Loading method and system for simulating heat source of straight seam submerged arc welding of pipeline steel

Abstract

This invention provides a method for loading a simulated heat source for submerged arc welding of straight seams in pipeline steel. The method includes: obtaining a generalized double ellipsoidal heat source model by processing internal and external welding parameters using pre-set logic; obtaining a new double ellipsoidal heat source model based on a three-dimensional element network through pre-set logic processing; determining the internal welding process parameters for the first to nth welding wires; determining the external welding process parameters for the first to nth welding wires; establishing the energy distribution parameters and shape distribution function of each welding wire in the new double ellipsoidal heat source model based on the instantaneous coordinate position and welding time of the moving heat source formed by each welding wire, thereby completing the internal welding loading; and loading an independent heat source for each welding wire in the external welding according to the aforementioned steps and the energy distribution parameters and shape distribution function. This invention solves the technical problems of low efficiency, high cost, and low effectiveness and correctness of subroutine loading.

Description

Technical Field

[0001] This invention relates to the simulation of double-sided straight seam submerged arc welding of pipeline steel pipes, specifically to a method and system for loading a heat source for simulating straight seam submerged arc welding of pipeline steel pipes. Background Technology

[0002] Long-distance steel pipelines, which carry oil and gas resources, are mainly composed of pipeline steel pipes. These pipeline steel pipes primarily include double-sided straight-seam submerged arc welded steel pipes and double-sided spiral-seam submerged arc welded steel pipes. Compared to double-sided spiral-seam submerged arc welded steel pipes, double-sided straight-seam submerged arc welded steel pipes have advantages such as shorter weld seams and higher safety performance. Double-sided straight-seam submerged arc welded steel pipes are almost universally used, especially in sections crossing geologically challenging terrain, high-risk areas, and densely populated regions.

[0003] Double-sided straight seam submerged arc welded steel pipes require welding to form, and the main welding processes include internal welding and external welding. Internal welding can be formed by single-wire multi-pass forming or by multiple wires forming at certain intervals in one pass, and the same applies to external welding. Currently, to balance production quality and efficiency requirements, manufacturers of double-sided straight seam submerged arc welded steel pipes generally adopt a single-pass forming process with multiple wires arranged in a straight line for both internal and external welding, with the forming sequence being internal welding first, followed by external welding.

[0004] In multi-wire welding processes involving internal and external welding, each wire has an independent welding power source, resulting in an independent molten pool for each wire. Whether this independent molten pool can form a boundless eutectic pool significantly impacts the weld quality of submerged arc welding. Multi-wire eutectic pool welding produces a higher molten pool temperature, and the protective effect of the flux in submerged arc welding results in a smaller cooling gradient during the cooling process. Consequently, the stress and deformation in the weld state are lower, reducing the probability of weld cracks and other defects. Furthermore, multi-wire welding significantly increases production efficiency compared to single-wire welding. Therefore, multi-wire eutectic pool welding is recommended in actual production to improve weld quality while maintaining production efficiency. However, achieving a multi-wire eutectic pool is challenging because the flux constantly covers the molten pool in submerged arc welding, preventing open-arc welding. Consequently, the molten pool cannot be directly observed with the naked eye during welding. Current limited methods involve repeatedly modifying the welding process parameters for each wire, conducting repeated experiments, and using methods such as cross-sectioning and etching with nitric acid and alcohol to observe the formation of the eutectic pool. This approach suffers from low efficiency and high experimental costs.

[0005] The existing patent document with publication number CN106529047A, entitled "A Modeling Method for a Numerical Simulation Heat Source Model of Tandem Twin-Wire Submerged Arc Welding," includes the following steps: Step 1, adding an attenuation function along the depth direction to the double ellipsoidal heat source model, and establishing a twin-wire model using two such double ellipsoidal heat source models; the attenuation function includes linear, exponential, and quadratic functions; Step 2, performing finite element inversion on the parameters of the double ellipsoidal heat source model using different attenuation functions to obtain the corresponding simulated molten pool shape; Step 3, using the degree of agreement between the simulated molten pool shape and the actual molten pool shape as the criterion for selecting the attenuation function, to obtain the optimal numerical simulation heat source model for tandem twin-wire submerged arc welding. The technical solution disclosed in the existing literature obtains the optimal heat source model through inversion and establishes a three-dimensional welding finite element model in the ABAQUS platform to simulate the temperature field; it defines the material property parameters of the weldment involved in the temperature field control equation and boundary condition equation, but does not disclose the processing logic for the shape distribution parameters of each wire in the submerged arc welding process. The existing solution focuses on obtaining the optimal simulated heat source model, while its specific loading method still needs to be repeatedly tested, so the actual application cost is high.

[0006] The existing patent application document CN110866359A, entitled "A Welding Simulation Method Based on a Modified Double Ellipsoid Heat Source Model," describes the following steps: obtaining a target workpiece model; obtaining parameters of the double ellipsoid heat source model; loading the weldment model with the modified double ellipsoid heat source model parameters; and performing welding simulation on the target workpiece model after loading the double ellipsoid heat source model to obtain simulation data. The prior art disclosed in this application document modifies the existing double ellipsoid model by changing the three constants before the coordinate parameters into variables. α, β, χ This technology aims to improve the simulation accuracy of controlling the gradient of heat flux along different directions, as well as the size of the molten pool and its energy distribution. However, this existing technology only modifies the coordinate parameters and does not disclose the specific logic of loading the shape distribution parameters during the actual control data loading process, which limits the loading accuracy of this technology.

[0007] In summary, existing technologies suffer from low efficiency, high usage costs, and low effectiveness and correctness of subroutine loading. Summary of the Invention

[0008] The technical problem to be solved by this invention is how to solve the technical problems of low efficiency, high cost of use and low effectiveness and correctness of subroutine loading in the prior art.

