Method for regulating and controlling structure performance of bottom and top cover of large-thickness and large-breadth seamless integral spinning box for spaceflight

Abstract

The method for regulating and controlling the structure performance of the top cover of the large-thickness and large-breadth seamless integral spinning box bottom for spaceflight comprises the following steps that S1, the generatrix direction and the thickness distribution condition of the seamless integral spinning box bottom for spaceflight are determined, and a heat treatment experiment is conducted; s2, sectioning the seamless integral spinning box bottom for spaceflight after the heat treatment experiment in the step S1, and performing performance analysis to obtain a performance insufficient area; s3, the seamless integral spinning box bottom for spaceflight is provided with the replacement patch; s4, if the replacement patch and the furnace test piece both meet the detection performance, the step S5 is carried out, and if the replacement patch and the furnace test piece do not meet the detection performance, the step S3 is carried out; and S5, performing a heat treatment experiment on the seamless integral spinning box bottom for spaceflight by using the heat treatment experiment parameters meeting the detection performance, and judging whether the detection performance is met or not. The invention provides a solution for regulating and controlling the structure performance of the large-scale integral spinning forming box bottom.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of spinning box bottom processing, and particularly relates to a large-thickness and large-face-width seamless integral spinning box bottom top cover organization performance regulation and control method for aerospace. BACKGROUND

[0002] The commercial aerospace launch demand is increasing, and it is expected that the annual launch frequency will exceed 100 launches / year in the next 3-5 years. The huge launch task demand and higher launch frequency put higher requirements on the efficient and low-cost manufacturing of rockets. The rocket storage tank is a key component of the rocket, and the storage tank bottom is the most core component of the rocket storage tank, and its production efficiency and production cost directly determine the economy and efficiency of the launch vehicle production and manufacturing. The current rocket storage tank bottom manufacturing process is still mainly based on melon-segment welding, each tank bottom contains 8 longitudinal seams and 2 ring seams, and the welding reliability is insufficient. At the same time, the welding and welding seam detection period is long, the process is complex, the production efficiency and economy are insufficient, and it is difficult to meet the current commercial aerospace reusable demand and the rapid increase in launch demand. The integral spinning forming tank bottom adopts an integral plate spinning forming process, which completely eliminates the tank bottom weld, significantly improves the reliability, has a short processing period, occupies less resources, and can meet the current commercial rocket efficient and low-cost reusable manufacturing demand. It is an ideal manufacturing scheme for the current commercial rocket storage tank bottom.

[0003] The shape and property regulation and control process of the large-scale spinning tank bottom is quite different from the traditional melon-segment welded tank bottom, and the existing heat treatment process cannot be borrowed. The research and application of the integral spinning forming tank bottom are still in the initial stage, and the organization performance regulation and control and evidence method are still in the blank. At the same time, the spinning forming tank bottom has large thickness and large cooling area, and the material organization performance regulation and control is extremely difficult. The heat treatment test of the test piece cannot reflect the organization performance difference of the tank bottom after heat treatment, and the whole tank test has extremely high cost and does not have the possibility of frequent heat treatment process test and performance section analysis. The related technical blank seriously limits the rapid application of the integral spinning forming tank bottom. SUMMARY

[0004] Therefore, the application aims to provide a large-thickness and large-face-width seamless integral spinning box bottom top cover organization performance regulation and control method for aerospace, so as to solve at least one technical problem in the background art.

