Construction process of fish belly side wall by welding to control flatness

Abstract

The application provides a fish belly side wall construction process for controlling flatness by welding, comprising the following steps: setting the assembly and welding sequence of the fish belly side wall framework according to the welding form between the lower edge beam and the cross beam of the fish belly framework; preforming the reverse deformation on the welding fixture and the tooling table surface according to the deformation amount generated during the welding of the fish belly framework; determining the support point and the pressing point positions during the adjustment and repair through tests, so as to determine the required workpiece interference amount during the adjustment and repair, and determining the flatness adjustment and repair range according to the flatness tests in each stage; designing the fish belly side wall welding process and trial producing the fish belly side wall according to the determined flatness adjustment and repair range. The construction process is mature and simple, and the long-term professional experience is not required to complete the process design and implementation of the fish belly side wall; in addition, the tooling cost is low, the use and maintenance are simple, the cost is easy to control, and the operation is simple, fast, and the production cycle is accelerated.

Description

Technical Field

[0001] This application belongs to the field of rail vehicle manufacturing technology, and in particular relates to a construction process for fish-belly sidewalls that controls flatness through welding. Background Technology

[0002] The double-decker stainless steel car body structure is a double-decker passenger car body, which differs significantly from ordinary subway and passenger cars in structure. Its length, height, width, weight, and load-bearing capacity far exceed those of domestic subway and railway passenger cars. The underframe structure is a ship-shaped three-dimensional structure, with the middle underframe lower than the end underframes. The end underframes are connected to the middle underframes by traction beams. The interface has a large amount of welding, and most of the welds are concentrated in the lower part. The deflection deformation of the underframe causes large wave deformation in the middle and upper part of the fish-belly sidewall of the underframe. The control of flatness is particularly important for the appearance of the fish-belly structure underframe.

[0003] Currently, most of the flatness is achieved by mechanically adjusting and correcting the flatness during the welding frame process, and then flame-adjusting the flatness dimensions of the fish belly frame to ensure the overall flatness of the subsequent fish belly sidewalls, as detailed below:

[0004] (1) Place the beams and columns of the fish belly side wall frame onto the workbench in sequence;

[0005] (2) Install the clamps and weld the various parts of the fish belly skeleton onto the inclined support platform of the welding clamps.

[0006] (3) After welding, the twisted and deformed skeleton is adjusted to the qualified range by mechanical and flame methods.

[0007] However, the above adjustments and modifications have the following problems:

[0008] (1) Adjusting the flatness of the fish belly sidewall frame by mechanical means and flame has its own drawbacks. Because the welds connecting the beams and columns of the fish belly sidewall frame are all three-sided fillet welds, there are no symmetrical welds. After welding, the fish belly sidewall frame will inevitably suffer from severe bending deformation, torsional deformation and angular deformation. Excessive flame adjustment temperature has a significant impact on the structural strength. Limiting the adjustment temperature will result in low flatness accuracy of the frame stage, affecting the visible flatness of the lower structure of the overall base frame.

[0009] (2) The setting of welding fixtures and tooling tables is very complicated. They must conform to the deflection curve and adjust the misalignment between the beams in the structure. Maintenance and repair are also very difficult and require a lot of manpower and resources. Summary of the Invention

[0010] In view of this, this application aims to propose a construction process for fish belly sidewalls that controls flatness through welding, so as to mechanically adjust and correct the problems of poor flatness accuracy in the skeleton stage and the difficulty of maintenance and repair.

[0011] To achieve the above objectives, the technical solution of this application is implemented as follows:

[0012] This application provides a construction process for fish-belly sidewalls that controls flatness through welding, including:

[0013] The assembly and welding sequence of the fish belly sidewall skeleton is determined based on the welding method between the lower side beam and the cross beam of the fish belly skeleton.

[0014] Based on the deformation generated during the welding of the fish belly skeleton, anti-deformation is prefabricated on the welding fixture and tooling table.

[0015] The positions of the support and clamping points during adjustment are determined through experiments, so as to determine the required workpiece interference during adjustment and clamping, and the flatness adjustment range is determined based on the flatness test at each stage.