[0009] This invention solves the above-mentioned technical problems by employing the following technical solution: A method for loading a simulated heat source for submerged arc welding of straight seams in pipeline steel, comprising:

[0010] S1. Establish a three-dimensional steel pipe model, divide the corresponding weld seam part and base material part, and assign material physical properties to the base material and weld seam part as they change with temperature.

[0011] S2. Set the time step and increment step corresponding to the base material and weld portion, set the initial temperature, ambient temperature, convection and radiation coefficients of the weldment, and input the Boltzmann constant.

[0012] S3. Load the subroutine and load the heat source for the weld section, wherein step S3 includes:

[0013] S31 uses pre-set logic to process the submerged arc welding heat process, simulate the large wall thickness of pipeline steel, and the number of independent welding wires used for internal and external welding, in order to determine the heat source model for each wire in internal and external welding.

[0014] S32. Obtain the origin of the welding wire coordinates based on the three-dimensional element network, and define... XOZ The plane is the longitudinal section at the center of the longitudinal seam. The number of inner and outer welding wires is [number missing]. Each welding wire forms an independent welding heat source, ensuring that each welding wire in the inner and outer welds [is [missing information]. XOZ The model is moved within the plane, and the generalized double ellipsoid model is rewritten based on the welding wire angle data to obtain a new double ellipsoid heat source model.

[0015] S33, Determine the first step of the inner weld n The welding process parameters for the inner welding of the root welding wire;

[0016] S34, Determine the external weld number n External welding process parameters for the root welding wire;

[0017] S35. Based on the instantaneous coordinate position and welding time of the moving heat source formed by each welding wire in the inner welding process, establish the energy distribution parameters and shape distribution parameters applied to each welding wire in the new double ellipsoidal heat source model. Use the time array TIME(2) of the DFLUX subroutine to judge the loading of the welding heat source of each wire in the inner welding process. Based on the energy distribution parameters and shape distribution parameters, complete the inner welding loading with the preset inner welding loading logic.

[0018] S36. Use the loading logic in step S35 to process the energy parameters and shape distribution parameters of the external weld, and use the time array TIME(2) of the DFLUX subroutine to judge the loading of the welding heat source of each wire of the external weld, so as to complete the external weld loading by setting the external weld loading logic.

[0019] This invention uses a simulation method to load the submerged arc welding heat source for each wire of the inner and outer welding process. For both inner and outer welding wires, this invention performs loading judgment based on the time array of the DFLUX subroutine. The judgment result is used to process the distributed parameters with specific logic to perform the loading operation of the welding heat source and the double ellipsoid model for each wire. This avoids the problems of low efficiency and high experimental costs caused by repeated experiments due to the inability to observe the molten pool in the prior art. It enables real-time observation of whether a eutectic pool state is formed on a computer, reducing experimental costs and improving experimental efficiency.

[0020] In this specific technical solution, the parameters assigned in step S2 include: density, thermal conductivity and specific heat capacity; dividing the three-dimensional unit mesh corresponding to the base material and weld portion; setting the time step and increment step corresponding to the base material and weld portion; and setting the corresponding time step and increment step according to the weld length, welding speed, time interval between inner and outer welds, and number of welding wires for inner and outer welds.

[0021] In this specific technical solution, in step S31, the heat source model is a generalized double ellipsoid model.

[0022] In this specific technical solution, in step S32, based on the generalized double ellipsoid model:

[0023]

[0024] Using the following logic, the generalized double ellipsoid model is rewritten based on the welding wire angle data to obtain a new double ellipsoid heat source model:

[0025]

[0026] In the formula, the arc axis is parallel to... x The included angle of the axis is β ,and y The included angle of the axis is γ ,and z The included angle of the axis is φ , Q For heat source power, For heat source efficiency, U For welding voltage, I For welding current, a 1. a 2. b , c For shape parameters, f 1. f 2 represents the heat distribution function. f 1 +f 2 = 2 .

[0027] This invention processes the heat source coordinate position data during the welding process, the positional relationship data between welding wires in three-dimensional coordinates, and the number of welding wires used in the inner and outer welding. It treats each welding wire as an independent welding heat source and rewrites the double ellipsoidal heat source model based on the geometric relationship data such as the angle between each welding wire and the XOZ plane in the inner and outer welding. This makes the heat source model suitable for separately loading the heat sources of the inner and outer welding wires, further improving the experimental efficiency.

[0028] In this specific technical solution, step S33 includes:

[0029] S331. Determine the welding process parameters for the inner weld, including: welding voltage. Current welding speed (The welding wires in the internal welding process operate at a consistent speed), and the welding efficiency is set to... The heat source power of each welding wire during internal welding is: = ; Assume internal welding n root welding wire and x The included angle of the axis is ,and z The included angle of the axis is (n=1,2,...);

[0030] S332, Determine the inner weld number n Coordinates of the heat source starting point of the root welding wire （ ） ;

[0031] S333; Determine the inner weld number n Heat source shape parameters of the root welding wire ;

[0032] S334. Determine the distance between each pair of adjacent front and rear wires for the inner weld;

[0033] S335, Let the welding distance for internal welding be... Therefore, the total welding time for the inner weld is: ( n=2, 3... ), and determine the time interval t between the inner and outer welds. 12 .

[0034] In this specific technical solution, step S34 includes:

[0035] S341. Determine the welding process parameters for external welding, including: welding voltage. Current welding speed The welding efficiency is set to The heat source power of each welding wire during external welding is... = ; Assume external welding n root welding wire and x The included angle of the axis is ,and z The included angle of the axis is , （n=1,2,...） ;

[0036] S342, Determine the external weld number n Coordinates of the heat source starting point of the welding wire ( );

[0037] S343, Determine the external weld number n Heat source shape parameters of the root welding wire ;

[0038] S344. Determine the distance between each pair of adjacent front and rear wires in the external weld. Based on the distance between each pair of adjacent front and rear wires in the external weld, determine the total welding time for the external weld, and determine the time from the start of the internal weld to the completion of the external weld. and the total time of thermal process simulation .

