Curved surface penetration piece welding optimization method and system

Abstract

The invention discloses a curved surface penetration piece welding optimization method and system. The method comprises the steps that a curved surface penetration piece three-dimensional model is established, and a curved surface penetration piece multi-layer and multi-pass welding seam equation is established; the multi-layer and multi-pass welding seam equation of the curved-surface penetration piece is combined with a Gaussian heat source to obtain a multi-layer and multi-pass welding moving heat source trajectory equation of the curved-surface penetration piece; the multi-layer and multi-channel welding moving heat source trajectory equation of the curved surface penetration piece is combined with a finite element theory, and multi-layer and multi-channel finite element values of the curved surface penetration piece are calculated; numerical simulation is conducted on the curved-surface penetration pieces according to different welding sequences, and the optimal welding sequence of the curved-surface penetration pieces is determined according to numerical simulation results; after the optimal welding sequence of the curved-surface penetration piece is determined, welding process parameters of the curved-surface penetration piece are collected; and an optimal welding process is comprehensively determined by utilizing an orthogonal experiment. According to the method, manual experiments can be effectively replaced, time and economic cost are reduced, and welding deformation and post-welding residual stress can be effectively restrained through the optimized welding method.

Description

Technical Field

[0001] The invention relates to the field of welding, and in particular to a method and system for optimizing the welding of curved surface penetration parts. Background Art

[0002] Welding technology is the main process for shipbuilding. There are many curved penetrations in the welding of small parts in ships. The weld of curved penetrations is a closed curve in space, with a relatively complex geometry and difficult to control the welding temperature. At present, curved penetrations are mainly welded manually. Robot welding has posture and segmentation restrictions, making it difficult to achieve continuous automatic welding of welds. In addition, pipelines are often inserted parallel to the ground on curved parts. The influence of gravity during welding makes it difficult to melt the welding wire, so segmented welding is required.

[0003] The Chinese invention patent application with application number CN202111673332.2 discloses a method for automatic cutting of round tubes by a robot. The intersection line welding method adopted in this scheme is suitable for small tube welding, but is not suitable for multi-layer and multi-pass segmented welding of large curved penetration parts, and the intersection line welding quality problem is not studied in depth.

[0004] Whether the welding sequence is reasonable and the welding parameters are appropriate not only affects the welding efficiency but also the welding quality, which may eventually lead to problems such as pipeline leakage. How to improve the welding quality and efficiency through the welding sequence has become the research focus in the field of robot welding. Traditional curved through-piece welding relies on manual testing methods, which usually requires a lot of manpower and economic costs and is very expensive. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a method and system for optimizing the welding of curved through-pieces, which can find the best welding sequence and optimize the welding process in advance while effectively reducing the cost of manual testing, and can effectively suppress welding deformation and post-welding residual stress.

[0006] Technical solution: A method for optimizing the welding of curved penetration parts of the present invention comprises:

[0007] Establish a three-dimensional model of the curved surface penetration part, and establish the multi-layer and multi-pass weld equations of the curved surface penetration part based on the three-dimensional model of the vertical curved surface penetration part;

[0008] The multi-layer multi-pass weld equation of curved surface penetration parts is combined with Gaussian heat source to obtain the moving heat source trajectory equation of multi-layer multi-pass welding of curved surface penetration parts; the moving heat source trajectory equation of multi-layer multi-pass welding of curved surface penetration parts is combined with finite element theory to calculate the multi-layer multi-pass finite element temperature field and deformation data of curved surface penetration parts;

[0009] In numerical simulation software, the multi-layer and multi-channel finite element temperature field and deformation data of the curved surface penetration parts are numerically simulated according to different welding sequences, and the optimal welding sequence of the curved surface penetration parts is determined according to the numerical simulation results;

[0010] After determining the optimal welding sequence of curved surface penetration parts, the welding process parameters of curved surface penetration parts are collected; and the optimal welding process is comprehensively determined using orthogonal experiments.

[0011] Furthermore, the multi-layer and multi-pass weld equations of the curved surface penetration are established based on the three-dimensional model of the vertical curved surface penetration, including:

[0012] Establish a suitable coordinate system in the three-dimensional model of the curved penetration, introduce the parameter θ and establish the intersection line equation:

[0013]

[0014] The intersecting line weld is a bevel that is inclined at a preset angle along the intersecting line. Each intersecting line weld is related to the original intersecting line. Based on this principle, the multi-layer and multi-pass welding trajectory equation r(θ) is established:

[0015]

[0016] Where a is the radius of the through-piece; b is the radius of the curved surface; e is i Indicates the distance between each weld and the penetration part; d j Indicates the distance between each weld and the curved surface;

[0017] Introduce angular velocity w and time t, let θ = wt, c i =a+e i , the trajectory equation of each weld is:

[0018]

[0019] Taking the derivative of time t, we can get the velocity equation of the welding heat source at any time:

[0020]

[0021] After converting v(t) into a scalar, v(t) can be obtained as:

[0022]

[0023] Furthermore, the expression of the moving heat source trajectory equation for the multi-layer and multi-pass welding of the curved surface penetration part is as follows:

[0024]

[0025] Where q(x, y, z, t) represents the trajectory equation of the moving heat source for multi-layer and multi-pass welding of curved penetration parts; R represents the arc heating radius; and Q represents the thermal power.

[0026] Furthermore, the maximum value Q of the thermal power is related to the voltage V and current I during welding, as follows:

[0027] Q=ηVI

[0028] Where η represents the conversion efficiency.

