Low heat input gas electric vertical welding method

Abstract

The present application relates to the technical field of gas-electric vertical welding, and discloses a low-heat-input gas-electric vertical welding method, which comprises the following steps: starting a welding gun, driving the welding gun to move along the length direction of a plate splicing joint, and driving the welding gun to reciprocate along the horizontal direction according to a preset track, wherein the preset track comprises a plurality of transverse tracks and a plurality of longitudinal tracks, the plurality of transverse tracks are arranged at intervals along the thickness direction of the plate splicing joint, the transverse track extends along the width direction of the plate splicing joint, a longitudinal track is connected between any two adjacent transverse tracks, and the longitudinal track extends along the thickness direction of the plate splicing joint. The low-heat-input gas-electric vertical welding method can reduce the temperature difference between the central region and the edge region of the liquid metal molten pool, so that the heat of the edge region of the liquid metal molten pool is sufficient, and the fusion between the weld metal and the plate is not prone to being poor, and the upper limit of the plate thickness suitable for welding is high.

Description

Technical Field

[0001] This invention relates to the field of gas-electric vertical welding technology, and in particular to a low-heat-input gas-electric vertical welding method. Background Technology

[0002] Gas-electric vertical welding is a highly efficient automatic gas-shielded welding method applied to butt joints of steel plates in vertical welding positions. A ceramic backing is installed on the back of the welding bevel, and a copper slider that forces the weld to form is located on the front of the welding bevel. The copper slider provides the protective gas for the weld pool, and circulating cooling water continuously flows through the copper slider (to cool the high-temperature liquid metal pool and solid weld). This welding method can achieve single-sided, single-pass welding with double-sided forming of plate butt joints, resulting in high welding efficiency.

[0003] Although gas-fired vertical welding requires only a single pass and has very high welding efficiency, its slow welding speed and large welding heat input (the energy input to a unit length of weld, calculated as: welding heat input = welding current x welding voltage ÷ welding speed) result in a significant decrease in the mechanical properties of the weld joint (including the weld, fusion zone, and heat-affected zone), especially impact toughness. Furthermore, current gas-fired vertical welding torches can only perform linear reciprocating oscillations (electrode manipulation) in the front-to-back direction of the weld pool's centerline, leading to a large temperature difference between the centerline and the edge areas (the area in contact with the base material) of the weld pool (the greater the plate thickness, the greater the temperature difference). To ensure full fusion between the edge area of ​​the weld pool and the base material, the welding current and welding voltage must be increased (to increase the weld width). Otherwise, incomplete fusion defects are likely to occur between the edge area of ​​the weld pool and the base material (due to insufficient heat and low temperature). This leads to a significant increase in the welding heat input, a marked increase in the overall temperature of the weld joint, and excessively high temperatures in the midline region (resulting in severe burn-off of beneficial alloying elements). This slows down the cooling rate of the weld joint, reduces the crystallization rate of the weld pool, and exacerbates regional segregation (low-melting-point substances concentrate in the center of the weld, solidify last, resulting in low strength and easy cracking). The resulting weld joint has coarse grains, ultimately leading to a decrease in the mechanical properties of the weld joint, and in severe cases, it may fail to meet technical and usage requirements.

[0004] Therefore, there is an urgent need for a low-heat-input gas-electric vertical welding method to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a low-heat-input gas-electric vertical welding method to reduce the temperature difference between the central and edge regions of the molten metal pool.

[0006] To achieve this objective, the present invention adopts the following technical solution: A low-heat-input gas-electric vertical welding method includes: starting a welding torch, driving the welding torch to move along the length direction of the plate joint, and simultaneously driving the welding torch to reciprocate horizontally along a preset trajectory. The preset trajectory includes multiple transverse trajectories and multiple longitudinal trajectories. The multiple transverse trajectories are spaced apart along the thickness direction of the plate joint, and the transverse trajectories extend along the width direction of the plate joint. A longitudinal trajectories connect two adjacent transverse trajectories, and the longitudinal trajectories extend along the thickness direction of the plate joint.

