Welding method

Abstract

The invention relates to the technical field of welding, and discloses a welding method, which is used for welding a T-shaped joint of a small assemblage, and comprises the following steps: S1, vertically placing a first rib plate and a second rib plate on the top surface of a bottom plate, and attaching the side surface of the second rib plate, which is provided with an over-welding hole, to the end surface of the first rib plate; s2, welding is started from the position close to the center of the over-welding hole, and a gap between the first rib plate and the second rib plate is welded; s3, welding is started from the position close to the center of the over-welding hole, and a gap between the second rib plate and the bottom plate is welded; and S4, welding is started from the position close to the intersection, and a gap between the first rib plate and the bottom plate is welded. In conclusion, by means of the welding method, the deformation generated when the T-shaped connector of the small assembly is welded can be reduced, so that the percent of pass of the part is increased, and then the production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of welding technology, and particularly to a welding method. Background Art

[0002] At present, in shipbuilding projects, the modular section construction technology has become the core process of modern shipbuilding. Among them, the hull structure is usually decomposed into multi-level components such as small assemblies, medium assemblies, and large assemblies for prefabrication and assembly. As the basic structural unit, the welding quality of small assemblies is directly related to the structural strength and service life of the overall hull. In a typical small assembly structure, the T-joint composed of a bottom plate and a vertical stiffener plate often requires a combined welding method of two fillet welds and one vertical fillet weld due to its special geometric configuration. The three welds form a spatial intersection point at the joint of the stiffener plate and the bottom plate. This special structural feature widely exists in key parts such as ship bulkheads and ribs.

[0003] The construction operations of such T-joints are usually completed manually by workers. However, in the actual production of shipyards, the first-pass qualification rate of welding at this part is not high. When it is unqualified, it mainly has defects such as a large deformation amount. The additional working hours generated for repairing these defects are relatively many, resulting in low production efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a welding method to solve the technical problem that the defects generated during the welding of small-assembly T-joints require a relatively large amount of additional working hours for repair, resulting in low production efficiency.

[0005] To achieve the above purpose, the present invention provides a welding method for welding the T-joint of a small assembly, including the following steps:

[0006] S1. Vertically place the first stiffener plate and the second stiffener plate on the top surface of the bottom plate, and attach the side surface of the second stiffener plate with a through-welding hole to the end surface of the first stiffener plate;

[0007] S2. Start welding from a position close to the center of the through-welding hole, and weld the gap between the first stiffener plate and the second stiffener plate;

[0008] S3. Start welding from a position close to the center of the through-welding hole, and weld the gap between the second stiffener plate and the bottom plate;

[0009] S4. Start welding from a position close to the intersection point, and weld the gap between the first stiffener plate and the bottom plate.

[0010] Optionally,

[0011] Set step S2 as the first welding operation, and the first welding operation includes a first starting process, a first transition process, and a first normal process that are carried out in sequence;

[0012] During the first starting process, the nozzle of the welding torch starts from a position near the center of the over-welding hole and moves towards the direction of the first rib plate until the nozzle of the welding torch is close to the position of the first rib plate corresponding to the over-welding hole;

[0013] During the first transition process, the welding torch starts from the position of the first rib plate corresponding to the over-welding hole, approaches the gap between the first rib plate and the second rib plate, and moves to the gap between the first rib plate and the second rib plate;

[0014] During the first normal process, the welding torch moves away from the over-welding hole to the end of the gap between the first rib plate and the second rib plate;

[0015] Set step S3 as the second welding operation, and the second welding operation includes the second starting process, the second transition process, and the second normal process carried out in sequence;

[0016] During the second starting process, the nozzle of the welding torch starts from a position near the center of the over-welding hole and moves towards the direction of the bottom plate until the nozzle of the welding torch is close to the position of the bottom plate corresponding to the over-welding hole;

[0017] During the second transition process, the welding torch starts from the position of the bottom plate corresponding to the over-welding hole, approaches the gap between the bottom plate and the second rib plate, and moves to the gap between the bottom plate and the second rib plate;

[0018] During the second normal process, the welding torch moves away from the over-welding hole to the end of the gap between the bottom plate and the second rib plate;

[0019] Set step S4 as the third welding operation, and the third welding operation includes the third starting process and the third normal process carried out in sequence;

[0020] During the third transition process, the welding torch starts from the intersection point, approaches the gap between the bottom plate and the first rib plate, and moves to the gap between the bottom plate and the first rib plate;

[0021] During the third normal process, the welding torch moves away from the over-welding hole to the end of the gap between the bottom plate and the first rib plate.