[0016] Based on the determined flatness adjustment range, the welding process for the fish belly sidewall was designed and the fish belly sidewall was trial-produced.

[0017] Furthermore, the assembled fish-belly side wall frame is tack-fixed as a whole, the tooling clamping device is fixed and then welded, and a process lower edge beam is added at the lower angle steel. The lower angle steel edge beam is not tack-fixed, and the welding sequence adopts an intermittent skip welding method.

[0018] The welds at the lower ends of the frame beams and the inner columns of the frame beams are welded when assembling the frame beams, and the welds at the upper ends are reserved for welding when assembling the fish belly side wall skeleton, so that the welds form symmetrical welds.

[0019] The flatness and deflection of the reference surface of the tooling table are measured and recorded before welding. After welding is completed, the welded test piece is constrained to a straight state on a straight platform and measured again.

[0020] Furthermore, based on the deformation trend generated after the weld is completed, anti-deformation is pre-fabricated using welding fixtures and tooling tables before welding to offset the welding deformation generated during welding.

[0021] Based on the actual required deflection of the fish belly sidewall skeleton, calculate the resulting deflection, the length of the upper and lower side beams after lateral bending, and the size allowance of each beam and column.

[0022] Design a fish belly skeleton welding test. After clamping the upper and lower side beams and each beam and column on the clamp, weld the lower side beam and each beam and column from the middle to both sides. The welding is carried out in an intermittent skip sequence without pre-tack fixing.

[0023] The upper beam is tack-fixed to all beams and columns. Then, welding is carried out sequentially from the middle to both sides. The lateral bending value and deflection curve of the whole component after welding are recorded. Based on the values, the welding fixture and tooling table are prefabricated to counter-deform.

[0024] Furthermore, based on the difference between the arc length value of the edge beam in its natural straight state and the lateral bending value generated after the edge beam is welded, the amount of pre-fabricated reverse deformation required in the vertical direction of the generated lateral bending value on the tooling table is obtained.

[0025] Furthermore, based on the difference between the arc length of the edge beam in its naturally straight state and the deflection value generated after welding, the required shrinkage length of the lower edge beam for the generated deflection value is obtained.

[0026] Furthermore, the frame components, columns, and square steel pipes are clamped in place on the fixture, and the upper and lower fish-belly side beams on the fixture are pressed and clamped in place.

[0027] Welding is performed on the beams and columns of the fish belly skeleton. The welding method is to weld from the middle of the fish belly skeleton to both sides in an intermittent, skipping sequence.

[0028] After welding the lower beam and the lower half of the column, mark the column with larger shrinkage deformation according to the measured and recorded flatness value of the fish belly skeleton, and prefabricate the reverse deformation in the length direction of the fish belly skeleton.

[0029] The upper beam and the upper part of the column are welded together. The welding method is to weld from the middle of the fish belly skeleton to both sides in an intermittent skipping sequence.

[0030] After the entire fish belly sidewall is welded, its flatness and deflection are checked against the theoretical flatness and deflection. Once the deviation meets the predetermined range, the process is fixed.

[0031] Furthermore, when welding the edge beams and the upper part of the columns, when encountering a marked column, it is simultaneously tack-fixed with the next column to be welded before welding.

[0032] Furthermore, the predetermined range for the deviation is ≤10%.

[0033] Compared with existing technologies, the fish-belly sidewall construction process for controlling flatness through welding described in this application has the following advantages:

[0034] The fish-belly sidewall construction process described in this application, which controls the flatness of the sidewall through welding, is a mature and simple process that does not require extensive professional experience to complete the design and implementation of the fish-belly sidewall. In addition, the tooling is low in cost, easy to use and maintain, easy to control costs, and simple and quick to operate, thus accelerating the production cycle. Attached Figure Description

[0035] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0036] Figure 1 This is a flowchart illustrating the construction process of a fish-belly sidewall with flatness controlled by welding, as described in an embodiment of this application.