[0005] The application provides a method for regulating and verifying the organizational performance of a large-thickness and large-width seamless integral spinning box bottom top cover for aerospace use, which aims at the problems of large thickness and large cooling width of the large integral spinning forming box bottom, difficulty in regulating and verifying the organizational performance of the box bottom after heat treatment, and the like, formulates a bottom performance regulation and verification scheme by analyzing the performance distribution trend of the box bottom after heat treatment, and finally realizes the optimization of the organizational performance of the box bottom and the performance verification, fills the related technical gap, and solves the problems of insufficient organizational performance, insufficient performance consistency, and ineffective evaluation of the performance of the body after heat treatment of the large-thickness and large-width integral spinning forming box bottom To achieve the above-mentioned purpose, the technical scheme of the application is as follows: A method for regulating the organizational performance of a large-thickness and large-width seamless integral spinning box bottom top cover for aerospace use, comprising the following steps: S1: determining the generatrix direction and thickness distribution of the seamless integral spinning box bottom for aerospace use, and performing a heat treatment experiment on the seamless integral spinning box bottom for aerospace use according to the generatrix direction and thickness distribution; S2: slicing the seamless integral spinning box bottom for aerospace use after the heat treatment experiment in step S1, performing performance analysis, and obtaining a performance deficiency area; S3: preparing a replacement patch according to the performance deficiency area obtained in step S2, installing the replacement patch to the seamless integral spinning box bottom for detection, and obtaining the seamless integral spinning box bottom for aerospace use with the replacement patch installed; S4: adjusting the heat treatment experiment parameters according to the performance analysis obtained in step S2, performing a heat treatment experiment on the seamless integral spinning box bottom for aerospace use with the replacement patch installed and the furnace test piece in step S3 by using the adjusted heat treatment experiment parameters, and performing performance detection on the replacement patch and the furnace test piece; if the replacement patch and the furnace test piece both meet the detection performance, step S5 is performed; if not, step S3 is performed; S5: performing a heat treatment experiment on the seamless integral spinning box bottom for aerospace use by using the heat treatment experiment parameters meeting the detection performance, judging whether the detection performance is met, and if met, outputting the heat treatment experiment data; if not, step S3 is performed.

[0006] The thickness of the box bottom is measured along the generatrix direction of the seamless integral spinning bottom, and the number of measured generatrixes is required to be not less than 3, the generatrixes are equally distributed in the ring direction of the box bottom, and the distance between the measurement points is ≤100mm. The heat treatment process is formulated according to the thickness measurement data, the heat treatment process parameters are formulated based on the maximum value of the thickness of the box bottom, and the heat treatment parameters are formulated according to GJB1694.

[0007] Further, the slicing of the seamless integral spinning box bottom for aerospace use after the heat treatment experiment in step S1 in step S2 is performed on the top cover area, the circular ring area and the transition ring area. The performance analysis in step S2 includes analysis of tensile strength, yield strength, and elongation at break.

[0008] Further, the patch sample, the in-furnace test piece, and the detection seamless integral spinning bottom in step S3 are made of the same material as the seamless integral spinning bottom in step S1. Step S3 further includes cutting the performance deficient area of the detection seamless integral spinning bottom and processing a mounting table, and the patch sample is welded to the detection seamless integral spinning bottom through the mounting table.

[0009] Further, the thickness of the in-furnace test piece is the same as or slightly thinner than (the difference is within 1 mm) the thinnest area of the seamless integral spinning bottom in step S1.

[0010] Further, after the performance deficient area is obtained in step S2, microscopic structure analysis is further performed on the performance deficient area, the cause of the performance deficient area is determined through the microscopic structure analysis, and then the heat treatment test parameters are adjusted. Generally, the material performance is deficient in one or more of the following characteristics: The alloy element is not dissolved: the quenching holding time needs to be increased, or the quenching holding temperature needs to be increased, or both process parameters are adjusted; The alloy element appears to be dissolved: the quenching transfer time needs to be reduced, or the cooling temperature needs to be increased, or both process parameters are adjusted; The material is overburned: the quenching holding time needs to be reduced, or the quenching temperature needs to be reduced, or both process parameters are adjusted; The precipitated phase is spherical: the aging holding time needs to be reduced, or the aging temperature needs to be reduced, or both process parameters are adjusted; The precipitated phase is sparse: the aging holding time needs to be extended, or the aging temperature needs to be increased, or both process parameters are adjusted.