[0022] Optionally, during the first starting process, the welding torch performs drag welding;

[0023] During the first transition process, the welding torch changes from drag welding to vertical welding or push welding;

[0024] During the first normal process, the welding torch performs vertical welding or push welding;

[0025] During the second starting process, the welding torch performs drag welding;

[0026] During the second transition process, the welding torch changes from drag welding to vertical welding;

[0027] During the second normal process, the welding torch performs vertical welding;

[0028] During the third starting process, the welding torch changes from drag welding to vertical welding;

[0029] During the third normal process, the welding torch performs vertical welding.

[0030] Optionally, during the first starting process, there is an angle of 40° to 50° between the welding torch and the first rib plate, an angle of 40° to 50° between the welding torch and the second rib plate, and an angle of 40° to 50° between the welding torch and the bottom plate;

[0031] During the first transition process, there is an angle of 40° to 50° between the welding torch and the first rib plate, an angle of 40° to 50° between the welding torch and the second rib plate, and the angle between the welding torch and the bottom plate gradually changes to -10° to 0°;

[0032] During the first normal process, there is an angle of 40° to 50° between the welding torch and the first rib plate, an angle of 40° to 50° between the welding torch and the second rib plate, and an angle of -5° to 5° between the welding torch and the bottom plate;

[0033] During the second starting process, there is an angle of 40° to 50° between the welding torch and the bottom plate, an angle of 40° to 50° between the welding torch and the second rib plate, and an angle of 35° to 45° between the welding torch and the first rib plate;

[0034] During the second transition process, there is an angle of 40° to 50° between the welding torch and the bottom plate, an angle of 40° to 50° between the welding torch and the second rib plate, and the angle between the welding torch and the first rib plate decreases to -5° to 5°;

[0035] During the second normal process, there is an angle of 40° to 50° between the welding torch and the bottom plate, an angle of 40° to 50° between the welding torch and the second rib plate, and an angle of -10° to 0° between the welding torch and the first rib plate;

[0036] During the third starting process, there is an angle of 40° to 50° between the welding torch and the bottom plate, an angle of 40° to 50° between the welding torch and the first rib plate, and an angle of 35° to 45° between the welding torch and the second rib plate;

[0037] During the third normal process, there is an angle of 40° to 50° between the welding torch and the bottom plate, an angle of 40° to 50° between the welding torch and the first rib plate, and an angle of -5° to 5° between the welding torch and the second rib plate.

[0038] Optionally, when performing the first transition process, the second transition process, and the third starting process, while the welding torch moves linearly and welds, it rotates the angle evenly.

[0039] Optionally, when performing the first starting process, before the welding torch moves, start the welding torch and keep it stationary for the first filling time;

[0040] When performing the second starting process, before the welding torch moves, start the welding torch and keep it stationary for the second filling time;

[0041] When performing the third starting process, before the welding torch moves, start the welding torch and keep it stationary for the third filling time.

[0042] Optionally, when performing the first starting process, the first filling time is 1.5 s to 2.5 s, and the starting arc current of the welding torch is 120 A to 140 A;

[0043] When performing the first transition process, the welding current of the welding torch is 120 A to 140 A, and the welding speed is 260 mm / min to 300 mm / min;

[0044] When performing the first normal process, the welding current of the welding torch is 100 A to 120 A, the swing amplitude is 2.5 mm to 3.5 mm, the swing length is 2 mm to 3 mm, the residence time on both sides is 0.6 s to 0.8 s, and the welding speed is 80 mm / min to 120 mm / min;

[0045] When performing the second starting process, the second filling time is 1.5 s to 2.5 s, and the starting arc current of the welding torch is 120 A to 140 A;

[0046] When performing the second transition process, the welding current of the welding torch is 120 A to 140 A, and the welding speed is 260 mm / min to 300 mm / min;

[0047] When performing the second normal process, the welding current of the welding torch is 270 A to 290 A, and the welding speed is 430 mm / min to 470 mm / min;

[0048] When performing the third starting process, the third filling time is 1.5 s to 2.5 s, the welding current of the welding torch is 120 A to 140 A, and the welding speed is 260 mm / min to 300 mm / min;

[0049] When performing the third normal process, the welding current of the welding torch is 270 A to 290 A, and the welding speed is 430 mm / min to 470 mm / min.

[0050] Optionally, the over-welding hole is a chamfered hole with a size of a×a;

[0051] During the first starting process, the distance between the tip of the welding torch and the intersection point is a / 2, and the distance between the tip of the welding torch and the first stiffener is equal to the distance between the tip of the welding torch and the bottom plate;

[0052] During the second starting process, the distance between the tip of the welding torch and the intersection point is a / 2, and the distance between the tip of the welding torch and the first stiffener is equal to the distance between the tip of the welding torch and the bottom plate.

[0053] Optionally, a is 8 mm to 12 mm.

