A method and device for automatic welding of pipes in all positions based on instantaneous heat input control

Abstract

The application discloses a pipeline all-position automatic welding method and device based on instantaneous heat input control, and the method comprises the following steps: S1, receiving basic parameters and welding process specifications of the pipeline to be welded through a welding control system; S2, matching welding process parameters based on the basic parameters and the welding process specifications; S3, controlling a welding torch to perform pipeline all-position welding based on the welding process parameters, and acquiring instantaneous welding current, instantaneous welding voltage, welding speed and sampling frequency collected by a welding power source; and S4, calculating instantaneous heat input according to the instantaneous welding current, the instantaneous welding voltage, the welding speed and the sampling frequency, and adjusting the walking speed and the position of the welding torch in real time based on the instantaneous heat input. The scheme can control the instantaneous heat input of a pipeline welding joint, and further control the grain size, phase transformation and segregation tendency of a weld nugget zone and a heat affected zone of a weld, improve the microstructure performance of the welding joint, and improve the welding quality of a pipeline girth weld.

Description

Technical Field

[0001] This invention relates to the field of pressure pipeline welding technology, specifically to a method and apparatus for automatic all-position pipeline welding based on instantaneous heat input control. Background Technology

[0002] Long-distance pipelines are developing towards higher steel grades, larger diameters, and longer service lives. Welding, as a crucial connection method for long-distance pipelines, significantly impacts pipeline lifespan due to the quality of the weld seams.

[0003] Welding heat input is a crucial indicator of weld microstructure and quality. It influences grain size, phase transformation, and segregation tendency in the weld nugget and heat-affected zone, thus affecting the joint's plasticity and toughness. Furthermore, it impacts alloying elements and precipitated phases, consequently affecting the joint's mechanical properties and corrosion resistance. Welding heat input is determined by welding current, welding voltage, and welding speed. Increased welding current or decreased welding speed leading to increased heat input results in coarser grain size and reduced toughness in the heat-affected zone. Conversely, insufficient welding current or increased cooling rate improves joint strength and hardness but reduces toughness. Excessive heat input leads to unnecessary power consumption and welding defects such as undercut, while insufficient heat input results in incomplete penetration and reduced joint strength.

[0004] Currently, the calculation method for welding heat input uses average current / voltage values ​​and average welding speed. The resulting welding heat input value is an average welding heat input, not the true instantaneous welding heat input, and cannot be used to express the impact of welding heat input at a specific welding position on the joint microstructure and properties. Therefore, the influence of welding heat input on joint microstructure and properties cannot be controlled by average heat input. This paper proposes a pipeline all-position welding method based on instantaneous heat input control to address the impact of welding heat input on joint microstructure and properties, thereby improving the welding quality of pipeline circumferential welds.

[0005] For example, patent document CN 112692406 A discloses a welding line energy acquisition device, which includes a detector for detecting the target instantaneous welding current and target instantaneous welding voltage of the target weld; and a controller for obtaining the welding line energy of the target weld based on the target instantaneous welding current, the target instantaneous welding voltage, and a preset welding speed. This welding line energy acquisition device acquires the target instantaneous welding current and target instantaneous welding voltage of the target weld, but it does not acquire the welding heat input, nor does it mention adjusting the position and speed of the welding torch by calculating the welding heat input.

[0006] Based on this, the inventors of this application recognize that there is still room for improvement in the current technical solutions of welding devices in terms of controlling the instantaneous heat input of the welded joint and automatically matching the welding process parameters according to the heat input control system specified in the welding process specification.

