Manufacturing defect acceptance method for high-temperature service welding component

Abstract

The invention relates to the technical field of safety evaluation or nondestructive testing acceptance of defect-containing welding structures, and provides a manufacturing defect acceptance method of a high-temperature service welding component, which comprises the following steps: calibrating parameters of a creep constitutive model by testing the creep performance of a defect-free material / structure; regularizing the defects, and constructing a defect-containing structure finite element model by utilizing a finite element tool; controlling defect variables to obtain creep life under different defects, performing normalization processing on the creep life under different defect characteristics, and performing regression analysis to obtain a mapping relation between the defect characteristics and the creep life; and determining a defect diameter acceptance limit value under a specific plate thickness, and if the defect diameter acceptance limit value is within the defect diameter acceptance limit value, passing acceptance. The acceptance limit value of the defect-containing structure is determined through the creep life weakening degree, whether the structure safely runs in the service period or not is judged, theoretical support is provided for nondestructive testing acceptance of nuclear power or chemical defect-containing equipment, and optimization of the acceptance limit value of the defect-containing structure is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of safety evaluation or nondestructive testing acceptance of defective welded structures of high-temperature service equipment such as nuclear energy and petrochemical industry, and in particular to a method for acceptance of manufacturing defects of high-temperature service welded components. Background Art

[0002] The key components of the fourth-generation nuclear island equipment, represented by fast reactors, have been serving in extreme environments such as high temperature and high stress for a long time, and face severe challenges of creep failure. At the same time, as nuclear power units develop towards larger sizes, welding, as a core manufacturing process, is difficult to completely avoid the generation of defects such as pores, inclusions, and unfusion when manufacturing ultra-large and complex structures. These defects will significantly reduce the performance of the joints and are a potential threat to structural failure.

[0003] Currently, the selection and development of acceptance standards for high-temperature defective components still rely on international standards such as ASME and RCC. However, these standards are based on foreign material systems and process foundations. In recent years, my country's welding technology has achieved breakthroughs in areas such as inverter welding machines, laser welding, and high-end welding materials, and welding process levels have steadily improved. Existing non-destructive testing technologies have developed rapidly, with breakthroughs in intelligent precision identification, micro- and nanoscale detection, multi-source fusion imaging, and cross-scale quantitative assessment, gradually optimizing the scale and accuracy of defect detection. If foreign defect acceptance methods such as those from ASME continue to be used, the applicability of defect acceptance criteria and the accuracy of defect acceptance results will remain unverified. Therefore, there is an urgent need to establish defect acceptance standards and evaluation methods that are tailored to the characteristics of my country's nuclear power equipment and possess independent intellectual property rights to ensure the safe and reliable operation of nuclear power equipment.

[0004] Existing standards, such as ASME BPVC Section XI, specify defect acceptance limits only for in-service components. Fracture mechanics methods are typically used to assess excessive defects, leading to significant conservatism, material waste, and increased repair costs. Furthermore, the impact of creep is not considered during defect safety assessments, often resulting in overly conservative or unsafe assessment results, potentially leading to unplanned downtime or potentially catastrophic accidents. Existing studies, such as BS 7910:2019 Annex P, have attempted to introduce the creep fracture mechanics parameter C* integral, but this only applies to the steady-state creep phase and fails to establish a quantitative correlation between defect geometry and remaining life. The morphological complexity of welding defects and the nonlinear evolution of creep damage in real-world applications limit the applicability of existing methods to critical structures such as nuclear island main welds and hydrogenation reactors. More importantly, existing nondestructive testing acceptance limits fail to consider the correlation between defect characteristics and lifespan. Establishing such a mapping is crucial for assessing the safety of manufacturing defects and conducting manufacturing defect acceptance. Previous studies have shown that the geometric characteristics of defects, such as size, shape, and orientation, significantly affect the fatigue life of materials; the degradation mechanism of material properties due to defect type also affects component life. Consequently, existing standards lack pre-service acceptance methods for defective components under high-temperature conditions. Furthermore, existing evaluation methods for high-temperature defective components are not highly accurate and fail to directly establish a mapping between defect characteristics and creep life.