[0039] In this specific technical solution, step S344 includes:

[0040] S3441. Multiply the welding speed by the time to determine the distance between each pair of adjacent wires in the welding process.

[0041] S3442, Based on the total welding time t1 of the inner welding and the time interval t between the inner and outer welding... 12 The following logic is used to determine the start time of welding the first welding wire in the external welding process. :

[0042] +

[0043] The welding distance is calculated by dividing the welding speed by the welding speed of the first weld and the welding distance of the second weld. n The distance between the welding wires, excluding the welding speed of the outer welding wire. Based on this, the total welding time for the external weld was obtained, where the welding distance for the external weld was... The total external welding time is obtained by the following logical processing. :

[0044] ( n=2,3... );

[0045] S3443. Determine the total welding time for both internal and external welds: Summate the total welding time for the internal weld. Time interval between inner and outer welding The total welding time t2 for the outer weld is used to obtain the time from the start of the inner weld to the completion of the outer weld using the following logic processing. :

[0046] = + + ,

[0047] And take into account the cooling time of the weld base material. Based on this, the total simulation time of the thermal process can be obtained. :

[0048] + .

[0049] In this specific technical solution, step S35 includes:

[0050] S351. Obtain the energy distribution parameters of the new double ellipsoidal heat source model for each welding wire in the inner weld during its movement using the following logic:

[0051]

[0052]

[0053] S352. Obtain the shape distribution parameters of the new double ellipsoidal heat source model for each welding wire in the inner weld during its movement using the following logic:

[0054] ;

[0055] S353, when TIME(2) is less than or equal to the inner welding time At that time, the heat source of each welding wire in the inner welding process is determined. The inner welding loading logic is as follows:

[0056]

[0057] S354, Instantaneous x-axis during the movement of the heat source of each wire in the inner weld. x Greater than or equal to (x) 内n +(v1 (TIME(2)+t 内n When )), the first half of the heat source model is loaded. ,implement = ;

[0058] S355, Instantaneous horizontal axis during the movement of the heat source of each wire in the inner weld. x Less than (x) 内n +(v1 (TIME(2)+t 内n When loading the heat source model in the second half, determine the heat source model in the second half. ,implement = ;

[0059] S356, at t1 <TIME(2)<t1+t 12 At that time, the heat source is set to an unloaded state.

[0060] In this specific technical solution, step S36 includes:

[0061] S361. Obtain the energy distribution parameters of the new double ellipsoidal heat source model for each welding wire during its movement in the external welding process using the following logic:

[0062]

[0063]

[0064] S362. Obtain the shape distribution parameters of the new double ellipsoidal heat source model for each welding wire during its movement using the following logic:

[0065] S363. Use the time array TIME(2) in the DFLUX subroutine to determine the loading of the welding heat source for each wire of the outer weld. If TIME(2) is greater than or equal to the welding time of the inner weld... Interval time between internal and external welding The sum of these is then applied to the heat source of each welding wire in the external welding process according to the following logic:

[0066]

[0067] S364, Instantaneous x-axis during the movement of the heat source of each wire in the external welding process. x Greater than or equal to (x) 外n +(v2 (TIME(2)+t 外n When loading the first half of the heat source model, ,implement = ;

[0068] S365, Instantaneous x-axis during the movement of the heat source for each wire in the external welding process. x Less than (x) 外n +(v2 (TIME(2)+t 外n When )), the second half of the heat source model is loaded. ,implement = .

[0069] This invention processes the energy distribution parameters and shape distribution parameters of internal and external welding with specific logic, and compares and judges the welding time with the welding start time of the welding wire to perform the loading operation of the welding heat source and double ellipsoid model for each wire. This replaces the previous technology, which required repeated actual experiments and dissection operations by repeatedly modifying the welding process parameters of each wire because the molten pool could not be observed, and further reduces the experimental cost.

[0070] In this specific technical solution, a loading system for simulating a heat source for straight seam submerged arc welding of pipeline steel includes:

[0071] The 3D model building module is used to build a 3D steel pipe model, divide the corresponding weld part and base material part, and assign material physical properties to the base material and weld part as they change with temperature.

[0072] The base metal weld parameter setting module is used to set the time step and increment step corresponding to the base metal and weld, set the initial temperature, ambient temperature, convection and radiation coefficients of the weldment, and input the Boltzmann constant. The base metal weld parameter setting module is connected to the three-dimensional model creation module.

[0073] The loading module is used to load subroutines and the heat source for the weld section. The loading module is connected to the base metal weld parameter setting module. The loading module includes:

[0074] The module for determining the heat source model of internal and external welding is used to process the submerged arc welding heat process with preset logic, simulate the large wall thickness of pipeline steel, and the number of independent welding wires used for internal and external welding, so as to determine the heat source model of each wire in internal and external welding.

[0075] The model optimization module is used to obtain the origin of the welding wire coordinates based on the three-dimensional element network, define the XOZ plane as the longitudinal section where the center of the longitudinal seam is located, determine the number of inner and outer welding wires, and ensure that each welding wire forms an independent welding heat source so that each welding wire of the inner and outer welding moves in the XOZ plane. The generalized double ellipsoid model is rewritten based on the welding wire angle data to obtain a new double ellipsoid heat source model. The model optimization module is connected to the inner and outer welding heat source model determination module.

