Fish belly side wall construction technology for controlling flatness through welding

Abstract

The invention provides a fish belly side wall construction process for controlling flatness through welding. The fish belly side wall construction process comprises the steps that the assembling and welding sequence of a fish belly side wall framework is set according to the welding form between a lower edge beam and a cross beam of the fish belly framework; prefabricating reversible deformation on a welding clamp and a tool table top according to deformation generated during welding of the fish-belly skeleton; the positions of a supporting point and a pressing point during adjustment and repair are determined through tests so as to determine the workpiece interference magnitude needed during adjustment and repair and pressing, and the flatness adjustment and repair range is determined according to flatness tests of all stages; and a fish belly side wall welding process is designed according to the determined flatness adjusting and repairing range, and the fish belly side wall is trial-manufactured. The construction process is mature and simple, and process design and implementation of the fish belly side wall can be completed without long-term professional experience; in addition, the tool is low in cost, simple to use and maintain, easy to control cost, simple, convenient and rapid to operate and short in production cycle.

Description

Technical Field

[0001] The present application belongs to the technical field of rail vehicle manufacturing, and in particular relates to a fish belly side wall construction process for controlling flatness through welding. Background Art

[0002] The double-deck stainless steel car body structure is a double-deck passenger car body, which is quite different from ordinary subways and passenger cars in structure. Whether in length, height, width, weight, or carrying capacity, it far exceeds domestic subways and railway passenger cars. The chassis structure is a ship-shaped three-dimensional structure, with the middle chassis lower than the end chassis, and the end chassis connected to the middle chassis by a traction beam. The amount of welding at the interface is large, and most of the welds are concentrated in the lower part. The chassis deflection deformation causes large wave deformation in the middle and upper parts of the fish belly side wall of the chassis. The control of flatness is particularly important for the appearance of the fish belly structure chassis.

[0003] At present, most of the flatness is achieved by mechanical adjustment and correction in advance during the welding skeleton process, and flame adjustment of the flatness size of the fish belly skeleton stage to ensure the overall flatness of the subsequent fish belly side wall, as follows:

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

[0005] (2) Install the fixture and restrain the various parts of the fish belly frame on the inclined support table of the welding fixture for welding;

[0006] (3) After welding is completed, the distorted and deformed frame is adjusted to the acceptable range through mechanical and flame adjustment.

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

[0008] (1) There are disadvantages in adjusting the flatness by mechanical and flame adjustment. Because the welds between the beams and columns of the fish belly wall frame are all three-sided fillet welds, there are no symmetrical welds. After welding, the fish belly wall frame will inevitably suffer from severe bending deformation, twisting deformation and angular deformation. Too high flame adjustment temperature has a great impact on the structural strength. Limiting the adjustment temperature will lead to low flatness accuracy of the frame stage, affecting the visual flatness of the overall chassis lower structure.

[0009] (2) The setting of welding fixtures and tooling tables is very complicated. They must not only conform to the deflection curve, but also adjust the misalignment between the beams in the structure. Maintenance and inspection are also very difficult and require a lot of manpower and material resources. Summary of the invention

[0010] In view of this, the present application aims to propose a fish belly side wall construction process that controls flatness through welding, so as to correct the problems of poor flatness accuracy in the skeleton stage and difficulty in maintenance and inspection through mechanical adjustment.

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

[0012] The present application provides a fish belly side wall construction process for controlling flatness by welding, comprising:

[0013] Set the assembly and welding sequence of the fish belly side wall frame according to the welding form between the lower side beam and the cross beam of the fish belly frame;

[0014] According to the deformation amount generated during the welding of the fish belly frame, the welding fixture and the tooling table are prefabricated with anti-deformation;

[0015] Determine the positions of the support points and clamping points during adjustment and repair through tests, so as to determine the interference required for the workpiece during adjustment and repair, and determine the flatness adjustment range based on the flatness tests at each stage;

[0016] According to the determined flatness adjustment range, the welding process of the fish belly side wall is designed and the fish belly side wall is trial-produced.

[0017] Furthermore, the assembled fish belly side wall frame is spot-fixed as a whole, the tooling clamping device is fixed and then welded, and a process lower side beam is added at the lower angle steel, wherein the lower angle steel side beam position is not spot-fixed, and the welding sequence adopts interval jump welding;

[0018] The welds at the lower ends of the frame beams and the inner columns of the frame beams are welded when the frame beams are assembled, and the welds at the upper ends are reserved for welding when the fish belly side wall skeleton is assembled, 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 welding test piece is constrained to a straight state on a linear platform and measured again.

