A method for controlling welding distortion of eccentric welded joints

Abstract

The application discloses a welding deformation control method for eccentric welding joints, and comprises the following steps: pre-deformation setting of a to-be-welded panel before welding, wherein the pre-deformation setting position is a welding deformation area, and the pre-deformation setting pre-bending direction is the opposite direction of the welding deformation trend; installing a reinforcing tool on the opposite side of the welding seam of the to-be-welded panel; welding and removing the reinforcing tool; and stress relief after welding. Through the pre-deformation before welding, the reinforcing tool constraint and the stress relief after welding, the welding deformation amount can be effectively controlled, and the manufacturing precision of the eccentric welding joint type steel member is ensured.

Description

Technical Field

[0001] This invention relates to the fabrication of steel components, and more specifically to a method for controlling welding deformation of eccentric welded joints. Background Technology

[0002] In steel components, corner joints are generally composed of steel plates with similar restraint and thickness. The weld filler is moderate, and the weld is centrally distributed compared to the web and cover plate. At the same time, due to the small weld filler, the tendency of web corner deformation and cover plate bending deformation during welding is small. Constrained by the steel plate itself, the stress often exists in the form of internal stress in the overall structural component, resulting in small welding deformation.

[0003] However, some steel components have special structures, requiring the welding of relatively rigid parts to a single thin plate using full penetration welds. Furthermore, there is no welding space on the inner side of the component, allowing only single-sided welding on the outer side. For example, in a steel tower project, the steel anchor beam requires welding the anchor beam block to the anchor beam base plate. Figure 6 As shown; there are also some welded joints designed for welding extra-thick plates with deep bevels to thin plates. For example, in a steel tower project, a 120mm extra-thick pressure plate needs to be beveled and welded to a 40mm thin-walled plate, such as... Figure 2 As shown.

[0004] In both of the above cases, the weld seam is eccentrically distributed relative to the overall or partial structure of the component. The flatness of the cover plate of such eccentric corner joints is seriously out of tolerance after welding, and it is difficult to correct the flatness through heat straightening later. This problem is particularly prominent in long weld seams. Summary of the Invention

[0005] Purpose of the invention: In view of the problems pointed out in the background art above, the present invention proposes a method for controlling welding deformation of eccentric welded joints.

[0006] Technical solution: This invention provides a method for controlling welding deformation of eccentric welded joints, comprising:

[0007] The panel to be welded is pre-deformed before welding. The pre-deformation setting position is the area where welding deformation occurs, and the pre-bending direction of the pre-deformation setting is the opposite direction of the welding deformation trend.

[0008] Install reinforcement fixtures on the opposite side of the weld seam of the panel to be welded;

[0009] Welding of the weld seam;

[0010] Reinforcement tooling dismantling;

[0011] Stress relief after welding.

[0012] Furthermore, a pre-deformation setting is performed before welding using a heating and bending method, with the pre-deformation setting angle being 6–16°.

[0013] Furthermore, the reinforcing fixture is a frame structure made of slats and ribs, with internal triangular partitions that provide structural stability.

[0014] Furthermore, the reinforcement fixture is fixed to the panel to be welded by spot welding.

[0015] Furthermore, low-energy multi-layer, multi-pass welding is employed for welding.

[0016] Furthermore, after welding is completed, carbon arc gouging is used to clean and position the reinforcing fixture, and then the reinforcing fixture is removed.

[0017] Furthermore, after welding, internal stress is eliminated by flame heating at a temperature of 550–650°C.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: by pre-deformation before welding, reinforcement tooling constraints and stress relief measures after welding, the amount of welding deformation is effectively controlled, ensuring the manufacturing accuracy of steel components with eccentric welded joints. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the pressure-bearing block structure;

[0021] Figure 2 This is a schematic diagram of the weld between the pressure plate and the wall panel;

[0022] Figure 3 This is a schematic diagram of pre-deformation by bending and heating over a fire. Figure 3 (a) in Figure (3) is a schematic diagram of the fire position line, and (b) in Figure (3) is a side view of the wall panel that has been pre-deformed by bending after being heated.