[0076] The internal welding process parameter module is used to determine the internal welding process parameters. n The welding process parameters for the inner welding of the root welding wire;

[0077] The external welding process parameter module is used to determine the external welding process parameters. n External welding process parameters for the root welding wire;

[0078] The inner welding loading module is used to determine the energy distribution parameters and shape distribution parameters applied to each welding wire in the new double ellipsoidal heat source model based on the instantaneous coordinate position of the moving heat source formed by each welding wire in the inner welding and the welding time. The loading judgment of the welding heat source of each wire in the inner welding is made by using the time array TIME(2) of the DFLUX subroutine. The inner welding loading is completed by the preset inner welding loading logic based on the energy distribution parameters and shape distribution parameters. The inner welding loading module is connected to the model optimization module and the inner welding process parameter module.

[0079] The external welding loading module is used to process the energy parameters and shape distribution parameters of the external welding using the loading logic in step S35, and to use the time array TIME(2) of the DFLUX subroutine to judge the loading of the welding heat source of each wire of the external welding, and to complete the external welding loading by setting the external welding loading logic. The external welding loading module is connected to the external welding process parameter module and the model optimization module.

[0080] Compared with the prior art, the present invention has the following advantages: The present invention loads the submerged arc welding heat source of each wire of the inner and outer welding through simulation. The present invention judges the loading based on the time array of the DFLUX subroutine for both inner and outer welding wires. The judgment result is used to process the distributed parameters with specific logic to perform the loading operation of the welding heat source and the double ellipsoid model for each wire. This avoids the problems of low efficiency and high experimental cost caused by repeated experiments due to the inability to observe the molten pool in the prior art. It realizes the real-time observation of whether a eutectic pool state is formed on the computer, which reduces the experimental cost and improves the experimental efficiency.

[0081] This invention processes the heat source coordinate position data during the welding process, the positional relationship data between welding wires in three-dimensional coordinates, and the number of welding wires used in the inner and outer welding. It treats each welding wire as an independent welding heat source and rewrites the double ellipsoidal heat source model based on the geometric relationship data such as the angle between each welding wire and the XOZ plane in the inner and outer welding. This makes the heat source model suitable for separately loading the heat sources of the inner and outer welding wires, further improving the experimental efficiency.

[0082] This invention processes the energy distribution and shape distribution parameters of internal and external welding using specific logic, and compares and judges the welding time with the welding wire start time to perform the loading operation of the welding heat source and double ellipsoid model for each wire. This replaces the existing technology that requires repeated actual experiments and dissection operations by repeatedly modifying the welding process parameters of each wire because the molten pool cannot be observed, further reducing experimental costs. This invention solves the technical problems of low efficiency, high cost, and low effectiveness and correctness of subroutine loading in the existing technology. Attached Figure Description

[0083] Figure 1This is a schematic diagram of the basic process of simulating the thermal process using ABAQUS software in Embodiment 1 of the present invention;

[0084] Figure 2 This is a schematic diagram illustrating the specific steps of subroutine loading in Embodiment 1 of the present invention;

[0085] Figure 3 This is a first schematic diagram of the simulated heat source for double-sided straight seam submerged arc welding of pipeline steel pipe in Embodiment 1 of the present invention;

[0086] Figure 4 This is a second schematic diagram of the simulated heat source for double-sided straight seam submerged arc welding of pipeline steel pipe in Embodiment 1 of the present invention;

[0087] Figure 5 This is a third schematic diagram of the simulated heat source for double-sided straight seam submerged arc welding of pipeline steel pipe in Embodiment 1 of the present invention;

[0088] Figure 6 This is a schematic diagram of the critical eutectic pool state of the internal welding twin wires in Embodiment 2 of the present invention;

[0089] Figure 7 This is a schematic diagram of the internal welding double-wire eutectic pool state with life and death units in Embodiment 2 of the present invention;

[0090] Figure 8 This is a schematic diagram of the external welding double-wire eutectic pool state with life and death units in Embodiment 2 of the present invention;

[0091] Figure 9 This is a schematic diagram of the external welding double wire single molten pool state in Embodiment 2 of the present invention. Detailed Implementation

[0092] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0093] Example 1

[0094] For example Figure 1As shown, this invention mainly utilizes the finite element software ABAQUS, employing DFLUX subroutines edited with FORTRAN language to apply the submerged arc welding heat source to each wire of the inner and outer welds. ABAQUS is a large-scale general-purpose finite element software capable of simulating mechanics, electricity, magnetism, heat, and thermodynamics, particularly excelling in nonlinear simulations. Since the welding thermal process exhibits strong transient nonlinear characteristics, ABAQUS simulations yield relatively accurate and reliable results. ABAQUS simulates both the welding thermal and stress processes, employing two methods: fully thermo-mechanically coupled simulation and sequential coupling simulation. Fully thermo-mechanically coupled simulation considers both the influence of the thermal process on the stress process and vice versa. Sequential coupling means simulating the thermal process first, followed by the stress-strain process. Regardless of the method, the application of the submerged arc welding heat source is indispensable. Taking the thermal process simulation as an example, the main sequence of the thermal process is simulated using ABAQUS software; in this embodiment, some parts of the sequence are adjustable.

[0095] like Figure 1 As shown, the simulation of the thermal process of submerged arc welding of double-sided straight seam steel pipes includes the following basic steps:

[0096] S1. Model building; In this embodiment, a three-dimensional steel pipe model is built, and the corresponding weld seam part and base material part are divided according to actual experience;

[0097] S2. Assigning properties to steel and weld materials. In this embodiment, the base material and weld portion are respectively assigned material physical properties that change with temperature. The assigned thermal parameters mainly include: density, thermal conductivity, specific heat capacity, latent heat, and solid-liquid phase temperature.