[0005] Therefore, it is urgent for those skilled in the art to design a defect acceptance method that determines the defect acceptance limit based on "defect characteristics-creep life". Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a method for inspecting manufacturing defects of high-temperature service welded components, the defect inspection method comprising:

[0007] Step (1) calibrating the parameters of the creep constitutive model by testing the creep performance of defect-free materials / structures;

[0008] Step (2) regularize the defects and construct a finite element model of the defective structure using finite element tools;

[0009] Step (3) Based on the finite element model of the defective structure, the defect variables are controlled to obtain the creep life under different defects, and the creep life t under different defect characteristics is normalized to obtain the weakening degree of creep life t / , and regression analysis is performed to obtain the mapping relationship between defect characteristics and creep life;

[0010] Step (4) Determine the defect diameter acceptance limit under a specific plate thickness T based on the mapping relationship between defect characteristics and creep life If the defect diameter acceptance limit If the test result is within 30 seconds, it will pass the acceptance.

[0011] Furthermore, the specific steps of step (1) are:

[0012] Wire cutting technology is used to cut samples from defect-free materials / structures to minimize processing residual stress and surface damage; by performing high temperature / room temperature creep tensile tests on the samples, the creep life and steady-state creep rate of the samples under different stress conditions are obtained, and the creep curves and strain rate curves under different stresses are obtained.

[0013] Creep constitutive models include:

[0014] Creep strain rate equation: exp (Formula 1)

[0015] in, is the creep strain rate tensor;

[0016] is the damage parameter, (Formula 2);

[0017] 、 It is a material-related parameter; A and n are material constants; n reflects the stress sensitivity. The larger n is, the more significant the effect of stress on creep strain rate. is the equivalent stress; p is the creep constitutive model parameter, and e represents the exponential function with e as the base;

[0018] Assuming that the material / structure is in the steady-state creep stage, the damage variable parameters =0, then exp(0)=1, and the logarithm of (Equation 1) is simplified to:

[0019] (Formula 3)

[0020] According to the experimental data, the material constants A and

[0021] Integrate (Equation 2) and take the initial time =0, initial damage parameter =0, the damage evolution equation is obtained as:

[0022] (Formula 4)

[0023] Simulating the creep life of defect-free structures for:

[0024] (Formula 5)

[0025] Taking the logarithm of (Equation 5), fitting the material parameters M and p according to the uniaxial creep rupture data, and substituting (Equation 4) into (Equation 2) to obtain the creep strain-time curve, the expression is:

[0026] (Formula 6)

[0027] The most appropriate q value at each stress level is determined by (Equation 6), and the constants A, n, and ;

[0028] Furthermore, the content of regularizing the defects in step (2) includes: the size of a single defect is the size of a rectangle or square that completely contains the defect area, and the shape of the defect is equivalent to an ellipse or a circle;

[0029] When analyzing the influence of different defect sizes, the ratio of the defect diameter to the plate thickness D / T is used as the parameter to describe the defect size; when analyzing the influence of different defect locations, the ratio of the defect location to the plate thickness L / T is used as the parameter to describe the defect location; when analyzing the influence of different defect shapes, the ratio of the defect major axis to the minor axis a / c is used as the parameter to describe the defect shape; when analyzing the influence of defect types, the ratio of the defect elastic modulus to the base material elastic modulus E is used as the parameter to describe the defect shape. d / E m As a parameter describing the defect type;

[0030] Furthermore, in step (2), the power law model in the finite element analysis software is used as the creep constitutive model, and a finite element model of the defective structure is constructed based on the calibrated creep constitutive parameters and a custom subroutine that independently defines the coupling relationship between the damage evolution equation and the creep constitutive model. The custom subroutine accurately describes the progressive damage behavior of the material / structure under high temperature conditions;

[0031] Furthermore, the custom subroutine is developed using Fortran language;

[0032] A custom subroutine detects the load state. If the element is subjected to pure hydrostatic pressure (the stress deviator is a zero matrix), it is determined that no creep deformation occurs and subsequent calculations are terminated to avoid numerical singularities. When a non-hydrostatic pressure load is detected, the creep strain increment is calculated based on the stress deviator, and the damage parameter is updated by coupling with the damage evolution equation. Ultimately, the cumulative damage parameter is used to achieve a quantitative prediction of the creep life, ensuring numerical stability and completing the continuous calculation process from stress analysis to life assessment.