[0054] Optionally, the following steps are further included: between step S2 and step S3, use a sensor to locate the first stiffener, the second stiffener and the bottom plate, and transmit the position parameters of the first stiffener, the second stiffener and the bottom plate to the controller;

[0055] In steps S2, S3 and S4, the controller controls the robot to use the welding torch for welding.

[0056] Compared with the prior art, the beneficial effect of the welding method according to an embodiment of the present invention is as follows:

[0057] In the welding method of the present invention, the first stiffener, the second stiffener and the bottom plate are first combined together to form a sub-assembled T-joint. Then, starting from the position of the through-welding hole of the second stiffener, the analysis between the first stiffener and the second stiffener is welded upward to complete the fillet weld. Next, starting from the position of the through-welding hole of the second stiffener, the gap between the second stiffener and the bottom plate is welded horizontally outwards to complete one of the fillet welds. Finally, starting from the intersection point of the first stiffener, the second stiffener and the bottom plate, the gap between the first stiffener and the bottom plate is welded horizontally outwards to complete the other fillet weld. Among them, since the fillet weld is carried out first, the heat is mainly concentrated in the weld area, the heat affected zone is relatively narrow, and the lateral diffusion of the heat to the base metal is limited, so that the heat input is more uniform. Further, the tensile stress generated by welding can be partially released in the vertical direction and will not be completely accumulated on the bottom plate, making the stress release more timely. Further, the geometric shape of the T-joint can be fixed, so that the thermal stress and deformation generated by the subsequent fillet weld will be absorbed or offset by the fixed structural part; In summary, the welding method of the present invention can reduce the deformation amount generated when welding the sub-assembled T-joint, improve the qualification rate of this part, and thus improve the production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is the sub-assembled T-joint of the present invention.

[0059] Figure 2 It is the most basic flowchart of the welding method of the present invention.

[0060] Figure 3 It is the flowchart of the welding method of the present invention that splits each welding operation into multiple processes.

[0061] Figure 4 This is a flowchart of the welding method using sensors, controllers, and robots in the present invention.

[0062] Reference numerals: 1, first rib plate; 2, second rib plate; 21, welding-through hole; 3, bottom plate; 4, intersection point. Detailed implementation manners

[0063] The following further describes in detail the specific implementation manners of the present invention in conjunction with the drawings and embodiments. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0064] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by terms such as "top", "bottom", "inner", "outer", "circumferential", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0065] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0066] Referring to Figure 1 and 2 As shown, a welding method of the present invention for welding the T-joint of a sub-assembly includes the following steps: S1. Vertically place the first rib plate 1 and the second rib plate 2 on the top surface of the bottom plate 3, and attach the side surface of the second rib plate 2 with the welding-through hole 21 to the end surface of the first rib plate 1; S2. Start welding from a position close to the center of the welding-through hole 21, and weld the gap between the first rib plate 1 and the second rib plate 2; S3. Start welding from a position close to the center of the welding-through hole 21, and weld the gap between the second rib plate 2 and the bottom plate 3; S4. Start welding from a position close to the intersection point 4, and weld the gap between the first rib plate 1 and the bottom plate 3.

[0067] In the above technical solution, the first rib plate 1, the second rib plate 2 and the bottom plate 3 are first combined together to form a sub-assembled T-joint. Then, starting from the position of the through-welding hole 21 of the second rib plate 2, the analysis between the first rib plate 1 and the second rib plate 2 is welded upward to complete the fillet weld. Next, starting from the position of the through-welding hole 21 of the second rib plate 2, the gap between the second rib plate 2 and the bottom plate 3 is welded horizontally outward to complete one of the fillet welds. Finally, starting from the intersection point 4 of the first rib plate 1, the second rib plate 2 and the bottom plate 3, the gap between the first rib plate 1 and the bottom plate 3 is welded horizontally outward to complete the other fillet weld. Among them, since the fillet weld is carried out first, the heat is mainly concentrated in the weld area, the heat-affected zone is relatively narrow, and the lateral diffusion of heat to the base metal is limited, making the heat input more uniform. Further, the tensile stress generated by welding can be partially released in the vertical direction and will not completely accumulate on the bottom plate 3, making the stress release more timely. Further, the geometric shape of the T-joint can be fixed, so that the thermal stress and deformation generated by the subsequent fillet weld will be absorbed or offset by the fixed structural part. On the contrary, if the fillet weld is carried out first, more heat will be transferred to the bottom plate 3, resulting in greater planar shrinkage and warping. Further, after the bottom plate 3 shrinks due to heat, the first rib plate 1 and the second rib plate 2 are not yet welded and fixed, which will cause greater angular deformation. Further, when the fillet weld is carried out again after the bottom plate 3 shrinks due to heat, the first rib plate 1 and the second rib plate 2 will have a greater angular offset due to the lack of early restraint, resulting in an increase in overall deformation. In summary, the welding method of the present invention can reduce the amount of deformation generated when welding the sub-assembled T-joint, improve the qualification rate of this part, and thus improve the production efficiency.