[0098] S3. Mesh generation; In this embodiment, a corresponding three-dimensional element mesh is generated, and a fine mesh is used for the weld area that needs to be studied in detail to improve the solution accuracy.

[0099] S4. Establish analysis steps; In this embodiment, corresponding time steps and increment steps are set according to the length of the weld bead, welding speed, time interval between inner and outer welds, and number of welding wires for inner and outer welds;

[0100] S5. Constructing interactions; In this embodiment, the initial temperature of the weldment, ambient temperature, convection and radiation coefficients are set, and Boltzmann constants are input;

[0101] S6. Loading subroutine; In this embodiment, the focus of the loading subroutine is the effective and correct loading process of the heat source;

[0102] S7. Submit the job; In this embodiment, submit the analysis job to obtain the simulation results. The static and dynamic display of the molten pool movement state and temperature field distribution can be displayed.

[0103] The step S6 of applying the welding heat source mentioned above also includes the following steps:

[0104] like Figure 2 and Figure 3 As shown, S61 uses pre-set logic to process the submerged arc welding heat process, simulates the large wall thickness of pipeline steel, and the number of independent welding wires used for internal and external welding, in order to determine the generalized double ellipsoidal heat source model for each wire heat source.

[0105] In this embodiment, based on the submerged arc welding thermal process, the simulation object being a pipeline steel with a large wall thickness, and the number of independent welding wires used for internal and external welding, the heat source model for each wire in the internal and external welding is determined. Generally, a generalized double ellipsoidal heat source model is adopted. The mathematical expressions for the heat source models of the first and second halves of the generalized double ellipsoidal heat source model are respectively (arc axis and...). x The included angle of the axis is β ,and y The included angle of the axis is γ ,and z The included angle of the axis is φ ):

[0106]

[0107] In the formula: Q For heat source power, For heat source efficiency, U I is the welding voltage (V) and I is the welding current (A). a 1 、a 2 b, c For shape parameters, f 1 、f 2 represents the heat distribution function of the front and rear ellipsoids. f 1 +f 2 =2 .

[0108] Each filament is an independent generalized double ellipsoidal heat source model as described above.

[0109] like Figure 4 As shown in S62, the origin of the welding wire coordinates, the longitudinal section of the longitudinal seam center, the number of inner and outer welding wires, and the independent welding heat source formed by each welding wire are obtained based on the three-dimensional element network. y The included angle of the axis is used to obtain a new double ellipsoidal heat source model through pre-set logic processing;

[0110] In this embodiment, the coordinate origin is located on the longitudinal axis of the weld center, and the XOZ plane is the cross-section where the longitudinal center of the weld is located. The inner and outer welds can be composed of the same or different numbers of welding wires, each of which forms an independent welding heat source. Each welding wire in the inner and outer welds moves within the XOZ plane, therefore... γ With an angle of 90°, the above double ellipsoidal heat source model can be rewritten as:

[0111]

[0112] S63, Determine the first to the second inner weld. n The welding process parameters for the inner welding of the root welding wire;

[0113] In this embodiment, the inner weld number is determined. n Welding process parameters for root welding wire: Welding voltage U 内n Current I 内n welding speed (The welding wires in the internal welding process operate at a consistent speed), and the welding efficiency is set to... (The welding efficiency is the same for both internal and external welding, depending only on the welding method), so the heat source power of each welding wire during internal welding is... = ; Assume internal welding n root welding wire and x The included angle of the axis is β 内n ,and z The included angle of the axis is ，（n=1,2,...）

[0114] Determine the inner weld number n Coordinates of the heat source starting point of the welding wire ( This step obtains the corresponding starting coordinates by setting the starting welding node position of each welding wire in the inner welding process. （n=1,2,...）

[0115] Determine the inner weld number n Heat source shape parameters of the root welding wire: Based on the shape of the double ellipsoidal heat source, the front half of the molten pool is typically used in submerged arc welding. f 1 is the second half of the zone f 1 / 3 of 2; （n=1,2,...）

[0116] The distance between each adjacent pair of wires in the inner weld is determined, and this distance is equal to the inner weld speed. Multiply by the welding time interval between the two, input the corresponding time in the DFLUX subroutine and then multiply by the welding time interval between the two to represent the input distance between each adjacent front and rear wires of the inner weld;

[0117] like Figure 5 As shown, the total welding time for the inner weld is determined by dividing the welding distance (the length of the straight weld seam in the simulated welded pipe model) by the welding speed, since the first welding wire should be located at the welding start point. Therefore, the total welding time for the inner weld is equal to the welding distance (the length of the straight weld seam in the simulated welded pipe model) divided by the welding speed, plus the time for the first and second welding wires. n The distance between the first and second welding wires is determined by dividing the welding speed. Let the welding distance be S0. nThe spacing between the root welding wires is The total time for internal welding is ( n=2,3... ).

[0118] The time interval between internal and external welding should be determined based on the actual situation. ;

[0119] S64. Determine the first to the second external weld. n External welding process parameters for the root welding wire;

[0120] In this embodiment, the outer weld number is determined. n Welding process parameters for root welding wire: Welding voltage Current welding speed (The welding wires are welded at the same speed for each weld), and the welding efficiency is also [missing information]. The heat source power of each welding wire during external welding is... = Determine the external welding number n root welding wire and x The included angle of the axis is β 外n ,and z The included angle of the axis is , （n=1,2,...）

[0121] Determine the external welding number n Coordinates of the heat source starting point of the welding wire ( This step obtains the corresponding starting coordinates by setting the starting welding node position of each welding wire in the external welding process. （n=1,2,...）

[0122] Determine the external welding number n Heat source shape parameters of the root welding wire: Based on the shape of the double ellipsoidal heat source, the front half of the molten pool is typically used in submerged arc welding. f 1 is the second half of the zone f 1 / 3 of 2; （n=1,2,...）