[0033] During the simulation, when the damage variable at a specific Gaussian integral point on the outer surface of the specimen reaches the critical threshold Dmax and reaches the critical damage value, the total time at this time is considered to be the creep life.

[0034] Furthermore, in step (3):

[0035] When studying the effect of defect size, the defect is idealized as a sphere, and the defect type is selected as a pore defect. Multiple models are established for analysis using the ratio of the defect diameter to the plate thickness D / T. The plate thickness T is kept constant, and the defect is placed at the geometric center to calculate the creep life of the defect-containing structure.

[0036] When studying the influence of defect location, the defect is idealized as a sphere, and the defect type is selected as a porosity defect. Multiple models are established for analysis using the ratio of defect location to plate thickness, L / T. The plate thickness T is kept constant, and the defect diameter is kept consistent to calculate the creep life of the defective structure.

[0037] When studying the influence of defect shape, the defect is idealized as an ellipsoid and placed at the geometric center of the unit body. Multiple models are established and analyzed by taking different ratios of the major axis to the minor axis a / c of ​​the defect. At this time, the minor axis c of the ellipse is kept unchanged, and the major axis size a is changed to solve the creep life of the defective structure.

[0038] Furthermore, the specific steps of step (3) are:

[0039] The creep life t under different defect characteristics is normalized to obtain the creep life reduction degree t / , whose expression is:

[0040]

[0041] in, is the creep life of the defect-free structure obtained by finite element / experiment; t is the creep life of the defective structure; h 、 and g All are coefficients;

[0042] is the ratio of the elastic modulus of the defect calculated from the test to the elastic modulus of the base material;

[0043] is the ratio of the defect diameter to the plate thickness calculated from the experimental test;

[0044] is the ratio of the defect position to the plate thickness calculated from the experimental test;

[0045] is the ratio of the major axis to the minor axis of the defect calculated from the experimental test;

[0046] By performing regression analysis on the creep life under different defect characteristics, we can obtain h 、 andg The mapping relationship between defect characteristics and creep life is:

[0047] .

[0048] The present invention has the following beneficial effects:

[0049] (1) The present invention determines the defect acceptance limit for a specific plate thickness based on the "defect characteristics-creep life" mapping relationship. The acceptance limit of the defective structure is determined by the degree of creep life reduction, thereby determining whether the structure can operate safely during its service life. This provides theoretical and technical support for the non-destructive testing and acceptance of defective equipment in nuclear power or chemical industry, and optimizes the acceptance limit of defective structures.

[0050] (2) This invention overcomes the shortcomings of my country's existing non-destructive testing acceptance standards. Based on the defect acceptance limit, it can quickly determine whether the defect is safe, thereby improving the acceptance efficiency of defective structures and ensuring the long-term service safety of defective structures.

[0051] (3) The present invention can be applied to optimize the non-destructive testing acceptance standards for defective structures, and is of great significance for establishing an independent defect acceptance standard and design evaluation system that conforms to the characteristics of my country's nuclear power equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is an acceptance flow chart of the present invention.

[0053] Figure 2 This is a graph showing the influence of defect characteristics (size) on creep life and the result of parameter normalization processing in the present invention.

[0054] Figure 3 This is a graph showing the influence of defect characteristics (positions) on creep life and the result of parameter normalization processing in the present invention.

[0055] Figure 4 This is a graph showing the influence of defect characteristics (shape: aspect ratio) on creep life and the result of parameter normalization processing in the present invention.

[0056] Figure 5 This is a result diagram of the mapping relationship between defect characteristics (size) and creep life obtained by regression analysis in the present invention.

[0057] Figure 6 To determine the acceptance limit of defect diameter under specific plate thickness T based on the mapping relationship between defect characteristics and creep life Schematic diagram. DETAILED DESCRIPTION

[0058] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments, but this embodiment is not intended to limit the present invention. All similar structures and similar variations of the present invention should be included in the scope of protection of the present invention. The semicolons in the present invention represent the relationship of and, and the English letters in the present invention are case-sensitive.

[0059] This embodiment takes 316H stainless steel, a typical material for nuclear power equipment, as an example to illustrate the manufacturing defect acceptance method of this solution.