[0029] Furthermore, the moving heat source trajectory equation of multi-layer and multi-pass welding of curved surface penetration parts is combined with finite element theory to calculate the multi-layer and multi-pass finite element temperature field and deformation data of curved surface penetration parts, including:

[0030] The moving heat source trajectory equation for multi-layer and multi-pass welding of curved surface penetrations is combined with the finite element theory, and the temperature field and deformation data of each weld are obtained through the multi-layer and multi-pass finite element numerical calculation method of curved surface penetrations.

[0031] Furthermore, the multi-layer and multi-channel finite element temperature field and deformation data of the curved surface penetration parts are numerically simulated in the numerical simulation software according to different welding sequences, and the optimal welding sequence of the curved surface penetration parts is determined according to the software numerical simulation results, including:

[0032] Numerical simulation software preprocessing: Based on the size of the surface penetration parts in the actual project, two other surface penetration parts with different thicknesses are selected, for a total of three surface penetration parts with different thicknesses; the numerical simulation software is preprocessed; the preprocessing includes meshing of the surface penetration parts, importing material parameters, and setting boundary conditions of the surface penetration parts;

[0033] Meshing of curved penetrations: In numerical simulation software, the area around the weld of the curved penetration is divided into fine meshes, the area away from the weld is divided into coarse meshes, and the edge is divided into coarse meshes;

[0034] Material parameter import: Based on the surface penetration material in actual engineering, the nonlinear high temperature characteristics of the material are imported into the software;

[0035] Setting boundary conditions for curved surface penetrations: Select appropriate convection heat transfer coefficient, initial temperature and curved surface penetration fixing method according to actual working conditions;

[0036] Welding process determination: Determine the welding process used for different sections of the inserted curved penetration;

[0037] Welding sequence setting: Design welding sequences for curved large-diameter penetrations with various plate thicknesses, which are used to weld horizontally inserted curved penetrations; weld three curved penetrations with different thicknesses according to different welding sequences to achieve numerical simulation;

[0038] Temperature field calculation: Based on the moving heat source trajectory equation q(x,y,z,t) of multi-layer and multi-pass welding of curved surface penetrations, the thermal source code and weld life and death unit code are compiled to calculate the welding temperature field of curved surface penetrations under different welding sequences;

[0039] Calculation of welding deformation value and residual stress after welding: After the calculation of the welding temperature field of the curved penetration is completed, the temperature field data of the curved penetration is imported into the transient structure, and the welding deformation value and residual stress after welding of three curved penetrations with different thicknesses under different welding sequences are further calculated.

[0040] Furthermore, the multi-layer and multi-channel finite element temperature field and deformation data of the curved surface penetration parts are numerically simulated in the numerical simulation software according to different welding sequences, and the optimal welding sequence of the curved surface penetration parts is determined according to the software numerical simulation results, including:

[0041] Based on the numerical simulation results, the optimal welding sequence for each curved surface penetration part is selected from a variety of welding sequences according to the comprehensive consideration of welding temperature field, welding deformation value and post-welding residual stress for three different thicknesses of curved surface penetration parts.

[0042] Furthermore, based on the numerical simulation results, the optimal welding sequence of each curved surface penetration part is comprehensively selected from a variety of welding sequences according to the welding temperature field, welding deformation value and residual stress after welding for three different thicknesses of the curved surface penetration parts, including:

[0043] Selecting a welding sequence corresponding to a minimum welding deformation value from a plurality of welding deformation values ​​as an optimal welding sequence;

[0044] If the welding deformation values ​​are not much different, the welding sequence corresponding to the smallest post-weld residual stress is selected from multiple post-weld residual stresses as the optimal welding sequence;

[0045] If the welding deformation value and the residual stress after welding are not much different, the welding sequence corresponding to the symmetrical and evenly distributed temperature field is selected from multiple temperature fields as the optimal welding sequence.

[0046] Furthermore, after determining the optimal welding sequence of the curved surface penetration, the welding process parameters of the curved surface penetration are collected; and the optimal welding process is comprehensively determined by using orthogonal experiments, including:

[0047] Select various commonly used welding process parameters for curved penetration parts in three welding processes: horizontal welding, vertical welding and overhead welding;

[0048] According to the selected welding process parameters, an orthogonal experimental scheme is designed; in the orthogonal experiment, the welding voltage is related to the arc heating radius R, the welding current is related to the maximum welding thermal power Q, the welding speed is related to the arc heating radius R and the maximum welding thermal power Q, and the welding current, welding voltage and welding speed affect each other;

[0049] According to the orthogonal experimental scheme, write the thermal source code and the life and death unit code, and use the numerical simulation software to perform numerical simulation on each group of orthogonal experimental schemes;

[0050] The orthogonal experimental results of each group of orthogonal experimental schemes were analyzed, and the extreme value of welding deformation of each welding process under the welding sequence was calculated according to the welding deformation value.

[0051] According to the extreme value of welding deformation, determine the welding section with the largest welding deformation value among the horizontal welding, vertical welding and overhead welding sections, and select the welding parameters with the smallest welding deformation value; on this basis, determine the optimal welding process parameters by comparing the welding residual stress; if there is a situation where the welding deformation and the welding residual stress are not much different, select the welding process scheme with high welding efficiency by comparing the welding efficiency under each welding process.

