All-position TIG automatic welding method for boiler water-cooled wall furnace outer tube

Abstract

The invention provides an all-position TIG (Tungsten Inert Gas) automatic welding method for an outer tube of a water-cooled wall of a boiler. The method comprises the following steps: acquiring a welding track of a pipeline; the welding track is sequentially divided into a flat welding section, a right vertical welding section and a left vertical welding section in the clockwise direction, the right vertical welding section and the left vertical welding section are symmetrically arranged along the center line of the welding track, and the right vertical welding section and the left vertical welding section are connected at the lowest point of the welding track; the welding trolley is controlled to move at a constant speed in the clockwise direction of the welding track; welding parameters including welding power, welding speed, wire feeding speed and shielding gas flow are adjusted according to the positions of the welding tractor on the right vertical welding section and the left vertical welding section, so that the molten pool generation speed is gradually reduced in the direction close to the lowest point. According to the method, the molten pool can be prevented from flowing down when the pipeline in the non-vertical state is welded, and the welding quality can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of automatic welding, and in particular to a full-position TIG automatic welding method for an outer tube of a water-cooled fireplace of a boiler. Background Art

[0002] The traditional maintenance mode for boiler water wall tube burst is to set up scaffolding (or lifting platform) inside the furnace and replace the tube by manual welding. This method has problems such as high safety risk, long maintenance period, high maintenance cost, poor construction environment, narrow tube spacing, high welding difficulty, and high difficulty in welding quality control. In order to solve the above problems, both domestic and foreign countries have begun to use automatic welding devices for pipeline welding.

[0003] like Figure 1 As shown, a conventional automatic welding device generally includes a track 1, a welding carriage 2, a welding gun 3 and a mechanical motion module 4, wherein the track 1 is sleeved outside the pipeline and fixed to the pipeline, the welding carriage 2 is arranged on the track 1 and can move along the track 1, and the welding gun 3 is installed on the welding carriage 2 through the mechanical motion module 4, and can swing under the action of the mechanical motion module 4 to achieve welding. During use, the welding carriage is generally set to move at a constant speed, and welding parameters such as welding current, wire feeding speed and shielding gas flow rate remain unchanged. However, when the pipeline is in a non-vertical state (such as horizontal setting, inclined setting), the molten pool will flow down under the action of gravity, especially on both sides of the pipeline, which will affect the welding quality. Summary of the invention

[0004] The embodiment of the present application at least provides a full-position TIG automatic welding method for the outer pipe of a boiler water-cooled fireplace, which can prevent the molten pool from dripping when welding the pipe in a non-vertical state, which is beneficial to improving the welding quality.

[0005] The present application provides a method for all-position TIG automatic welding of a boiler water-cooled fireplace outer tube, comprising:

[0006] Obtain the welding trajectory of the pipeline;

[0007] The welding track is divided into a flat welding section, a right vertical welding section and a left vertical welding section in a clockwise direction, the right vertical welding section and the left vertical welding section are symmetrically arranged along the center line of the welding track, and the right vertical welding section and the left vertical welding section are connected at the lowest point of the welding track;

[0008] Controlling the welding carriage to move at a constant speed in a clockwise direction along the welding track;

[0009] The welding parameters are adjusted according to the positions of the welding carriage at the right vertical welding section and the left vertical welding section to gradually reduce the molten pool generation speed in the direction approaching the lowest point. The welding parameters include welding power, welding speed, wire feeding speed and shielding gas flow rate.

[0010] In an optional embodiment, adjusting the welding parameters according to the position of the welding carriage at the right vertical welding section and the left vertical welding section includes:

[0011] When the welding carriage moves toward the lower point along the right vertical welding section, the welding power, welding speed and wire feeding speed are gradually reduced, and the flow rate of the shielding gas is gradually increased;

[0012] When the welding carriage moves toward the high point along the left vertical welding section, the welding power, welding speed and wire feeding speed are gradually increased, and the flow rate of the shielding gas is gradually reduced.

[0013] In an optional embodiment, the reducing / increasing the welding power, welding speed, wire feeding speed and shielding gas flow rate includes:

[0014] Obtaining the moving distance of the welding carriage;

[0015] Whenever the moving distance of the welding carriage reaches a set distance value, the welding power, welding speed, wire feeding speed and shielding gas flow rate are reduced / increased according to the preset parameter changes.