[0007] Therefore, a method and device for automatic all-position welding of pipelines based on instantaneous heat input control is designed. By controlling the instantaneous heat input of the weld joint, the position and speed of the welding torch are coordinated and controlled based on the instantaneous welding heat input. This solves the problem of incomplete fusion defects on the bevel sidewall, reduces the work of repairing and patching pipeline welds, and improves the welding quality and weld qualification rate. According to the heat input specified in the welding process specification, the control system automatically matches the welding process parameters, reduces human intervention during the welding process, and accurately controls the influence of welding heat input at each welding position on the weld joint structure, thereby improving the service life of the pipeline. Summary of the Invention

[0008] To address existing technical problems, this invention proposes an automatic pipeline welding method and apparatus based on instantaneous heat input control. This method achieves coordinated control of the welding torch position and speed based on instantaneous welding heat input by controlling the instantaneous heat input of the weld joint. It can solve the problem of incomplete fusion defects on the bevel sidewall, reduce the work of repairing and patching pipeline welds, improve the quality and qualification rate of pipeline welding, and the automatic matching of welding process parameters by the welding control system also reduces human intervention in the welding process.

[0009] According to one aspect of the present invention, a method for fully automated pipe welding based on instantaneous heat input control is provided, comprising the following steps performed by a welding control system:

[0010] S1. Receive the basic parameters and welding process specifications of the pipe to be welded;

[0011] S2. Match welding process parameters based on the basic parameters and welding process specifications;

[0012] S3. Based on the welding process parameters, control the welding torch to perform all-position welding of the pipeline, and acquire the instantaneous welding current, instantaneous welding voltage, welding speed and sampling frequency of the welding power source.

[0013] S4. Calculate the instantaneous heat input based on the instantaneous welding current, instantaneous welding voltage, welding speed and sampling frequency, and adjust the torch travel speed and position in real time based on the instantaneous heat input.

[0014] According to an embodiment of the present invention, in step S4, the instantaneous heat input is calculated according to the following expression:

[0015]

[0016] Where: λ is the instantaneous welding heat input, in J / mm; P is the instantaneous welding power, in J / s or W; S is the instantaneous welding time, in s; and L is the instantaneous welding length, in mm.

[0017] According to an embodiment of the present invention, step S1, receiving the basic parameters and welding process specifications of the pipe to be welded, includes:

[0018] Receive the pipe diameter, pipe wall thickness, bevel type, and weld thickness.

[0019] According to an embodiment of the present invention, step S1, receiving the basic parameters and welding process specifications of the pipe to be welded, includes:

[0020] The welding heat input specifications, current specifications, voltage specifications, and welding speed specifications specified in the welding process specification shall be received.

[0021] According to an embodiment of the present invention, in step S2, matching welding process parameters based on the basic parameters and welding process specifications includes:

[0022] Based on the aforementioned basic parameters and welding procedure specifications, the welding procedure parameters in the welding expert database are matched and the welding instructions are executed.

[0023] According to one embodiment of the present invention, the sampling frequency is not less than 10 times the waveform frequency.

[0024] According to one embodiment of the present invention, it further includes:

[0025] The pipe to be welded is beveled, and after beveling, rust removal and burr cleaning are performed.

[0026] According to an embodiment of the present invention, the step of acquiring the instantaneous welding current and instantaneous welding voltage collected by the welding power source includes:

[0027] The instantaneous welding current and instantaneous welding voltage are collected by the arc voltage feedback line built into the welding torch, and the data is transmitted to the welding power source.

[0028] According to another aspect of the present invention, an automatic pipe welding device based on instantaneous heat input control is provided, comprising:

[0029] A welding power source, wherein the welding power source has a built-in current and voltage sensor for acquiring instantaneous welding current and instantaneous welding voltage;

[0030] A welding control system, wherein the welding control system is used to receive the current / voltage digital signals transmitted by the welding power source and the angle signals of the welding carriage;

[0031] A welding carriage, the welding carriage including a welding torch and used to execute motion commands of a welding control system;

[0032] The welding control system is configured to: receive the basic parameters and welding process specifications of the pipe to be welded; match welding process parameters based on the basic parameters and welding process specifications; control the welding torch to perform all-position welding of the pipe based on the welding process parameters, and acquire the instantaneous welding current, instantaneous welding voltage, welding speed and sampling frequency collected by the welding power source; calculate the instantaneous heat input based on the instantaneous welding current, instantaneous welding voltage, welding speed and sampling frequency, and adjust the walking speed and position of the welding torch in real time based on the instantaneous heat input.