[0023] Figure 4 This is a structural schematic diagram of the reinforcement tooling;

[0024] Figure 5 This is a schematic diagram of the reinforcement fixture installed on the outside of the wall panel;

[0025] Figure 6 This is a schematic diagram of a steel anchor beam structure. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0027] This invention provides a method for controlling welding deformation of eccentric welded joints. The method primarily involves pre-deforming the panel before welding and using reinforcing fixtures to forcibly constrain the back of the panel to enhance the rigidity of the corner joint panel, thereby reducing welding deformation and meeting the acceptance requirements of steel components. The specific steps of this welding deformation control method are as follows:

[0028] (1) Pre-deformation setting before welding

[0029] Pre-deformation settings are performed using a heat-bending method. The pre-deformation setting location is the area where welding deformation occurs, the pre-bending direction is the opposite direction of the welding deformation trend of the steel component, and the pre-deformation setting angle is 6-16°.

[0030] (2) Fabrication of reinforcement fixtures

[0031] The heating process can only achieve a maximum bending angle of 16°. Therefore, when fabricating reinforcement fixtures, the structural form and characteristics of the steel component to be fabricated should be taken into account. The outline dimensions of the reinforcement fixture should be designed in full consideration of the structural characteristics of the steel component and the area covered by welding deformation. The reinforcement fixture should preferably be fabricated as a frame structure with an internal triangle to achieve its own stabilizing function with minimal material usage.

[0032] (3) Assemble the reinforcement fixture

[0033] The reinforcement fixture is installed on the weaker side of the eccentric welded joint to balance the rigidity of the welded joint. Specifically, the weaker side of the eccentric welded joint is the opposite side of the panel to be welded. The reinforcement fixture is fixed to the panel by spot welding, which aims to control deformation while minimizing the difficulty of removing the reinforcement fixture after welding.

[0034] (4) Welding of the weld seam

[0035] Low heat input multi-layer multi-pass welding is used to reduce welding deformation during the welding process.

[0036] (5) Reinforcement tooling dismantling

[0037] After welding, carbon arc gouging is used to clean the tack welds of the reinforcing fixture, and then the reinforcing fixture is removed. After removal, any accidentally damaged parts of the base material and the reinforcing fixture are repaired by welding and grinding. The reinforcing fixture can be reused multiple times.

[0038] (6) Post-weld stress relief

[0039] Due to the forced deformation, the internal stress in the component is relatively large. After welding, the internal stress is relieved by flame heating to 550-650℃.

[0040] The following section provides a further description of the welding deformation control method for eccentric welded joints proposed in this invention, using specific examples.

[0041] Example 1

[0042] like Figure 1 The image shows a load-bearing block structure for a large bridge steel tower. The extra-thick load-bearing plate is joined to the tower wall panel via a beveled fillet weld. The extra-thick load-bearing plate is octagonal, 120mm thick, with a maximum outline dimension of 15790mm × 15790mm. The tower wall panel is 40mm thick and 1000mm wide. The load-bearing plate is required to be welded to the tower wall panel with a weld penetration depth of at least 80mm on all four sides. Figure 2 The diagram shows the weld between the pressure plate and the wall panel. The welded joint is an eccentric structure, and such a large amount of weld filler will inevitably cause the flatness of the wall panel to exceed the tolerance. In order to ensure the manufacturing accuracy of the component, the above-mentioned welding deformation control method is used in the fabrication of this pressure block.

[0043] (1) Pre-deformation setting before welding

[0044] After the wall panel and the pressure plate are assembled and positioned, they are subjected to heat bending. Specifically, first, the assembly position line of the pressure plate is marked on the side of the wall panel without welds. The heat-bending position is on the outer side of the wall panel, 20mm away from the position line of the pressure plate, and the heat-bending direction is along the length of the weld. Figure 3 As shown in (a) above. The heating temperature is 700℃, the pre-bending direction is the outward bending of the wall panel, and the pre-deformation setting angle is 10°, as shown below. Figure 3 As shown in (b) of the diagram.