[0007] As an improvement to the above technical solution, the plurality of transverse tracks include a first transverse track, a second transverse track, and a third transverse track arranged sequentially and at intervals along the thickness direction of the board splice joint, and the plurality of longitudinal tracks include a first longitudinal track and a second longitudinal track. The first longitudinal track connects the middle part of the length direction of the first transverse track with the middle part of the length direction of the second transverse track, and the second longitudinal track connects the middle part of the length direction of the second transverse track with the middle part of the length direction of the third transverse track.

[0008] As an improvement to the above technical solution, multiple stopping positions are provided at intervals on the first horizontal trajectory, the second horizontal trajectory and the third horizontal trajectory. When the welding torch moves to the stopping position, the welding torch stays at the stopping position for a preset time.

[0009] As an improvement to the above technical solution, the multiple stopping positions on the first transverse trajectory include a first stopping position, a second stopping position, and a third stopping position. The first stopping position is located in the middle of the length direction of the first transverse trajectory, and the second stopping position and the third stopping position are located at both ends of the length direction of the first transverse trajectory, respectively. The multiple stopping positions on the second transverse trajectory include a fourth stopping position, a fifth stopping position, and a sixth stopping position. The fourth stopping position is located in the middle of the length direction of the second transverse trajectory, and the fifth stopping position and the sixth stopping position are located at both ends of the length direction of the second transverse trajectory, respectively. The multiple stopping positions on the third transverse trajectory include a seventh stopping position, an eighth stopping position, and a ninth stopping position. The seventh stopping position is located in the middle of the length direction of the third transverse trajectory, and the eighth and ninth stopping positions are located at the two ends of the length direction of the third transverse trajectory, respectively.

[0010] As an improvement to the above technical solution, the welding torch reciprocates in the following sequence: first dwell position, second dwell position, first dwell position, third dwell position, first dwell position, fourth dwell position, fifth dwell position, fourth dwell position, sixth dwell position, fourth dwell position, seventh dwell position, eighth dwell position, seventh dwell position, ninth dwell position, seventh dwell position, fourth dwell position, fifth dwell position, fourth dwell position, sixth dwell position, fourth dwell position, first dwell position, second dwell position, first dwell position, third dwell position, and first dwell position.

[0011] As an improvement to the above technical solution, it further includes: cooling the weld by a cooling slider and cooling the cooling slider by a cooling water circulation system. A temperature sensor is provided at the bottom of the cooling slider. The temperature sensor is used to monitor the temperature of the weld that is in contact with the bottom of the cooling slider. The cooling water circulation system includes a water circulation system and a heat dissipation device provided on the water circulation system. The heat dissipation device is used to dissipate heat from the water in the water circulation system. The operating power of the heat dissipation device is determined based on the monitoring value of the temperature sensor.

[0012] As an improvement to the above technical solution, determining the operating power of the heat dissipation device based on the monitoring value of the temperature sensor includes: If the temperature sensor reading is lower than the first preset temperature, the heat dissipation device is controlled to operate at the first operating power. If the temperature sensor's monitored value is not less than the first preset temperature and not greater than the second preset temperature, then the heat dissipation device is controlled to operate at a second operating power, which is greater than the first operating power. If the temperature sensor reading is greater than the second preset temperature, the heat dissipation device is controlled to operate at a third operating power, which is greater than the second operating power.