[0123] The distance between each pair of adjacent wires in the external welding process is determined, and this distance is equal to the external welding speed. Multiply by the welding time interval between the two, input the corresponding time in the DFLUX subroutine and then multiply by the welding time interval between the two to represent the input distance between each adjacent front and rear wires of the outer weld;

[0124] Determine the time when the first welding wire of the external welding begins to weld, i.e., the start time of external welding. t 外1 ,but

[0125] + The total welding time for external welding is calculated by dividing the welding distance by the external welding speed and adding the time required for the first welding wire to be at the starting point of the weld. n Root wire distance excluding external welding speed Confirmed, the welding distance is also... The first root and the second root n The spacing between the root welding wires is The total time for external welding ( n=2,3... )

[0126] Determine the time t from the start of internal welding to the completion of external welding. 内外 : equals the inner welding time + the time interval between inner and outer welding + the outer welding time, i.e. = + + Determine the cooling time of the weld and base material after all external welding is completed. Therefore, the total simulation time for the thermal process is... + ;

[0127] Based on the instantaneous position of the moving heat source formed by each welding wire in the inner and outer welding processes and the welding time, the energy distribution and shape distribution functions in the specific double ellipsoidal heat source model applied to each welding wire in the inner and outer welding processes are established. Let the instantaneous coordinates of each welding wire during its heat source movement be... (x,y,z) ;

[0128] Different heat sources are applied based on time constraints, etc. The specific process is as follows:

[0129] S65. Based on the instantaneous coordinate position and welding time of the moving heat source formed by each welding wire in the inner welding, establish the energy distribution parameters and shape distribution parameters applied to each welding wire in the new double ellipsoidal heat source model. Use the time array TIME(2) of the DFLUX subroutine to judge the loading of the welding heat source of each wire in the inner welding. Based on the energy distribution parameters and the shape distribution parameters, complete the inner welding loading with the preset inner welding loading logic.

[0130] In this embodiment, for internal welding: the energy distribution parameters of the double ellipsoid (front and rear ellipsoids) model of each welding wire during its movement are as follows:

[0131]

[0132]

[0133] The shape distribution parameters of the double ellipsoid (front and rear ellipsoids) model of each welding wire during the inner welding process are as follows:

[0134] The loading of the welding heat source for each wire in the inner welding is judged using the time array TIME(2) in the DFLUX subroutine. If TIME(2) is less than or equal to the inner welding time... Then the heat source for each welding wire in the inner welding process is applied, that is:

[0135]

[0136] If the instantaneous x-axis of each wire in the internal welding process moves as the heat source moves... x Greater than or equal to (x 内n +(v1 (TIME(2)+t 内n Then load the first half of the heat source model. ;

[0137] If the instantaneous x-axis of each wire in the internal welding process moves as the heat source moves... x Less than (x) 内n +(v1 (TIME(2)+t 内n Then load the second half of the heat source model. ;

[0138] During the interval between inner and outer welding: After completing the inner welding according to the above operations, when t1 <TIME(2)<t1+t 12 The heat source should be set to an unloaded state, i.e., the heat source model. q=0 ;

[0139] S66. The energy parameters and shape distribution parameters of the outer weld are processed using the loading logic in step S65 above, and the loading judgment of the welding heat source of each wire of the inner weld is made using the time array TIME(2) of the DFLUX subroutine to complete the loading of the outer weld.

[0140] In this embodiment, for external welding: the energy distribution parameters of the double ellipsoid (front and rear ellipsoids) model of each welding wire during its movement are as follows:

[0141]

[0142]

[0143] The shape distribution parameters of the double ellipsoid (front and rear ellipsoids) model of each welding wire during the external welding process are as follows:

[0144]

[0145] The judgment of the heat source loading for each wire of the internal welding is carried out by using the time array TIME(2) in the DFLUX subroutine. If TIME(2) is greater than or equal to the internal welding time and the interval time between the internal and external weldings sum, then the heat source of each wire of the external welding is loaded, that is:

[0146]

[0147] i) If the instantaneous abscissa during the movement of the heat source of each wire of the external welding x is greater than or equal to (x 外n +(v2 (TIME(2)+t_external_n)), then the first half of the heat source model is loaded ;

[0148] ii) If the instantaneous abscissa during the movement of the heat source of each wire of the external welding x is less than (x 外n +(v2 (TIME(2)+t_external_n)), then the second half of the heat source model is loaded ;

[0149] Further explanation: As shown in the above figure, assume that the total length of the weld is , then the length of the heat source loading path of the first wire , the length of the heat source loading path of the second wire is ,..., the length of the heat source loading path of the n th wire is . Since there is no material on the right side of the model, the 1~（n-1） th wire is equivalent to being unloaded for a period of time along the positive direction of the x axis, which has no impact on the simulation results.

[0150] Example 2

[0151] As Figures 6 to 9 shown, the above information is used to write the heat source related parameters of each wire in the DFLUX subroutine with FORTRAN language, and the simulation operation is carried out with the help of ABAQUS software. Taking two wires and three wires as examples, the heat source loading effect of the internal and external straight seam submerged arc welding of the pipe is simulated. The birth and death elements are used during the simulation, and the lower limit of the molten pool temperature is set to 1500 °C. The simulation results are shown in Appendices Figure 6 、 Figure 7 、 Figure 8 and Figure 9 .

[0152] In summary, this invention uses a simulation method to load the submerged arc welding heat source for each wire of the inner and outer welding process. For both the inner and outer welding wires, the invention performs loading judgment based on the time array of the DFLUX subroutine. The judgment result is then used to process the distributed parameters using specific logic to load the welding heat source and the double ellipsoid model for each wire. This avoids the inefficiency and high cost of repeated experiments due to the inability to observe the molten pool in existing technologies. It enables real-time observation of whether a eutectic pool state is formed on a computer, reducing experimental costs and improving experimental efficiency.