[0011] Further, the performance of the replacement patch and the in-furnace test piece is detected in step S4. If both the replacement patch and the in-furnace test piece meet the detection performance, step S5 is performed. If not, step S3 is performed, which includes A1: cutting the patch sample of the seamless integral spinning bottom for aerospace use in step S1 after heat treatment and mounting the replacement patch; A2: the replacement patch is subjected to tensile strength test, yield strength test, and elongation at break test to determine whether the performance of the replacement patch meets the performance indicators of tensile strength, yield strength, and elongation at break. If yes, step A3 is performed. If not, step S3 is performed. A3: The tensile strength test, yield strength test, and elongation at break test are performed on the in-furnace test piece, and whether the in-furnace test piece is overburned is observed; whether the performance of the replacement patch meets the performance indicators of tensile strength, yield strength, and elongation at break, and whether the replacement patch is overburned are determined; if yes, step S5 is performed, and if no, step S3 is performed.

[0012] Further, whether the detection performance meets the requirements in step S5 includes slicing the seamless integral spinning bottom for aerospace use after the heat treatment experiment, performing performance analysis, and obtaining the performance deficiency area.

[0013] Further, the seamless integral spinning bottom for aerospace use after the heat treatment experiment is sliced into a top cover area, a ring area, and a transition ring area; the performance analysis includes analyzing the tensile strength, yield strength, and elongation at break; if the performance requirements of the tensile strength, yield strength, and elongation at break are met, the heat treatment experiment parameters are output, and if not, step S3 is performed.

[0014] Compared with the prior art, the method for controlling the microstructure and performance of a large-thickness and large-width seamless integral spinning bottom top cover for aerospace use has the following advantages: (1) The present application proposes a method for controlling the microstructure and performance of a large-thickness and large-width seamless integral spinning bottom top cover for aerospace use and a supporting method. The present application proposes a combined bottom preparation process and verification method for the optimization of the heat treatment process of a large-scale integral spinning formed bottom and the performance supporting, thereby providing a solution for controlling the microstructure and performance of a large-scale integral spinning formed bottom.

[0015] (2) The present application proposes a combined bottom performance supporting method to solve the problem that part of the integral spinning formed bottom cannot be sampled in the body, thereby solving the problem of performance supporting of a large-scale integral spinning formed bottom. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which form a part of the present application, are used to provide a further understanding of the present application, and the illustrative embodiments of the present application and their description serve the purpose of explaining the present application, and do not constitute an improper limitation of the present application. In the drawings: Figure 1 The spinning bottom thickness distribution diagram described in Example 1; Figure 2 The bottom area division diagram described in Example 1; Figure 3 The bottom sample SEM photos of the bottom described in Example 1 (a, b, and c are three different areas of the bottom); Figure 4 The schematic diagram of the seamless integral spinning bottom for aerospace use provided with a replacement patch described in Example 1; Figure 5Actual view of the seamless integral spin-formed case bottom for space use with the replacement patch installed as described in Example 1; Figure 6 Schematic view of the replacement patch as described in Example 1; Figure 7 Top view of the seamless integral spin-formed case bottom for space use with the replacement patch installed as described in Example 1; Figure 8 Microstructure photos of the case top cover area under different conditions (A: quenching temperature 535℃ (target set value), quenching holding time 140min, quenching transfer time 30s, there are large undissolved phases of alloy elements in the material after quenching, B: quenching temperature 535℃ (target set value), quenching holding time 280min, quenching transfer time 30s, the area of undissolved alloy phases is obviously reduced); Figure 9 Microstructure photos of the case top cover area under different conditions (C, D: quenching temperature 535℃ (target set value), quenching holding time 280min, cooling water flow rate 50%, quenching transfer time 30s, strengthening phase precipitation after aging, the strengthening phase is sparse and thick, EF: quenching temperature 535℃ (target set value), quenching holding time 280min, cooling water flow rate 100%, quenching transfer time 30s, strengthening phase precipitation after aging, the strengthening phase is fine and dense). DETAILED DESCRIPTION

[0017] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0018] The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0019] The diameter of the large area specified is 4200mm or more, and the large thickness refers to 50mm or more, both of which are raw materials, and subsequent edge processing is required.