[0052] Based on the same inventive concept, a curved penetration welding optimization system of the present invention comprises:

[0053] The weld equation establishment module is used to establish a three-dimensional model of a curved surface penetration component, and to establish multi-layer and multi-pass weld equations of the curved surface penetration component based on the three-dimensional model of the vertical curved surface penetration component;

[0054] Finite element numerical calculation module, used to combine the multi-layer and multi-pass weld equation of curved surface penetration with Gaussian heat source to obtain the moving heat source trajectory equation of multi-layer and multi-pass welding of curved surface penetration; combine the moving heat source trajectory equation of multi-layer and multi-pass welding of curved surface penetration with finite element theory to calculate the multi-layer and multi-pass finite element numerical value of curved surface penetration;

[0055] The optimal welding sequence determination module is used to perform numerical simulation on the curved surface penetration parts according to different welding sequences in the numerical simulation software, and determine the optimal welding sequence of the curved surface penetration parts according to the numerical simulation results;

[0056] The optimal welding process determination module is used to determine the optimal welding sequence of the curved surface penetration parts, collect the welding process parameters of the curved surface penetration parts, and use orthogonal experiments to comprehensively determine the optimal welding process.

[0057] Beneficial effects: Compared with the prior art, the significant technical effects of the present invention are as follows:

[0058] The multi-layer and multi-pass welding trajectory equation established in the method of the present invention can load the heat source trajectory better and more accurately, making the welding numerical simulation closer to the actual welding situation, ensuring the accuracy of the welding temperature field, and further ensuring the accuracy of the calculation of welding deformation and post-welding residual stress.

[0059] The welding of inserted curved through-pieces has different welding positions and each section has different welding processes. Four welding sequences are proposed. To avoid the contingency of the simulation, two other thicknesses of curved weldments are selected to determine the best welding sequence. Under this welding sequence, the best welding process for curved through-pieces is determined, which can effectively suppress welding deformation and residual stress after welding and ensure welding quality.

[0060] Compared with the traditional manual experiment to determine the welding process of curved through-pieces, the curved through-piece welding optimization method of the present invention uses software numerical simulation to select the best welding sequence and optimize the welding process for the optimal welding sequence, which can greatly reduce labor and economic costs and alleviate the burden on enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 A schematic diagram of a flow chart of a curved surface penetration welding optimization method disclosed in an embodiment of the present invention;

[0062] Figure 2 A schematic diagram of a curved surface penetration welding model disclosed in an embodiment of the present invention;

[0063] Figure 3 A model diagram of an intersecting line disclosed in an embodiment of the present invention;

[0064] Figure 4 A schematic diagram of a multi-layer and multi-pass weld of a curved penetration member disclosed in an embodiment of the present invention;

[0065] Figure 5 A mesh division diagram of a curved surface penetration component disclosed in an embodiment of the present invention;

[0066] Figure 6 A nonlinear high temperature characteristic curve diagram of a weldment material disclosed in an embodiment of the present invention;

[0067] Figure 7 A schematic diagram of the welding process division of an inserted curved surface penetration member disclosed in an embodiment of the present invention;

[0068] Figure 8 A schematic diagram of the welding sequence of an inserted curved surface penetration member disclosed in an embodiment of the present invention;

[0069] Fig. 9 A schematic diagram of the temperature field after welding of a 15 mm curved plate in different welding sequences disclosed in an embodiment of the present invention;

[0070] Fig.10 A schematic diagram of welding deformation and residual stress after welding of a 15 mm curved plate in different welding sequences disclosed in an embodiment of the present invention;

[0071] Fig.11 A comparison chart of the quality of curved panels with different thicknesses after welding disclosed in an embodiment of the present invention;

[0072] Fig.12 Schematic diagram of 9 groups of welding deformations of an orthogonal experiment of a 15 mm curved panel disclosed in an embodiment of the present invention;

[0073] Fig.13 A schematic diagram of residual stress after welding of 9 sets of orthogonal experiments on a 15 mm curved panel disclosed in an embodiment of the present invention;

[0074] Fig.14 It is a schematic structural diagram of a curved through-piece welding optimization system disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0075] The technical solution of the present invention is described in detail below in conjunction with specific implementation methods and the accompanying drawings of the specification.

[0076] Example 1

[0077] like Figure 1 As shown, a curved surface penetration welding optimization method of the present invention comprises the following steps:

[0078] S1. Establishment of mathematical model of curved surface penetration: Establish a three-dimensional model of curved surface penetration, and establish multi-layer and multi-pass weld equations of curved surface penetration based on the three-dimensional model of curved surface penetration.

[0079] like Figure 2 As shown, based on the curved surface parts with a curvature of 0.2m and a thickness of 15mm and the penetrating parts with a diameter of 320mm in actual engineering, the three-dimensional model diagram of the curved penetrating parts is drawn using software.

[0080] like Figure 3 As shown, in this embodiment, the multi-layer and multi-pass weld equations of the curved surface penetration component are established based on the three-dimensional model of the vertical curved surface penetration component, including:

[0081] Establish a suitable coordinate system in the three-dimensional model of the curved penetration, introduce the parameter θ and establish the intersection line equation:

[0082]

[0083] like Figure 4 As shown in the figure, the intersecting line weld is cut along the intersecting line at a 45-degree angle. Each intersecting line weld has a certain relationship with the original intersecting line. Based on this principle, the multi-layer multi-pass welding trajectory equation r(θ) is established:

[0084]

[0085] Where a is the radius of the through-piece; b is the radius of the curved surface; e is i Indicates the distance between each weld and the penetration part; d j Indicates the distance between each weld and the curved surface;

[0086] Introduce angular velocity w and time t, let θ = wt, c i =a+e i ;

[0087] The trajectory equation for each weld is:

[0088]

[0089] By taking the derivative of time t, we can get the velocity equation of the welding heat source:

[0090]

[0091] After converting v(t) into a scalar, v(t) can be obtained as:

[0092]

[0093] The welding speed in welding usually refers to the scalar speed. The value of ω at time t can be approximately inversely calculated based on the welding speed value and substituted into the equation to obtain the multi-layer and multi-pass welding trajectory equation at this welding speed, which ensures the correctness of the welding heat source trajectory and makes the welding numerical simulation closer to the actual welding situation.

