High heat input welding joint temperature field and stress field forecasting method and system

Abstract

The invention provides a high heat input welding joint temperature field and stress field forecasting method and system, and the method comprises the following steps: S1, carrying out the analysis and calculation based on the chemical components of a welding material, and obtaining the physical parameters of the welding material; s2, establishing a first finite element three-dimensional welding model based on the physical parameters of the welding material and the actual welding process parameters; s3, boundary conditions of the model are established through technological parameters in the actual welding process, heat source parameters are adjusted, and a second finite element three-dimensional welding model is obtained; s4, the model is corrected according to the shape and size of an actual welding sample molten pool, and a third finite element three-dimensional welding model is obtained; and S5, through model parameter change, finishing forecasting of a post-welding temperature field and a post-welding strain field of the material under different processes. According to the method, the temperature and stress distribution after welding can be calculated by inputting the physical parameters of the material and the welding process, and theoretical support and technical guidance are provided for evaluation and improvement of the welding process.

Description

Technical Field

[0001] The present invention relates to the technical field of metal welding process design and evaluation, and particularly to a method and system for predicting the temperature field and stress field of a high heat input welding joint.

Background Art

[0002] Welding technology is one of the basic manufacturing technologies in the field of metal manufacturing. As a means of permanent connection that can ensure a certain strength, it is a very crucial core technology in the shipbuilding process. The welding process is a very complex process, and key parameters such as welding speed, welding power, and post-welding treatment methods will greatly affect the performance of the weld area and the heat affected zone, thereby affecting the strength of the entire welded part. Once the welding process is inappropriate, it will pose great safety hazards during the use of the welded part. Often, a large number of experiments need to be carried out before welding to adjust the welding process to ensure the reliability of the weld to the greatest extent. However, for high heat input welding of ship plate steel, welding experiments often require a large amount of manpower, material resources, and high cost. Therefore, it is necessary to propose a method to more conveniently obtain the temperature and stress distribution of the welded part during the welding process to help us evaluate the welding process.

[0003] Therefore, it is necessary to study a method and system for predicting the temperature field and stress field of a high heat input welding joint to address the deficiencies of the existing technology and solve or mitigate one or more of the above problems.

Summary of the Invention

[0004] In view of this, the present invention provides a method and system for predicting the temperature field and stress field of a high heat input welding joint. By using finite element software to establish a three-dimensional finite element welding model, the temperature and stress distribution after welding can be calculated by inputting material physical parameters and welding processes, providing theoretical support and technical guidance for the evaluation and improvement of the welding process.

[0005] On the one hand, the present invention provides a method for predicting the temperature field and stress field of a high heat input welding joint, and the temperature field and stress field prediction method includes the following steps:

[0006] S1: Analyze and calculate based on the chemical composition of the welding material to obtain the physical parameters of the welding material;

[0007] S2: Based on the physical parameters of the welding material and the actual welding process parameters, establish a first three-dimensional finite element welding model;

[0008] S3: Establish the boundary conditions of the first three-dimensional finite element welding model through the process parameters in the actual welding process, and adjust the heat source parameters to obtain a second three-dimensional finite element welding model;

[0009] S4: Calibrate the second three-dimensional finite element welding model based on the actual molten pool morphology and size of the welded sample to obtain the third three-dimensional finite element welding model;

[0010] S5: Complete the prediction of the post-welding temperature field and strain field of materials under different processes by changing the model parameters of the third three-dimensional finite element welding model.

[0011] In the above-mentioned aspects and any possible implementation manners, a further implementation manner is provided. The method for obtaining the physical parameters of the welding material in S1 includes, but is not limited to, calculating the physical parameters of the welding material through JMatPro software.

[0012] In the above-mentioned aspects and any possible implementation manners, a further implementation manner is provided. The physical parameters in S1 include, but are not limited to, density, thermal conductivity, elastoplasticity, and specific heat that vary with time.

[0013] In the above-mentioned aspects and any possible implementation manners, a further implementation manner is provided. The actual welding process parameters in S2 include, but are not limited to, welding speed, welding power, and consumable size.

[0014] In the above-mentioned aspects and any possible implementation manners, a further implementation manner is provided. The heat source in S3 is a hybrid heat source model, and the hybrid heat source model describes the heat input process of welding through the coupling of heat source models.

[0015] In the above-mentioned aspects and any possible implementation manners, a further implementation manner is provided. The coupling method of the hybrid heat source model is that two heat source models are stacked layer by layer in the melt depth direction, and the double ellipsoid heat source model is used to describe the upper part of the molten pool.