[0020] Example 1 The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments. Step 1: Determine the thickness distribution of the case bottom along the generatrix direction. During the spin forming process of the case bottom, the thickness distribution in different height directions is greatly different due to the influence of the curvature of the case bottom, and the thickness gradually thins from the top to the bottom. The thickness of the case bottom directly determines the heat treatment process, so it is necessary to first determine the thickness distribution of the case bottom along the generatrix direction, as shown in Figure 1 .

[0021] Step 2: Perform the whole bottom heat treatment test. Preliminarily determine the performance distribution of the box bottom by whole bottom heat treatment.

[0022] Step 3: Analyze the performance of the cut box bottom. As shown in the figure, the heat-treated box bottom is cut and analyzed according to three regions to determine the performance distribution of the heat-treated box bottom, as shown in Figure 2 According to the box bottom cutting test, the performance distribution trend of the whole bottom of the box bottom is gradually decreasing from the transition ring to the top cover, and the lowest point of the performance of the box bottom is located in the top cover area of the product, and the mechanical properties of this area are lower than the design indicators of tensile strength, yield strength and elongation at break.

[0023] Step 4: Microstructure analysis of the box bottom top cover area sample with the lowest performance. Determine the reason for the insufficient performance of the box bottom top cover area through microstructure analysis. According to the SEM photo analysis, the heat-treated box bottom sample has a large range of undissolved alloy phase, and the heat treatment process optimization should be carried out to increase the solubility of the alloying elements.

[0024] Step 5: Combination of whole bottom design and preparation. Performance analysis shows that the insufficient performance area of the box bottom is located in the top cover area, so the combination of the whole bottom is used to carry out performance analysis, and the replaceable whole bottom can be prepared as follows: Step 5-1: Preparation of insufficient performance area. Measure the profile and thickness of the insufficient performance area of the spinning box bottom determined in step 3; Step 5-2: Prepare a replaceable patch sample according to the measurement results of step 5-1. The sample material grade, deformation and heat treatment process should be consistent with the actual box bottom, and the thickness should be consistent with or slightly larger than the actual replacement area thickness (<5mm). In the example, the insufficient performance area is located in the top area, so the thickness and profile of the top area are measured, and the thickness of the replaceable patch sample is 50mm, and the curvature is small, so a flat plate can be used instead; Step 5-3: Prepare a reusable box bottom heat treatment process part. Optionally, a piece of waste box bottom with the same specification and material is removed from the corresponding position of the area determined in step 3; Step 5-4: Weld the combined whole bottom. The box bottom heat treatment process part described in step 5-3 and the replaceable patch described in step 5-2 are machined to form a welding assembly surface, and then welded, thus completing the preparation of the combined whole bottom.

[0025] Step 6: Develop a heat treatment test process and carry out a heat treatment test. According to the test requirements, carry out the heat treatment process test. The heat treatment test needs to be accompanied by a furnace test piece, and the test piece material grade, deformation and heat treatment process should be consistent with the actual box bottom, and the test piece thickness should be consistent with or slightly thinner than the thinnest area of the box bottom described in step 1 (<5mm).

[0026] Step 7: Cutting the replaceable patch sample.

[0027] Step 8: Performance analysis of the replaceable patch sample, the performance should meet the three design indicators of tensile strength, yield strength and elongation at break.

[0028] Step 9: Performance analysis and overburning analysis of the accompanying furnace test piece, the performance of the test piece should meet the three performance indicators of tensile strength, yield strength and elongation at break and there should be no organizational overburning.

[0029] Step 10: Comprehensive analysis of the analysis results of steps 8 and 9, the performance results meet the requirements of the three design indicators of tensile strength, yield strength and elongation at break, and there is no organizational overburning, then the heat treatment process described in step 6 is determined to meet the actual needs, otherwise steps 5-9 are repeated until the heat treatment process meets the actual needs.