[0060] like Figure 1 As shown, the defect acceptance method includes:

[0061] S1, calibrate the parameters of the creep constitutive model by testing the creep properties of defect-free materials / structures (316H stainless steel);

[0062] Specimens were cut from 316H stainless steel using wire cutting technology to minimize machining residual stress and surface damage. High-temperature and room-temperature creep tensile tests were conducted on 316H materials and structures according to the national standard GB / T 2039-2024, "Metallic Materials Uniaxial Tension Creep Test Method." The tests were conducted at a constant temperature of 580°C, applying tensile loads at three stress levels: 180 MPa, 190 MPa, and 200 MPa. The creep life and steady-state creep rate of the specimens under different stress conditions were determined, and creep curves and strain rate curves were obtained under different stresses.

[0063] Creep constitutive models include:

[0064] Creep strain rate equation: exp (Formula 1)

[0065] in, is the creep strain rate tensor;

[0066] is the damage parameter, (Formula 2);

[0067] 、 It is a material-related parameter; A and n are material constants; n reflects the stress sensitivity. The larger n is, the more significant the effect of stress on creep strain rate. is the equivalent stress; its value can be taken as the stress load applied in the creep test; p is the creep constitutive model parameter, e represents the exponential function with e as the base;

[0068] Assume that the material / structure is in the steady-state creep stage. =0, then exp(0)=1, and the logarithm of (Equation 1) is simplified to:

[0069] (Formula 3)

[0070] According to the experimental data, the material constants A and

[0071] Integrate (Equation 2) and take the initial time =0, initial damage parameter =0, the damage evolution equation is obtained as:

[0072] (Formula 4)

[0073] Simulating the creep life of defect-free structures for:

[0074] (Formula 5)

[0075] Taking the logarithm of (Equation 5), fitting the material parameters M and p according to the uniaxial creep rupture data, and substituting (Equation 4) into (Equation 2) to obtain the creep strain-time curve, the expression is:

[0076] (Equation 6)

[0077] The most appropriate q value at each stress level is determined by (Equation 6), and the constants A, n, and ;

[0078] S2, regularize the defects and use finite element tools to construct a finite element model of the defective structure;

[0079] The content of regularization of defects includes: the size of a single defect is the size of a rectangle or square that completely contains the defect area, and the shape of the defect is equivalent to an ellipse or a circle;

[0080] When analyzing the influence of different defect sizes, the ratio of the defect diameter to the plate thickness D / T is used as the parameter to describe the defect size; when analyzing the influence of different defect locations, the ratio of the defect location to the plate thickness L / T is used as the parameter to describe the defect location; when analyzing the influence of different defect shapes, the ratio of the defect major axis to the minor axis a / c is used as the parameter to describe the defect shape; when analyzing the influence of defect types, the ratio of the defect elastic modulus to the base material elastic modulus E is used as the parameter to describe the defect shape. d / E m As a parameter describing the defect type;

[0081] The power-law model in the finite element analysis software is used as the creep constitutive model. A finite element model of the defective structure is constructed based on calibrated creep constitutive parameters and a custom subroutine that independently defines the coupling relationship between the damage evolution equation and the creep constitutive model. This custom subroutine accurately describes the progressive damage behavior of the material / structure under high temperature conditions.

[0082] The custom subroutine was developed using the Fortran language. It detects the load state. If the element is subjected to pure hydrostatic pressure (the stress deviator is a zero matrix), it determines that no creep deformation has occurred and terminates subsequent calculations to avoid numerical singularities. When a non-hydrostatic pressure load is detected, the creep strain increment is calculated based on the stress deviator, and the damage parameter is updated by coupling with the damage evolution equation. Ultimately, quantitative prediction of creep life is achieved through the accumulation of damage parameters, ensuring numerical stability while fully realizing the continuous calculation process from stress analysis to life assessment.

[0083] During the simulation, when the damage variable at a specific Gaussian integration point on the outer surface of the specimen reaches a critical threshold The total time when the damage critical value is reached is considered to be the creep life.

[0084] S3, based on the finite element model of the defective structure, the defect variables are controlled to obtain the creep life under different defects, and the creep life t under different defect characteristics is normalized to obtain the weakening degree of creep life t / , and regression analysis is performed to obtain the mapping relationship between defect characteristics and creep life;

[0085] When studying the influence of defect size, the defect is idealized as a sphere, the defect type is selected as a pore defect, and D / T=0.02, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, and 0.50 are taken respectively. Nine models are established for analysis, in which the plate thickness T is kept unchanged at 20 mm and the defect is placed at the geometric center. The results of the influence of defect characteristics (size) on creep life are shown in the figure below. Figure 2 As shown; when t / =1, the defect size D=0 (no defect); when t / =0.9, the defect size D=6 mm. For a 20 mm thick plate, the critical defect size considered by ASME and other standards is about 6 mm.