[0016] In an optional embodiment, the reducing / increasing the welding power, welding speed, wire feeding speed and shielding gas flow rate includes:

[0017] Obtaining the moving time of the welding carriage;

[0018] Whenever the moving time of the welding carriage reaches the time setting value, the welding power, welding speed, wire feeding speed and shielding gas flow rate are reduced / increased according to the preset parameter changes.

[0019] In an optional implementation, the obtaining the welding trajectory of the pipeline includes:

[0020] Use laser vision sensors to obtain the three-dimensional coordinates of the pipeline;

[0021] The welding trajectory of the pipeline is obtained according to the three-dimensional coordinates.

[0022] In an optional embodiment, controlling the welding carriage to move at a constant speed in a clockwise direction along the welding track includes:

[0023] The driving parameters of the welding carriage are adjusted according to the positions of the welding carriage at the right vertical welding section and the left vertical welding section so that the actual speed of the welding carriage is consistent with the target speed.

[0024] In an optional embodiment, adjusting the driving parameters of the welding carriage according to the position of the welding carriage in the right vertical welding section and the left vertical welding section includes:

[0025] When the welding carriage moves toward a lower point along the right vertical welding section, the driving parameters of the welding carriage are gradually reduced;

[0026] When the welding carriage moves toward a high point along the left vertical welding section, the driving parameters of the welding carriage are gradually increased.

[0027] In an optional embodiment, the reducing / increasing the driving parameters of the welding carriage includes:

[0028] Obtaining the moving distance of the welding carriage;

[0029] Whenever the moving distance of the welding carriage reaches a set distance value, a correction amount is calculated according to the actual speed and the target speed of the welding carriage, and the motor driving power of the welding carriage is adjusted according to the correction amount.

[0030] In an optional embodiment, the method further includes:

[0031] The molten pool information is monitored in real time, and the oscillation frequency of the welding gun is controlled according to the molten pool information.

[0032] In an optional embodiment, the method further includes:

[0033] After welding is completed, one or more instruments including X-ray flaw detector, ultrasonic detector and magnetic particle detector are used to detect internal defects of the weld.

[0034] The above technical solution of the present application has the following beneficial technical effects:

[0035] The full-position TIG automatic welding method for the outer pipe of the boiler water-cooled fireplace in the embodiment of the present application can adjust the welding parameters according to the position of the welding carriage when the welding carriage moves in the right vertical welding section and the left vertical welding section, so as to gradually reduce the molten pool generation speed in the direction close to the lowest point, thereby better controlling the molten pool and preventing the molten pool from dripping when welding the pipeline in a non-vertical state, which is beneficial to improving the welding quality.

[0036] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. The drawings herein are incorporated into the specification and constitute a part of the specification. These drawings illustrate embodiments consistent with the present application and are used together with the specification to illustrate the technical solutions of the present application. It should be understood that the following drawings only illustrate certain embodiments of the present application and should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can also be obtained based on these drawings without creative work.

[0038] Figure 1 It shows a structural schematic diagram of a boiler water-cooled fireplace outer pipe full-position TIG automatic welding in the prior art;

[0039] Figure 2 A flow chart of a method for all-position TIG automatic welding of an outer tube of a water-cooled fireplace of a boiler provided in an embodiment of the present application is shown;

[0040] Figure 3 A schematic diagram of a welding track provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0041] like Figure 1 As shown, a conventional automatic welding device generally includes a track 1, a welding carriage 2, a welding gun 3 and a mechanical motion module 4, wherein the track 1 is sleeved outside the pipeline and fixed to the pipeline, the welding carriage 2 is arranged on the track 1 and can move along the track 1, and the welding gun 3 is installed on the welding carriage 2 through the mechanical motion module 4, and can swing under the action of the mechanical motion module 4 to achieve welding. During use, the welding carriage is generally set to move at a constant speed, and welding parameters such as welding current, wire feeding speed and shielding gas flow rate remain unchanged. However, when the pipeline is in a non-vertical state (such as horizontal setting, inclined setting), the molten pool will flow down under the action of gravity, especially on both sides of the pipeline, which will affect the welding quality.

[0042] To this end, an embodiment of the present application provides a full-position TIG automatic welding method for the outer pipe of a boiler water-cooled fireplace, which can prevent the molten pool from dripping when welding a pipe in a non-vertical state, thereby improving the welding quality.

[0043] like Figure 2 As shown, the embodiment of the present application shows a full-position TIG automatic welding method for the outer tube of a water-cooled fireplace of a boiler, and the method includes the following steps S100 to S400.