[0037] Figure 2 This is a schematic diagram of the lateral bending and deflection described in the embodiments of this application;

[0038] Figure 3 This is a schematic diagram of the beam-column distribution as described in the embodiments of this application;

[0039] Figure 4 This is a schematic diagram of the column anchoring as described in the embodiments of this application;

[0040] Figure 5 This is a schematic diagram of the broken line deflection of the upper and lower beams as described in the embodiments of this application. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0042] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0043] To address the requirement for flatness of the fish belly sidewall, this application designs a new process that is simpler, more efficient, less labor-intensive, and with easily maintainable welding fixtures, in order to improve the flatness accuracy and production efficiency of the fish belly.

[0044] The embodiments of this application are described in detail below with reference to the accompanying drawings.

[0045] Please see Figure 1 As shown, this embodiment provides a construction process for fish-belly sidewalls that controls flatness through welding, specifically including the following steps:

[0046] Step S101: Set the assembly and welding sequence of the fish belly side wall frame according to the welding method between the lower side beam and the cross beam of the fish belly frame.

[0047] Specifically, in this embodiment, the fish belly skeleton is composed of a side frame, a base frame with lower angle steel, columns, and longitudinal beams. The welding method is full arc welding. Since the side frame has greater strength and rigidity than the lower angle steel, the upper and lower parts shrink differently after welding, resulting in a large deflection after welding. The skeleton is all arc welded, with a large amount of welding, and the flatness after welding is difficult to meet the requirements.

[0048] ① In order to design a reasonable assembly and welding sequence for the fish belly sidewall skeleton and to simulate the shrinkage state during welding to the greatest extent, the overall experimental welding method of the fish belly sidewall is consistent with the original welding method.

[0049] Assemble the fish-belly sidewall frame of the base frame. After assembly, tack fix the entire frame except for the lower angle steel edge beams. After fixing the tooling clamping device, proceed with welding. The welding sequence adopts an intermittent skip welding method. A process lower edge beam is added at the lower angle steel to increase the rigidity of the frame and facilitate tooling clamping. The purpose of the experimental welding method is mainly to measure the changes in the flatness of the fish-belly frame at different stages.

[0050] ② Treat the fish belly sidewall skeleton as a whole structure. The weld should be considered as a whole. Try to plan the weld as a symmetrical weld so that the weld shrinks symmetrically and reduces welding deformation.

[0051] The welds at the lower ends of the frame beams and the columns inside the frame beams are welded when assembling the frame beams, while the welds at the upper ends need to be welded when assembling the fish-belly side wall frame. In this way, the welds of the fish-belly side wall frame are basically symmetrical welds with very little deformation.

[0052] ③ Measure and record the flatness and deflection of the reference surface of the tooling table, then weld. After welding, constrain the welded test piece to a straight state on a straight platform and measure again.

[0053] Step S102: Based on the deformation generated during the welding of the fish belly skeleton, prefabricate the reverse deformation on the welding fixture and tooling table.

[0054] Specifically, in this embodiment, the purpose of this step is to reduce the workload of adjustment and repair, and it includes the following steps:

[0055] ① Based on the deformation trend after the weld is completed, anti-deformation is prefabricated on the welding fixture and tooling table before welding to offset the welding deformation generated during welding, reduce the amount of workpiece adjustment, and ensure the flatness of the fish belly side wall skeleton.

[0056] ②Calculate the deflection, length of upper and lower side beams after lateral bending, and size allowance of each beam and column based on the actual required deflection of the fish belly side wall frame.

[0057] like Figure 2 As shown, A is the arc length of the edge beam in its natural straight state, B is the lateral bending value of the edge beam after welding, and C is the deflection value.

[0058] The difference between the left and right side beams, S = AB, is the amount of reverse deformation that needs to be prefabricated in the left and right directions of the tooling table to generate the lateral bending value; the difference between the upper and lower arc lengths, X = AC, is the length of the lower side beam shrinkage required to generate the C deflection value.

[0059] ③ Design a fish belly skeleton welding test. After clamping the upper and lower side beams and each beam and column on the clamp, weld the lower side beam and each beam and column from the middle to both sides first, and weld them in a skip-the-end sequence without pre-tack fixing.