[0013] As an improvement to the above technical solution, the cooling slider is connected to a first circulating water connector and a second circulating water connector, and a circulating water channel is provided inside the cooling slider. One end of the circulating water channel is connected to the first circulating water connector, and the other end is connected to the second circulating water connector. The circulating water channel includes a horizontal channel, a first vertical channel, and a second vertical channel. The top end of the first vertical channel is connected to the first circulating water connector, and the bottom end is connected to one end of the horizontal channel. The top end of the second vertical channel is connected to the second circulating water connector, and the bottom end is connected to the other end of the horizontal channel.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The low heat input gas-electric vertical welding method of the present invention, in the process of filling the plate joint by single-wire welding, the welding torch moves not only along the length direction of the plate joint, but also reciprocates horizontally along a preset trajectory. Multiple transverse trajectories of the preset trajectory are spaced apart along the thickness direction of the plate joint, and extend along the width direction of the plate joint. A longitudinal trajectory connects adjacent transverse trajectories, extending along the thickness direction of the plate joint. This allows the welding arc of the welding torch to reach both the center and edge regions of the molten metal pool in the plate joint, resulting in a small temperature difference between the center and edge regions of the molten metal pool. The edge region of the molten metal pool receives sufficient heat, reducing the likelihood of poor fusion between the weld metal and the plate. This method is suitable for welding plates of a higher upper limit in thickness. Compared with existing technologies, when welding steel plates of the same thickness, the low heat input gas-electric vertical welding method of the present invention can reduce welding current and welding voltage, thus reducing welding heat input. Attached Figure Description

[0015] Figure 1 This is a structural schematic diagram (bottom view) of the low heat input gas-electric vertical welding method provided in the embodiment of the present invention when welding preparation is completed. Figure 2 This is a schematic diagram (top view) of the relative position of the plate splice seam and the preset trajectory in the low heat input gas-electric vertical welding method provided in the embodiment of the present invention. Figure 3 This is a schematic diagram of the preset trajectory in the low heat input gas-electric vertical welding method provided in the embodiments of the present invention; Figure 4 This is a schematic diagram showing the completion of welding between the first plate and the second plate in the low heat input gas-electric vertical welding method provided in this embodiment of the invention. Figure 5 This is a partial schematic diagram of the cooling slider used in the low heat input gas-electric vertical welding method provided in the embodiments of the present invention; Figure 6 This is a side view of the cooling slider used in the low heat input gas-electric vertical welding method provided in the embodiments of the present invention; Figure 7 This is a bottom view of the cooling slider used in the low heat input gas-electric vertical welding method provided in the embodiments of the present invention.

[0016] In the picture: 10. Joints between panels; 20. Cooling slider; 201. First circulating water connector; 202. Second circulating water connector; 203. Circulating water channel; 2031. Horizontal channel; 2032. First vertical channel; 2033. Second vertical channel; 204. Carbon dioxide gas chamber; 205. Carbon dioxide inlet pipe; 30. First sheet material; 40. Second sheet material; 50. Temperature sensor; 60. Ceramic gasket; 70. Temporary fixing clip; 90. Welds; 1. First lateral trajectory; 11. First stop position; 12. Second stop position; 13. Third stop position; 2. Second lateral trajectory; 21. Fourth stop position; 22. Fifth stop position; 23. Sixth stop position; 3. The third lateral trajectory; 31. Seventh stop position; 32. Eighth stop position; 33. Ninth stop position; 4. First longitudinal trajectory; 5. Second longitudinal trajectory. Detailed Implementation

[0017] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0018] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0020] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0021] like Figures 1-6 As shown, this embodiment provides a low-heat-input gas-electric vertical welding method, including: starting the welding torch, driving the welding torch to move along the length direction of the plate splice seam 10, and simultaneously driving the welding torch to reciprocate horizontally along a preset trajectory. The preset trajectory includes multiple transverse trajectories and multiple longitudinal trajectories. The multiple transverse trajectories are spaced apart along the thickness direction of the plate splice seam 10, and the transverse trajectories extend along the width direction of the plate splice seam 10. A longitudinal trajectories connect adjacent transverse trajectories, and the longitudinal trajectories extend along the thickness direction of the plate splice seam 10. In this embodiment, the thickness direction of the plate splice seam 10 is also the thickness direction of the plate. In this embodiment, the plate includes a first plate 30 and a second plate 40, and the plate splice seam 10 is the gap located between the first plate 30 and the second plate 40.