[0094] S2. Finite element numerical calculation of curved surface penetration parts: Combine the multi-layer and multi-pass weld equations of curved surface penetration parts with Gaussian heat source to obtain the moving heat source trajectory equation of multi-layer and multi-pass welding of curved surface penetration parts; Combine the moving heat source trajectory equation of multi-layer and multi-pass welding of curved surface penetration parts with finite element theory to calculate the multi-layer and multi-pass finite element temperature field and deformation data of curved surface penetration parts.

[0095] In this embodiment, the expression of the moving heat source trajectory equation for multi-layer and multi-pass welding of curved surface penetration parts is as follows:

[0096]

[0097] Where q(x, y, z, t) represents the trajectory equation of the moving heat source for multi-layer and multi-pass welding of curved penetration parts; R represents the arc heating radius; and Q represents the thermal power.

[0098] Among them, the maximum value of thermal power Q is related to the voltage V and current I during welding, which can be expressed as:

[0099] Q=ηVI

[0100] Where η represents the conversion efficiency.

[0101] Combining the moving heat source trajectory equation of multi-layer and multi-pass welding of curved surface penetrations with the finite element theory, the temperature field and deformation data of each weld can be calculated through the multi-layer and multi-pass finite element numerical calculation method of curved surface penetrations, as follows:

[0102] Transient heat transfer is expressed by the matrix:

[0103]

[0104] Where [K] is the total heat transfer matrix of the unit, {Q} is the total load matrix, [C] is the specific heat matrix, and {T} is the node

[0105] Point temperature, is the derivative of the node temperature;

[0106] Since the physical properties of the material change with temperature during the entire welding process and change nonlinearly, the above equation can be written as:

[0107]

[0108] According to the theory of thermoelasticity, it is assumed that the total elastic strain of the material is composed of the increments of elastic strain and thermal strain respectively. The strain stress caused by external force is calculated using the principles of elasticity, and the stress strain caused by temperature change is calculated using the principles of thermoelasticity, and finally the two are added together.

[0109] {ε} all ={ε} el +{ε} hot

[0110] The relationship between elastic strain and elastic stress is shown below:

[0111] {σ} el =[D]{ε} el

[0112] Where [D] is the three-dimensional elastic matrix, which is determined by the elastic modulus E and Poisson's ratio u.

[0113] Since the thermodynamic properties of the base material are in nonlinear change during welding, the linear expansion coefficient will change with temperature. The thermal strain increment is related to the linear expansion coefficient. The thermal strain increment {ε} hot It can be written as.

[0114] {ε} hot ={αt',αt',αt',0,0,0} T

[0115] Where α is the linear expansion coefficient of the weldment, t' is the temperature change, {ε} allAt any point inside the unit, the smaller the value of unit e, the more accurate the calculation.

[0116] Considering the plastic deformation near the welding pool, the strain equation {ε} all It can be written as the following formula, where {ε} p is the plastic deformation increment, which is related to the yield function of the material.

[0117] {ε} all ={ε} el +{ε} p +{ε} hot

[0118] Establish the displacement increment {δ} of each node of element e e and the initial strain increment caused by temperature [R] e , we can get the equation:

[0119] {R e}=[K e ]{δ e}

[0120] [R] e =∫[B] T [C]dVdT

[0121] [K] e =∫[B] T [D][B]dV

[0122] Where, [K] e is the element stiffness matrix, [B] is the coefficient matrix associated with the element nodes.

[0123] When welding weldments, due to the complex welding conditions, in order to minimize the difference, the correction coefficient matrix [G] is introduced to correct the stiffness matrix. The corrected unit stiffness matrix is ​​as follows:

[0124]

[0125] Nodal displacement increment {δ} e It can be written as:

[0126] {δ e}=[∫[B] T [D][B][G]dV] -1 ∫[B] T [C]dVdT

[0127] The total welding deformation w is:

[0128]

[0129] Finite element theory is used to perform numerical calculations to further verify the accuracy of the temperature field and deformation from a theoretical perspective.

[0130] S3. Optimization of welding sequence of curved surface penetrations: numerical simulation of multi-layer and multi-channel finite element temperature field and deformation data of curved surface penetrations is performed in numerical simulation software according to different welding sequences, and the optimal welding sequence of curved surface penetrations is determined based on the software numerical simulation results.

[0131] Using software to numerically simulate different welding sequences of curved penetrations can greatly reduce time and economic costs compared to actual manual welding tests. The specific steps are as follows:

[0132] S3.1. Preprocessing of numerical simulation software: Based on the dimensions of surface penetrations in actual projects, two other surface penetrations with different thicknesses are selected, for a total of three surface penetrations with different thicknesses; the numerical simulation software is preprocessed; the preprocessing includes meshing of surface penetrations, importing of material parameters, and setting of boundary conditions of surface penetrations.

[0133] In this embodiment, a 15 mm curved plate thickness is used in actual engineering, and curved parts with thicknesses of 10 mm and 20 mm are selected to make the selected welding sequence more general and avoid the occurrence of accidents. The specific data is shown in Table 1. The numerical simulation software is pre-processed, including meshing of curved surface penetration parts, importing material parameters, and setting boundary conditions of curved surface penetration parts.

