Welding trolley and welding method for ensuring penetration rate of U-shaped ribs on steel bridge deck

Abstract

The present invention relates to a welding trolley and welding method that precisely controls the penetration rate of U-shaped ribs on steel bridge decks by controlling groove dimensional accuracy, adding a swing head to the welding trolley, and adjusting welding gun angle and swing parameters, as well as welding current, voltage, and stick-out length. Advantages include a simple structure, ease of operation, and adaptability to simple tooling, high production efficiency, and stable quality.

Description

Technical Field

[0001] The present invention relates to a welding trolley and a welding method for precisely controlling the penetration rate of U-shaped ribs on the top plate of a steel bridge by controlling the groove size accuracy, adding a swing head to the welding trolley, adjusting the welding gun angle and swing parameters, welding current, voltage, dry extension and other parameters, and other technical measures to ensure the penetration rate of the U-shaped ribs on the steel bridge deck. Background Art

[0002] Steel box girder bridge is a typical thin-walled box structure, and its top surface structure is usually composed of steel bridge deck and U-shaped stiffening ribs. Figure 1 , the fatigue characteristics of the top plate under the action of wheel load are obvious. In order to improve the fatigue resistance of this type of structure, it is usually required that the weld between the U rib and the panel must reach a penetration rate of more than 75%, and at the same time, it is required that the root must not be burned through. 1. The traditional process generally uses a welding trolley or a special welding machine to clamp the welding gun. After adjusting the angle of the welding gun, it moves longitudinally along the weld to weld the panel and the U rib. However, in actual operation, it is found that the welding gun angle is prone to change during the welding process, or the tracking accuracy deviation causes the molten pool to deviate from the preset position, resulting in the weld penetration rate cannot be guaranteed. Figure 4 2. Using welding robots for operation, this operation method has a better U-rib weld penetration rate, but the equipment occupies a large area, is expensive to purchase, and has high maintenance costs, making it less economical. Summary of the Invention

[0003] Design purpose: In view of the problems existing in the background technology, a welding trolley and welding method for the U-rib and panel welds is designed to achieve a penetration rate of more than 75% without burning through the root. At the same time, it requires little investment and does not require a fixed site. It can be promoted and used in various factories and construction sites to improve production efficiency and ensure the quality of the welds. It can also ensure the penetration rate of the U-shaped ribs of the steel bridge panel.

[0004] Design Plan: To achieve the above design objectives, the welding carriage mechanically tracks and locates the weld position. A rocker is installed on the carriage, which oscillates the arc, preventing the weld from being centered at a specific location. This prevents burn-through of the weld root during welding and allows for adaptive adjustment of the welding gun angle and weld tracking errors. The rocker is powered by a rechargeable battery. The top plate U-rib weld utilizes two passes. The first pass allows the molten pool to flow into the weld groove and fuse with the steel plates on both sides, ensuring full penetration. The groove is fine-machined using a milling machine. The size and angle of the groove's blunt edge significantly influence root formation. A large blunt edge will not meet full penetration requirements, while a small groove angle prevents the arc from melting the root. Surface tension prevents the high-temperature solution from flowing into the sharp corner. Full penetration is achieved when the weld fills the groove. The welding torch is tilted forward 5-15°. The arc's blowing force causes the molten pool to flow toward the already melted groove, resulting in deeper weld penetration. A vertical or backward tilt would cause the molten pool to flow in the direction of the weld, affecting weld penetration. This method accommodates weld tracking deviations within a 2mm range, reducing tracking requirements and enabling the use of a standard welding carriage to achieve the same precision as robotic welding.

[0005] Regarding welding tool design, this invention utilizes a magnetic automatic welding trolley, building upon existing ones. This trolley utilizes mechanical tracking with guide wheels to move longitudinally along the weld seam. The trolley features magnetic attraction, guidance, tracking, and speed adjustment. A welding oscillator is mounted on the trolley, allowing for adjustment of swing amplitude and frequency, as well as the angle of the welding gun after clamping it. The oscillator is powered by a rechargeable battery. The welding gun is secured to the oscillator, and after the lateral and longitudinal inclination angles are adjusted, the adjustment knobs are tightened to secure the trolley.

