A method for fixing and controlling tensile deformation in tension bending forming

Abstract

This invention discloses a method for fixing and controlling tensile deformation in stretch bending forming, comprising: S1, prioritizing the shape and dimensions of key components during the stretch bending process; S2, simulating and calculating the stretch bending forming of the profile; S3, designing the stretch bending die based on the derived die curve; S4, manufacturing the die; S5, writing a stretch bending program using the simulated stretch bending curve calculated from the simulation; S6, marking lines on the bottom of the profile before stretch bending to measure the tensile deformation after stretch bending; S7, conducting a stretch bending test using the die; S8, inspecting the shape of the stretch bending part using a test template; and S9, reprocessing and correcting the die curve, and conducting a stretch bending test according to step S7. This stretch bending forming method effectively controls the tensile deformation of the stretch bending part by using a reasonable minimum fixed tensile deformation parameter, and adds springback compensation for the pure bending deformation component, which can reduce the shrinkage deformation and angular distortion of the cross-section, ensuring the stability and accuracy of the cross-sectional shape.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of profile large curvature radius profile bending forming process, and particularly relates to a stretch bending forming method for fixing and controlling tensile deformation. BACKGROUND

[0002] The stretch bending forming process is one of the methods for bending and forming stainless steel, carbon steel and aluminum alloy profiles with large curvature radius. The process forces the profile to produce bending deformation on the die under the action of tensile force and bending moment, and the springback is small and there is no wrinkling. It is one of the main processes for bending and forming profiles for railway vehicles. Referring to Figures 1a-1b , Fig. 1 shows the structure of a stainless steel bending profile stretch bending forming part and a typical cross-sectional shape. Figure 1a , Fig. 2 shows the structure of a typical cross-sectional shape of an aluminum alloy extruded profile stretch bending forming part. Figure 1b , Fig. 3 shows the structure of a typical cross-sectional shape of an aluminum alloy extruded profile stretch bending forming part. Figure 2a , Fig. 4 shows the structure of a typical cross-sectional shape of an aluminum alloy extruded profile stretch bending forming part. Figure 2b , Fig. 5 shows the structure of a typical cross-sectional shape of an aluminum alloy extruded profile stretch bending forming part. Figure 2a , Fig. 6 shows the structure of a typical cross-sectional shape of an aluminum alloy extruded profile stretch bending forming part. Figure 2b , Fig. 7 shows the structure of a typical cross-sectional shape of an aluminum alloy extruded profile stretch bending forming part.

[0003] In the prior art, the stretch bending die design and debugging mainly increase the tensile force to reduce the springback to ensure the shape and size of the profile, without paying attention to the influence of the tensile deformation on the cross-sectional shape. As a result, the profile cross-sectional size shrinks greatly and the cross-sectional shape angle distorts seriously after the part is stretch bent, the quality cannot meet the expected requirements, and the number of die modification increases. Secondly, the existing die design and stretch bending part production do not pay enough attention to the size of the tensile deformation, which affects the quality of the final product and has no concept and data accumulation.

[0004] Therefore, based on the above technical problems, the technical personnel in the field urgently need to develop a stretch bending forming method for fixing and controlling tensile deformation. SUMMARY

[0005] The purpose of the present application is to provide a stretch bending forming method for fixing and controlling the tensile deformation of the profile bottom during the stretch bending process, optimizing and improving the design and debugging method of the stretch bending forming die, avoiding excessive tensile deformation during the stretch bending process, ensuring that the cross-sectional size shrinkage deformation of the final formed part is minimized, the angle distortion is minimized, and the profile shape and size are fixed and controlled.

[0006] In order to achieve the above purpose, the present application provides the following technical scheme:

[0007] The stretch bending forming method for fixing and controlling the tensile deformation of the present application mainly includes the following steps:

[0008] S1. The order of importance of key shape and size during the bending process is as follows: cross-sectional shape accuracy, tensile deformation control, and overall shape accuracy.

[0009] S2. Simulation calculation of profile bending forming: The deformation at the bottom of the profile in the stress-deformation curve displayed by the simulation calculation results is controlled as follows:

[0010] The tensile deformation of carbon steel and stainless steel materials is controlled within 1% to 3%;

[0011] The tensile deformation of aluminum alloy materials is controlled within 0 to 2% by a fixed parameter.