[0045] (2) Fabrication of reinforcement fixtures

[0046] Based on the weld distribution and welding deformation area, reinforcement fixtures are fabricated using lath ribs. For example... Figure 4 As shown, the reinforcement fixture is a frame structure, 3000mm long, 400mm wide, and 200mm high. The interior of the fixture is divided into several triangular areas to provide structural stability. The ribs are made of Q235B steel, 40mm thick, 200mm wide, and their lengths are determined according to the drawings. The ribs are connected using shallow bevels or fillet welds.

[0047] (3) Assemble the reinforcement fixture

[0048] like Figure 5As shown, the reinforcement fixture is assembled to the outside of the wall panel to enhance the rigidity of the wall panel. The assembly position of the reinforcement fixture is aligned with the center of the welding joint. The reinforcement fixture is fixed to the steel tower wall panel by spot welding with a spot weld length of 50mm and a spot weld interval of 100mm.

[0049] (4) Welding of the weld seam

[0050] The weld joint bevel is designed as a double-sided J-shaped bevel to reduce the amount of weld filler. During welding, the lower limit of the welding heat input in the welding process specification is adopted. In this embodiment, the welding heat input is 15KJ / cm to reduce welding deformation.

[0051] (5) Reinforcement tooling dismantling

[0052] After welding, carbon arc gouging is used to clean the tack welds of the reinforcing fixture, and then the reinforcing fixture is removed. After removal, any damaged parts of the base material and the reinforcing fixture are repaired by welding and grinding. The reinforcing fixture can be reused multiple times.

[0053] (6) Post-weld stress relief

[0054] Due to the forced deformation, the internal stress in the component is relatively large. After welding, the component is heated to 600°C to relieve stress.

[0055] Example 2

[0056] like Figure 6 The diagram shows the steel anchor beam structure of a large bridge steel tower. The upper anchor beam block is a rigid component, requiring welding to the anchor beam base plate using a single-sided penetration weld. The anchor beam base plate requires a flatness accuracy of 1 mm / m. Such a large filler weld will inevitably cause the flatness of the anchor beam base plate to exceed the tolerance. To ensure the manufacturing accuracy of the component, the aforementioned welding deformation control method is used to fabricate the steel anchor beam. The fabrication method is similar to that in Example 1. Note that the dimensions of the reinforcement fixture need to be designed separately based on the actual weld length and distribution of the component, and the reinforcement fixture should be assembled on the underside of the anchor beam base plate.

[0057] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for controlling welding deformation of an eccentric welded joint, characterized in that, Used for welding a 120mm extra-thick bearing plate with a bevel to a 40mm thin-walled plate, the thin-walled plate being the panel to be welded, including: The panel to be welded is pre-deformed using a heat-bending method. The pre-deformation setting angle is 6~16°, the pre-deformation setting position is the area where welding deformation occurs, and the pre-bending direction is the opposite direction of the welding deformation trend. Reinforcing fixtures are installed on the opposite side of the weld seam of the panel to be welded, which serves to forcibly constrain and enhance the rigidity of the panel. For welding seams, low heat input multi-layer multi-pass welding is used to reduce welding deformation during the welding process; Reinforcement tooling dismantling; After welding, internal stress is eliminated by flame heating.

2. The method according to claim 1, characterized in that, The reinforcement fixture is a frame structure made of ribs and has internal triangular partitions that stabilize the structure.

3. The method according to claim 1, characterized in that, The reinforcement fixture is fixed to the panel to be welded by spot welding.

4. The method according to claim 3, characterized in that, After welding, carbon arc gouging was used to clean and position the reinforcing fixture, and then the reinforcing fixture was removed.

5. The method according to claim 1, characterized in that, Heating temperature: 550~650℃.

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