[0022] The low heat input gas-electric vertical welding method provided in this embodiment, during the process of filling the plate splice seam 10 with single-wire welding, in addition to moving along the length direction of the plate splice seam 10, also moves back and forth in the horizontal direction according to a preset trajectory. Multiple transverse trajectories of the preset trajectory are spaced apart along the thickness direction of the plate splice seam 10, and extend along the width direction of the plate splice seam 10. A longitudinal trajectory connects two adjacent transverse trajectories, and the longitudinal trajectory extends along the thickness direction of the plate splice seam 10. This allows the welding arc of the welding torch to reach both the central and edge regions of the molten metal pool in the plate splice seam 10, resulting in a small temperature difference between the central and edge regions of the molten metal pool and sufficient heat in the edge region. This reduces the likelihood of poor fusion between the weld metal and the plate, and allows for a higher upper limit on the thickness of the steel plate suitable for welding. Compared with existing technologies, the low heat input gas-electric vertical welding method provided in this embodiment can reduce welding current and welding voltage, and reduce welding heat input when welding plates of the same thickness.

[0023] Further, the plurality of transverse trajectories includes a first transverse trajectory 1, a second transverse trajectory 2 and a third transverse trajectory 3 which are sequentially arranged at intervals along the thickness direction of the plate splicing seam 10, the plurality of longitudinal trajectories includes a first longitudinal trajectory 4 and a second longitudinal trajectory 5, the first longitudinal trajectory 4 connects the middle part in the length direction of the first transverse trajectory 1 and the middle part in the length direction of the second transverse trajectory 2, and the second longitudinal trajectory 5 connects the middle part in the length direction of the second transverse trajectory 2 and the middle part in the length direction of the third transverse trajectory 3. That is to say, the preset trajectory in this embodiment is in a shape of the Chinese character "Wang".

[0024] Further, a plurality of stay positions are arranged at intervals on the first transverse trajectory 1, the second transverse trajectory 2 and the third transverse trajectory 3, and when the welding torch moves to the stay positions, the welding torch stays at the stay positions for a preset time.

[0025] Further, the plurality of stay positions on the first transverse trajectory 1 includes a first stay position 11, a second stay position 12 and a third stay position 13, the first stay position 11 is located in the middle part in the length direction of the first transverse trajectory 1, and the second stay position 12 and the third stay position 13 are respectively located at two ends in the length direction of the first transverse trajectory 1. The plurality of stay positions on the second transverse trajectory 2 includes a fourth stay position 21, a fifth stay position 22 and a sixth stay position 23, the fourth stay position 21 is located in the middle part in the length direction of the second transverse trajectory 2, and the fifth stay position 22 and the sixth stay position 23 are respectively located at two ends in the length direction of the second transverse trajectory 2. The plurality of stay positions on the third transverse trajectory 3 includes a seventh stay position 31, an eighth stay position 32 and a ninth stay position 33, the seventh stay position 31 is located in the middle part in the length direction of the third transverse trajectory 3, and the eighth stay position 32 and the ninth stay position 33 are respectively located at two ends in the length direction of the third transverse trajectory 3.

[0026] In this embodiment, the stay time of the welding torch at the seventh stay position 31, the eighth stay position 32 and the ninth stay position 33 is 2-3 seconds, the stay time at the fourth stay position 21, the fifth stay position 22 and the sixth stay position 23 is 1-2 seconds, and the stay time at the first stay position 11, the second stay position 12 and the third stay position 13 is 0.5-1 second.