[0012] And based on the simulation results, the simulated mold curve is derived;

[0013] S3. Based on the mold curve derived from the simulation results in step S2, design the bending die and predict the cross-sectional deformation of the bending part based on the mold curve obtained from the simulation analysis, so as to analyze whether the final part meets the usage requirements.

[0014] S4. Design and manufacture the mold according to the exported mold surface curve diagram;

[0015] S5. Write a bending program using the simulated bending curve calculated by simulation, and ensure that the tensile deformation of the bending using this program is within the range required by S2.

[0016] S6. Before stretch bending, scribing lines on the bottom of the profile part is used to measure the stretch deformation of the profile after stretch bending.

[0017] S7. Conduct a mold stretching and bending test, and adjust the stretching and bending program to ensure that the deformation at the bottom of the profile meets the requirements of S2. Measure the optimal dimensions of the cross-sectional deformation, record the tensile deformation at the bottom of the profile at this point, and use this as a fixed tensile deformation parameter to be controlled for future use in actual production.

[0018] S8. Use the test template to test the shape of the bending part in step S7, and adjust the mold curve according to the difference in size between the test template and the large arc of the bending part.

[0019] S9. Reprocess and correct the mold curve, and conduct a tensile bending test according to step S7.

[0020] Furthermore, in step S3, the mold curve is derived based on the simulation results to derive the upper and lower surface curves of the mold surface.

[0021] Furthermore, step S4 is divided into a mold suitable for bending stainless steel or carbon steel parts and a mold suitable for forming aluminum alloy extruded profiles.

[0022] Furthermore, the mold suitable for bending stainless steel or carbon steel parts includes:

[0023] Mold body; and

[0024] A forming mold side plate fixed to the side of the upper part of the mold body;

[0025] The forming space for stainless steel bending forming is formed between the mold body and the forming mold side plate.

[0026] Furthermore, the die suitable for forming aluminum alloy extruded profiles includes:

[0027] Mold body; and

[0028] A forming mold side plate fixed to the side of the upper part of the mold body;

[0029] The forming space between the mold body and the forming mold side plate forms a carbon steel bending forming part.

[0030] Furthermore, in step S6, lines are drawn on the bottom of the profile at intervals of L=50mm using a scribing ruler;

[0031] Based on the marked area, determine the elongation L1 after bending, and the elongation is:

[0032] Φ%=(L1-50) / 50.

[0033] Furthermore, the tensile deformation of the carbon steel and stainless steel materials is fixed within 1%-3%;

[0034] The tensile deformation of the aluminum alloy extruded profile is fixed within 0-2%.

[0035] Furthermore, in step S8, the method for adjusting the mold curve based on the dimensional inspection results of the bent part is as follows:

[0036] The rebound amount is compensated by increasing the wrap angle, i.e., reducing the radius size, while keeping the arc length constant.

[0037] In the above technical solution, the tension bending forming method for fixing and controlling the amount of tensile deformation provided by the present invention has the following beneficial effects:

[0038] The tension bending forming method of this invention effectively controls the amount of tensile deformation, increases the springback compensation of pure bending deformation, reduces the amount of shrinkage deformation and angular distortion of the cross-section, and ensures the stability and accuracy of the cross-sectional shape and dimensions. Furthermore, in subsequent production, the fixed tensile deformation parameters are tested and controlled by a program for debugging and production.

[0039] The tension bending forming method of the present invention can reduce the difference in cross-sectional shape and size of each curve segment for tension bending forming parts composed of multiple curvature radii, increase consistency, and improve part quality; the mold design and debugging have specific fixed digital parameter control basis, and the forming accuracy is improved by accurately controlling the deformation parameters. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0041] Figure 1a This is a schematic diagram of the structure of a stainless steel or carbon steel profile bending forming part disclosed in an embodiment of the present invention;

[0042] Figure 1b This is a schematic diagram of a typical cross-sectional shape of a stainless steel or carbon steel profile bending forming part disclosed in an embodiment of the present invention;

[0043] Figure 2a This is a schematic diagram of the structure of the aluminum alloy extruded profile bending forming part disclosed in the embodiment of the present invention;

[0044] Figure 2b This is a schematic diagram of a typical cross-sectional shape of an aluminum alloy extruded profile bending forming part disclosed in an embodiment of the present invention;

[0045] Figure 3a This is a schematic diagram illustrating the stress distribution across the cross-section of a tension-bending formed part, as disclosed in an embodiment of the present invention, using a tension-bending forming method for fixing and controlling tensile deformation.