[0068] In addition, the intersection point 4 is the intersection of the extension line of the gap between the first rib plate 1 and the second rib plate 2, the extension line of the gap between the first rib plate 1 and the bottom plate 3, and the extension line of the gap between the second rib plate 2 and the bottom plate 3, and is also the intersection of the three welds.

[0069] Further, set step S2 as the first welding operation. The first welding operation includes a first starting process, a first transition process, and a first normal process that are carried out in sequence. When carrying out the first starting process, the nozzle of the welding torch starts from a position close to the center of the over-welding hole 21 and moves in the direction close to the first rib plate 1 until the nozzle of the welding torch is close to the position of the first rib plate 1 corresponding to the over-welding hole 21. When carrying out the first transition process, the welding torch starts from the position of the first rib plate 1 corresponding to the over-welding hole 21, approaches the gap between the first rib plate 1 and the second rib plate 2, and moves to the gap between the first rib plate 1 and the second rib plate 2. When carrying out the first normal process, the welding torch moves in the direction away from the over-welding hole 21 to the end of the gap between the first rib plate 1 and the second rib plate 2. Set step S3 as the second welding operation. The second welding operation includes a second starting process, a second transition process, and a second normal process that are carried out in sequence. When carrying out the second initial process, the nozzle of the welding torch starts from a position close to the center of the over-welding hole 21 and moves in the direction close to the bottom plate 3 until the nozzle of the welding torch is close to the position of the bottom plate 3 corresponding to the over-welding hole 21. When carrying out the second transition process, the welding torch starts from the position of the bottom plate 3 corresponding to the over-welding hole 21, approaches the gap between the bottom plate 3 and the second rib plate 2, and moves to the gap between the bottom plate 3 and the second rib plate 2. When carrying out the second normal process, the welding torch moves in the direction away from the over-welding hole 21 to the end of the gap between the bottom plate 3 and the second rib plate 2. Set step S4 as the third welding operation. The third welding operation includes a third starting process and a third normal process that are carried out in sequence. When carrying out the third transition process, the welding torch starts from the intersection point 4, approaches the gap between the bottom plate 3 and the first rib plate 1, and moves to the gap between the bottom plate 3 and the first rib plate 1. When carrying out the third normal process, the welding torch moves in the direction away from the over-welding hole 21 to the end of the gap between the bottom plate 3 and the first rib plate 1.

[0070] Wherein, during the first welding operation, the second welding operation, and the third welding operation, the welding torch is always in the starting state to weld and form the weld seams between the first rib plate 1 and the second rib plate 2, between the second rib plate 2 and the bottom plate 3, and between the first rib plate 1 and the bottom plate 3, and fill the over-welding hole 21. Further, in the first starting process and the second starting process, the nozzle of the welding torch starts from a position close to the center of the over-welding hole 21 to have a better effect of filling the over-welding hole 21.

[0071] Further, when carrying out the first starting process, the welding torch performs drag welding. When carrying out the first transition process, the welding torch changes from drag welding to vertical welding or push welding. When carrying out the first normal process, the welding torch performs vertical welding or push welding. When carrying out the second starting process, the welding torch performs drag welding. When carrying out the second transition process, the welding torch changes from drag welding to vertical welding. When carrying out the second normal process, the welding torch performs vertical welding. When carrying out the third starting process, the welding torch changes from drag welding to vertical welding. When carrying out the third normal process, the welding torch performs vertical welding.

[0072] Among them, in the first welding operation, the second welding operation, and the third welding operation, using drag welding first can have a relatively fast starting welding speed, a better effect of filling the over-welding hole 21, a lower difficulty in controlling the molten pool shape, can better control the molten pool and form a stable weld base, and can avoid the interference between equipment such as the welding torch and each plate. In addition, in the first welding operation, there is also an effect of preventing the molten slag from flowing downward.

[0073] In addition, in the first welding operation, changing from drag welding to push welding helps to smooth the weld surface, reduce defects (such as undercut), while maintaining a good penetration depth and appearance, and makes the weld strength between the first rib plate 1 and the second rib plate 2 relatively high; if changing from drag welding to vertical welding in the first welding operation, the welding torch or electrode is perpendicular to the workpiece, and the difficulty of controlling the molten pool is relatively large, which is likely to cause the molten pool to get out of control or the weld to be uneven, and is likely to cause the molten slag or molten droplets to droop.