[0020] Furthermore, according to the deformation trend generated after the weld is completed, before welding, the welding fixture and the tooling table are prefabricated with anti-deformation to offset the welding deformation generated during welding;

[0021] According to the actual deflection required by the fish belly side wall frame, calculate the deflection, the length of the upper and lower side beams after the lateral bending, and the size of each beam column;

[0022] Design a fish belly frame welding test, clamp the upper and lower side beams and each beam column on the fixture, and weld the welds between the lower side beam and each beam column from the middle to both sides, in which the welding is carried out in an interval jump sequence without pre-tightening;

[0023] The upper beam and all beams and columns are spot-fixed, and then welded from the middle to both sides in sequence. The lateral bending value and deflection change curve of the overall component after welding are recorded, and the welding fixture and tooling table are prefabricated with anti-deformation according to the values.

[0024] Furthermore, according to the difference between the arc length value of the side beam in a naturally straight state and the lateral bending value generated after the side beam is welded, the reverse deformation amount required to be prefabricated in the upper and lower directions of the tooling table is obtained.

[0025] Furthermore, according to the difference between the arc length value of the side beam in a naturally straight state and the deflection value generated after the side beam is welded, the contraction length of the lower side beam required for the generated deflection value is obtained.

[0026] Further, the frame components, columns, and square steel pipes are clamped in position on the tooling, and the upper and lower side beams of the fish belly on the tooling are pressed and clamped in position;

[0027] The beams and columns of the fish belly frame are welded, wherein the welding method is to weld sequentially from the middle of the fish belly frame to both sides in an interval jumping manner;

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

[0029] The upper side beam and the upper part of the column are welded, wherein the welding method is from the middle of the fish belly frame to the two sides, and the welding is performed in an interval jumping sequence;

[0030] After the entire ventral side wall is welded, its flatness and deflection are tested for deviations from the theoretical flatness and theoretical deflection. When the deviation meets the predetermined range, the process is fixed.

[0031] Furthermore, when welding the side beam and the upper part of the column, when encountering a marked column, it is combined with the next column to be welded and then spot-fixed and welded.

[0032] Further, the predetermined range of the deviation is ≤10%.

[0033] Compared with the prior art, the fish belly side wall construction process for controlling flatness by welding described in the present application has the following beneficial effects:

[0034] The application describes a fish belly side wall construction process that controls flatness through welding. The process is mature and simple, and does not require long-term professional experience 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 and fast, which accelerates the production cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0036] Figure 1 This is a flow chart of a fish belly side wall construction process for controlling flatness by welding as described in an embodiment of the present application;

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

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

[0039] Figure 4 This is a schematic diagram of point fixing of a column according to an embodiment of the present application;

[0040] Figure 5 This is a schematic diagram of the deflection of the upper and lower beams according to the embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0042] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like 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] In response to the requirement for flatness of the fish belly side wall, this application designs a new process that is simpler, more efficient, and labor-saving, and the welding tooling is easy to maintain, so as to improve the flatness accuracy and production efficiency of the fish belly.

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

[0045] See also Figure 1 As shown, this embodiment provides a fish belly side wall construction process for controlling flatness by welding, which specifically includes the following steps:

[0046] Step S101, setting the assembly and welding sequence of the fish belly side wall frame according to the welding form 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 bottom angle steel of the base frame, columns, and longitudinal beams, and the welding method is full arc welding. Since the strength and rigidity of the side frame are stronger than the bottom angle steel, the upper and lower parts shrink differently after welding, which will produce a large deflection. The skeleton is all arc welded, and the welding amount is large, and it is difficult to meet the flatness requirements after welding.

[0048] ① In order to design a reasonable assembly welding sequence for the fish belly side wall frame and to simulate the shrinkage state during welding to the greatest extent, the overall test welding form of the fish belly side wall is kept consistent with the original welding form.

[0049] Assemble the bottom frame fish belly side wall frame, first point fix the whole after assembly, the lower angle steel side beam position is not point fixed, fix the tooling clamping device and then weld, the welding sequence adopts interval jump welding, add process lower side beam at the lower angle steel to increase the frame rigidity, and facilitate tooling clamping. The purpose of the test welding form is mainly to measure the change of the flatness of the fish belly frame stage.