[0027] Furthermore, the welding torch reciprocates in the following sequence: first stop position 11, second stop position 12, first stop position 11, third stop position 13, first stop position 11, fourth stop position 21, fifth stop position 22, fourth stop position 21, sixth stop position 23, fourth stop position 21, seventh stop position 31, eighth stop position 32, seventh stop position 31, ninth stop position 33, seventh stop position 31, fourth stop position 21, fifth stop position 22, fourth stop position 21, sixth stop position 23, fourth stop position 21, first stop position 11, second stop position 12, first stop position 11, third stop position 13, and first stop position 11. The reciprocating motion mentioned here specifically refers to starting from the first stop position 11, passing through the second stop position 12, the first stop position 11, the third stop position 13, the first stop position 11, the fourth stop position 21, the fifth stop position 22, the fourth stop position 21, the sixth stop position 23, the fourth stop position 21, the seventh stop position 31, the eighth stop position 32, the seventh stop position 31, the ninth stop position 33, the seventh stop position 31, the fourth stop position 21, the fifth stop position 22, the fourth stop position 21, the sixth stop position 23, and the fourth stop position 21, finally returning to the first stop position. Position 11; then continue from the first stop position 11, passing through the second stop position 12, the first stop position 11, the third stop position 13, the first stop position 11, the fourth stop position 21, the fifth stop position 22, the fourth stop position 21, the sixth stop position 23, the fourth stop position 21, the seventh stop position 31, the eighth stop position 32, the seventh stop position 31, the ninth stop position 33, the seventh stop position 31, the fourth stop position 21, the fifth stop position 22, the fourth stop position 21, the sixth stop position 23, and the fourth stop position 21, finally returning to the first stop position 11. That is, repeating the process starting from the first stop position 11, passing through the second stop position 12, the first stop position 11, the third stop position 13, the first stop position 11, the fourth stop position 21, the fifth stop position 22, the fourth stop position 21, the sixth stop position 23, the fourth stop position 21, the seventh stop position 31, the eighth stop position 32, the seventh stop position 31, the ninth stop position 33, the seventh stop position 31, the fourth stop position 21, the fifth stop position 22, the fourth stop position 21, the sixth stop position 23, and the fourth stop position 21, and finally returning to the first stop position 11.

[0028] Optionally, the low heat input gas-electric vertical welding method provided in this embodiment further includes: cooling the weld 90 by a cooling slider 20 and cooling the cooling slider 20 by a cooling water circulation system. A temperature sensor 50 is provided at the bottom of the cooling slider 20 to monitor the temperature of the weld 90 in contact with the bottom of the cooling slider 20. The cooling water circulation system includes a water circulation system and a heat dissipation device disposed on the water circulation system to dissipate heat from the water. The operating power of the heat dissipation device is determined based on the monitoring value of the temperature sensor 50. This avoids excessively low temperatures in the molten metal pool, indirectly reducing the heat input requirement of the welding torch for the molten metal pool.

[0029] Further, the operating power of the heat dissipation device is determined based on the monitoring value of the temperature sensor 50. This includes controlling the heat dissipation device to operate at a first operating power if the monitoring value of the temperature sensor 50 is less than a first preset temperature; controlling the heat dissipation device to operate at a second operating power, where the second operating power is greater than the first operating power, if the monitoring value of the temperature sensor 50 is greater than the second preset temperature; and controlling the heat dissipation device to operate at a third operating power, where the third operating power is greater than the second operating power. In this embodiment, the first preset temperature is 500°C, and the second preset temperature is 800°C.

[0030] Optionally, the cooling slider 20 is connected to a first circulating water connector 201 and a second circulating water connector 202. A circulating water channel 203 is provided inside the cooling slider 20. One end of the circulating water channel 203 is connected to the first circulating water connector 201, and the other end is connected to the second circulating water connector 202. The circulating water channel 203 includes a horizontal channel 2031, a first vertical channel 2032, and a second vertical channel 2033. The top end of the first vertical channel 2032 is connected to the first circulating water connector 201, and the bottom end is connected to one end of the horizontal channel 2031. The top end of the second vertical channel 2033 is connected to the second circulating water connector 202, and the bottom end is connected to the other end of the horizontal channel 2031. By placing the horizontal channel 2031 at the lower part of the cooling slider 20, the required heat input of the welding torch from the molten metal pool can be further reduced.