[0074] In addition, in the second welding operation and the third welding operation, changing from drag welding to vertical welding has the following advantages: 1. Better molten pool control. When using drag welding, the molten pool is affected by the backward movement of the arc and has less fluidity. After transitioning to vertical welding, the molten pool can sink controllably along the direction of gravity, avoiding the uncontrollability of the forward flow of the molten pool during push welding; 2. Uniform weld formation. Vertical welding can make the weld width and height more consistent by adjusting the welding torch angle and moving speed. Especially in the position transition area, it can reduce weld defects (such as undercut or lack of fusion); 3. Strong adaptability: The transition from drag welding to vertical welding is smoother technically because both methods emphasize the direct control of the molten pool, while push welding requires readapting to the change in the direction of the arc thrust; 4. Reduced spatter: Drag welding and vertical welding generally produce less spatter than push welding, especially when using gas shielded welding (such as MIG / MAG), which helps to improve welding efficiency and surface cleanliness.

[0075] Further, during the first starting process, there is an angle of 40° to 50° between the welding torch and the first rib plate 1, an angle of 40° to 50° between the welding torch and the second rib plate 2, and an angle of 40° to 50° between the welding torch and the bottom plate 3; during the first transition process, there is an angle of 40° to 50° between the welding torch and the first rib plate 1, an angle of 40° to 50° between the welding torch and the second rib plate 2, and the angle between the welding torch and the bottom plate 3 gradually changes to -10° to 0°; during the first normal process, there is an angle of 40° to 50° between the welding torch and the first rib plate 1, an angle of 40° to 50° between the welding torch and the second rib plate 2, and an angle of -5° to 5° between the welding torch and the bottom plate 3; during the second starting process, there is an angle of 40° to 50° between the welding torch and the bottom plate 3, an angle of 40° to 50° between the welding torch and the second rib plate 2, and an angle of 35° to 45° between the welding torch and the first rib plate 1; during the second transition process, there is an angle of 40° to 50° between the welding torch and the bottom plate 3, an angle of 40° to 50° between the welding torch and the second rib plate 2, and the angle between the welding torch and the first rib plate 1 decreases to -5° to 5°; during the second normal process, there is an angle of 40° to 50° between the welding torch and the bottom plate 3, an angle of 40° to 50° between the welding torch and the second rib plate 2, and an angle of -10° to 0° between the welding torch and the first rib plate 1; during the third starting process, there is an angle of 40° to 50° between the welding torch and the bottom plate 3, an angle of 40° to 50° between the welding torch and the first rib plate 1, and an angle of 45° to 55° between the welding torch and the second rib plate 2; during the third normal process, there is an angle of 40° to 50° between the welding torch and the bottom plate 3, an angle of 40° to 50° between the welding torch and the first rib plate 1, and an angle of -5° to 5° between the welding torch and the second rib plate 2.

[0076] Among them, in the T-joint of the sub-assembly composed of the first rib plate 1, the second rib plate 2 and the bottom plate 3, the first rib plate 1, the second rib plate 2 and the bottom plate 3 are perpendicular to each other. During the first welding operation, the second welding operation and the third welding operation, the welding torch is located in the middle of the two components on both sides of its advancing direction, and the angle between the welding torch and the third component changes.

[0077] Specifically, in the first welding operation, the welding torch is located in the middle of the first rib plate 1 and the second rib plate 2. The angles between the welding torch and both the first rib plate 1 and the second rib plate 2 are 40° to 50°, preferably 45°. The angle between the welding torch and the bottom plate 3 changes from 40° to 50° to -10° to 0°, preferably from 45° to -5°. Among them, when the angle between the welding torch and the bottom plate 3 is positive, it is a pull weld; when it is zero degree, it is a vertical weld; when it is negative, it is a push weld. Additionally, the angle between the welding torch and its advancing direction is related to the angle between the welding torch and the bottom plate 3. The angle between the welding torch and its advancing direction is 40° to 50°, preferably 45°, and gradually changes to 90° to 100°, preferably 95° during the welding process;

[0078] Specifically, in the second welding operation, the welding torch is located in the middle of the bottom plate 3 and the second rib plate 2. The angles between the welding torch and both the bottom plate 3 and the second rib plate 2 are 40° to 50°, preferably 45°. The angle between the welding torch and the third rib plate changes from 35° to 45° to -5° to 5°, preferably from 40° to 0°. Among them, when the angle between the welding torch and the first rib plate 1 is positive, it is a pull weld; when it is zero degree, it is a vertical weld; when it is negative, it is a push weld. Additionally, the angle between the welding torch and its advancing direction is related to the angle between the welding torch and the first rib plate 1. The angle between the welding torch and its advancing direction is 45° to 55°, preferably 50°, and gradually changes to 85° to 95°, preferably 90° during the welding process;

[0079] Specifically, in the third welding operation, the welding torch is located in the middle of the bottom plate 3 and the first rib plate 1. The angles between the welding torch and both the bottom plate 3 and the first rib plate 1 are 40° to 50°, preferably 45°. The angle between the welding torch and the second rib plate 2 changes from 35° to 45° to -5° to 5°, preferably from 40° to 0°. Among them, when the angle between the welding torch and the second rib plate 2 is positive, it is a pull weld; when it is zero degree, it is a vertical weld; when it is negative, it is a push weld. Additionally, the angle between the welding torch and its advancing direction is related to the angle between the welding torch and the second rib plate 2. The angle between the welding torch and its advancing direction is 45° to 55°, preferably 50°, and gradually changes to 85° to 95°, preferably 90° during the welding process.