[0016] In the above-mentioned aspects and any possible implementation manners, a further implementation manner is provided. The greater the similarity between the calibration process in S4 and the actual sample, the higher the accuracy of the third three-dimensional finite element welding model.

[0017] In the above-mentioned aspects and any possible implementation manners, a further implementation manner is provided. The prediction results in S5 include the temperature and stress distributions at the positions of the weld and the heat affected zone during the welding process.

[0018] In the above-mentioned aspects and any possible implementation manners, a further implementation manner is provided. The method for predicting the temperature field and stress field further includes: evaluating the welding process based on the temperature and stress distributions at the positions of the weld and the heat affected zone during the welding process.

[0019] In the above-mentioned aspects and any possible implementation manners, a further implementation manner is provided for a prediction system of the temperature field and stress field of a high heat input welding joint. The temperature field and stress field prediction system includes:

[0020] A parameter calculation module analyzes and calculates based on the chemical composition of the welding material to obtain the physical parameters of the welding material;

[0021] A model establishment module establishes a first three-dimensional finite element welding model based on the physical parameters of the welding material and the actual welding process parameters;

[0022] A heat source parameter adjustment module establishes the boundary conditions of the first three-dimensional finite element welding model through the process parameters in the actual welding process, and adjusts the heat source parameters to obtain a second three-dimensional finite element welding model;

[0023] A model correction module corrects the second three-dimensional finite element welding model through the molten pool morphology and size of the actual welding sample to obtain a third three-dimensional finite element welding model;

[0024] An application prediction module completes the prediction of the post-weld temperature field and strain field of the material under different processes by changing the model parameters of the third three-dimensional finite element welding model.

[0025] Compared with the prior art, the present invention can obtain the following technical effects:

[0026] The present invention establishes a three-dimensional finite element welding model through finite element software. Through finite element calculation software, the temperature and stress distributions at the positions of the weld and the heat affected zone during the welding process are calculated, and then the advantages and disadvantages of the welding process are evaluated. Based on this, a process improvement plan and simulation experiment are made. On the basis of the prior art, the present invention changes to transient thermal analysis and adopts the coupling of two heat source models, which can accurately describe the welding heat input and realize the real-time change of the physical parameters of the material, and more precisely reflect the real working conditions during the welding process.

[0027] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned technical effects simultaneously.

Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 It is a comparison diagram of the weld morphology calculated in an embodiment of the present invention and the actual weld morphology;

[0030] Figure 2 It is a temperature field and stress field diagram when the welding process reaches 1 / 2 in an embodiment of the present invention;

[0031] Figure 3 This is a graph showing the temperature and stress in the heat affected zone under different welding parameters in an embodiment of the present invention.

Specific Embodiments

[0032] To better understand the technical solution of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] It should be clear that the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0034] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms of "a", "the" and "said" used in the embodiments of the present invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0035] The present invention provides a method for predicting the temperature field and stress field of a large heat input welded joint, and the method for predicting the temperature field and stress field includes the following steps:

[0036] S1: Based on the chemical composition of the welding material, analyze and calculate to obtain the physical parameters of the welding material;

[0037] S2: Based on the physical parameters of the welding material and the actual welding process parameters, establish a first three-dimensional finite element welding model;

[0038] S3: Through the process parameters in the actual welding process, establish the boundary conditions of the first three-dimensional finite element welding model, and adjust the heat source parameters to obtain a second three-dimensional finite element welding model;

[0039] S4: Calibrate the second three-dimensional finite element welding model through the molten pool morphology and size of the actual welding sample to obtain a third three-dimensional finite element welding model;

[0040] S5: By changing the model parameters of the third three-dimensional finite element welding model, complete the prediction of the post-weld temperature field and strain field of the material under different processes.

[0041] The method for obtaining the physical parameters of the welding material in S1 includes, but is not limited to, calculating the physical parameters of the welding material through JMatPro software.

[0042] The physical parameters in S1 include, but are not limited to, density, thermal conductivity, elastoplasticity and specific heat that change with time.

[0043] The actual welding process parameters in S2 include but are not limited to welding speed, welding power, and welding material size.

[0044] The heat source in S3 is a hybrid heat source model, and the hybrid heat source model describes the heat input process of welding through the coupling of heat source models.

[0045] The coupling method of the hybrid heat source model is that two heat source models are stacked layer by layer in the melt depth direction, and the double ellipsoid heat source model is used to describe the upper part of the molten pool.

[0046] In S4, the greater the similarity between the correction process and the actual sample, the higher the accuracy of the third finite element three-dimensional welding model.

[0047] The prediction results in S5 include the temperature and stress distributions at the positions of the weld and the heat affected zone during the welding process.