[0046] Figure 3b This invention discloses a tension bending forming method for fixing and controlling tensile deformation, and provides a stress distribution diagram of various parts of the tension bending formed part after simulation.

[0047] Figure 3c The top and bottom surface curves of the mold surface are derived from a tension bending forming method for fixing and controlling tensile deformation disclosed in an embodiment of the present invention.

[0048] Figure 4a This is a schematic diagram of the structure of a mold suitable for stainless steel or carbon steel stretch bending forming parts, which is a stretch bending forming method for fixing and controlling the amount of stretch deformation disclosed in an embodiment of the present invention.

[0049] Figure 4b This is a schematic diagram of the structure of a mold for aluminum alloy bending forming parts, which is a method for fixing and controlling the amount of tensile deformation disclosed in an embodiment of the present invention.

[0050] Figure 5 This is a schematic diagram of a scribing ruler used in a method for fixing and controlling tensile deformation in a bending forming process disclosed in an embodiment of the present invention.

[0051] Figure 6 This is a schematic diagram of the bottom marking state of a tension bending blank profile in a tension bending forming method for fixing and controlling tensile deformation disclosed in an embodiment of the present invention.

[0052] Figure 7 This is a schematic diagram of the scribing area of ​​a formed part after a stretch bending forming method for fixing and controlling the amount of stretch deformation disclosed in an embodiment of the present invention.

[0053] Figure 8a This is a schematic diagram of the structure of the tension-bending formed part to be tested, according to a tension-bending forming method for fixing and controlling tensile deformation disclosed in an embodiment of the present invention.

[0054] Figure 8b This is a schematic diagram of the test template for a tension bending forming method for fixing and controlling tensile deformation disclosed in an embodiment of the present invention.

[0055] Figure 8c This is a schematic diagram illustrating the principle of a tension bending forming method for fixing and controlling tensile deformation disclosed in an embodiment of the present invention, which uses a test template to test tension bending formed parts.

[0056] Explanation of reference numerals in the attached figures:

[0057] 101. Mold body; 102. Molding mold side plate; 103. Molding space;

[0058] 2. Marking ruler;

[0059] 3. Profile components;

[0060] 4. Stretch-formed parts;

[0061] 5. Test samples. Detailed Implementation

[0062] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0063] See Figures 1a-8c As shown;

[0064] This embodiment provides a tension bending forming method for fixing and controlling the amount of tensile deformation, which mainly includes the following steps:

[0065] S1. The order of importance of key dimensions in the forming process of bending parts is as follows: cross-sectional shape accuracy, tensile deformation control, and shape accuracy. Among them, the control of the bottom deformation of the profile is divided into: the tensile deformation of carbon steel and stainless steel materials is controlled within 1% to 3%; the tensile deformation of aluminum alloy extruded profiles is controlled within 0 to 2%.

[0066] S2. Simulation calculation of profile bending forming: The deformation at the bottom of the profile in the stress-deformation curve displayed by the simulation calculation results is controlled as follows:

[0067] The tensile deformation of carbon steel and stainless steel materials is controlled within 1% to 3%;

[0068] The tensile deformation of aluminum alloy extruded profiles is controlled within 0 to 2%;

[0069] And based on the simulation results, the simulated mold curve is derived;

[0070] See Figure 3a As shown, this illustrates the stress distribution across the cross-section of the tension-formed part. The entire cross-section is under normal tensile stress, the purpose of which is to prevent wrinkling at the bottom and reduce bending springback. Figure 3a A smaller H-value results in less stretching, which is more beneficial for maintaining the cross-sectional shape. (See also...) Figure 3b As shown, Figure 3b A schematic diagram showing the stress distribution at various points of the tension-bending formed part 4 after simulation is shown.

[0071] S3. Based on the mold curve derived from the simulation results in step S2, design the bending die and predict the cross-sectional deformation of the bending part based on the mold curve obtained from the simulation analysis, so as to analyze whether it meets the usage requirements.

[0072] S4. Design and manufacture the mold according to the exported mold surface curve diagram;

[0073] S5. Write a bending program using the simulated bending curve calculated by simulation. The bending program must ensure that the deformation at the bottom of the formed profile meets the requirements of S1;

[0074] S6. Before bending, scribing lines on the bottom of profile 3 is used to measure the deformation after bending.

