: The shallow dish-shaped spinning blank is spun for the first time to obtain a spinning blank, which is then subjected to vacuum solution treatment. S4: A blank is spun a second time to form an extra-large curved generatrix extension section with variable wall thickness. The large end diameter of the extension section is not less than φ1180mm and the axial length is not less than 1485mm.
2. The forming method according to claim 1, characterized in that: In step S1, two tangential circles are fixed in a welding fixture for electron beam welding. The welding fixture includes a support assembly (16), a first fixing plate (17), a second fixing plate (18), and a third fixing plate (19). The surface of the support assembly (16) is used to place the two tangential circles. The first fixing plate (17), the second fixing plate (18), and the third fixing plate (19) are all located above the two tangential circles and are detachably connected to the support assembly at both ends. The first fixing plate (17) and the second fixing plate (18) are pressed on the larger tangential circle, and the third fixing plate (19) is pressed on the smaller tangential circle. The second fixing plate and the third fixing plate are located on both sides of the splicing position of the two tangential circles.
3. The forming method according to claim 1, characterized in that: In step S2, the preforming mold includes a pressure ring (1), a positioning post (2), a female mold (3), an ejector pin (4), and a male mold (5). The female mold (3) and the male mold (5) are arranged opposite to each other. The positioning post (2) is connected to the middle of the parting surface of the male mold (5) and cooperates with the center hole of the flat blank. The pressure ring (1) is sleeved on the outside of the male mold (5) and is slidably connected to the male mold along the moving direction of the female mold (3).
4. The forming method according to any one of claims 1-3, characterized in that: In step S2, after the flat blank is drawn into a shallow dish shape by the pre-forming mold, the shallow dish-shaped blank is rotated 90° around its own axis and then stretched again by the pre-forming mold to correct the wrinkling deformation at the large end of the shallow dish-shaped blank, and then a vacuum solution treatment is performed.
5. The forming method according to claim 1, characterized in that: In step S3, the first spinning process uses a single-spin mold, which includes a first tail fin (6), a first positioning pin (7), a first spinning die (8), a first adapter plate (9), and a first push rod (10). The large end of the first spinning die (8) is fixed on the first adapter plate (9). A through hole is provided at the axial position of the first spinning die (8). The first push rod (10) is located in the through hole and can move along the axial direction of the first spinning die (8). One end of the first push rod (10) covers the first spinning die. The small end of the press body is coaxially fixedly connected to the end of the first push rod. The first tail top (6) is provided with a positioning hole that cooperates with the first positioning post (7) so that the first positioning post (7) and the first tail top (6) are coaxially connected. The shallow saucer blank is located between the small end of the first spinning press body (8) and the first tail top (6). The first positioning post (7) passes through the center positioning hole of the shallow saucer blank. After spinning, the first push rod (10) is used to loosen the shallow saucer blank from the first spinning press body (8).
6. The forming method according to claim 1, characterized in that: In step S3, the initial allowance is determined based on the material of the shallow dish-shaped blank, and the initial spinning gap of each part is obtained. The initial spinning gap = theoretical wall thickness of each part of the blank - allowance. Based on the initial spinning gap, 1Cr18Ni9Ti test material with the same shape as the shallow dish-shaped blank is first used for trial spinning, and the spinning gap is continuously adjusted until the wall thickness of the test material meets the requirements after trial spinning, and the adjusted spinning gap is obtained. Then, the shallow dish-shaped blank is spun using the adjusted spinning gap to obtain a first-spin blank.
7. The forming method according to claim 1, characterized in that: In step S3, before the first spinning, the wall thickness of the shallow dish-shaped blank is measured on at least four generatrices, with a distance of 50-60mm between each measurement. During the first spinning process, the spinning gap is adjusted according to the measured wall thickness value. When the wall thickness value of the part is large, the spinning gap is smaller, and when the wall thickness value is small, the spinning gap is larger. The adjustment value of the spinning gap is within ±0.06mm.
8. The forming method according to claim 1, characterized in that: In step S3, during the first spinning process, the spinning speed is 10 mm / min, the spindle speed is 54-25 rpm, and the radius of the spinning wheel radius R is 8-10 mm.
9. The forming method according to claim 1, characterized in that: In step S4 The initial allowance is determined based on the material of the first-spin blank, and the initial spinning gap of each part is obtained. The initial spinning gap = theoretical wall thickness of each part of the second-spin blank - allowance. Based on the initial spinning gap, a 1Cr18Ni9Ti test material with the same shape as the first spinning blank is first tested and spun. The spinning gap is continuously adjusted until the wall thickness of the test material meets the requirements after the test spinning, and the adjusted spinning gap is obtained. The blank is then spun again using the adjusted spinning gap. During the second spinning process, the spinning speed is 10 mm / min and the spindle speed is 54-25 rpm. The radius of the spinning wheel radius R is 8-10 mm. This yields a variable wall thickness extension section of the ultra-large curved generatrix.
10. The forming method according to claim 9, characterized in that: In step S4, before the second spinning, the actual wall thickness of a spun blank is measured at different locations on at least four evenly distributed generatrices. A wall thickness value is measured every 10-20mm on each generatrice. The spinning gap is adjusted according to the actual wall thickness. When the wall thickness of the part is large, the spinning gap is smaller, and when the wall thickness is small, the spinning gap is larger. The gap adjustment value is within ±0.06mm.