[0060] Note: The tooling is not set with deflection and the flatness reference is zero. This ensures that the upper and lower side beams and columns are in a fixed and clamped state. During welding, the length and width of each side beam and column of the fish belly frame can be reduced.

[0061] ④ Secure the upper beam to all the beam and column supports, and then weld sequentially from the middle outwards. Record the lateral bending value and deflection curve of the overall component after welding, and prefabricate the anti-deformation of the welding fixture and tooling table based on the values.

[0062] Step S103: Determine the positions of the support point and clamping point during adjustment through testing, so as to determine the workpiece interference required during adjustment and clamping, and determine the flatness adjustment range based on the flatness test at each stage.

[0063] Specifically, in this embodiment, in order to ensure the strength of the structure, flame adjustment cannot be used after welding deformation occurs. A simple gantry frame for adjustment is made according to the site conditions and the size of the workpiece. Adjustment is carried out in conjunction with jacks. The positions of the support points and clamping points during adjustment are determined through experiments, and the interference of the workpiece during adjustment and clamping is determined to achieve "overcorrection". The deformation position and adjustment and clamping value of the fish belly side wall frame when various deformations such as bending deformation, torsion deformation and angular deformation are determined.

[0064] If the flatness of the skeleton stage is 0, and the flatness value of the overall cover plate after spot welding is greater than the specified value, then the flatness value of the fish belly skeleton stage needs to be adjusted according to the flatness of all components of the fish belly sidewall. The skeleton stage value should be reduced to a negative number and the test should be repeated until the overall flatness of the fish belly sidewall is ≤1mm, and the flatness values ​​of each beam and column of the skeleton should be recorded.

[0065] Step S104: Design the welding process for the fish belly sidewall based on the determined flatness adjustment range and trial-produce the fish belly sidewall.

[0066] Specifically, in this embodiment, this step involves designing the welding process for the entire fish belly sidewall and prototyping the fish belly sidewall to solidify the process. This includes the following steps:

[0067] ① First, secure the frame components, columns, and square steel pipes to the tooling.

[0068] Note: The tooling has no deflection and the flatness reference is zero; the clamping and locking positions of the upper and lower side beams of the fish belly on the tooling ensure that the upper and lower side beams and columns are in a positioned and locked state, allowing for contraction in the length and width directions of each side beam and column of the fish belly frame during welding.

[0069] ② Weld the beams and columns of the fish belly skeleton. The welding method is to weld them sequentially from the middle of the fish belly skeleton outwards, one beam at a time, so that the shrinkage of each beam and column will not affect the flatness.

[0070] ③ After completing the welding of the lower beam and the lower half of the column, according to the measured and recorded flatness values ​​of the fish-belly skeleton, such as... Figure 3 As shown, the columns with larger shrinkage deformation are marked (corresponding to...). Figure 3 (The gray lines in the image) are used to pre-deform the fish belly skeleton along its length.

[0071] ④ Weld the upper beam and the upper part of the column. The welding method is to start from the middle of the fish belly skeleton and work outwards from both sides, welding one beam at a time in a skipping manner. At this time, the upper beam can freely shrink in the length direction during the welding process.

[0072] When encountering a marked column, it should be tack-fixed simultaneously with the next column to be welded before welding. This allows for relative shrinkage between the two beams and columns during welding, effectively controlling the deflection tendency and flatness of the fish-belly skeleton. The column tack-fixing is as follows: Figure 4 As shown, the arrows indicate the welding sequence.

[0073] Note: This process creates a deflection in a zigzag pattern, with a very small error compared to the theoretical deflection, within 1.5mm, which meets the usage requirements. The zigzag deflection of the upper and lower beams is as follows: Figure 5 As shown.

[0074] ⑤ After the entire fish belly sidewall is welded, check its flatness and deflection to see if they deviate from the theoretical flatness and deflection. If the error is no more than 10%, it can be used. Then the process can be fixed.

[0075] It should be noted that the tooling and positioning fixtures involved in this embodiment are all conventional devices used in the field. This embodiment does not involve any improvement to the structure of the device itself, and will not be described in detail here.