[0134] Table 1 Dimensions of curved penetrations

[0135]

[0136] S3.2. Meshing of curved surface penetrations: In the numerical simulation software, the area around the weld of the curved surface penetration is divided into a fine mesh, the area away from the weld is divided into a coarse mesh, the edge is divided into a coarse mesh, and the area around the weld of the curved surface penetration is divided into a fine mesh.

[0137] like Figure 5 As shown in the figure, the area around the weld of the curved through-part is divided into a fine grid, the area far from the weld is divided into a coarser grid, and the edge is divided into a coarse grid, which can effectively save computing resources and speed up the calculation.

[0138] S3.3. Material parameter import: Based on the surface penetration material in actual engineering, the nonlinear high-temperature characteristics of the material are imported into the software.

[0139] like Figure 6 As shown, based on the actual curved surface penetration material, high-strength structural steel DH36 was selected in this project. The nonlinear high-temperature characteristics of the material were introduced into the software, which can make the simulation results more accurate and closer to the actual welding.

[0140] S3.4. Setting boundary conditions for curved surface penetrations: Select appropriate convection heat transfer coefficient, initial temperature and curved surface penetration fixing method according to actual working conditions.

[0141] In this embodiment, the convection heat transfer coefficient is set to 5W / m according to the actual working conditions. 2 , the initial temperature is 20℃, and the curved penetration piece is fixed all around.

[0142] S3.5. Determination of welding process: Determine the welding process used for different sections of the inserted curved penetration.

[0143] like Figure 7 As shown in the figure, the welding processes used in different sections of the inserted curved penetration parts are different. In order to ensure the welding quality, different welding parameters need to be adopted in different sections. Sections c and d are horizontal welding, sections b and e are vertical welding, sections a and f are overhead welding, and the welding directions are shown in the figure.

[0144] S3.6. Welding sequence setting: Design the welding sequence of curved large-diameter penetrations with various plate thicknesses for welding horizontally inserted curved penetrations; weld three curved penetrations with different thicknesses according to different welding sequences to achieve numerical simulation.

[0145] like Figure 8 As shown in the figure, for the curved penetration piece inserted parallel to the ground, four welding sequences of thick plate curved large-diameter penetration pieces are proposed, including N1, N2, N3 and N4; among them, the N1 welding sequence is first left-right symmetrical and then up-down symmetrical welding; the N2 welding sequence is first left-right symmetrical and then up-down oblique symmetrical welding; the N3 welding sequence is first up-down oblique symmetrical and then left-right symmetrical; the N4 welding sequence is first partially up-down oblique symmetrical and then left-right symmetrical, and finally up-down oblique symmetrical welding; a welding process parameter is selected to numerically simulate the curved penetration pieces with different welding sequences, with a voltage of 25.2V, a current of 230A, and a welding speed of 8.3mm / s. Figure 8 Figure (a) shows that N1 is welded symmetrically first left and right and then up and down. Figure 8 Figure (b) shows that N2 is welded first symmetrically left and right and then symmetrically up and down. Figure 8 Figure (c) shows that N3 is first obliquely symmetrical up and down and then symmetrical left and right. Figure 8 Figure (d) shows that N4 is first partially symmetrical up and down, then symmetrical left and right, and finally welded symmetrically up and down.

[0146] S3.7. Calculation of welding temperature field: Based on the moving heat source trajectory equation q(x, y, z, t) for multi-layer and multi-pass welding of curved surface penetrations, write the thermal source code and weld life and death unit code to calculate the welding temperature field of curved surface penetrations under different welding sequences.

[0147] The temperature field calculation of 15mm curved panel is as follows Fig. 9As shown, after cooling for 15 minutes, the temperature field distribution of welding sequences N3 and N4 is relatively symmetrical. Fig. 9 Figure (a) shows the temperature field of the 15 mm curved plate N1 welding sequence. Fig. 9 Figure (b) shows the temperature field of the N2 welding sequence of a 15 mm curved plate. Fig. 9 Figure (c) shows the temperature field of the 15mm curved plate N3 welding sequence. Fig. 9 Figure (d) shows the temperature field of the N4 welding sequence of 15mm curved panel.

[0148] S3.8. Calculation of welding deformation value and residual stress after welding: After the calculation of the welding temperature field of the curved penetration is completed, the temperature field data of the curved penetration is imported into the transient structure, and the welding deformation value and residual stress after welding of three curved penetrations with different thicknesses under different welding sequences are further calculated.

[0149] 15mm curved plate welding deformation and residual stress after welding Fig.10 As shown, it can be seen from the welding cloud diagram that N3 welding deformation is the smallest. Fig.10 Figure (a) shows the welding deformation of a 15 mm curved plate in the N1 welding sequence. Fig.10 Figure (b) shows the residual stress after welding of the 15 mm curved plate in the N1 welding sequence. Fig.10 Figure (c) shows the welding deformation of the 15 mm curved plate under the N2 welding sequence. Fig.10 Figure (d) shows the residual stress after welding of the 15 mm curved plate in the N2 welding sequence. Fig.10 Figure (e) shows the welding deformation of a 15 mm curved plate under the N3 welding sequence. Fig.10 Figure (f) shows the residual stress after welding of the 15 mm curved plate in the N3 welding sequence. Fig.10 Figure (g) shows the welding deformation of a 15 mm curved plate under the N4 welding sequence. Fig.10 Figure (h) shows the residual stress after welding of a 15 mm curved plate under the N4 welding sequence.