[0050] ② Consider the fish belly side wall skeleton as an integral structure, and consider the welds as a whole. Try to plan the welds into symmetrical welds to make the welds shrink symmetrically and reduce welding deformation.

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

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

[0053] Step S102, prefabricating anti-deformation on the welding fixture and the tooling table according to the deformation amount generated during the welding of the fish belly frame.

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

[0055] ① According to the deformation trend after the weld is completed, the welding fixture and tooling table are pre-deformed before welding to offset the welding deformation generated during welding, reduce the adjustment amount of the workpiece, and ensure the flatness of the fish belly side wall frame.

[0056] ② According to the actual deflection required by the fish belly side wall frame, calculate the deflection, the length of the upper and lower side beams after lateral bending, and the size of each beam and column.

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

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

[0059] ③ Design a fish belly frame welding test. After clamping the upper and lower side beams and each beam column on the fixture, weld the welds between the lower side beam and each beam column from the middle to both sides, one by one in a skipping sequence without pre-fixing.

[0060] Note: There is no deflection on the tooling, and the flatness benchmark is zero, to ensure that the upper and lower side beams and columns are in a positioned and clamped state, and the side beams and columns of the fish belly frame can shrink in length and width when welding.

[0061] ④Fix the upper beam and all the beam-column points together, and then weld them from the middle to both sides in sequence. Record the lateral bending value and deflection change curve of the overall component after welding, and prefabricate the welding fixture and tooling table according to the value.

[0062] Step S103, determining the positions of the support points and the pressing points during adjustment and repair through experiments, so as to determine the interference of the workpiece required during adjustment and repair and pressing, and determining the flatness adjustment range according to the flatness tests 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 for adjustment is made according to the on-site conditions and the size of the workpiece, and adjustment is carried out in conjunction with a jack. The positions of the support points and clamping points during adjustment are determined through experiments, as well as the amount of interference fit during adjustment and clamping, so as to achieve "overcorrection" and determine the deformation position and adjustment and clamping value of the fish belly side wall skeleton when various deformations such as bending deformation, twisting deformation and angular deformation occur.

[0064] If the flatness of the skeleton stage is 0, and the flatness value of the overall covering cover after spot welding is greater than the specified value, it is necessary to adjust the flatness value of the fish belly skeleton stage according to the flatness of all the components of the fish belly side wall, reduce the skeleton stage value to a negative number and test again until the overall flatness of the fish belly side wall is ≤1mm, and record the flat values ​​of each beam and column of the skeleton.

[0065] Step S104, designing the welding process of the fish belly side wall according to the determined flatness adjustment range and trial-producing the fish belly side wall.

[0066] Specifically, in this embodiment, this step is to design the welding process of the entire fish belly side wall and trial-produce the fish belly side wall to fix the process. Specifically, it includes the following steps:

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

[0068] Note: There is no deflection on the fixture, and the flatness benchmark is zero; the upper and lower side beams of the fish belly on the fixture are pressed and clamped to ensure that the upper and lower side beams and columns are in a positioned and clamped state, and the side beams and columns of the fish belly frame can shrink in length and width during welding

[0069] ② Weld the beams and columns of the fish belly frame from the middle of the fish belly frame to both sides, one at a time and one at a time, in a skipping sequence, so that the shrinkage of each beam and column will not affect the flatness.

[0070] ③ After completing the welding of the lower side beam and the lower part of the column, according to the measured and recorded flatness value of the fish belly frame, such as Figure 3 As shown, mark the columns with larger shrinkage deformation (corresponding to Figure 3 The gray line in the figure is used to pre-deform the fish belly skeleton in the length direction.

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

[0072] When encountering a marked column, it is combined with the next column to be welded and then welded together, so that the two beams of the lower beam can shrink relatively during welding, and the bending trend and flatness of the fish belly frame can be effectively controlled. Figure 4 As shown, the arrow indicates the direction of welding sequence.

[0073] Note: This process forms a deflection in a folding line state, which has a small error from the theoretical deflection, within 1.5mm, and can meet the use requirements. The deflection of the upper and lower side beams is as follows: Figure 5 shown.

[0074] ⑤ After the entire fish belly side wall is welded, check its flatness, deflection and the deviation from the theoretical flatness and deflection. It can be used if the error is no more than 10%, and then the process can be fixed.