[0086] When studying the influence of defect position, the defect is idealized as a sphere, the defect type is selected as a pore defect, and L / T=0.20, 0.25, 0.30, 0.40, and 0.50 are taken respectively. Five models are established for analysis, in which the plate thickness T is kept constant at 20 mm and the defect diameter D is kept at 6 mm. The results of the influence of defect characteristics (position) on creep life are shown in the figure below. Figure 3As shown in the figure, under the premise of t / tr≥0.9, it is considered that pore defects smaller than 6 mm (in line with the ASME standard limit) have no effect on creep properties. Figure 3 It can be seen that the location of internal defects has little effect on creep life. In the figure, tr' is the creep life corresponding to a spherical defect with a size of 6 mm.

[0087] When studying the influence of defect shape, the defect is idealized as an ellipsoid and placed at the geometric center of the unit body. Seven models are established for analysis with a / c=1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0. The minor axis c of the ellipse is kept constant at 3 mm and 1 mm, and the major axis size a is changed. The results of the influence of defect characteristics (shape) on creep life are shown in the figure below. Figure 4 As shown in the figure, as the defect aspect ratio increases, the creep life decreases continuously. When a / c approaches infinity (i.e., plane crack), the creep life is the lowest. This is consistent with the fact that plane crack defects are not allowed in ASME and other specifications. Under the premise of t / tr≥0.9 (tr is the creep life of defect-free components), it is considered that defects with an aspect ratio of less than 1 (6 mm circle display) meet the requirements. Figure 4 It can be seen that when c = 1 mm and a / c = 3, the ratio of the structural life to the defect-free structure life is 0.99, which is approximately insignificant. Under the premise that the semi-minor axis c = 1 mm, the defect length can be increased to 20 mm, at which point the life is only 0.95 of the defect-free component life, indicating that defects are sensitive to size factors.

[0088] To simplify the calculation of the mapping relationship between defect characteristics and creep life, a simple univariate / multivariate linear regression can be used to obtain it. If a high-precision relationship such as a nonlinear mapping relationship is required, professional mathematical methods can be used to obtain it.

[0089] like Figure 5As shown in the figure, 47 groups of observations were used to build a model and regression statistics were performed on it. The regression coefficient reflects the "marginal effect" of the independent variable on the dependent variable, and the creep life statistic is used to test the significance of the regression coefficient. The significance of the coefficient determines whether the independent variable is "statistically significant" (usually P < 0.05 is the significance standard), and the 95% confidence interval is used to judge the reasonable range of the coefficient. The regression statistics show that the regression coefficient of the intercept term is 1.1195, and the coefficient significance is 1.63E-14, which is much less than 0.05. The creep life statistic is 11.46431, which is extremely large and statistically significant. The 95% confidence interval is [0.9224, 1.3 166], does not include 0, verifying the significance; the type (Ed / Em) item, its regression coefficient is 0.0035 (for every 1 unit increase in Ed / Em, the creep life increases by 0.0035 on average), the coefficient significance is 0.0300, less than 0.05, the creep life statistic is 2.246258, the 95% confidence interval is [0.0004, 0.0067], does not include 0, supporting the significance, indicating that Ed / Em has a significant positive effect on creep life; the size (D / T) item, its regression coefficient is -1.0406 (for every 1 unit increase in D / T, the creep life decreases by 1.0406 on average), the coefficient significance is 6. 28E-14, the creep life statistic is -10.9864, its absolute value is extremely statistically significant, and the 95% confidence interval is [-1.2317, -0.8494]. All are negative numbers, verifying the negative effect, indicating that D / T has a significant negative effect on the dependent variable; the position (L / T) term, its regression coefficient is 0.07798 (for every 1 unit increase in L / T, the creep life increases by 0.078 on average), the coefficient significance is 0.6912, which is much greater than 0.05, the creep life statistic is 0.399968, which is not statistically significant, and the 95% confidence interval is [-0.3155, 0.4714], including 0. Further The step verification is not significant, indicating that L / T has no significant effect on the dependent variable; the shape (a / c) item has a regression coefficient of 0.0279 (creep life increases by 0.0279 on average for every 1 unit increase in a / c), the coefficient significance is 0.00039, which is less than 0.05, and the creep life statistic is 3.856283, which is statistically significant. The 95% confidence interval is [0.0133, 0.0425], which does not include 0, supports significance, indicating that a / c has a significant positive effect on the dependent variable; at the coefficient level, the intercept is significantly non-zero; type, size, and shape have significant effects on creep life, with type and shape being positive and size being negative; the position has no significant effect.