[0153] This invention processes the heat source coordinate position data during the welding process, the positional relationship data between welding wires in three-dimensional coordinates, and the number of welding wires used in the inner and outer welding. It treats each welding wire as an independent welding heat source and rewrites the double ellipsoidal heat source model based on the geometric relationship data such as the angle between each welding wire and the XOZ plane in the inner and outer welding. This makes the heat source model suitable for separately loading the heat sources of the inner and outer welding wires, further improving the experimental efficiency.

[0154] This invention processes the energy distribution and shape distribution parameters of internal and external welding using specific logic, and compares and judges the welding time with the welding wire start time to perform the loading operation of the welding heat source and double ellipsoid model for each wire. This replaces the existing technology that requires repeated actual experiments and dissection operations by repeatedly modifying the welding process parameters of each wire because the molten pool cannot be observed, further reducing experimental costs. This invention solves the technical problems of low efficiency, high cost, and low effectiveness and correctness of subroutine loading in the existing technology.

[0155] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for simulating a heat source of a straight seam submerged arc welding of a pipeline steel, characterized in that, The method includes: S1. Establish a three-dimensional steel pipe model, divide the corresponding weld seam part and base material part, and assign material physical properties to the base material and the weld seam part as they change with temperature. S2. Set the time step and increment step corresponding to the base material and the weld portion, set the initial temperature, ambient temperature, convection and radiation coefficients of the weldment, and input the Boltzmann constant; S3. Load the subroutine and load the heat source for the weld portion, wherein step S3 includes: S31. Use pre-set logic to process the submerged arc welding heat process, simulate the large wall thickness of pipeline steel, and the number of independent welding wires used for internal and external welding, so as to determine the heat source model of each wire for internal and external welding. S32. Obtain the origin of the welding wire coordinates based on the three-dimensional element network, and define... XOZ The plane is the longitudinal section at the center of the longitudinal seam. The number of inner and outer welding wires is specified, and each welding wire forms an independent welding heat source, ensuring that each welding wire in the inner and outer welds is within the specified range. XOZ The model is moved within the plane, and the generalized double ellipsoid model is rewritten based on the welding wire angle data to obtain a new double ellipsoid heat source model. S33, Determine the first step of the inner weld. n The internal welding process parameters based on the welding wire; S34, determining the first n the welding parameters of the outside welding of the welding wire S35. Based on the instantaneous coordinate position and welding time of the moving heat source formed by each welding wire in the inner welding, establish the energy distribution parameters and shape distribution parameters applied to each welding wire in the new double ellipsoidal heat source model. Use the time array TIME(2) of the DFLUX subroutine to judge the loading of the welding heat source of each wire in the inner welding. Based on the energy distribution parameters and the shape distribution parameters, complete the inner welding loading with the preset inner welding loading logic. S36. The energy distribution parameters and shape distribution parameters of the outer weld are processed using the loading logic in step S35, and the loading judgment of the welding heat source of each wire of the outer weld is made using the time array TIME(2) of the DFLUX subroutine, so as to complete the outer weld loading by presetting the outer weld loading logic.

2. The method for simulating the loading of a linearly moving heat source for the welding of a pipe according to claim 1, characterized in that, In step S2, the parameters assigned include: density, thermal conductivity and specific heat capacity; three-dimensional unit mesh corresponding to the base material and the weld portion is divided; and time step and increment step corresponding to the base material and the weld portion are set; and the corresponding time step and increment step are set according to the weld length, welding speed, time interval between inner and outer welds and the number of welding wires in the inner and outer welds.

3. The method of claim 1, wherein the method is characterized by: In step S32, according to the generalized double ellipsoid model: Using the following logic, the generalized double ellipsoid model is rewritten based on the welding wire angle data to obtain the new double ellipsoid heat source model: In the formula, the arc axis is parallel to... x The included angle of the axis is β ,and y The included angle of the axis is γ ,and z The included angle of the axis is φ , Q For heat source power, For heat source efficiency, U For welding voltage, I For welding current, a 1. a 2. b , c For shape parameters, f 1. f 2 represents the heat distribution function. f 1 +f 2 =2 .

4. The method of claim 1, wherein the method is characterized by: Step S33 includes: S331. Determine the welding process parameters for the inner weld, including: welding voltage. Current welding speed The welding speed of each welding wire in the internal welding is consistent, and the welding efficiency is set to... The heat source power of each welding wire during internal welding is: = ; Assume internal welding n root welding wire and x The included angle of the axis is The angle between the z-axis and the z-axis is (n=1,2,...); S332, Determine the inner weld number n Coordinates of the heat source starting point of the welding wire ( ); S333; determine inner weld n Root weld wire heat source shape parameter ; S334. Determine the distance between each pair of adjacent front and rear wires for the inner weld; S335, set the inner welding welding distance as , the total welding time of inner welding is: n=2,3... , and determine the time interval t 12 between inner welding and outer welding.​ 5. The method of claim 1, wherein the method is characterized by: Step S34 includes: S341. Determine the welding process parameters for the external weld, including: welding voltage. Current welding speed The welding efficiency is set to The heat source power of each welding wire during external welding is... = ; Assume external welding n root welding wire and x The included angle of the axis is ,and z The included angle of the axis is (n=1,2,...); S342, Determine the external weld number n Coordinates of the heat source starting point of the welding wire ( ); S343、determining the outer welding n the heat source shape parameter of the root welding wire ; S344. Determine the distance between each pair of adjacent front and rear wires in the outer weld. Based on the distance between each pair of adjacent front and rear wires in the outer weld, determine the total welding time for the outer weld, and determine the time from the start of the inner weld to the completion of the outer weld. and the total time of thermal process simulation .