[0030] Step 11: According to the heat treatment process determined in step 10, the whole bottom heat treatment is carried out. According to the heat treatment process determined in step 10, the spinning whole bottom heat treatment test is carried out.

[0031] Step 12: According to the performance analysis method of the box bottom described in step 3, the performance of the box bottom described in step 11 is analyzed, and the performance of the section meets the requirements of the indicators, which proves that the heat treatment process completely meets the actual needs and production conditions.

[0032] Step 13: Performance verification of the spinning box bottom after heat treatment. For the spinning box bottom that cannot be sampled, the combined bottom heat treatment method is used to verify the product performance. The specific steps are as follows: Step 13-1: Repeat step 1 to measure the thickness of the box bottom that cannot be sampled; Step 13-2: Repeat step 3 to select a piece for section performance analysis in the same material and same specification box bottom that cannot be sampled; Step 13-3: Prepare a combined whole bottom according to step 5; Step 13-4: Heat treatment or batch heat treatment of the combined whole bottom and the spinning box bottom that cannot be sampled in the same furnace; Step 13-5: Performance analysis of the combined whole bottom described in step 13-4, the performance meets the three design indicators of tensile strength, yield strength and elongation at break, which proves that the performance of this batch of box bottom is qualified. The adjustment process is shown in Table 1.

[0033] Table 1 Process parameter adjustment and effect The performance requirement is tensile strength σ b ≥ 370 MPa; yield strength σ0.2 ≥ 260 MPa; and the elongation at break δ5≥ 7%. After the third adjustment, the requirements are met, and 350,000 can be saved for each bottom, saving 15 days.

[0034] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for controlling the microstructure and properties of a thick, large-area seamless integral spun-formed box bottom and top cover for aerospace applications, characterized in that: Includes the following steps: S1: Determine the generatrix direction and thickness distribution of the seamless integral spinning box bottom for aerospace applications, and conduct heat treatment experiments on the seamless integral spinning box bottom for aerospace applications based on the generatrix direction and thickness distribution. S2: The seamless integral spinning box bottom for aerospace applications after the heat treatment experiment in step S1 is cut open and its performance is analyzed to identify areas with insufficient performance. S3: Prepare replacement patches for the performance deficient areas obtained in step S2, and install the replacement patches onto the seamless integral spinning box bottom for testing to obtain aerospace seamless integral spinning box bottom with replacement patches installed. S4: Adjust the heat treatment experimental parameters according to the performance analysis obtained in step S2, and conduct heat treatment experiments with adjusted heat treatment experimental parameters on the aerospace seamless integral spinning box bottom and the furnace test piece with the replacement patch installed in step S3. Test the performance of the replacement patch and the furnace test piece. If the replacement patch and the furnace test piece meet the test performance, proceed to step S5; otherwise, proceed to step S3. S5: Perform a heat treatment experiment on the seamless integral spinning box bottom for aerospace using heat treatment experimental parameters that meet the testing performance, and determine whether the testing performance is met. If it is met, output the heat treatment experimental data; otherwise, proceed to step S3.

2. The method for controlling the microstructure and properties of a thick, large-area seamless integral spun-formed box bottom and top cover for aerospace applications according to claim 1, characterized in that: The thickness of the box bottom is measured along the direction of the seamless integral spinning bottom generatrix for aerospace applications. The number of generatrixes to be measured is no less than 3, and each generatrix is ​​evenly distributed around the bottom of the box. The distance between the measurement points is ≤100mm. The heat treatment process is formulated based on the thickness measurement data, and the heat treatment process parameters are formulated with the maximum thickness of the bottom of the box as the benchmark.

3. The method for controlling the microstructure and properties of a thick, large-area seamless integral spun-formed box bottom and top cover for aerospace applications according to claim 1, characterized in that: In step S2, the seamless integral spinning box bottom for aerospace applications after the heat treatment experiment in step S1 is cut into a top cover area, a circular area, and a transition ring area. The performance analysis in step S2 includes analysis of tensile strength, yield strength, and elongation at break.