[0006] In terms of welding method: This method achieves the purpose of accurately controlling the penetration rate of the U-shaped rib of the steel bridge top plate by controlling the groove size accuracy, adding a swing head to the welding carriage, adjusting the welding gun angle and swing parameters, welding current, voltage and dry extension parameters and other technical measures.

[0007] Beveling: According to the design principle of the present invention, the beveling accuracy has a great influence on the penetration rate. Therefore, the traditional planing process cannot meet the accuracy requirements. The beveling needs to be processed by a forming milling machine to control the beveling dimensional accuracy. P = 1 ± 0.5 mm, α = 45 ± 2 °, see the attached Figure 3 .

[0008] Welding tool: After the U rib is positioned on the steel bridge deck, it is fixed on the anti-deformation tire frame, and the tire frame is rotated 30-40 degrees to form the ship position welding. β = 30° ~ 40°, see attached Figure 2 .

[0009] Welding carriage and oscillator: A magnetic automatic welding carriage is used, which uses guide wheels to mechanically track the longitudinal movement of the weld seam. The carriage has magnetic attraction, guide tracking, and speed adjustment functions. A welding oscillator is installed on the carriage. The oscillator can adjust the swing amplitude and number of swings, and adjust the welding gun angle after clamping the welding gun. The oscillator is powered by a rechargeable battery. The welding gun is fixed to the oscillator. After the horizontal and vertical angles of the welding gun are adjusted, tighten the adjustment knob to secure it. The automatic welding carriage, oscillator, and rechargeable battery are all existing products. See attached. Figure 1 .

[0010] Welding method and welding parameters:

[0011] 4-1 Fine-process the welding groove, bend the U-shaped rib into shape, and assemble the U-shaped rib on the bridge deck according to product requirements.

[0012] 4-2 The assembled top plate unit is placed on a special anti-deformation tire frame, its two sides are clamped by a hydraulic device, and then the anti-deformation tire frame is rotated 30-40 degrees.

[0013] 4-3 Place the automatic welding carriage at one end of the weld, with the guide wheel close to the U-shaped rib to ensure the continuity of the weld; clamp the welding gun on the oscillator, and adjust the welding gun angle so that the center of the welding wire swing is on the bisector of the groove angle. Figure 2 ; Adjust the forward tilt angle of the welding gun so that the angle with the welding forward direction is 70-85 degrees, see Figure 1 ;

[0014] 4-4 Weld the first weld. Use flux-cored CO2 gas shielded welding as the welding method. Use metal powder flux-cored wire T492T1-0C1A with a wire diameter of φ=1.4mm. Use CO2 as the shielding gas.

[0015] The welding parameters are: welding wire current I=240-280 (A), welding voltage U=30-32 (V), dry extension length L=15-20 (mm), welding speed v=350-500 (mm / min), swing amplitude △=3-4 (mm). After welding is completed, remove the slag on the surface of the first weld.

[0016] 4-5 Weld the second weld. The welding method is flux-cored CO2 gas shielded welding. The welding wire is metal powder flux-cored wire T492T1-0C1A, the welding wire diameter is φ=1.4mm, and the shielding gas is CO2.

[0017] Welding parameters are: welding current I = 280-350 (A), welding voltage U = 32-35 (V), dry stickout L = 15-20 (mm), welding speed v = 300-400 (mm / min), swing amplitude △ = 4-5 (mm), swing frequency n = 110-150 (times / minute). After welding is completed, remove the slag from the surface of the second weld.

[0018] Repeat the above process to complete the welding of the remaining U-shaped rib welds of the top plate unit on the ship tire frame.

[0019] 4-6 Rotate the tire frame in the opposite direction so that it is 30-40 degrees to the ground, and repeat the above steps to complete the U-shaped rib weld on the other side of the top plate unit.

[0020] Technical Solution 1: A welding trolley that ensures the penetration rate of the U-shaped ribs of the steel bridge deck, including a magnetic automatic welding trolley, wherein the welding part of the magnetic automatic welding trolley is connected to the L-type connecting plate and the angle of the welding gun head is adjustable, the L-type connecting plate is connected to the rocker and the pitch angle of the L-type connecting plate along the L-type connecting plate is adjustable around the axis, the L-type connecting plate is connected to the transverse adjustment rod and the transverse adjustment rod moves horizontally left and right or up and down along the column, the column is fixed on the magnetic automatic welding trolley, the rocker adjusts the swing amplitude and number of swings of the welding gun and adjusts the angle of the welding gun after clamping the welding gun, and the rocker is powered by a rechargeable battery.