[0075] S7. Conduct a die stretching and bending test. Adjust the stretching and bending program to ensure that the deformation at the bottom of the profile meets the requirements of S1. Measure the optimal deformation dimensions of the cross-section and record the tensile deformation at the bottom of the profile at this point. This value will be used as a fixed deformation parameter to be controlled in future production.

[0076] S8. Use the test template 5 to test the shape of the bending forming part 4 in step S7, and adjust the mold curve according to the difference in size between the test template 5 and the large arc of the bending forming part 4.

[0077] S9. Reprocess and correct the mold curve, and conduct a tensile bending test according to step S7.

[0078] Specifically, this embodiment discloses a forming method suitable for bending parts with large curvature radii. By controlling the amount of stretching at the bottom of the profile during the stretch bending process, optimizing and improving the design and debugging method of the stretch bending forming mold, excessive stretching during the stretch bending process is avoided, ensuring that the cross-sectional shrinkage deformation and angular distortion of the final formed part are minimized.

[0079] Preferably, in step S3 of this embodiment, the mold curve is derived based on the simulation results to derive the upper and lower surface curves of the mold surface.

[0080] Preferably, step S4 in this embodiment is divided into a mold suitable for stainless steel or carbon steel bending forming parts and a mold suitable for aluminum alloy extruded profile forming parts.

[0081] The molds applicable to stainless steel or carbon steel bending forming parts in this embodiment include:

[0082] Mold body 101; and

[0083] A forming mold side plate 102 is fixed to the side of the upper part of the mold body 101;

[0084] A forming space 103 for forming stainless steel bending parts is formed between the mold body 101 and the forming mold side plate 102.

[0085] In addition, similar to stainless steel or carbon steel molds, the molds used in this embodiment for forming aluminum alloy extruded profiles include:

[0086] Mold body 101; and

[0087] A forming mold side plate 102 is fixed to the side of the upper part of the mold body 101;

[0088] A forming space 103 for a carbon steel bending forming part is formed between the mold body 101 and the forming mold side plate 102.

[0089] A line is drawn on the bottom of profile 3. The purpose of the line drawing is to measure the deformation after bending. That is, the extension length after bending, 50mm apart. In step S6, lines are drawn on the bottom of profile 3 at intervals of L=50mm using a scribing ruler 2.

[0090] Based on the marked area, determine the elongation L1 after bending, and the elongation is:

[0091] Φ%=(L1-50) / 50.

[0092] Among them, see Figure 5 As shown, Figure 5 The structure of the scribing ruler 2 used for scribing lines is shown, and Figure 6 This diagram shows the marking state of the bottom of the bent blank profile, which can be marked at any location where measurement is required. Figure 7 It refers to the scribing area of ​​the formed part.

[0093] Preferably, in this embodiment, the tensile deformation of carbon steel and stainless steel materials is controlled within 1%-3%;

[0094] The tensile deformation of aluminum alloy extruded profiles is controlled within 0-2% of the fixed parameter.

[0095] Adjust the bending procedure according to whether the extension length meets the specified extension standard, so that the tensile deformation of carbon steel and stainless steel materials is fixed between 1% and 3%, and the tensile deformation of aluminum alloy extruded profiles is fixed between 0% and 2%.

[0096] A tensile bending test is conducted using a pre-programmed procedure. The deformation at the bottom of the profile is measured. If the deformation is outside the specified range, the bending program is adjusted to control the deformation within this range. Priority is given to carbon steel and stainless steel materials, with the tensile deformation parameter fixed within 1%-3%, and aluminum alloy extruded profiles, with the parameter fixed within 0-2%. The tensile bending is then finalized. Subsequent production is then conducted using the fixed tensile deformation parameters, controlled by testing and the program.

[0097] Preferably, in step S8 where the process is still going smoothly, the method for adjusting the mold curve based on the dimensional inspection results of the bent part 4 is as follows:

[0098] Compensate for the rebound by increasing the wrap angle, i.e., reducing the radius, while keeping the arc length constant.

[0099] Based on the bending formed part 4 obtained in step S7, the shape of the bending formed part 4 is inspected, wherein, Figure 8a For parts after stretch bending, Figure 8b For testing samples, Figure 8c The structure is for testing. The first test showed that the difference between the template 5 and the large arc of the part was 'a'. Based on the inspection results of the external dimensions of the bending part 4, the mold curve was adjusted, that is, the springback was compensated by increasing the wrap angle, i.e., reducing the radius, while keeping the arc length unchanged.