[0048] The temperature field and stress field prediction method further includes: evaluating the welding process through the temperature and stress distributions at the positions of the weld and the heat affected zone during the welding process.

[0049] The present invention also provides a temperature field and stress field prediction system for a large heat input welding joint, and the temperature field and stress field prediction system includes:

[0050] A parameter calculation module, which analyzes and calculates based on the chemical composition of the welding material to obtain the physical parameters of the welding material;

[0051] A model establishment module, which establishes a first finite element three-dimensional welding model based on the physical parameters of the welding material and the actual welding process parameters;

[0052] A heat source parameter adjustment module, which establishes the boundary conditions of the first finite element three-dimensional welding model through the process parameters in the actual welding process and adjusts the heat source parameters to obtain a second finite element three-dimensional welding model;

[0053] A model correction module, which corrects the second finite element three-dimensional welding model through the molten pool morphology and size of the actual welding sample to obtain a third finite element three-dimensional welding model;

[0054] An application prediction module, which completes the prediction of the post-welding temperature field and strain field of the material under different processes by changing the model parameters of the third finite element three-dimensional welding model.

[0055] Example 1:

[0056] The present invention provides a temperature field and stress field prediction method for a large heat input welding joint. The method is used to predict the temperature and stress distributions near the weld and the heat affected zone during the welding process. The method includes the following steps:

[0057] S1: Based on the chemical composition of the welding material, use JMatPro software to calculate its physical parameters as the initial conditions for model establishment;

[0058] S2: Based on the physical properties of the material and the actual welding process parameters, establish a three-dimensional welding model using finite element software;

[0059] S3: Refer to the process parameters in the actual welding process, establish the boundary conditions of the finite element model, and adjust the heat source parameters;

[0060] S4: Refer to the molten pool morphology and size of the actual welded sample to correct the finite element model;

[0061] S5: By changing the model parameters, it is possible to realize the prediction of the post-welding temperature field and strain field of the material under different processes.

[0062] The result of the first-stage calculation in S1 is the curve of the physical parameters changing with time, and the main contents include density, thermal conductivity, elastoplasticity, specific heat, etc.

[0063] The welding technical parameters in S2 include welding speed, welding power, and welding material size, etc.

[0064] The heat source model in S3 selects a hybrid heat source model of a comprehensive heat source and a surface heat source. The heat source model in S3 is a newly developed hybrid heat source model in this study, and the coupling of the heat source models is used to describe the heat input process of welding. The two heat source models are stacked in layers in the melt depth direction, where the double-ellipsoid heat source model is used to describe the upper part of the molten pool, and its heat source equation is:

[0065]

[0066] Among them, qf and qr respectively describe the front and rear ellipsoids of the double-ellipsoid heat source, in units of W / m3; a, b, cf, and cr respectively correspond to the width, depth, and length of the front and rear parts of the molten pool. f f and f r represent the proportion of the heat transferred to the front and rear ellipsoids. The generally accepted ratio is ff:fr = 60:40. Q is the welding heat input, which is determined according to the actual welding process. The heat of hot water for high heat input welding is usually above 100 kJ; x, y, z are the spatial coordinate positions.

[0067] The Gaussian rotational body heat source model is:

[0068]

[0069] Where r0 represents the radius of the heat source, which can be adjusted during the coupling process to control the top size of the heat source, and the parameter H is used to adjust the penetration depth of the lower part of the heat source; r is the radial distance from the center of the heat source; z is the axial distance from the center of the heat source, and h is used to describe the attenuation of the heat source in the z-axis direction. Q is the welding heat input, which is determined according to the actual welding process.

[0070] In step S4, the correction of the finite element model should be as close to the actual situation as possible. The greater the similarity to the actual sample, the higher the accuracy of the model.

[0071] Taking a certain grade of metal material as an example, under the process conditions of laser welding with a laser power of 2000W and a welding speed of 4mm / s, the comparison between the calculated weld appearance and the actual welding appearance is as Figure 1 shown.

[0072] Taking the width of the molten pool as a reference, the measured width of the molten pool during the actual welding process is 2.443mm, and the calculated width of the molten pool is 2.228mm. The calculation results have a certain degree of accuracy and reference value. The temperature field and stress field when the welding process reaches 1 / 2 are as Figure 2 shown.

[0073] By adjusting the welding parameters, this method can also compare different welding processes. On the basis of a laser power of 2kW and a welding speed of 4mm / s, the power and speed are respectively changed, and the stress distribution in the heat affected zone of the welded parts after the change is as Figure 3 shown.

[0074] It can be concluded from the calculation results that when the welding power is fixed, the faster the welding speed, the lower the temperature in the heat affected zone of the weld, and the smaller the width of the high stress zone on both sides of the weld; when the welding speed is fixed, the higher the welding power, the higher the temperature in the heat affected zone, the width of the high stress zone on both sides of the weld remains unchanged, but the position moves away from the weld.