[0021] Technical Solution 2: A welding trolley adjustment method to ensure the penetration rate of the U-shaped rib of the steel bridge deck. The magnetic automatic welding trolley has magnetic suction function, guide tracking function and speed adjustment function, and uses a guide wheel mechanical tracking method to move longitudinally along the weld. The welding gun is fixed on a rocker, and the rocker adjusts the swing amplitude and number of swings of the welding gun. After the horizontal angle and longitudinal inclination angle of the welding gun are adjusted, the adjustment knob is tightened and fixed. The rocker is powered by a rechargeable battery.

[0022] Technical Solution 3: A single-sided welding method for ensuring the penetration rate of the U-shaped rib of a steel bridge deck, (1) fine-machine the welding groove, bend the U-shaped rib into shape, and assemble the U-shaped rib on the bridge deck according to product requirements; (2) place the assembled top plate unit on the anti-deformation frame, clamp it on both sides with a hydraulic device, and then rotate the anti-deformation frame 30-40 degrees; (3) place the magnetic automatic welding trolley at one end of the weld, so that the guide wheel is close to the U-shaped rib to ensure the continuity of the tracking weld; clamp the welding gun on the rocker, adjust the welding gun angle so that the center of the welding wire swing is placed on the bisector of the groove angle, and adjust the welding gun forward angle so that the angle with the welding forward direction is 70-85 degrees; (4) For the first weld, flux-cored CO2 gas shielded welding was selected as the welding method. The welding wire was metal powder flux-cored wire T492T1-0C1A, the welding wire diameter was φ=1.4mm, and the shielding gas was CO2. The welding parameters were: welding current I=240-280 (A), welding voltage U=30-32 (V), dry extension L=15-20 (mm), welding speed v=350-500 (mm / min), swing amplitude △=3-4 (mm), swing frequency n=150-200 (times / minute). After welding, the slag on the surface of the first weld was removed. (5) For the second weld, the welding method was selected. Flux-cored wire CO2 gas shielded welding, the welding wire is metal powder type flux-cored wire T492T1-0C1A, the welding wire diameter φ = 1.4mm, and the shielding gas is CO2; the welding parameters are: welding current I = 280-350 (A), welding voltage U = 32-35 (V), dry extension L = 15-20 (mm), welding speed v = 300-400 (mm / min), swing amplitude △ = 4-5 (mm), swing frequency n = 110-150 (times / minute), after welding is completed, remove the slag on the surface of the second weld; repeat the above process to complete the welding of the remaining U-shaped rib welds of the top plate unit on the ship's tire frame; (6) rotate the tire frame in the opposite direction so that it is 30-40° with the ground, and repeat the above steps to complete the welding of the U-shaped rib welds on the other side of the top plate unit.

[0023] Compared with the traditional process, the present invention has a large number of welds between the steel box girder bridge deck and the U-shaped rib, and the welding volume is large. The fatigue characteristics of the welds are obvious, and a certain penetration rate is required to improve the fatigue resistance of the welds. The traditional process uses a welding trolley or an integrated special welding machine. The welding gun is fixed at a fixed angle and position during welding, and the welding process window is narrow. In actual operation, it is easy to cause the weld root to fail to fully fuse or burn through due to angle and position deviations. Figure 4 The process of the present invention takes the accuracy of groove processing as the premise of penetration rate. The first weld is welded by swinging to prevent the root from burning through. It can adapt to the tracking deviation within a small range during the welding process. The weld fusion is good and the penetration rate is guaranteed. See the attached Figure 5Secondly, the equipment is simple and easy to operate; secondly, the welding process window is wide, which can ensure the penetration rate within a large range; thirdly, the process is convenient for workshop layout, does not require a dedicated site, and can flexibly arrange workstations; it has high production efficiency and stable quality.