[0100] In the above technical solution, the tension bending forming method for fixing and controlling the amount of tensile deformation provided by the present invention has the following beneficial effects:

[0101] The tension bending forming method of the present invention effectively controls the amount of tensile deformation, increases the springback compensation of pure bending deformation, reduces the amount of shrinkage deformation and angular distortion of the cross section, and ensures the stability and accuracy of the cross section shape.

[0102] The bending forming method of the present invention can reduce the difference in cross-sectional shape and size of each curve segment for bending forming parts 4 composed of multiple curvature radii, increase consistency, and improve part quality; the mold design and debugging have specific digital control basis, and the forming accuracy is improved by accurately controlling the deformation parameters.

[0103] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for fixing and controlling the amount of tensile deformation in a tension bending forming process, characterized in that, The stretch bending forming method mainly includes the following steps: S1. The order of importance of ensuring the shape and size of key components during the bending process is as follows: cross-sectional shape and size accuracy, tensile deformation control, and shape accuracy. S2. Simulation calculation of profile bending forming: The tensile deformation at the bottom of the profile in the stress-deformation curve displayed by the simulation calculation results is controlled as follows: The tensile deformation of carbon steel and stainless steel materials is controlled within 1% to 3%; The tensile deformation of aluminum alloy extruded profiles is controlled within 0 to 2% by a fixed parameter. And based on the simulation results, the simulated mold curve is derived; S3. Based on the mold curve derived from the simulation results in step S2, design the bending die and predict the cross-sectional deformation of the bending part based on the mold curve obtained from the simulation analysis, so as to analyze whether it meets the usage requirements. S4. Design and manufacture the mold according to the exported mold surface curve diagram; S5. Write a bending program using the simulated bending curve calculated by simulation, and ensure that the tensile deformation of the bending using this program is within the range required by S2. S6. Before bending, scribing lines on the bottom of the profile (3) is used to measure the tensile deformation after bending. S7. Conduct a mold stretching and bending test, and adjust the stretching and bending program so that the stretching deformation at the bottom of the profile meets the requirements of S2. S8. Use the test template (5) to test the shape of the bending forming part (4) in step S7, and adjust the mold curve according to the difference in size between the test template (5) and the arc of the bending forming part (4). S9. Reprocess and correct the mold curve, and conduct a tensile bending test according to step S7.

2. The method for fixing and controlling tensile deformation according to claim 1, characterized in that, In step S3, the mold curve is derived based on the simulation results to derive the upper and lower surface curves of the mold surface.

3. The method for fixing and controlling tensile deformation according to claim 1, characterized in that, Step S4 is divided into molds suitable for bending stainless steel or carbon steel parts and molds suitable for forming aluminum alloy extruded profiles.

4. The method for fixing and controlling tensile deformation according to claim 3, characterized in that, The molds suitable for bending stainless steel or carbon steel parts include: Mold body (101); and A forming mold side plate (102) is fixed to the side of the upper part of the mold body (101); A forming space (103) for forming a stainless steel bending forming part is formed between the mold body (101) and the forming mold side plate (102).

5. The method for fixing and controlling tensile deformation according to claim 3, characterized in that, The die used for forming aluminum alloy extruded profiles includes: Mold body (101); and A forming mold side plate (102) is fixed to the side of the upper part of the mold body (101); A forming space (103) for a carbon steel bending forming part is formed between the mold body (101) and the forming mold side plate (102).

6. The method for fixing and controlling tensile deformation according to claim 1, characterized in that, In step S6, lines are drawn on the bottom of the profile (3) at intervals of L = 50mm using a scribing ruler (2); Based on the marked area, determine the elongation L1 after bending, and the elongation is: Φ%=(L1-50) / 50.

7. The method for fixing and controlling tensile deformation as described in claim 6, characterized in that, The tensile deformation parameters of the carbon steel and stainless steel materials are controlled within 1%-3%; The tensile deformation of the aluminum alloy material is fixed within 0-2%.

8. The method for fixing and controlling tensile deformation according to claim 1, characterized in that, In step S8, the method for adjusting the mold curve based on the external dimensions of the bending forming part (4) is as follows: Compensate for the rebound by increasing the wrap angle, i.e., reducing the radius, while keeping the arc length constant.

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