6. A method of simulating a heat source for loading of a pipe steel SAWL according to claim 5, characterized in that, Step S344 includes: S3441. Multiply the welding speed by the time to determine the distance between each adjacent pair of wires in the outer weld; S3442、according to the inner welding total welding time t1 and the inner welding and outer welding time interval t 12 , the outer welding first welding wire starting welding time is determined by using the following logic : + The processing of the welding distance, divided by the external welding speed, plus the first and second... n The distance between the welding wires, excluding the welding speed of the external welding wire. Based on this, the total welding time for the external weld was obtained, where the welding distance for the external weld was... The total external welding time is obtained by the following logical processing. : （ n=2,3... ）； S3443. Determine the total welding time for both internal and external welds: Summate the total welding time for the internal weld. The time interval between the inner and outer welding. The total welding time t2 of the outer weld is used to obtain the time from the start of the inner weld to the completion of the outer weld using the following logic processing. : = + + ， and the weld base metal cooling time is taken into account from which the total time of the thermal process simulation is obtained : + 。 7. The method of claim 1, wherein the method is characterized by: Step S35 includes: S351. Obtain the energy distribution parameters of the new double-ellipsoidal heat source model during the movement of each welding wire in the inner weld using the following logic: S352. Obtain the shape distribution parameters of the new double-ellipsoidal heat source model during the movement of each of the welding wires in the inner weld using the following logic: ； S353, when TIME(2) is less than or equal to the inner welding time At that time, the heat source of each welding wire in the inner welding process is determined. The inner welding loading logic is as follows: S354, Instantaneous x-axis during the movement of the heat source of each wire in the inner weld. x Greater than or equal to (x) 内n +(v1 (TIME(2)+t 内n When )), the first half of the heat source model is loaded. ,implement = ; S355, Instantaneous abscissa during the movement of the heat source of each wire in the inner weld. x Less than (x) 内n +(v1 (TIME(2)+t 内n When loading the heat source model in the second half, determine the heat source model in the second half. ,implement = ; S356, at t1 < TIME(2) < t1 + t 12 The heat source is set to an empty state.

8. The method of claim 1, wherein the method is characterized by: Step S36 includes: S361. Obtain the energy distribution parameters of the new double ellipsoidal heat source model for each welding wire during its movement in the external welding process using the following logic: S362. Obtain the shape distribution parameters of the new double ellipsoidal heat source model during the movement of each of the welding wires in the external welding process using the following logic: S363. Use the time array TIME(2) in the DFLUX subroutine to determine the loading of the welding heat source for each wire of the outer weld. If TIME(2) is greater than or equal to the welding time of the inner weld... Interval time between internal and external welding The sum of these is then applied to the heat source of each welding wire in the external welding process according to the following logic: S364, Instantaneous x-axis during the movement of the heat source of each wire in the external welding process. x Greater than or equal to (x) 外n +(v2 (TIME(2)+t 外n When loading the first half of the heat source model, ,implement = ; S365, Instantaneous abscissa during the movement of the heat source of each wire in the external welding process x Less than (x) 外n +(v2 (TIME(2)+t 外n When )), the second half of the heat source model is loaded. ,implement = .

9. A loading system of a pipe line steel SAWL simulating heat source, characterized in that, The system includes: The 3D model building module is used to build a 3D steel pipe model, divide the corresponding weld seam part and base material part, and assign material physical properties to the base material and the weld seam part as they change with temperature. The base metal weld parameter setting module is used to set the time step and increment step corresponding to the base metal and the weld portion, set the initial temperature, ambient temperature, convection and radiation coefficients of the weldment, and input the Boltzmann constant. The base metal weld parameter setting module is connected to the three-dimensional model establishment module. A loading module is used to load subroutines and load the heat source for the weld portion. The loading module is connected to the base metal weld parameter setting module. The loading module includes: The module for determining the heat source model of internal and external welding is used to process the submerged arc welding heat process with preset logic, simulate the large wall thickness of pipeline steel, and the number of independent welding wires used for internal and external welding, so as to determine the heat source model of each wire in internal and external welding. The model optimization module is used to obtain the origin of the welding wire coordinates based on the three-dimensional unit network, define the XOZ plane as the longitudinal section where the center of the longitudinal seam is located, determine the number of inner and outer welding wires, and ensure that each welding wire forms an independent welding heat source, so that each welding wire of the inner and outer welding moves in the XOZ plane, and rewrite the generalized double ellipsoid model based on the welding wire angle data to obtain a new double ellipsoid heat source model. The model optimization module is connected to the inner and outer welding heat source model determination module. The internal welding process parameter module is used to determine the internal welding process parameter. n The internal welding process parameters based on the welding wire; The external welding process parameter module is used to determine the external welding process parameter. n External welding process parameters for the root welding wire; The inner welding loading module is used to determine the energy distribution parameters and shape distribution parameters of each welding wire in the new double ellipsoidal heat source model based on the instantaneous coordinate position of the moving heat source formed by each welding wire in the inner welding and the welding time. The loading judgment of the welding heat source of each wire in the inner welding is made by using the time array TIME(2) of the DFLUX subroutine. The inner welding loading is completed by the preset inner welding loading logic based on the energy distribution parameters and the shape distribution parameters. The inner welding loading module is connected to the model optimization module and the inner welding process parameter module. The external welding loading module is used to process the energy distribution parameters and shape distribution parameters of the external weld using the loading logic in step S35, and to use the time array TIME(2) of the DFLUX subroutine to judge the loading of the welding heat source of each wire of the external weld, so as to complete the external welding loading by presetting the external welding loading logic. The external welding loading module is connected to the external welding process parameter module and the model optimization module.

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