[0150] Based on the numerical simulation results, the best welding sequence for each curved surface penetration part is selected from a variety of welding sequences based on the comprehensive consideration of welding temperature field, welding deformation value and residual stress after welding for three different thicknesses of the curved surface penetration parts. The specific steps are as follows:

[0151] (1) selecting a welding sequence corresponding to a minimum welding deformation value from multiple welding deformation values ​​as the optimal welding sequence;

[0152] (2) If the welding deformation values ​​are not much different, the welding sequence corresponding to the smallest post-weld residual stress is selected from multiple post-weld residual stresses as the optimal welding sequence;

[0153] (3) If the welding deformation value and the residual stress after welding are not much different, the welding sequence corresponding to the symmetrical and evenly distributed temperature field is selected from multiple temperature fields as the optimal welding sequence.

[0154] like Fig.11 As shown, based on the numerical simulation of the welding sequence using software, the optimal welding sequence N3 is selected based on the comprehensive consideration of the post-welding temperature field, welding deformation and post-welding residual stress for curved parts of three thicknesses, which can effectively suppress welding deformation and post-welding residual stress. Fig.11 Figure (a) shows the comparison of welding deformation results of curved panels with different thicknesses. Fig.11 Figure (b) shows the comparison of residual stress diagrams of curved panels of different thicknesses after welding.

[0155] S4. Improvement of welding process for optimal welding sequence: After determining the optimal welding sequence for curved surface penetrations, collect the welding process parameters for curved surface penetrations; and use orthogonal experiments to comprehensively determine the optimal welding process. The specific steps are as follows:

[0156] S4.1. Select various commonly used welding process parameters for curved penetration parts in three welding processes: horizontal welding, vertical welding and overhead welding.

[0157] Combined with Table 2, three commonly used welding parameters are selected in the horizontal welding, vertical welding and overhead welding processes of curved penetration parts.

[0158] Table 2 Optimization table of segmented welding parameters for curved through-pieces

[0159]

[0160] S4.2. On the basis of selecting the best welding sequence, collect the welding process parameters of different sections under the determined size of the curved surface penetration.

[0161] S4.3. Design an orthogonal experimental plan based on the selected welding process parameters; in the orthogonal experiment, the welding voltage is related to the arc heating radius R, the welding current is related to the welding heat Q, the welding speed is related to the arc heating radius R and the welding heat Q, and the welding current, welding voltage and welding speed affect each other.

[0162] S4.4. Combined with Table 3, according to the orthogonal experimental scheme, write the thermal source code and life and death unit code, and use numerical simulation software to perform numerical simulation on each group of orthogonal experimental schemes.

[0163] Table 3 Segmented orthogonal experimental scheme for penetrations

[0164]

[0165] S4.5,The orthogonal experimental results of each group of orthogonal experimental schemes are shown in Table 4;

[0166] Table 4 Orthogonal simulation results of T15mm curved panel

[0167]

[0168] The orthogonal experimental results of each group of orthogonal experimental schemes were analyzed, and the extreme value of welding deformation of each welding process under the welding sequence was calculated based on the welding deformation value, as shown in Table 5.

[0169] Table 5 Analysis of orthogonal simulation results of T15mm curved panel

[0170]

[0171] S4.6. According to the extreme value of welding deformation, determine the welding section with the largest welding deformation value among the horizontal welding, vertical welding and overhead welding sections, and select the welding parameters with the smallest welding deformation value; on this basis, determine the best welding process parameters by comparing the welding residual stress; if there is a situation where the welding deformation and welding residual stress are not much different, select the welding process scheme with high welding efficiency by comparing the welding efficiency under each welding process.

[0172] like Fig.12 As shown, according to the extreme value of welding deformation, determine which section of the horizontal welding, vertical welding and overhead welding sections has the greatest welding deformation, and select the welding parameters with the smallest welding deformation; on this basis, determine the best welding process parameters by comparing the welding residual stress; if there is a situation where the welding deformation and welding residual stress are not much different, compare the welding efficiency under each welding process and select the welding process with high welding efficiency; in the case of 15mm rear curved panel, the welding deformation of the horizontal welding section has the greatest impact, and select the welding parameters of groups 1, 6 and 7 with the smallest welding deformation; on this basis, compare the welding residual stress, the welding deformation distribution of groups 6 and 7 is relatively symmetrical, and the post-welding residual stress of group 7 is more symmetrical than that of group 6, and the value is smaller, so the best welding process is determined to be group 7, which can effectively suppress welding deformation and post-welding residual stress and ensure welding quality.

[0173] Fig.12 Figure (a) shows the welding deformation under an orthogonal welding sequence. Fig.12 Figure (b) shows the welding deformation under two orthogonal welding sequences. Fig.12 Figure (c) shows the welding deformation under three orthogonal welding sequences. Fig.12 Figure (d) shows the welding deformation under four orthogonal welding sequences. Fig.12 Figure (e) shows the welding deformation under 5 orthogonal welding sequences. Fig.12 Figure (f) shows the welding deformation under 6 orthogonal welding sequences. Fig.12 Figure (g) shows the welding deformation under 7 orthogonal welding sequences. Fig.12Figure (h) shows the welding deformation under 8 orthogonal welding sequences. Fig.12 Figure (i) shows the welding deformation under 9 orthogonal welding sequences.

[0174] Fig.13 Figure (a) shows the residual stress after orthogonal welding. Fig.12 Figure (b) shows the residual stress after two orthogonal welding. Fig.12 Figure (c) shows the residual stress after three orthogonal welding. Fig.12 Figure (d) shows the residual stress after four orthogonal welding. Fig.12 Figure (e) shows the residual stress after five orthogonal welding. Fig.12 Figure (f) shows the residual stress after six orthogonal welding. Fig.12 Figure (g) shows the residual stress after 7 orthogonal welding. Fig.12 Figure (h) shows the residual stress after 8 orthogonal welding groups, and (i) shows the residual stress after 9 orthogonal welding groups.