[0033] According to one embodiment of the present invention, the welding torch includes the ability to collect instantaneous welding current and instantaneous welding voltage, and transmit the data to the welding power source via an arc voltage feedback line.

[0034] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0035] 1. This method achieves coordinated control of the welding torch speed and position based on the instantaneous welding heat input by controlling the instantaneous heat input of the weld joint. It can solve the incomplete fusion defect of the bevel sidewall, reduce the work of repairing and patching pipe welds, and improve the quality and qualification rate of pipe welding.

[0036] 2. Based on the heat input specified in the welding process specification, the welding control system automatically matches the welding process parameters, saving time in exploring welding process parameters, reducing human intervention during the welding process, and lowering the intensity of manual labor during the welding process;

[0037] 3. Controlling the instantaneous heat input of the welded joint can precisely control the impact of the welding heat input at each welding position on the microstructure of the welded joint, which is beneficial to improving the microstructure and properties of the circumferential weld joint of the pipeline, reducing the tendency of crack defects to propagate, and increasing the service life of the pipeline. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some implementation examples of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 A schematic flowchart of an automatic pipe welding method based on instantaneous heat input control according to the present invention is shown.

[0040] Figure 2A schematic diagram of a method for automatic welding of pipes in all positions based on instantaneous heat input control according to the present invention is shown.

[0041] Figure 3 A schematic diagram of an automatic pipe welding device based on instantaneous heat input control according to the present invention is shown;

[0042] Figure 4 A schematic diagram of the bevel configuration is shown for an automatic pipe welding method based on instantaneous heat input control according to the present invention.

[0043] The reference numerals in the figure are explained as follows:

[0044] 1-Welding power source; 2-Welding carriage; 3-Welding track; 4-Welding control system. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0046] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, 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 this invention.

[0047] like Figure 1 As shown, this invention provides an automatic pipe welding method in all positions based on instantaneous heat input control. Figure 1 A schematic flowchart of an exemplary automatic pipe welding method based on instantaneous heat input control according to the present invention is shown, which may specifically include the following steps:

[0048] S1. Receive the basic parameters and welding process specifications of the pipe to be welded;

[0049] S2. Match welding process parameters based on the basic parameters and welding process specifications;

[0050] S3. Based on the welding process parameters, control the welding torch to perform all-position welding of the pipeline, and acquire the instantaneous welding current, instantaneous welding voltage, welding speed and sampling frequency collected by the welding power source 1;

[0051] S4. Calculate the instantaneous heat input based on the instantaneous welding current, instantaneous welding voltage, welding speed and sampling frequency, and adjust the torch travel speed and position in real time based on the instantaneous heat input.

[0052] like Figure 2 As shown, in some embodiments, step S1, receiving the basic parameters and welding process specifications of the pipe to be welded, includes: receiving the pipe diameter, pipe wall thickness, bevel type, and weld thickness. Step S1, receiving the basic parameters and welding process specifications of the pipe to be welded, includes: receiving the welding heat input specifications, current specifications, voltage specifications, and welding speed specifications specified in the welding process procedure. The pipe diameter, pipe wall thickness, bevel type, and weld thickness are input into the welding control system 4. The welding heat input, current specifications, voltage specifications, and welding speed specifications specified in the welding process procedure are also input into the welding control system 4. The welding control system 4 retrieves the welding expert database and automatically matches the welding process parameters.

[0053] In step S4, the instantaneous heat input is calculated according to the following expression:

[0054]

[0055] Where: λ is the instantaneous welding heat input, in J / mm; P is the instantaneous welding power, in J / s or W; S is the instantaneous welding time, in s; and L is the instantaneous welding length, in mm.