[0031] Optionally, based on the thickness of the plate being welded and the corresponding range of welding parameters, the welding current and welding voltage are gradually selected from the lower limit of the range upwards. The fusion state of the weld pool's edge is then observed. Welding can continue at these parameters once the edge of the weld pool is completely fused. The selection of welding parameters is based on the corresponding welding procedure specification. The lower limit welding parameters in the corresponding welding procedure specification are preferred. For example, if the corresponding welding procedure specification specifies a welding current of 300A-350A and a welding voltage of 31V-34V, welding should begin with a welding current of 300A and a welding voltage of 31V, gradually increasing the welding parameters while continuously monitoring the weld pool's state. This continues until the plate at the edge of the weld pool (i.e., the weld bevel surface) changes from dark to dark red, and then to bright red (at which point the plate at the edge of the weld pool is completely fused). This parameter combination is then maintained for continued welding, ensuring both weld fusion quality and a low heat input during the welding process.

[0032] Optionally, this embodiment provides a low heat input gas-electric vertical welding method, which further includes the following steps before starting the welding torch: 1. Welding groove preparation: The edge of the ship plate to be welded is beveled by thermal cutting or machining. The bevel is a single-sided V-shaped bevel. In this embodiment, the bevel angle is 30±5 degrees. The welding filler cross-sectional area is small, the welding speed is fast, the welding efficiency is high, the welding material consumption is low, the welding heat input is small, and the mechanical properties of the weld are good.

[0033] 2. Assembly and fixing of vertical joints: The beveled steel plates are installed onto the corresponding ship section frames for prefabrication. The completed sections are then hoisted and assembled. During the assembly phase, the vertical joints of the steel plates to be welded using gas-electric welding are leveled and secured. After leveling, temporary fixing clips 70 are used for welding. The temporary fixing clips 70 are installed on the reverse side of the welding bevel, and a weld hole is provided in the center of the temporary fixing clips 70 (to ensure the ceramic gasket 60 passes through smoothly).

[0034] 3. Install ceramic gasket 60: Install and temporarily fix the ceramic gasket 60 on the reverse side of the welding bevel. The center of the ceramic gasket 60 is aligned with the center of the welding bevel. The surface of the ceramic gasket 60 must be in full contact with the surface of the steel plate. The joint area of ​​the ceramic gasket 60 and the ceramic gasket 60 (two adjacent ceramic gaskets 60) must be in full contact (each ceramic gasket 60 is approximately 300mm-600mm long).

[0035] 4. Laying rails, installing welding trolley, welding torch and cooling slider 20: On the surface of the steel plate on one side of the weld bevel, mark a line at a certain distance from the center of the weld bevel (parallel to the center of the weld bevel), and then lay the rails according to the marked line. Install the welding carriage onto the laid rails and lock the clutch. Finally, install the welding torch and cooling slider 20 on the extended structure of the welding carriage and adjust their spatial positions.

[0036] 5. Install cooling slider 20: By pressing the cooling slider 20 against the cross-shaped groove of the cooling slider 20 using the pressing device connected to the welding carriage, the cooling slider 20 is installed on the front side of the welding bevel. The center of the cooling slider 20 is aligned with the center of the welding bevel. The cooling slider 20 maintains appropriate pressure with the surface of the steel plate, ensuring that the cooling slider 20 can move synchronously with the welding carriage and that the high-temperature liquid molten pool does not flow from the gap between the cooling slider 20 and the steel plate.