[0080] Welding with the above parameters can facilitate welding and achieve good welding effects. If welding deviates from the above parameters, the risk of interference between the welding equipment and the rib plates and the bottom plate 3 will increase, and it will also lead to problems such as difficult control of the weld seam, decreased weld strength, and increased weld defects, thereby reducing the qualification rate and further resulting in a decrease in production efficiency.

[0081] Further, when performing the first transition process, the second transition process, and the third starting process, while the welding torch moves linearly and welds, it rotates the angle evenly, so that the heat distribution during welding is more uniform, thereby making the weld quality more stable, maintaining the stability of the molten pool, reducing the defects generated in the weld, enabling the weld to transition more smoothly, and further reducing the stress concentration area in the weld, so that the weld has better mechanical properties.

[0082] Further, when performing the first starting process, before the welding torch moves, start the welding torch and keep it stationary for the first filling time; when performing the second starting process, before the welding torch moves, start the welding torch and keep it stationary for the second filling time; when performing the third starting process, before the welding torch moves, start the welding torch and keep it stationary for the third filling time, so as to ensure that the over-welding hole 21 is filled.

[0083] Further, during the first starting process, the first filling time is 1.5 s to 2.5 s, preferably 2 s, the starting arc current of the welding torch is 120 A to 140 A, preferably 130 A; during the first transition process, the welding current of the welding torch is 120 A to 140 A, preferably 130 A, and the welding speed is 260 mm / min to 300 mm / min, preferably 280 mm / min; during the first normal process, the welding current of the welding torch is 100 A to 120 A, preferably 110 A, the swing amplitude is 2.5 mm to 3.5 mm, preferably 3 mm, the swing length is 2 mm to 3 mm, preferably 2.5 mm, the dwell time on both sides is 0.6 s to 0.8 s, preferably 0.7 s, and the welding speed is 80 mm / min to 120 mm / min, preferably 100 mm / min; during the second starting process, the second filling time is 1.5 s to 2.5 s, preferably 2 s, the starting arc current of the welding torch is 120 A to 140 A, preferably 130 A; during the second transition process, the welding current of the welding torch is 120 A to 140 A, preferably 130 A, and the welding speed is 260 mm / min to 300 mm / min, preferably 280 mm / min; during the second normal process, the welding current of the welding torch is 270 A to 290 A, preferably 280 A, and the welding speed is 430 mm / min to 470 mm / min, preferably 450 mm / min; during the third starting process, the third filling time is 1.5 s to 2.5 s, preferably 2 s, the welding current of the welding torch is 120 A to 140 A, preferably 130 A, and the welding speed is 260 mm / min to 300 mm / min, preferably 280 mm / min; during the third normal process, the welding current of the welding torch is 270 A to 290 A, preferably 280 A, and the welding speed is 430 mm / min to 470 mm / min, preferably 450 mm / min; the above parameters can be applied to the welding of the T-joints in the sub-assembly, especially suitable for the welding of the base material with a thickness of about 6 mm. It can have a good filling effect and prevent the base material from being burned through by the current; in addition, welding according to the parameters in the first starting process can also prevent the molten pool from flowing down easily and affecting the weld formation.

[0084] Further, the over-welding hole 21 is a chamfered hole with a size of a×a; during the first starting process, the distance between the gun head of the welding torch and the intersection point 4 is a / 2, and the distance between the gun head of the welding torch and the first rib plate 1 is equal to the distance between the gun head of the welding torch and the bottom plate 3; during the second starting process, the distance between the gun head of the welding torch and the intersection point 4 is a / 2, and the distance between the gun head of the welding torch and the first rib plate 1 is equal to the distance between the gun head of the welding torch and the bottom plate 3, so as to ensure that the first welding operation and the second welding operation start welding from the center of the over-welding hole 21, and thus have a good filling effect on it.

[0085] Furthermore, a is 8 mm to 12 mm, preferably 10 mm. In the welding of the T-joint of the sub-assembly, a chamfer hole of 10 mm × 10 mm is usually opened.