[0056] In step S2, matching welding process parameters based on the basic parameters and welding process specifications includes: matching welding process parameters from the welding expert database based on the basic parameters and welding process specifications and executing welding commands. The welding control system 4 retrieves the welding expert database and automatically matches welding process parameters based on the basic parameters and welding process specifications.

[0057] In step S3, the sampling frequency is not less than 10 times the waveform frequency.

[0058] The automatic pipe welding method based on instantaneous heat input control further includes: beveling the pipe to be welded, and then removing rust and cleaning the burrs after beveling.

[0059] In some embodiments, the two pipes to be welded are beveled according to the bevel form specified in the welding process specification; the two pipes after beveling are beveled and derusted and their burrs are cleaned; the two cleaned pipes are then assembled and root-welded using an internal welding machine.

[0060] The steps of acquiring the instantaneous welding current and instantaneous welding voltage collected by the welding power source 1 include: acquiring the instantaneous welding current and instantaneous welding voltage through the arc voltage feedback line built into the welding torch, and transmitting the data to the welding power source 1.

[0061] The welding carriage 2 serves as the actuator of the welding control system 4, executing the motion commands of the welding control system 4. The welding torch of the welding carriage 2 has a built-in arc voltage feedback line, which collects the instantaneous welding current and instantaneous welding voltage and transmits them to the welding power source 1.

[0062] like Figure 3 As shown, this application also provides an automatic pipe welding device based on instantaneous heat input control, which includes:

[0063] Welding power source 1, wherein the welding power source 1 has a built-in current and voltage sensor for acquiring instantaneous welding current and instantaneous welding voltage;

[0064] Welding control system 4, which is used to receive the current / voltage digital signal transmitted by welding power source 1 and the angle signal of welding carriage 2;

[0065] Welding carriage 2, which includes a welding torch and is used to execute motion commands from welding control system 4;

[0066] The welding control system 4 is configured to: receive the basic parameters and welding process specifications of the pipe to be welded; match welding process parameters based on the basic parameters and welding process specifications; control the welding torch to perform all-position welding of the pipe based on the welding process parameters, and acquire the instantaneous welding current, instantaneous welding voltage, welding speed and sampling frequency collected by the welding power source 1; calculate the instantaneous heat input based on the instantaneous welding current, instantaneous welding voltage, welding speed and sampling frequency, and adjust the walking speed and position of the welding torch in real time based on the instantaneous heat input.

[0067] The welding torch includes a sensor for collecting instantaneous welding current and instantaneous welding voltage, and transmits the data to the welding power source 1 via an arc voltage feedback line.

[0068] In some real-time examples, the welding power source 1 has a built-in current and voltage sensor for acquiring instantaneous welding current and instantaneous welding voltage.

[0069] The current sensor is a Hall effect current probe clipped around the cable carrying the total welding current. The voltage sensor is connected to two induction leads spanning the arc gap. These two leads are connected to a 5-pin socket on the back of welding power source 1. One of the two induction leads from the 5-pin socket is fixed to the welding torch, and the other is clamped to the workpiece.

[0070] The analog signals generated by the sensors representing current and voltage are converted into digital signals by the signal processing unit, and a CAN (Controller Area Network) interface is established to collect instantaneous welding current and instantaneous welding voltage. The sampling frequency is not less than 10 times the waveform frequency, and the data is transmitted to the data recording unit of the welding control system 4 through the 26-pin socket on the back of the welding power supply 1.

[0071] The welding carriage 2 serves as the actuator of the welding control system 4, executing the motion commands of the welding control system 4; the welding torch of the welding carriage 2 has a built-in arc voltage feedback line, which collects the instantaneous welding current and instantaneous welding voltage and transmits them to the welding power source 1.