4. The method for controlling the microstructure and properties of a thick, large-area seamless integral spun-formed box bottom and top cover for aerospace applications according to claim 1, characterized in that: The patch sample, furnace test piece, and seamless integral spinning box bottom for testing in step S3 are all made of the same material as the aerospace seamless integral spinning box bottom in step S1. Step S3 also includes cutting out the performance deficient area of ​​the seamless integral spinning chamber bottom for testing and machining a mounting platform, through which the patch sample is welded to the seamless integral spinning chamber bottom for testing.

5. The method for controlling the microstructure and properties of a thick, large-area seamless integral spun-formed box bottom and top cover for aerospace applications according to claim 4, characterized in that: The thickness of the test piece in the furnace is the same as or slightly thinner than the thinnest area of ​​the bottom of the seamless integral spinning box for aerospace applications in step S1.

6. The method for controlling the microstructure and properties of a thick, large-area seamless integral spun-formed box bottom and top cover for aerospace applications according to claim 1, characterized in that: After obtaining the region with insufficient performance in step S2, the process also includes microstructure analysis of the region to determine the cause of the insufficient performance and adjust the heat treatment test parameters accordingly. Typically, the microstructure of a material with insufficient performance has one or more of the following characteristics: 1) Undissolved alloying elements: It is necessary to increase the quenching and holding time, or increase the quenching and holding temperature, or adjust both process parameters simultaneously. 2) Redissolution of alloying elements: It is necessary to reduce the quenching transfer time, increase the cooling temperature, or adjust both process parameters simultaneously. 3) Overheating of the material: It is necessary to reduce the quenching holding time, or lower the quenching temperature, or adjust both process parameters at the same time; 4) The precipitated phase is spherical: It is necessary to reduce the aging holding time, lower the aging temperature, or adjust the two process parameters; 5) Sparse distribution of precipitated phase: It is necessary to extend the aging holding time, increase the aging temperature, or adjust the two process parameters.

7. The method for controlling the microstructure and properties of a thick, large-area seamless integral spun-formed box bottom and top cover for aerospace applications according to claim 1, characterized in that: In step S4, the performance of the replacement patch and the furnace-fed test piece is tested. If both the replacement patch and the furnace-fed test piece meet the performance requirements, proceed to step S5; otherwise, proceed to step S3. A1: Cut out a patch sample of the seamless integral spun bottom of an aerospace-grade box after heat treatment and installation of replacement patches; A2: Perform tensile strength test, yield strength test, and elongation at break test on the replacement patch to determine whether the performance of the replacement patch meets the performance indicators of tensile strength, yield strength, and elongation at break. If it meets the requirements, proceed to step A3; otherwise, proceed to step S3. A3: Perform tensile strength, yield strength, and elongation at break tests on the furnace-fed test pieces and observe whether there is any over-burning of the furnace-fed test pieces; determine whether the performance of the replacement patch meets the performance indicators of tensile strength, yield strength, and elongation at break, and whether the replacement patch does not meet the requirement of no over-burning of the furnace. If it meets the requirements, proceed to step S5; otherwise, proceed to step S3.

8. The method for controlling the microstructure and properties of a thick, large-area seamless integral spun-formed box bottom and top cover for aerospace applications according to claim 1, characterized in that: Step S5 involves determining whether the performance meets the requirements, which includes cutting the bottom of the seamless integral spinning box for aerospace applications after the heat treatment experiment in step S5, performing performance analysis, and identifying areas with insufficient performance.

9. The method for controlling the microstructure and properties of a thick, large-area seamless integral spun-formed box bottom and top cover for aerospace applications according to claim 8, characterized in that: After the heat treatment experiment, the seamless integral spinning box bottom for aerospace is cut into a top cover area, a circular ring area, and a transition ring area. Performance analysis is performed, including analysis of tensile strength, yield strength, and elongation at break. If the performance requirements of tensile strength, yield strength, and elongation at break are met, the heat treatment experiment parameters are output; otherwise, step S3 is performed.

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