[0075] The above has introduced in detail a method and system for predicting the temperature field and stress field of a large heat input welding joint provided by an embodiment of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

[0076] As used in the specification and claims, certain terms are used to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. The specification and claims do not distinguish components by the difference in names, but by the difference in their functions. As used throughout the specification and claims, the terms "comprising" and "including" are open-ended terms and should be interpreted as "comprising / including but not limited to". "Substantially" means within an acceptable error range. Those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The following description in the specification is the preferred embodiment for implementing the present application, but the description is for the purpose of explaining the general principles of the present application and is not intended to limit the scope of the present application. The protection scope of the present application shall be determined by the scope defined by the appended claims.

[0077] It should also be noted that the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, such that a commodity or system including a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such commodity or system. Without further limitation, an element defined by the statement "including one..." does not exclude the presence of another identical element in the commodity or system including said element.

[0078] It should be understood that the term "and / or" used herein is only an associative relationship describing associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0079] The above description shows and describes several preferred embodiments of the present application. However, as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the application concept described herein through the above teachings or the technology or knowledge in the relevant field. And any changes and variations made by those skilled in the art without departing from the spirit and scope of the present application shall fall within the protection scope of the appended claims of the present application.

Claims

1. A method for predicting the temperature field and stress field of a high heat input welded joint, characterized in that The temperature field and stress field prediction method includes the following steps: S1: Analyze and calculate based on the chemical composition of the welding material to obtain the physical parameters of the welding material; S2: Based on the physical parameters of the welding material and the actual welding process parameters, establish a first three-dimensional finite element welding model; S3: Through the process parameters in the actual welding process, establish the boundary conditions of the first three-dimensional finite element welding model, and adjust the heat source parameters to obtain a second three-dimensional finite element welding model; S4: Calibrate the second three-dimensional finite element welding model through the molten pool morphology and size of the actual welding sample to obtain a third three-dimensional finite element welding model; S5: By changing the model parameters of the third three-dimensional finite element welding model, complete the prediction of the post-weld temperature field and strain field of the material under different processes.

2. The temperature field and stress field prediction method according to claim 1, characterized in that The method for obtaining the physical parameters of the welding material in S1 includes, but is not limited to, calculating the physical parameters of the welding material through JMatPro software.

3. The temperature field and stress field prediction method according to claim 1, characterized in that The physical parameters in S1 include, but are not limited to, density, thermal conductivity, elastoplasticity, and specific heat that vary with time.

4. The temperature field and stress field prediction method according to claim 1, characterized in that The actual welding process parameters in S2 include, but are not limited to, welding speed, welding power, and welding material size.

5. The temperature field and stress field prediction method according to claim 1, characterized in that The heat source in S3 is a hybrid heat source model, and the hybrid heat source model describes the heat input process of welding through the coupling of heat source models.

6. The temperature field and stress field prediction method according to claim 5, characterized in that The coupling method of the hybrid heat source model is that two heat source models are stacked in layers in the melt depth direction, and the double ellipsoid heat source model is used to describe the upper part of the molten pool.

7. The temperature field and stress field prediction method according to claim 1, characterized in that In S4, the greater the similarity between the calibration process and the actual sample, the higher the accuracy of the third three-dimensional finite element welding model.

8. The temperature field and stress field prediction method according to claim 1, characterized in that, The prediction results in S5 include the temperature and stress distributions at the positions of the weld and heat affected zone during the welding process.

9. The temperature field and stress field prediction method according to claim 8, wherein The temperature field and stress field prediction method further includes: evaluating the welding process through the temperature and stress distributions at the positions of the weld and heat affected zone during the welding process.

10. A temperature field and stress field prediction system for large heat input welded joints, characterized in that, The temperature field and stress field prediction system includes: A parameter calculation module that analyzes and calculates based on the chemical composition of the welding material to obtain the physical parameters of the welding material; A model establishment module that establishes a first three-dimensional finite element welding model based on the physical parameters of the welding material and the actual welding process parameters; A heat source parameter adjustment module that establishes the boundary conditions of the first three-dimensional finite element welding model through the process parameters in the actual welding process and adjusts the heat source parameters to obtain a second three-dimensional finite element welding model; A model calibration module that calibrates the second three-dimensional finite element welding model through the molten pool morphology and size of the actual welding sample to obtain a third three-dimensional finite element welding model; An application prediction module that completes the prediction of the post-weld temperature field and strain field of the material under different processes by changing the model parameters of the third three-dimensional finite element welding model.

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