[0072] The welding carriage 2 consists of a horizontal and vertical adjustment mechanism for the welding torch, a traveling and clamping mechanism, and a wire feeding mechanism. The horizontal and vertical adjustment mechanisms for the welding torch execute the motion control commands transmitted by the welding control system 4 during the welding process, and coordinate the up-down and left-right control of the welding torch; the clamping mechanism reliably fixes the welding carriage 2 on the welding track 3, and the traveling mechanism ensures that the welding carriage 2 moves stably along the welding track 3.

[0073] The wire feeding mechanism is installed on the welding carriage 2, and the wire feeding method is a pull-type wire feeding method to ensure the stability of wire feeding during the welding process.

[0074] The welding control system 4 serves as a human-machine interface, executing welding commands by calling welding process parameters from the welding expert database according to a preset program. The data recording unit of the welding control system 4 receives electrical signals transmitted from the welding power source 1, calculates and records the data, and displays the instantaneous welding current, instantaneous welding voltage, and welding heat input on the touchscreen. Based on the heat input specified in the welding process specification and the instantaneous welding current, instantaneous welding voltage, and welding speed transmitted from the welding power source 1, the welding control system 4 executes various parameters from the welding expert database, sending control signals to the welding carriage 2 drive unit and the welding power source 1 control unit to adjust the up / down and left / right movements of the welding torch and the travel speed of the welding carriage 2 in real time, thereby controlling the instantaneous welding heat input during the welding process.

[0075] The following specific embodiments illustrate the automatic welding method for all positions of pipelines based on instantaneous heat input control.

[0076] Example 1

[0077] Taking the all-position welding of an X80 grade, Φ1219mm pipe with a wall thickness of 22mm as an example, the specific implementation steps are as follows:

[0078] Step 1: As Figure 4 As shown, the two pipes to be welded are beveled according to the bevel form specified in the welding process specification.

[0079] Step 2: Remove rust and burrs from the beveling of the two pipes with completed beveling processes, within a 100mm range at the pipe ends;

[0080] Step 3: Assemble the pipe ends according to the requirements specified in the process specification. There should be no gaps in the assembly, and the misalignment should be ≤2mm.

[0081] Step 4: Preheat the pipe opening to 80℃-120℃, and complete the root welding using an internal welding machine;

[0082] Step 5: Install the traveling track of the welding trolley 2 parallel to the position 135mm from the pipe opening to be welded;

[0083] Step 6: Mount the welding carriage 2 onto the welding track 3, and the welding carriage 2 will move along the welding track 3.

[0084] Step 7: Move the welding carriage 2 to the welding arc starting position and adjust the welding torch to the center position of the bevel of the assembled pipe opening;

[0085] Step 8: Input the pipe diameter Φ1219mm, pipe wall thickness 22mm, bevel type (inner bevel height 1.5mm, blunt edge 1mm, inflection point height 5mm, outer bevel angle 5°) and weld thickness 3mm into the welding control system 4;

[0086] Step 9: Input the welding heat input specifications of 520-780J / mm, current specifications of 150-250A, voltage specifications of 19-27V and welding speed specifications of 300-600mm / min as specified in the welding process specification into the welding control system 4;

[0087] Step 10: Based on the input pipe material and bevel parameters, and the process specifications of the welding procedure, the welding control system 4 retrieves the welding expert database and automatically matches the welding process parameters.

[0088] Step 11: Activate the handheld box welding button to begin welding;

[0089] Step 12: During the welding process, the welding control system 4 calculates the instantaneous heat input based on the instantaneous welding current, instantaneous welding voltage, welding speed and sampling frequency collected by the welding power source 1, and adjusts the up-down and left-right movements of the welding torch and the walking speed of the welding carriage 2 in real time, thereby controlling the instantaneous welding heat input during the welding process.