[0090] The creep life t under different defect characteristics is normalized to obtain the creep life reduction degree t / , whose expression is:

[0091]

[0092] in, is the creep life of the defect-free structure obtained by finite element / experiment; t is the creep life of the defective structure; h 、 and g All are coefficients;

[0093] is the ratio of the elastic modulus of the defect calculated from the test to the elastic modulus of the base material;

[0094] is the ratio of the defect diameter to the plate thickness calculated from the experimental test;

[0095] is the ratio of the defect position to the plate thickness calculated from the experimental test;

[0096] is the ratio of the defect major axis to the minor axis calculated by the test; by performing regression analysis on the creep life under different defect characteristics, we can obtain 、 、 、 and , then the mapping relationship between defect characteristics and creep life is:

[0097] t / = (Formula 8).

[0098] S4, based on the mapping relationship between defect characteristics and creep life, determine the defect diameter acceptance limit under specific plate thickness T , the analysis shows that the defect type and shape are negatively correlated with the lifespan, the defect position has no significant effect on the lifespan, and the aspect ratio a / c of ​​the circular defect is 3 at most, so the circular pore located at the geometric center is selected for research, that is, E d / E m =0, L / T=0.5, a / c=3 and T=20 mm. Ideally, the defect weakens t / =1 can be considered as having no effect on creep life. Substituting it into (Equation 8), the critical size can be calculated to be 4.66 mm. In fact, the existence of defects will affect the stress field of the component and have an impact on the life, so t / It is difficult to reach 1.0. ≥0.9, it is considered that the defect has no effect on the creep performance. According to the above recalculation, the critical size can be obtained as 6.57 mm. Figure 6 From the perspective of defect acceptance limit optimization, a larger defect acceptance size can be obtained by utilizing the weakening degree.

[0099] This paper determines the defect acceptance limit for a specific plate thickness based on a mapping between defect characteristics and creep life. By determining the acceptance limit for a defective structure based on the degree of creep life reduction, the structure's safe operation during service can be determined. This provides theoretical and technical support for nondestructive testing and acceptance of defective equipment in nuclear power or chemical engineering, and optimizes the acceptance limit for defective structures.

[0100] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

Claims

1. A method for inspecting manufacturing defects of high-temperature service welded components, characterized in that: The defect acceptance method includes: Step (1) calibrating the parameters of the creep constitutive model by testing the creep performance of defect-free materials / structures; Step (2) regularize the defects and construct a finite element model of the defective structure using finite element tools; Step (3) Based on the finite element model of the defective structure, the defect variables are controlled to obtain the creep life under different defects, and the creep life t under different defect characteristics is normalized to obtain the weakening degree of creep life t / , and regression analysis is performed to obtain the mapping relationship between defect characteristics and creep life; Step (4) Determine the defect diameter acceptance limit under a specific plate thickness T based on the mapping relationship between defect characteristics and creep life If the defect diameter acceptance limit If the test result is within 30 seconds, it will pass the acceptance.