[0037] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A low-heat-input gas-electric vertical welding method, characterized in that, include: Start the welding torch and drive it to move along the length of the plate splice joint (10). At the same time, drive the welding torch to move back and forth in the horizontal direction according to the preset trajectory. The preset trajectory includes multiple horizontal trajectories and multiple vertical trajectories. The multiple horizontal trajectories are spaced apart along the thickness direction of the plate splice joint (10). The horizontal trajectories extend along the width direction of the plate splice joint (10). The vertical trajectories are connected between two adjacent horizontal trajectories. The vertical trajectories extend along the thickness direction of the plate splice joint (10). The plurality of transverse tracks include a first transverse track (1), a second transverse track (2) and a third transverse track (3) arranged sequentially and at intervals along the thickness direction of the board splice seam (10), and the plurality of longitudinal tracks include a first longitudinal track (4) and a second longitudinal track (5). The first longitudinal track (4) connects the middle part of the length direction of the first transverse track (1) and the middle part of the length direction of the second transverse track (2), and the second longitudinal track (5) connects the middle part of the length direction of the second transverse track (2) and the middle part of the length direction of the third transverse track (3). Multiple stopping positions are provided at intervals on the first horizontal trajectory (1), the second horizontal trajectory (2) and the third horizontal trajectory (3). When the welding torch moves to the stopping position, the welding torch stays at the stopping position for a preset time. The multiple stopping positions on the first transverse trajectory (1) include a first stopping position (11), a second stopping position (12) and a third stopping position (13). The first stopping position (11) is located in the middle of the length direction of the first transverse trajectory (1), and the second stopping position (12) and the third stopping position (13) are located at the two ends of the length direction of the first transverse trajectory (1), respectively. The multiple stopping positions on the second transverse trajectory (2) include a fourth stopping position (21), a fifth stopping position (22) and a sixth stopping position (23). The fourth stopping position (21) is located in the middle of the length direction of the second transverse trajectory (2), and the fifth stopping position (22) and the sixth stopping position (23) are located at the two ends of the length direction of the second transverse trajectory (2), respectively. The third transverse trajectory (3) includes a seventh stop position (31), an eighth stop position (32) and a ninth stop position (33). The seventh stop position (31) is located in the middle of the length direction of the third transverse trajectory (3), and the eighth stop position (32) and the ninth stop position (33) are located at the two ends of the length direction of the third transverse trajectory (3).

2. The low heat input gas-electric vertical welding method according to claim 1, characterized in that, The welding torch reciprocates in the following order: first stop position (11), second stop position (12), first stop position (11), third stop position (13), first stop position (11), fourth stop position (21), fifth stop position (22), fourth stop position (21), sixth stop position (23), fourth stop position (21), seventh stop position (31), eighth stop position (32), seventh stop position (31), ninth stop position (33), seventh stop position (31), fourth stop position (21), fifth stop position (22), fourth stop position (21), sixth stop position (23), fourth stop position (21), first stop position (11), second stop position (12), first stop position (11), third stop position (13), and first stop position (11).

3. The low heat input gas-electric vertical welding method according to claim 1, characterized in that, Also includes: The weld (90) is cooled by a cooling slider (20) and the cooling slider (20) is cooled by a cooling water circulation system. A temperature sensor (50) is provided at the bottom of the cooling slider (20). The temperature sensor (50) is used to monitor the temperature of the weld (90) that is in contact with the bottom of the cooling slider (20). The cooling water circulation system includes a water circulation system and a heat dissipation device provided on the water circulation system. The heat dissipation device is used to dissipate heat from the water in the water circulation system. The operating power of the heat dissipation device is determined based on the monitoring value of the temperature sensor (50).

4. The low heat input gas-electric vertical welding method according to claim 3, characterized in that, Determining the operating power of the heat dissipation device based on the monitoring value of the temperature sensor (50) includes: If the temperature sensor (50) monitors a value less than a first preset temperature, the heat dissipation device is controlled to operate at a first operating power. If the monitored value of the temperature sensor (50) is not less than the first preset temperature and not greater than the second preset temperature, then the heat dissipation device is controlled to operate at a second operating power, which is greater than the first operating power. If the temperature sensor (50) monitors a value greater than the second preset temperature, the heat dissipation device is controlled to operate at a third operating power, which is greater than the second operating power.

5. The low heat input gas-electric vertical welding method according to any one of claims 1-4, characterized in that, The cooling slider (20) is connected to a first circulating water connector (201) and a second circulating water connector (202). A circulating water channel (203) is provided inside the cooling slider (20). One end of the circulating water channel (203) is connected to the first circulating water connector (201), and the other end is connected to the second circulating water connector (202). The circulating water channel (203) includes a horizontal channel (2031), a first vertical channel (2032) and a second vertical channel (2033). The top end of the first vertical channel (2032) is connected to the first circulating water connector (201), and the bottom end is connected to one end of the horizontal channel (2031). The top end of the second vertical channel (2033) is connected to the second circulating water connector (202), and the bottom end is connected to the other end of the horizontal channel (2031).

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