[0090] In an embodiment of the present invention, an automatic pipeline welding method and apparatus based on instantaneous heat input control is provided. Building upon existing technologies, by controlling the instantaneous heat input of the weld joint, coordinated control of the welding torch's up-and-down and left-and-right movements and the welding carriage's travel speed is achieved. This resolves incomplete fusion defects on the bevel sidewalls, reduces pipeline welding repair and patching work, and improves pipeline welding quality and weld qualification rate. According to the heat input specified in the welding procedure, the welding control system automatically matches welding process parameters, saving time spent exploring welding process parameters, reducing human intervention during welding, and lowering the intensity of manual labor during welding. Controlling the instantaneous heat input of the weld joint allows for precise control of the influence of welding heat input at each welding position on the weld joint microstructure, which is beneficial for improving the microstructure of the pipeline circumferential weld joint, reducing the tendency for crack expansion, and extending the pipeline's service life.

[0091] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method for automatic all-position welding of pipelines based on instantaneous heat input control, characterized in that, This includes performing the following steps through the welding control system: S1. Receive the basic parameters and welding process specifications of the pipe to be welded. The basic parameters include pipe diameter, pipe wall thickness, bevel type and weld layer thickness. The welding process specifications include the welding heat input specifications, current specifications, voltage specifications and welding speed specifications specified in the welding process procedure. S2. Match welding process parameters based on the basic parameters and welding process specifications; S3. Based on the welding process parameters, control the welding torch to perform all-position welding of the pipeline, and acquire the instantaneous welding current, instantaneous welding voltage, welding speed and sampling frequency of the welding power source. S4. Calculate the instantaneous heat input based on the instantaneous welding current, instantaneous welding voltage, welding speed and sampling frequency, and adjust the walking speed and position of the welding torch in real time based on the instantaneous heat input; In step S3, the sampling frequency is not less than 10 times the waveform frequency; the welding power supply has a built-in current and voltage sensor to acquire the instantaneous welding current and instantaneous welding voltage.

2. The automatic pipe welding method based on instantaneous heat input control according to claim 1, characterized in that, In step S4, the instantaneous heat input is calculated according to the following expression: in: λ This refers to the instantaneous welding heat input, expressed in J / mm. P Instantaneous welding power, unit: J / s or W; S The instantaneous welding time is expressed in seconds (s). L The instantaneous welding length is expressed in mm.

3. The automatic pipe welding method based on instantaneous heat input control according to claim 1, characterized in that, In step S2, matching welding process parameters based on the basic parameters and welding process specifications includes: Based on the aforementioned basic parameters and welding procedure specifications, the welding procedure parameters in the welding expert database are matched and the welding instructions are executed.

4. The automatic pipe welding method based on instantaneous heat input control according to claim 1, characterized in that, Also includes: The pipe to be welded is beveled, and after beveling, rust removal and burr cleaning are performed.

5. A fully automatic pipe welding device based on instantaneous heat input control, characterized in that, include: A welding power source, wherein the welding power source has a built-in current and voltage sensor for acquiring instantaneous welding current and instantaneous welding voltage; A welding control system, wherein the welding control system is used to receive the current / voltage digital signals transmitted by the welding power source and the angle signals of the welding carriage; A welding carriage, the welding carriage including a welding torch and used to execute motion commands of a welding control system; The welding control system is configured to: receive the basic parameters and welding process specifications of the pipe to be welded; match welding process parameters based on the basic parameters and welding process specifications; control the welding torch to perform all-position welding of the pipe based on the welding process parameters, and acquire the instantaneous welding current, instantaneous welding voltage, welding speed, and sampling frequency collected by the welding power source; calculate the instantaneous heat input based on the instantaneous welding current, instantaneous welding voltage, welding speed, and sampling frequency, and adjust the traveling speed and position of the welding torch in real time based on the instantaneous heat input. The basic parameters include pipe diameter, pipe wall thickness, bevel type, and weld layer thickness. The welding process specifications include the welding heat input specifications, current specifications, voltage specifications, and welding speed specifications specified in the welding process procedure. The sampling frequency is not less than 10 times the waveform frequency.

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