[0086] Furthermore, the following steps are further included: between step S2 and step S3, use a sensor to locate the first rib plate 1, the second rib plate 2 and the bottom plate 3, and transmit the position parameters of the first rib plate 1, the second rib plate 2 and the bottom plate 3 to the controller; in steps S2, S3 and S4, the controller controls the robot to use a welding torch for welding.

[0087] Wherein, after the sensor locates the positions of the first rib plate 1, the second rib plate 2 and the bottom plate 3, the sensor sends the position parameters of the three weld seams, the through-welding hole 21 and the intersection point 4 to the controller, and the controller generates control codes using the position parameters, and controls the robot to achieve automatic welding through the control codes. In addition, the sensor can be a contact sensor or a laser sensor.

[0088] In summary, the embodiment of the present invention provides a welding method, and its technical effects are as follows:

[0089] In the welding method of the present invention, first, the first rib plate 1, the second rib plate 2 and the bottom plate 3 are combined together to form a T-joint of the sub-assembly. Then, starting from the position of the through-welding hole 21 of the second rib plate 2, weld the analysis between the first rib plate 1 and the second rib plate 2 upward to complete the fillet weld. Next, starting from the position of the through-welding hole 21 of the second rib plate 2, weld the gap between the second rib plate 2 and the bottom plate 3 horizontally outward to complete one of the fillet welds. Finally, starting from the intersection point 4 of the first rib plate 1, the second rib plate 2 and the bottom plate 3, weld the gap between the first rib plate 1 and the bottom plate 3 horizontally outward to complete the other fillet weld. Among them, because the fillet weld is carried out first, the heat is mainly concentrated in the weld area, the heat-affected zone is relatively narrow, and the lateral diffusion of the heat to the base metal is limited, making the heat input more uniform. Furthermore, the tensile stress generated by welding can be partially released in the vertical direction and will not be completely accumulated on the bottom plate 3, making the stress release more timely. Further, the geometric shape of the T-joint can be fixed, so that the thermal stress and deformation generated by the subsequent fillet weld will be absorbed or offset by the fixed structural part; in summary, the welding method of the present invention can reduce the deformation amount generated when welding the T-joint of the sub-assembly, improve the qualification rate of this part, and thus improve the production efficiency.

[0090] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A welding method, characterized in that: The method for welding a small group of T-joints includes the following steps: S1, vertically placing the first rib plate and the second rib plate on the top surface of the bottom plate, and attaching the side surface of the second rib plate with the welding hole to the end surface of the first rib plate; S2, start welding from a position close to the center of the through-welding hole to weld the gap between the first rib plate and the second rib plate; S3, start welding from a position close to the center of the through-welding hole to weld the gap between the second rib plate and the bottom plate; S4. Start welding from a position close to the intersection and weld the gap between the first rib plate and the bottom plate.

2. The welding method according to claim 1, characterized in that: Step S2 is set as a first welding operation, and the first welding operation includes a first starting process, a first transition process, and a first normal process performed in sequence; When performing the first starting process, the nozzle of the welding gun starts from a position close to the center of the through-welding hole and moves toward the first rib plate until the nozzle of the welding gun is close to the position of the first rib plate corresponding to the through-welding hole; When performing the first transition process, the welding gun starts from the position of the first rib plate corresponding to the through-welding hole, approaches the gap between the first rib plate and the second rib plate, and moves to the gap between the first rib plate and the second rib plate; When performing the first normal process, the welding gun moves in a direction away from the through-welding hole to the end of the gap between the first rib plate and the second rib plate; Step S3 is set as a second welding operation, and the second welding operation includes a second starting process, a second transition process, and a second normal process performed in sequence; When performing the second initial process, the nozzle of the welding gun starts from a position close to the center of the through-welding hole and moves toward the bottom plate until the nozzle of the welding gun is close to the position of the bottom plate corresponding to the through-welding hole; When performing the second transition process, the welding gun starts from the position of the bottom plate corresponding to the through-welding hole, approaches the gap between the bottom plate and the second rib plate, and moves to the gap between the bottom plate and the second rib plate; When performing the second normal process, the welding gun moves in a direction away from the through-welding hole to the end of the gap between the bottom plate and the second rib plate; Step S4 is set as a third welding operation, and the third welding operation includes a third starting process and a third normal process performed in sequence; When performing the third transition process, the welding gun starts from the intersection point, approaches the gap between the bottom plate and the first rib plate, and moves to the gap between the bottom plate and the first rib plate; When performing the third normal process, the welding gun moves in a direction away from the through-welding hole to the end of the gap between the bottom plate and the first rib plate.