[0175] The technical solution of the present invention can effectively reduce the cost of manual testing in advance, find out the best welding sequence and optimize the welding process, and can effectively suppress the effects of welding deformation and post-welding residual stress.

[0176] Example 2

[0177] like Fig.14 As shown, a curved surface penetration welding optimization system of the present invention comprises:

[0178] The weld equation establishment module is used to establish a three-dimensional model of a curved surface penetration component, and to establish multi-layer and multi-pass weld equations of the curved surface penetration component based on the three-dimensional model of the vertical curved surface penetration component;

[0179] Finite element numerical calculation module, used to combine the multi-layer and multi-pass weld equation of curved surface penetration with Gaussian heat source to obtain the moving heat source trajectory equation of multi-layer and multi-pass welding of curved surface penetration; combine the moving heat source trajectory equation of multi-layer and multi-pass welding of curved surface penetration with finite element theory to calculate the multi-layer and multi-pass finite element numerical value of curved surface penetration;

[0180] The optimal welding sequence determination module is used to perform numerical simulation on the curved surface penetration parts according to different welding sequences in the numerical simulation software, and determine the optimal welding sequence of the curved surface penetration parts according to the numerical simulation results;

[0181] The optimal welding process determination module is used to determine the optimal welding sequence of the curved surface penetration parts, collect the welding process parameters of the curved surface penetration parts, and use orthogonal experiments to comprehensively determine the optimal welding process.

[0182] In an optional embodiment, the optimization method for the welding of curved penetrations includes: a) establishing a three-dimensional model of the curved penetration, and establishing a multi-layer and multi-pass weld equation for the curved penetration based on the three-dimensional model of the curved penetration; b) establishing a moving heat source trajectory equation for the multi-layer and multi-pass welding of the curved penetration, and calculating the multi-layer and multi-pass finite element values ​​of the curved penetration; c) using software to numerically simulate different welding sequences of the curved penetration, and comprehensively select the best welding sequence for the curved penetration; d) based on the selected best welding sequence for the curved penetration, collecting the welding process parameters of the curved penetration; and using orthogonal experiments to comprehensively determine the best welding process.

Claims

1. A method for optimizing the welding of curved penetration parts, characterized in that: include: Establish a three-dimensional model of the curved surface penetration part, and establish the multi-layer and multi-pass weld equations of the curved surface penetration part based on the three-dimensional model of the vertical curved surface penetration part; The multi-layer multi-pass weld equation of curved surface penetration parts is combined with Gaussian heat source to obtain the moving heat source trajectory equation of multi-layer multi-pass welding of curved surface penetration parts; the moving heat source trajectory equation of multi-layer multi-pass welding of curved surface penetration parts is combined with finite element theory to calculate the multi-layer multi-pass finite element temperature field and deformation data of curved surface penetration parts; In numerical simulation software, the multi-layer and multi-channel finite element temperature field and deformation data of the curved surface penetration parts are numerically simulated according to different welding sequences, and the optimal welding sequence of the curved surface penetration parts is determined according to the numerical simulation results of the software; After determining the optimal welding sequence of curved surface penetration parts, the welding process parameters of curved surface penetration parts are collected; and the optimal welding process is comprehensively determined using orthogonal experiments.

2. The method for optimizing curved surface penetration welding according to claim 1, characterized in that: The multi-layer and multi-pass weld equations of curved surface penetration parts are established based on the three-dimensional model of the vertical curved surface penetration parts, including: Establish a suitable coordinate system in the three-dimensional model of the curved penetration, introduce the parameter θ and establish the intersection line equation: The intersecting line weld is a bevel that is inclined at a preset angle along the intersecting line. Each intersecting line weld is related to the original intersecting line. Based on this principle, the multi-layer and multi-pass welding trajectory equation r(θ) is established: Where a is the radius of the through-piece; b is the radius of the curved surface; e is i Indicates the distance between each weld and the penetration part; d j Indicates the distance between each weld and the curved surface; Introduce angular velocity w and time t, let θ = wt, c i =a+e i , then the trajectory equation of each weld is: Taking the derivative with respect to time t, we can obtain the velocity equation of the heat source at any time: After converting v(t) into a scalar, v(t) can be obtained as:

3. The method for optimizing the welding of curved penetrations according to claim 1, characterized in that: The expression of the moving heat source trajectory equation for multi-layer and multi-pass welding of curved surface penetration parts is as follows: Where q(x, y, z, t) represents the trajectory equation of the moving heat source for multi-layer and multi-pass welding of curved penetration parts; R represents the arc heating radius; and Q represents the thermal power.

4. The method for optimizing the welding of curved penetrations according to claim 3, characterized in that: The maximum value Q of the thermal power is related to the voltage V and current I during welding, as follows: Q=ηVI Where η represents the conversion efficiency.

5. The method for optimizing the welding of curved penetrations according to claim 1, characterized in that: The moving heat source trajectory equation of multi-layer and multi-pass welding of curved surface penetration parts is combined with finite element theory to calculate the multi-layer and multi-pass finite element temperature field and deformation data of curved surface penetration parts, including: The moving heat source trajectory equation for multi-layer and multi-pass welding of curved surface penetrations is combined with the finite element theory, and the temperature field and deformation data of each weld are obtained through the multi-layer and multi-pass finite element numerical calculation method of curved surface penetrations.