[0075] It should be noted that the tooling and positioning fixtures involved in this embodiment are all devices commonly used in the art. This embodiment does not involve improvements to the structure of the device itself, and will not be elaborated on here.

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

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

[0078] The embodiments of the present 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 the present application should be included in the scope of protection of the present application.

Claims

1. A fish belly side wall construction process for controlling flatness by welding, characterized in that: include: Set the assembly and welding sequence of the fish belly side wall frame according to the welding form between the lower side beam and the cross beam of the fish belly frame; According to the deformation amount generated during the welding of the fish belly frame, the welding fixture and the tooling table are prefabricated with anti-deformation; Determine the positions of the support points and clamping points during adjustment and repair through tests, so as to determine the interference required for the workpiece during adjustment and repair, and determine the flatness adjustment range based on the flatness tests at each stage; According to the determined flatness adjustment range, the welding process of the fish belly side wall is designed and the fish belly side wall is trial-produced.

2. A fish belly side wall construction process for controlling flatness by welding according to claim 1, characterized in that: The assembled fish belly side wall frame is spot-fixed as a whole, the tooling clamping device is fixed and then welded, and a process lower side beam is added at the lower angle steel, wherein the lower angle steel side beam position is not spot-fixed, and the welding sequence adopts interval jump welding; The welds at the lower ends of the frame beams and the inner columns of the frame beams are welded when the frame beams are assembled, and the welds at the upper ends are reserved for welding when the fish belly side wall skeleton is assembled, so that the welds form symmetrical welds; The flatness and deflection of the reference surface of the tooling table are measured and recorded before welding. After welding is completed, the welding test piece is constrained to a straight state on a linear platform and measured again.

3. The process for constructing a fish belly side wall with flatness controlled by welding according to claim 1, characterized in that: According to the deformation trend of the weld after welding, the welding fixture and tooling table are used to pre-form anti-deformation before welding to offset the welding deformation; According to the actual deflection required by the fish belly side wall frame, calculate the deflection, the length of the upper and lower side beams after the lateral bending, and the size of each beam column; Design a fish belly frame welding test, clamp the upper and lower side beams and each beam column on the fixture, and weld the welds between the lower side beam and each beam column from the middle to both sides, in which the welding is carried out in an interval jump sequence without pre-tightening; The upper beam and all beams and columns are spot-fixed, and then welded from the middle to both sides in sequence. The lateral bending value and deflection change curve of the overall component after welding are recorded, and the welding fixture and tooling table are prefabricated with anti-deformation according to the values.

4. A fish belly side wall construction process for controlling flatness by welding according to claim 3, characterized in that: According to the difference between the arc length value of the side beam in the naturally straight state and the lateral bending value generated after the side beam is welded, the reverse deformation amount required to be prefabricated in the upper and lower directions of the tooling table for the generated lateral bending value is obtained.

5. The process for constructing a fish belly side wall with flatness controlled by welding according to claim 3, characterized in that: According to the difference between the arc length value of the side beam in the naturally straight state and the deflection value generated after the side beam is welded, the length of the lower side beam contraction required for the generated deflection value is obtained.

6. The process for constructing a fish belly side wall with flatness controlled by welding according to claim 1, characterized in that: Clamp the frame components, columns, and square steel pipes on the fixture, and press and clamp the upper and lower side beams of the fish belly on the fixture; The beams and columns of the fish belly frame are welded, wherein the welding method is to weld sequentially from the middle of the fish belly frame to both sides in an interval jumping manner; After welding the lower side beam and the lower half of the column, mark the column with the larger shrinkage deformation according to the measured flatness value of the fish belly frame, and prefabricate the reverse deformation in the length direction of the fish belly frame; The upper side beam and the upper part of the column are welded, wherein the welding method is from the middle of the fish belly frame to the two sides, and the welding is performed in an interval jumping sequence; After the entire ventral side wall is welded, its flatness and deflection are tested for deviations from the theoretical flatness and theoretical deflection. When the deviation meets the predetermined range, the process is fixed.

7. The process for constructing a fish belly side wall with flatness controlled by welding according to claim 6, characterized in that: When welding the side beams and the upper part of the columns, when encountering a marked column, it will be combined with the next column to be welded and then spot-fixed before welding.

8. The process for constructing a fish belly side wall with flatness controlled by welding according to claim 6, characterized in that: The predetermined range of deviation is ≤ 10%.

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