[0024] . BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the application of the welding trolley. In the figure, 1 is the steel bridge deck, 2 is the U-shaped rib, 3 is the welding trolley, 4 is the rocker, 5 is the rechargeable battery, 6 is the L-shaped plate, 7 is the transverse adjustment rod, 8 is the column, and 9 is the welding gun.

[0026] Figure 2 It is a schematic diagram of U-rib groove processing.

[0027] Figure 3 It is a schematic diagram of the U-rib anti-deformation tooling.

[0028] Figure 4 This is a schematic diagram of cross-sectional defects in traditional welds. If the image does not meet the requirements, it can be deleted.

[0029] Figure 5 This is a schematic diagram of the weld cross section of this process. If the picture does not meet the requirements, it can be deleted. DETAILED DESCRIPTION

[0030] Example 1: Refer to the attached Figure 1 A welding trolley for ensuring the penetration rate of the U-shaped ribs of a steel bridge deck comprises a magnetic automatic welding trolley 3, wherein the welding trolley 3 comprises a welding gun 9 connected to an L-type connecting plate 6 and the welding gun 9 head angle is adjustable, the L-type connecting plate 6 is connected to a rocker 4 and the L-type connecting plate is adjustable in pitch angle along the L-type connecting plate around an axis, the L-type connecting plate is connected to a transverse adjustment rod 7 and the transverse adjustment rod 7 moves horizontally left and right or up and down along a column 8, the column 8 is fixed on the magnetic automatic welding trolley, the rocker 4 adjusts the swing amplitude and number of swings of the welding gun and adjusts the angle of the welding gun after clamping the welding gun, and the rocker 4 is powered by a rechargeable battery 5. The automatic welding trolley and the rocker are both existing products and will not be described here. The welding trolley adjustment method is as follows: the magnetic automatic welding trolley has magnetic suction function, guide tracking function and speed adjustment function, and adopts guide wheel mechanical tracking method to move along the longitudinal direction of the weld seam. The welding gun is fixed on the rocker, and the rocker adjusts the swing amplitude and number of swings of the welding gun. After the horizontal angle and longitudinal inclination angle of the welding gun are adjusted, the adjustment knob is tightened and fixed. The rocker is powered by a rechargeable battery.

[0031] Example 2: Based on Example 1, Figure 2 and 3 and Figure 5A single-sided welding method for ensuring the penetration rate of the U-shaped rib of a steel bridge deck, (1) fine-machine the welding groove, bend the U-shaped rib into shape, and assemble the U-shaped rib on the bridge deck according to product requirements; (2) place the assembled top plate unit on an anti-deformation frame, clamp it on both sides with a hydraulic device, and then rotate the anti-deformation frame 30-40 degrees; (3) place a magnetic automatic welding trolley at one end of the weld, so that the guide wheel is close to the U-shaped rib to ensure the continuity of the tracking weld; clamp the welding gun on the rocker, adjust the welding gun angle so that the center of the welding wire swing is placed on the groove angle bisector, and adjust the welding gun forward angle so that the angle with the welding forward direction is 70-85 degrees; (4) For welding the first weld, the welding method is flux-cored CO2 gas shielded welding, the welding wire is metal powder flux-cored wire T492T1-0C1A, the welding wire diameter φ=1.4mm, and the shielding gas is CO2; the welding parameters are: welding current I=240-280 (A), the best choice is 250A-260A; welding voltage U=30-32 (V), the best choice is 31-31.5V; dry extension L=15-20 (mm), welding speed v=350-500 (mm / min), the best is v=400-410 (mm / min); swing amplitude △=3-4 (mm), swing frequency n=150-200 (times / minute), the optimal swing amplitude △=3mm or 3.5mm, and swing frequency n=170 or 180 times / minute of the present invention. The purpose and effect of such selection are: it can not only ensure 100% weld penetration rate, but also avoid welding burn-through. After welding is completed, remove the slag on the surface of the first weld; (5) weld the second weld, select flux-cored CO2 gas shielded welding as the welding method, select metal powder flux-cored wire T492T1-0C1A, wire diameter φ=1.4mm, and shielding gas is CO2; welding parameters are: welding current I=280-350 (A), optimal is 320A; welding voltage U=32-35 (V), optimal is 33V; dry extension L=15-20 (mm), welding speed v=300-400 (mm / min), optimal is 380mm / min; swing amplitude △=4-5 (mm), optimal is 4mm; swing frequency n=110-150 (times / minute), optimal is 130 times / minute; after welding is completed, remove the slag on the surface of the second weld. Repeat the above process to complete the remaining U-shaped rib welds on the top plate unit on the ship's tire frame. The purpose and effect of this choice is to ensure that the filler weld can fill the weld, ensuring that the welding quality qualification rate reaches 100%, and also ensure the appearance of the weld. (6) Rotate the tire frame in the opposite direction so that it is 30-40 degrees with the ground, and repeat the above steps to complete the U-shaped rib weld on the other side of the top plate unit.