6. The method for optimizing curved penetration welding according to claim 1, characterized in that: In numerical simulation software, multi-layer and multi-channel finite element temperature field and deformation data of curved surface penetration parts are numerically simulated according to different welding sequences. The optimal welding sequence of curved surface penetration parts is determined according to the numerical simulation results, including: Numerical simulation software preprocessing: Based on the size of the surface penetration parts in the actual project, two other surface penetration parts with different thicknesses are selected, for a total of three surface penetration parts with different thicknesses; the numerical simulation software is preprocessed; the preprocessing includes meshing of the surface penetration parts, importing material parameters, and setting boundary conditions of the surface penetration parts; Meshing of curved penetrations: In numerical simulation software, the area around the weld of the curved penetration is divided into fine meshes, the area away from the weld is divided into coarse meshes, and the edge is divided into coarse meshes; Material parameter import: Based on the surface penetration material in actual engineering, the nonlinear high temperature characteristics of the material are imported into the software; Setting boundary conditions for curved surface penetrations: Select appropriate convection heat transfer coefficient, initial temperature and curved surface penetration fixing method according to actual working conditions; Welding process determination: Determine the welding process used for different sections of the inserted curved penetration; Welding sequence setting: Design welding sequences for curved large-diameter penetrations with various plate thicknesses, which are used to weld horizontally inserted curved penetrations; weld three curved penetrations with different thicknesses according to different welding sequences to achieve numerical simulation; Welding temperature field calculation: Based on the moving heat source trajectory equation q(x,y,z,t) for multi-layer and multi-pass welding of curved surface penetrations, the thermal source code and weld life and death unit code are compiled to calculate the welding temperature field of curved surface penetrations under different welding sequences; Calculation of welding deformation value and residual stress after welding: After the calculation of the welding temperature field of the curved penetration is completed, the temperature field data of the curved penetration is imported into the transient structure, and the welding deformation value and residual stress after welding of three curved penetrations with different thicknesses under different welding sequences are further calculated.

7. The method for optimizing curved penetration welding according to claim 6, characterized in that: In numerical simulation software, multi-layer and multi-channel finite element temperature field and deformation data of curved surface penetration parts are numerically simulated according to different welding sequences. The optimal welding sequence of curved surface penetration parts is determined according to the numerical simulation results, including: Based on the numerical simulation results, the optimal welding sequence for each curved surface penetration part is selected from a variety of welding sequences according to the comprehensive consideration of welding temperature field, welding deformation value and post-welding residual stress for three different thicknesses of curved surface penetration parts.

8. The method for optimizing curved penetration welding according to claim 7, characterized in that: Based on the numerical simulation results, the optimal welding sequence for each curved surface penetration part is comprehensively selected from a variety of welding sequences according to the welding temperature field, welding deformation value and residual stress after welding for three different thicknesses of the curved surface penetration parts, including: Selecting a welding sequence corresponding to a minimum welding deformation value from a plurality of welding deformation values ​​as an optimal welding sequence; If the welding deformation values ​​are not much different, the welding sequence corresponding to the smallest post-weld residual stress is selected from multiple post-weld residual stresses as the optimal welding sequence; If the welding deformation value and the residual stress after welding are not much different, the welding sequence corresponding to the symmetrical and evenly distributed temperature field is selected from multiple temperature fields as the optimal welding sequence.

9. The method for optimizing curved penetration welding according to claim 1, characterized in that: After determining the optimal welding sequence of the curved surface penetration, collect the welding process parameters of the curved surface penetration; use orthogonal experiments to comprehensively determine the optimal welding process, including: Select various commonly used welding process parameters for curved penetration parts in three welding processes: horizontal welding, vertical welding and overhead welding; According to the selected welding process parameters, an orthogonal experimental scheme is designed; in the orthogonal experiment, the welding voltage is related to the arc heating radius R, the welding current is related to the maximum welding thermal power Q, the welding speed is related to the arc heating radius R and the maximum welding thermal power Q, and the welding current, welding voltage and welding speed affect each other; According to the orthogonal experimental scheme, write the thermal source code and the life and death unit code, and use the numerical simulation software to perform numerical simulation on each group of orthogonal experimental schemes; The orthogonal experimental results of each group of orthogonal experimental schemes are analyzed, and the extreme value of welding deformation of each welding process under the welding sequence is calculated according to the welding deformation value; According to the extreme value of welding deformation, determine the welding section with the largest welding deformation value among the horizontal welding, vertical welding and overhead welding sections, and select the welding parameters with the smallest welding deformation value; on this basis, determine the optimal welding process parameters by comparing the welding residual stress; if there is a situation where the welding deformation and the welding residual stress are not much different, select the welding process scheme with high welding efficiency by comparing the welding efficiency under each welding process.

10. A curved through-piece welding optimization system, characterized in that: include: The weld equation establishment module is used to establish a three-dimensional model of a curved surface penetration component, and to establish multi-layer and multi-pass weld equations of the curved surface penetration component based on the three-dimensional model of the vertical curved surface penetration component; Finite element numerical calculation module, used to combine the multi-layer and multi-pass weld equation of curved surface penetration with Gaussian heat source to obtain the moving heat source trajectory equation of multi-layer and multi-pass welding of curved surface penetration; combine the moving heat source trajectory equation of multi-layer and multi-pass welding of curved surface penetration with finite element theory to calculate the multi-layer and multi-pass finite element numerical value of curved surface penetration; The optimal welding sequence determination module is used to perform numerical simulation on the curved surface penetration parts according to different welding sequences in the numerical simulation software, and determine the optimal welding sequence of the curved surface penetration parts according to the numerical simulation results; The optimal welding process determination module is used to determine the optimal welding sequence of the curved surface penetration parts, collect the welding process parameters of the curved surface penetration parts, and use orthogonal experiments to comprehensively determine the optimal welding process.

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