2. The method for accepting manufacturing defects of high-temperature service welded components according to claim 1, characterized in that: The specific steps of step (1) are: Wire cutting technology is used to cut samples from defect-free materials / structures. By performing high temperature / room temperature creep tensile tests on the samples, the creep life and steady-state creep rate of the samples under different stress conditions are obtained, and the creep curves and strain rate curves under different stresses are obtained. Creep constitutive models include: Creep strain rate equation: (Formula 1) in, is the creep strain rate tensor; is the damage parameter, (Formula 2); 、 are material-related parameters; A and n are material constants; is the equivalent stress; p is the creep constitutive model parameter, and e represents the exponential function with e as the base; Assume that the material / structure is in the steady-state creep stage. =0, then exp(0)=1, and the logarithm of (Equation 1) is simplified to: (Formula 3) According to the experimental data, the material constants A and n ; Integrate (Equation 2) and take the initial time =0, initial parameter =0, the damage evolution equation is obtained as: (Formula 4) Simulating the creep life of defect-free structures for: (Formula 5) Taking the logarithm of (Equation 5), fitting the material parameters M and p according to the uniaxial creep rupture data, and substituting (Equation 4) into (Equation 2) to obtain the creep strain-time curve, the expression is: (Formula 6) The most appropriate q value at each stress level is determined by (Equation 6), and the constants A, n, and .

3. The method for accepting manufacturing defects of high-temperature service welded components according to claim 1, characterized in that: The content of regularizing the defects in step (2) includes: the size of a single defect is the size of a rectangle or square that completely contains the defect area, and the shape of the defect is equivalent to an ellipse or a circle; When analyzing the influence of different defect sizes, the ratio of the defect diameter to the plate thickness D / T is used as the parameter to describe the defect size; when analyzing the influence of different defect locations, the ratio of the defect location to the plate thickness L / T is used as the parameter to describe the defect location; when analyzing the influence of different defect shapes, the ratio of the defect major axis to the minor axis a / c is used as the parameter to describe the defect shape; when analyzing the influence of defect types, the ratio of the defect elastic modulus to the base material elastic modulus E is used as the parameter to describe the defect shape. d / E m As a parameter describing the defect type.

4. The method for accepting manufacturing defects of high-temperature service welded components according to claim 1, characterized in that: In the step (2), the power law model in the finite element analysis software is used as the creep constitutive model, and a finite element model of the defective structure is constructed according to the calibrated creep constitutive parameters and a custom subroutine that independently defines the coupling relationship between the damage evolution equation and the creep constitutive model.

5. The method for accepting manufacturing defects of high-temperature service welded components according to claim 4, characterized in that: The custom subroutine is developed using Fortran language; A custom subroutine detects the load state. If the element is subjected to pure hydrostatic pressure, it is determined that no creep deformation occurs and subsequent calculations are terminated to avoid numerical singularities. When a non-hydrostatic pressure load is detected, the creep strain increment is calculated based on the stress deviator, and the damage parameter is updated by coupling with the damage evolution equation. Ultimately, the cumulative damage parameter is used to achieve a quantitative prediction of the creep life.

6. The method for accepting manufacturing defects of high-temperature service welded components according to claim 1, characterized in that: In step (3): When studying the effect of defect size, the defect is idealized as a sphere, and the defect type is selected as a pore defect. Multiple models are established for analysis using the ratio of the defect diameter to the plate thickness D / T. The plate thickness T is kept constant, and the defect is placed at the geometric center to calculate the creep life of the defect-containing structure. When studying the influence of defect location, the defect is idealized as a sphere, and the defect type is selected as a porosity defect. Multiple models are established for analysis using the ratio of defect location to plate thickness, L / T. The plate thickness T is kept constant, and the defect diameter is kept consistent to calculate the creep life of the defective structure. When studying the influence of defect shape, the defect is idealized as an ellipsoid and placed at the geometric center of the unit body. Multiple models are established for analysis by taking different ratios of the major axis to the minor axis a / c of ​​the defect. At this time, the minor axis c of the ellipse is kept unchanged, and the major axis size a is changed to solve the creep life of the defective structure.

7. The method for accepting manufacturing defects of high-temperature service welded components according to claim 3, characterized in that: The specific steps of step (3) are: The creep life t under different defect characteristics is normalized to obtain the creep life reduction degree t / , whose expression is: ； in, is the creep life of the defect-free structure obtained by finite element / experiment; t is the creep life of the defective structure; h 、 and g All are coefficients; is the ratio of the elastic modulus of the defect calculated from the test to the elastic modulus of the base material; is the ratio of the defect diameter to the plate thickness calculated from the experimental test; is the ratio of the defect position to the plate thickness calculated from the experimental test; is the ratio of the major axis to the minor axis of the defect calculated from the experimental test; By performing regression analysis on the creep life under different defect characteristics, we can obtain h 、 and g The mapping relationship between defect characteristics and creep life is: 。

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