[0032] It should be understood that although the above embodiments provide a detailed textual description of the design ideas of the present invention, these textual descriptions are only simple textual descriptions of the design ideas of the present invention, rather than limitations on the design ideas of the present invention. Any combination, addition or modification that does not exceed the design ideas of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A single-sided welding method for ensuring the penetration rate of U-shaped ribs on steel bridge decks, comprising a magnetic automatic welding trolley, characterized by: The welding part of the magnetic automatic welding trolley is connected to the L-type connecting plate and the angle of the welding gun head is adjustable, the L-type connecting plate is connected to the oscillator and the pitch angle of the L-type connecting plate is adjustable around the axis along the L-type connecting plate, the L-type connecting plate is connected to the lateral adjustment rod and the lateral adjustment rod moves horizontally left and right or up and down along the column, the column is fixed on the magnetic automatic welding trolley, the oscillator adjusts the swing amplitude and number of swings of the welding gun and adjusts the angle of the welding gun after clamping the welding gun, and the oscillator is powered by a rechargeable battery; the magnetic automatic welding trolley has a magnetic suction function, a guide tracking function and a speed adjustment function and adopts a guide wheel mechanical tracking method to move longitudinally along the weld, the welding gun is fixed on the oscillator, the oscillator adjusts the swing amplitude and number of swings of the welding gun, and after the lateral angle and longitudinal inclination angle of the welding gun are adjusted, the adjustment knob is tightened and fixed, and the oscillator is powered by a rechargeable battery; (1) Fine-machine the welding groove, bend the U-shaped rib into shape, and assemble the U-shaped rib on the bridge deck according to product requirements; (2) The assembled top plate unit is placed on the anti-deformation tire frame, and its two sides are clamped by a hydraulic device, and then the anti-deformation tire frame is rotated 30-40°; (3) Place the magnetic automatic welding trolley at one end of the weld, with the guide wheel close to the U-shaped rib to ensure the continuity of the weld tracking; clamp the welding gun on the oscillator, adjust the welding gun angle so that the center of the welding wire swing is placed on the bisector of the groove angle, and adjust the forward tilt angle of the welding gun so that the angle with the welding forward direction is 70-85°; (4) Weld the first weld. The welding method is flux-cored CO2 gas shielded welding. The welding wire is metal powder flux-cored wire T492T1-0C1A, the welding wire diameter is φ=1.4mm, and the shielding gas is CO2; The welding parameters are: welding current I = 240-280A, welding voltage U = 30-32V, dry extension L = 15-20mm, welding speed v = 350-500mm / min, swing amplitude △ = 3-4mm, swing frequency n = 150-200 times / min. After welding is completed, remove the slag on the surface of the first weld; (5) Weld the second weld. The welding method is flux-cored CO2 gas shielded welding. The welding wire is metal powder flux-cored wire T492T1-0C1A, the welding wire diameter is φ=1.4mm, and the shielding gas is CO2; The welding parameters are: welding current I = 280-350A, welding voltage U = 32-35V, dry extension L = 15-20mm, welding speed v = 300-400mm / min, swing amplitude △ = 4-5mm, swing frequency n = 110-150 times / min. After welding is completed, remove the slag on the surface of the second weld; Repeat the above process to complete the welding of the remaining U-shaped rib welds on the top plate unit of the ship tire frame; (6) Rotate the tire frame in the opposite direction so that it is 30-40 degrees to the ground, and repeat the above steps to complete the U-shaped rib weld on the other side of the top plate unit.

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