[0044] Step S100: obtaining the welding trajectory of the pipeline.

[0045] The welding track (i.e., weld) of the pipeline is the seam between the two end faces of the pipeline, that is, the welding track of the pipeline is circular. In practical applications, the three-dimensional coordinates of the pipeline can be obtained by using a laser vision sensor, and then the welding track of the pipeline can be obtained according to the three-dimensional coordinates.

[0046] Step S200, dividing the welding trajectory into a flat welding section, a right vertical welding section and a left vertical welding section in a clockwise direction, the right vertical welding section and the left vertical welding section are symmetrically arranged along the center line of the welding trajectory, and the right vertical welding section and the left vertical welding section are connected at the lowest point of the welding trajectory.

[0047] like Figure 3 As shown, the two ends of the flat welding section are connected to the right vertical welding section and the left vertical welding section respectively, and the midpoint of the flat welding section is the highest point of the welding trajectory and corresponds to the lowest point. In practical applications, the flat welding section, the right vertical welding section and the left vertical welding section can be divided according to the angle. For example, the boundary between the flat welding section and the right vertical welding section and the left vertical welding section is divided by tilting 30° to the left and right from the highest point, that is, the flat welding section occupies 60° of the entire welding trajectory, and the right vertical welding section and the left vertical welding section each occupy 150° of the entire welding trajectory. It should be understood that when the pipeline is in a non-vertical state, its welding trajectory is bound to have a highest point and a lowest point.

[0048] Step S300, controlling the welding carriage to move at a constant speed in the clockwise direction along the welding track.

[0049] The crawling (moving) modes of the welding trolley are mainly as follows:

[0050] (1) The trolley crawls by magnetic wheels. In this method, the welding trolley is adsorbed on the pipeline by magnetic wheels, and the walking wheels are driven, and the trolley automatically crawls around the pipeline. This method requires that the adsorption force of the magnetic wheel is large enough and the adsorption is reliable, otherwise it is easy to fall off due to the drag of the cable. In addition, its walking direction is easily affected by the deformation of the pipeline surface and foreign matter, and the walking trajectory is a spiral line.

[0051] (2) The trolley crawls along the chain with the help of a sprocket. The sprocket on the welding trolley moves along the chain tightly wrapped around the outer circle of the pipe. This method has a complex structure, requires a lot of work to install the crawling trolley and the track, and takes a long time to assist in welding.

[0052] (3) The trolley crawls along the punched steel belt with magnets by the gear. This method has a complex structure, is difficult to process, and has poor walking stability.

[0053] (4) Crawling in the form of friction transmission. The movement of the trolley is achieved by the friction between the running wheel and the track. Friction transmission is more stable, the friction pair composed of the friction wheel and the flexible track is more convenient to install, and the structure is simpler, but the wear of the contact surface should be considered, and factors such as slippage need to be fully calculated.

[0054] When the welding carriage moves to a high point or a low point, the speed of the welding carriage will be affected by gravity. That is, the speed of the welding carriage will be lower than the target speed when it moves to a high point, and the speed of the welding carriage will be higher than the target speed when it moves to a low point. This will cause the welding carriage to be unable to move at a uniform speed, which may affect the welding quality. In this article, the target speed refers to the speed of the welding carriage in the flat welding section when the drive parameters remain unchanged.

[0055] In order to avoid the problem that the welding carriage cannot move at a uniform speed and thus affects the welding quality, in this embodiment, the driving parameters of the welding carriage are adjusted according to the positions of the welding carriage in the right vertical welding section and the left vertical welding section, so that the actual speed of the welding carriage is consistent with the target speed. In this way, the actual speed of the welding carriage can be consistent with the target speed, that is, the welding carriage can be moved at a uniform speed, thereby avoiding the problem that the welding carriage cannot move at a uniform speed and thus affects the welding quality.

[0056] Optionally, the driving parameters of the welding trolley are adjusted according to the positions of the welding trolley in the right vertical welding section and the left vertical welding section, specifically including: when the welding trolley moves toward the low point along the right vertical welding section, the driving parameters of the welding trolley are gradually reduced; when the welding trolley moves toward the high point along the left vertical welding section, the driving parameters of the welding trolley are gradually increased. In a specific implementation, the driving parameters may be power, torque, transmission ratio, battery voltage, etc. Of course, although there is a proportional relationship between the above parameters (such as power, torque, transmission ratio, etc.) and vehicle speed, in actual applications, these relationships are affected by a variety of complex factors, including but not limited to mass, air resistance, rolling resistance, transmission efficiency, and characteristics of the motor and battery system. Therefore, optimizing these parameters in practice to achieve optimal performance is a comprehensive consideration process.