3. The welding method according to claim 2, characterized in that: When performing the first starting process, the welding gun performs pull welding; When performing the first transition process, the welding gun changes from pull welding to vertical welding or push welding; When performing the first normal process, the welding gun performs vertical welding or push welding; When performing the second starting process, the welding gun performs pull welding; When performing the second transition process, the welding gun changes from pulling welding to vertical welding; When performing the second normal process, the welding gun performs vertical welding; When performing the third starting process, the welding gun changes from pulling welding to vertical welding; When performing the third normal process, the welding gun performs vertical welding.

4. The welding method according to claim 3, characterized in that: When performing the first starting process, the welding gun and the first rib plate have an angle of 40° to 50°, the welding gun and the second rib plate have an angle of 40° to 50°, and the welding gun and the bottom plate have an angle of 40° to 50°; During the first transition process, the welding gun and the first rib plate have an angle of 40° to 50°, the welding gun and the second rib plate have an angle of 40° to 50°, and the angle between the welding gun and the bottom plate gradually changes to -10° to 0°; When performing the first normal process, the welding gun and the first rib plate have an angle of 40° to 50°, the welding gun and the second rib plate have an angle of 40° to 50°, and the welding gun and the bottom plate have an angle of -5° to 5°; When performing the second starting process, the welding gun and the bottom plate have an angle of 40° to 50°, the welding gun and the second rib plate have an angle of 40° to 50°, and the welding gun and the first rib plate have an angle of 35° to 45°; During the second transition process, the welding gun and the bottom plate have an angle of 40° to 50°, the welding gun and the second rib plate have an angle of 40° to 50°, and the angle between the welding gun and the first rib plate is reduced to -5° to 5°; When performing the second normal process, the welding gun and the bottom plate have an angle of 40° to 50°, the welding gun and the second rib plate have an angle of 40° to 50°, and the welding gun and the first rib plate have an angle of -10° to 0°; When performing the third starting process, the welding gun and the bottom plate have an angle of 40° to 50°, the welding gun and the first rib plate have an angle of 40° to 50°, and the welding gun and the second rib plate have an angle of 35° to 45°; When performing the third normal process, the angle between the welding gun and the base plate is 40° to 50°, the angle between the welding gun and the first rib plate is 40° to 50°, and the angle between the welding gun and the second rib plate is -5° to 5°.

5. The welding method according to claim 3, characterized in that: When performing the first transition process, the second transition process and the third starting process, the welding gun moves linearly and welds while rotating at an even angle.

6. The welding method according to claim 2, characterized in that: When performing the first starting process, before the welding gun moves, the welding gun is started and kept stationary for the first filling time; When performing the second starting process, before the welding gun moves, start the welding gun and keep it still for the second filling time; When performing the third starting process, before the welding gun moves, start the welding gun and keep it still for the third filling time.

7. The welding method according to claim 6, characterized in that: When performing the first starting process, the first filling time is 1.5s to 2.5s, and the arc starting current of the welding gun is 120A to 140A; During the first transition process, the welding current of the welding gun is 120A to 140A, and the welding speed is 260mm / min to 300mm / min; When performing the first normal process, the welding current of the welding gun is 100A to 120A, the swing amplitude is 2.5mm to 3.5mm, the swing length is 2mm to 3mm, the dwell time on both sides is 0.6s to 0.8s, and the welding speed is 80mm / min to 120mm / min; When performing the second starting process, the second filling time is 1.5s to 2.5s, and the arc starting current of the welding gun is 120A to 140A; During the second transition process, the welding current of the welding gun is 120A to 140A, and the welding speed is 260mm / min to 300mm / min; When performing the second normal process, the welding current of the welding gun is 270A to 290A, and the welding speed is 430mm / min to 470mm / min; When performing the third starting process, the third filling time is 1.5s to 2.5s, the welding current of the welding gun is 120A to 140A, and the welding speed is 260mm / min to 300mm / min; When performing the third normal process, the welding current of the welding gun is 270A to 290A, and the welding speed is 430mm / min to 470mm / min.

8. The welding method according to claim 2, characterized in that: The through-welding hole is a corner cut hole with a size of a×a; When performing the first starting process, the distance between the welding gun tip and the intersection point is a / 2, and the distance between the welding gun tip and the first rib plate is equal to the distance between the welding gun tip and the bottom plate; When performing the second starting process, the distance between the welding gun tip and the intersection point is a / 2, and the distance between the welding gun tip and the first rib plate is equal to the distance between the welding gun tip and the bottom plate.

9. The welding method according to claim 8, characterized in that: a is 8mm to 12mm.

10. The welding method according to claim 1, characterized in that: The following steps are also included: Between step S2 and step S3, using a sensor to locate the first rib plate, the second rib plate and the bottom plate, and transmitting position parameters of the first rib plate, the second rib plate and the bottom plate to a controller; In steps S2, S3 and S4, the controller controls the robot to perform welding using a welding gun.

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