[0076] The construction process described in this embodiment is mature and simple, and the process design and implementation of the fish belly sidewall can be completed without long-term professional experience; in addition, the tooling is low in cost, simple to use and maintain, and easy to control costs; the construction method is simple, fast, and accelerates the production cycle.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

[0078] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A fish belly side wall construction process by welding to control flatness, characterized by, Comprise: According to the welding form between the lower side beam and the cross beam of the fishbone skeleton, the assembly and welding sequence of the fishbone side wall skeleton is set; According to the deformation amount generated during the welding of the fishbone skeleton, the counter-deformation is prefabricated on the welding fixture and the workbench, including: According to the deformation trend generated after the welding of the weld, before welding, the counter-deformation is prefabricated on the welding fixture and the workbench to offset the welding deformation generated during welding, including: According to the difference between the arc length value of the side beam in the natural straight state and the side bending value generated after the welding of the side beam, the required prefabricated counter-deformation amount of the generated side bending value in the up-down direction of the workbench is obtained; According to the difference between the arc length value of the side beam in the natural straight state and the deflection value generated after the welding of the side beam, the length of the lower side beam required to shrink the deflection value is obtained; According to the actual required deflection of the fishbone side wall skeleton, the length of the upper and lower side beams and the size of each beam column after generating deflection and side bending is calculated; Design the fishbone skeleton welding test, clamp the upper and lower side beams and each beam column on the fixture, then weld the weld between the lower side beam and each beam column from the middle to both sides, wherein, weld in interval jumping sequence, without pre-fixing; Fix the upper side beam and all beam columns, then weld from the middle to both sides in turn, and record the side bending value and deflection change curve of the whole part after welding, and prefabricate counter-deformation on the welding fixture and the workbench according to the numerical value; Determine the support point and pressing point position during adjustment and repair through the test to determine the required workpiece interference amount during adjustment and pressing, and determine the flatness adjustment range according to the flatness test at each stage; Design the fishbone side wall welding process according to the determined flatness adjustment range and trial-produce the fishbone side wall.

2. The fishbone side wall construction process for controlling flatness by welding according to claim 1, wherein: The assembled fishbone side wall skeleton is fixed as a whole, the workbench is fixed after the workbench pressing device is fixed, and welding is performed, and a process lower side beam is added at the lower corner steel, wherein the lower corner steel side beam position is not fixed, and the welding sequence adopts interval jumping welding; The welds of the frame beam and the inner stand column of the frame beam are welded when the frame beam is assembled, and the welds at the upper end are reserved for welding when the fishbone side wall skeleton is assembled, so that the welds form symmetrical welds; The reference surface flatness and deflection of the workbench are measured, recorded, and then welded, and after the welding is completed, the welded test piece is constrained to be flat on a straight platform and then measured again.

3. The fishbone side wall construction process for controlling flatness by welding according to claim 1, wherein: The frame composition, stand column and square steel tube are clamped on the workbench, and the fishbone upper and lower side beams on the workbench are pressed and clamped; Each beam column of the fishbone skeleton is welded, wherein the welding method is from the middle to both sides of the fishbone skeleton, and the welding is in interval jumping sequence; After the welding of the lower side beam and the lower half of the stand column is completed, according to the measured and recorded fishbone skeleton flatness value, the stand column with larger shrinkage deformation amount is marked, and the counter-deformation is prefabricated in the length direction of the fishbone skeleton; The upper side beam and the upper half of the stand column are welded, wherein the welding method is from the middle to both sides of the fishbone skeleton, and the welding is in interval jumping sequence; After the entire fish belly side wall is welded, the deviation of the flatness and deflection from the theoretical flatness and deflection is detected, and the process is fixed when the deviation meets the predetermined range.

4. The fish belly side wall construction process for controlling flatness by welding according to claim 3, characterized in that: When welding the side beam and the upper part of the column, the marked column is welded after being simultaneously fixed with the next column to be welded.

5. The fish belly side wall construction process for controlling flatness by welding according to claim 3, characterized in that: The predetermined range of the deviation is ≤10%.

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