[0057] Furthermore, reducing / increasing the driving parameters of the welding trolley specifically includes: obtaining the moving distance of the welding trolley; whenever the moving distance of the welding trolley reaches a set distance value, calculating a correction amount according to the actual speed and target speed of the welding trolley, and adjusting the motor driving power of the welding trolley according to the correction amount.

[0058] Step S400, adjusting welding parameters according to the positions of the welding carriage in the right vertical welding section and the left vertical welding section to gradually reduce the molten pool generation speed in the direction close to the lowest point, the welding parameters including welding power, wire feeding speed and shielding gas flow rate.

[0059] Before adjusting the welding parameters, the position of the welding carriage can be obtained first. In practical applications, the position of the welding carriage can be monitored in real time using devices such as laser vision sensors or encoders. As the position of the welding carriage changes, the system can automatically adjust the welding parameters based on the position information.

[0060] Optionally, the welding parameters are adjusted according to the position of the welding carriage in the right vertical welding section and the left vertical welding section, specifically including: when the welding carriage moves toward the low point along the right vertical welding section, the welding power and wire feeding speed are gradually reduced, and the shielding gas flow rate is gradually increased; when the welding carriage moves toward the high point along the left vertical welding section, the welding power and wire feeding speed are gradually increased, and the shielding gas flow rate is gradually reduced. Specifically, the closer the welding carriage is to the lowest point, the welding power and wire feeding speed are relatively reduced, and the shielding gas flow rate is relatively increased. Among them, after the welding power is reduced, the heat input can be reduced, the cooling rate of the molten pool is slowed down, which helps to better control the flow of the molten pool and prevent the molten droplets from dripping. After the wire feeding speed is reduced, too much filler metal can be prevented from entering the molten pool, increasing the risk of sagging, making the molten pool easier to control. After the shielding gas flow rate is increased, it can help better protect the molten pool and reduce defects such as pores. According to the above means, the molten pool generation speed can be gradually reduced in the direction close to the lowest point, so that the molten pool can be better controlled to prevent the molten pool from dripping.

[0061] Further, the welding power, wire feeding speed and shielding gas flow rate are reduced / increased, specifically including: obtaining the moving distance of the welding carriage; whenever the moving distance of the welding carriage reaches the distance setting value, the welding power, wire feeding speed and shielding gas flow rate are reduced / increased according to the preset parameter change amount. For example, for every 10mm the welding carriage moves forward to the low point, the welding gun power is reduced by 1%, the wire feeding speed is reduced by 0.05m / min, and the argon gas flow rate is reduced by 0.3L / min.

[0062] Further, the welding power, wire feeding speed and shielding gas flow rate are reduced / increased, specifically including: obtaining the moving time of the welding carriage; whenever the moving time of the welding carriage reaches the time setting value, the welding power, wire feeding speed and shielding gas flow rate are reduced / increased according to the preset parameter change amount. For example, every time the welding carriage moves toward the low point for 5 seconds, the welding gun power is reduced by 1%, the wire feeding speed is reduced by 0.05m / min, and the argon gas flow rate is reduced by 0.3L / min.

[0063] In this embodiment, the all-position TIG automatic welding method for the outer tube of the water-cooled fireplace of the boiler further includes: real-time monitoring of the molten pool information, and controlling the swing frequency of the welding gun according to the molten pool information.

[0064] During the welding process, the width of the molten pool directly affects the quality and appearance of the weld. By monitoring the molten pool width in real time and dynamically adjusting the oscillation frequency of the welding gun according to its changes, the state of the molten pool can be effectively controlled to avoid problems caused by the molten pool being too wide or too narrow. In practical applications, the width of the molten pool can be obtained by scanning with a laser vision sensor.

[0065] In this embodiment, the all-position TIG automatic welding method for the outer tube of the water-cooled fireplace of the boiler further includes: after the welding is completed, using one or more instruments selected from among an X-ray flaw detector, an ultrasonic detector and a magnetic particle detector to detect internal defects of the weld.

[0066] The full-position TIG automatic welding method for the outer pipe of the boiler water-cooled fireplace in the embodiment of the present application can adjust the welding parameters according to the position of the welding carriage when the welding carriage moves in the right vertical welding section and the left vertical welding section, so as to gradually reduce the molten pool generation speed in the direction close to the lowest point, thereby better controlling the molten pool and preventing the molten pool from dripping when welding the pipeline in a non-vertical state, which is beneficial to improving the welding quality.

[0067] The term "first" or "second" in the specification and claims of this application may include one or more of the features explicitly or implicitly. In the description of this application, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the objects connected before and after are in an "or" relationship.

[0068] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0069] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0070] One or more embodiments of this specification are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this specification should be included in the scope of protection of this application.

[0071] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A full-position TIG automatic welding method for the outer tube of a boiler water-cooled fireplace, characterized in that: include: Obtain the welding trajectory of the pipeline; The welding track is divided into a flat welding section, a right vertical welding section and a left vertical welding section in a clockwise direction, the right vertical welding section and the left vertical welding section are symmetrically arranged along the center line of the welding track, and the right vertical welding section and the left vertical welding section are connected at the lowest point of the welding track; Controlling the welding carriage to move at a constant speed in a clockwise direction along the welding track; The welding parameters are adjusted according to the positions of the welding carriage at the right vertical welding section and the left vertical welding section to gradually reduce the molten pool generation speed in the direction approaching the lowest point. The welding parameters include welding power, welding speed, wire feeding speed and shielding gas flow rate.

2. The method according to claim 1, characterized in that The step of adjusting the welding parameters according to the position of the welding carriage at the right vertical welding section and the left vertical welding section comprises: When the welding carriage moves toward the lower point along the right vertical welding section, the welding power, welding speed and wire feeding speed are gradually reduced, and the flow rate of the shielding gas is gradually increased; When the welding carriage moves toward the high point along the left vertical welding section, the welding power, welding speed and wire feeding speed are gradually increased, and the flow rate of the shielding gas is gradually reduced.

3. The method according to claim 2, characterized in that The reducing / increasing the welding power, welding speed, wire feeding speed and shielding gas flow rate comprises: Obtaining the moving distance of the welding carriage; Whenever the moving distance of the welding carriage reaches a set distance value, the welding power, welding speed, wire feeding speed and shielding gas flow rate are reduced / increased according to the preset parameter changes.

4. The method according to claim 2, characterized in that: The reducing / increasing the welding power, welding speed, wire feeding speed and shielding gas flow rate comprises: Obtaining the moving time of the welding carriage; Whenever the moving time of the welding carriage reaches the time setting value, the welding power, welding speed, wire feeding speed and shielding gas flow rate are reduced / increased according to the preset parameter changes.

5. The method according to claim 1, characterized in that The step of obtaining the welding trajectory of the pipeline includes: Use laser vision sensors to obtain the three-dimensional coordinates of the pipeline; The welding trajectory of the pipeline is obtained according to the three-dimensional coordinates.

6. The method according to claim 1, characterized in that The controlling the welding carriage to move at a constant speed in the clockwise direction along the welding track comprises: The driving parameters of the welding carriage are adjusted according to the positions of the welding carriage at the right vertical welding section and the left vertical welding section so that the actual speed of the welding carriage is consistent with the target speed.

7. The method according to claim 6, characterized in that The step of adjusting the driving parameters of the welding carriage according to the position of the welding carriage at the right vertical welding section and the left vertical welding section includes: When the welding carriage moves toward a lower point along the right vertical welding section, the driving parameters of the welding carriage are gradually reduced; When the welding carriage moves toward a high point along the left vertical welding section, the driving parameters of the welding carriage are gradually increased.

8. The method according to claim 6, characterized in that The reducing / increasing the driving parameters of the welding carriage includes: Obtaining the moving distance of the welding carriage; Whenever the moving distance of the welding carriage reaches a set distance value, a correction amount is calculated according to the actual speed and the target speed of the welding carriage, and the motor driving power of the welding carriage is adjusted according to the correction amount.

9. The method according to claim 1, characterized in that: The method further comprises: The molten pool information is monitored in real time, and the oscillation frequency of the welding gun is controlled according to the molten pool information.

10. The method according to claim 1, characterized in that The method further comprises: After welding is completed, one or more instruments including X-ray flaw detector, ultrasonic detector and magnetic particle detector are used to detect internal defects of the weld.

Images