Safety performance evaluation method and device for soft area-containing P91 pipe fitting

Abstract

The invention provides a safety performance evaluation method and device for a P91 pipe fitting containing a soft area, and the method comprises the steps: carrying out the hardness detection of the pipe fitting at a first number of detection points, and judging whether the soft area exists or not; if yes, hardness detection is carried out at the second number of detection points, and the soft region boundary is determined; constructing a normal area and soft area three-dimensional geometric model based on the specification and the soft area boundary, and performing finite element mesh division to obtain a pipe fitting three-dimensional geometric model; performing numerical simulation on the high-temperature creep behaviors of the normal area and the soft area based on the creep parameters of the normal area and the soft area and the creep damage constitutive model to obtain a numerical simulation result, performing stress analysis, and determining the damage stress of the soft area of the pipe fitting based on the obtained first stress and second stress; and determining the safety level of the pipe fitting based on the soft area damage stress. Therefore, numerical simulation is carried out by dividing the soft area and respectively constructing models, so that the obtained soft area damage stress can reflect the real stress level of the pipe fitting, and the accuracy of safety performance evaluation of the P91 pipe fitting containing the soft area is improved.

Description

Technical Field

[0001] The present application relates to the technical field of pipe component safety performance evaluation, and particularly to a safety performance evaluation method and device for P91 pipe components with soft zones. Background Art

[0002] Due to its excellent high-temperature creep strength, P91 steel has been widely used in high-temperature and high-pressure components such as main steam pipes in thermal power plants. However, under the long-term coupling action of the temperature field and stress field, P91 pipe components will inevitably undergo creep damage, affecting their structural integrity and operation reliability. Therefore, it is necessary to evaluate the safety performance of P91 pipe components.

[0003] The existing methods for evaluating the safety performance of P91 pipe components determine the damage stress of the pipe components through numerical simulation and stress analysis of the high-temperature creep behavior of P91 pipe components, and judge their safety performance based on the damage stress. However, since soft zones (Soft-Zone) often exist in P91 pipe components, the existence of soft zones will affect the distribution of internal creep stress in P91 pipe components, resulting in the determined damage stress being unable to reflect the true stress level of the pipe components with soft zones, and the accuracy of the safety performance evaluation of P91 pipe components with soft zones is relatively low. Summary of the Invention

[0004] In view of this, at least one embodiment of the present application provides a safety performance evaluation method and device for P91 pipe components with soft zones. By dividing the soft zones and respectively constructing models for numerical simulation, the obtained damage stress of the soft zones can reflect the true stress level of the pipe components, improving the accuracy of the safety performance evaluation of P91 pipe components with soft zones.

[0005] The present application mainly includes the following aspects:

[0006] In a first aspect, an embodiment of the present application provides a safety performance evaluation method for P91 pipe components with soft zones, the method comprising:

[0007] Performing hardness detection on a target pipe component at a first number of detection measuring point positions to determine whether there is a soft zone in the target pipe component;

[0008] If so, performing hardness detection on the target pipe component at a second number of detection measuring point positions to determine the soft zone boundary of the target pipe component; the second number is greater than the first number, and the second number of detection measuring point positions are arranged in a grid pattern on the surface of the target pipe component;

[0009] Based on the specifications of the target pipe component and the soft zone boundary, respectively construct a three-dimensional geometric model of the normal zone and a three-dimensional geometric model of the soft zone of the target pipe component, and perform finite element mesh division to obtain a three-dimensional geometric model of the target pipe component;

[0010] Based on the three-dimensional geometric model of the target pipe fitting, the creep parameters of the normal zone, the creep parameters of the soft zone, and the creep damage constitutive model, numerically simulate the high-temperature creep behavior of the normal zone and the soft zone of the target pipe fitting to obtain the numerical simulation results of the high-temperature creep behavior of the target pipe fitting;

[0011] Based on the numerical simulation results, perform stress analysis on the target pipe fitting to obtain the first stress and the second stress; the first stress is the peak stress of the maximum principal stress in the soft zone of the target pipe fitting at creep steady state, and the second stress is the peak stress of the Von Mises equivalent stress in the soft zone of the target pipe fitting;

[0012] Based on the first stress and the second stress, determine the damage stress of the soft zone of the target pipe fitting;

[0013] Based on the damage stress of the soft zone, determine the safety level of the target pipe fitting.

[0014] In a second aspect, an embodiment of the present application further provides a safety performance evaluation device for a P91 pipe fitting with a soft zone, and the safety performance evaluation device for a P91 pipe fitting with a soft zone includes:

[0015] A soft zone judgment module, configured to perform hardness detection on the target pipe fitting at the positions of the first number of detection points to judge whether there is a soft zone in the target pipe fitting;

[0016] A boundary division module, configured to, if so, perform hardness detection on the target pipe fitting at the positions of the second number of detection points to determine the soft zone boundary of the target pipe fitting; the second number is greater than the first number, and the positions of the second number of detection points are arranged in a grid pattern on the surface of the target pipe fitting;

[0017] A model construction module, configured to respectively construct a three-dimensional geometric model of the normal zone and a three-dimensional geometric model of the soft zone of the target pipe fitting based on the specifications of the target pipe fitting and the soft zone boundary, and perform finite element mesh division to obtain the three-dimensional geometric model of the target pipe fitting;

[0018] A numerical simulation module, configured to numerically simulate the high-temperature creep behavior of the normal zone and the soft zone of the target pipe fitting based on the three-dimensional geometric model of the target pipe fitting, the creep parameters of the normal zone, the creep parameters of the soft zone, and the creep damage constitutive model to obtain the numerical simulation results of the high-temperature creep behavior of the target pipe fitting;

[0019] A stress analysis module, configured to perform stress analysis on the target pipe fitting based on the numerical simulation results to obtain the first stress and the second stress; the first stress is the peak stress of the maximum principal stress in the soft zone of the target pipe fitting at creep steady state, and the second stress is the peak stress of the Von Mises equivalent stress in the soft zone of the target pipe fitting;

[0020] A first determination module, configured to determine the soft zone damage stress of the target pipe fitting based on the first stress and the second stress;

[0021] A second determination module, configured to determine the safety level of the target pipe fitting based on the soft zone damage stress.

[0022] In a third aspect, an embodiment of the present application further provides an electronic device, including: a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device runs, the processor communicates with the memory through the bus. When the machine-readable instructions are run by the processor, the steps of the safety performance evaluation method for the P91 pipe fitting with a soft zone as described above are executed.

[0023] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium. A computer program is stored on the computer-readable storage medium. When the computer program is run by a processor, the steps of the safety performance evaluation method for the P91 pipe fitting with a soft zone as described above are executed.

[0024] A safety performance evaluation method and device for a P91 pipe fitting with a soft zone provided by an embodiment of the present application perform hardness detection on a target pipe fitting at the positions of a first number of detection measurement points to determine whether there is a soft zone in the target pipe fitting; if so, perform hardness detection on the target pipe fitting at the positions of a second number of detection measurement points to determine the soft zone boundary of the target pipe fitting; the second number is greater than the first number, and the positions of the second number of detection measurement points are arranged in a grid pattern on the surface of the target pipe fitting; based on the specifications of the target pipe fitting and the soft zone boundary, a three-dimensional geometric model of the normal zone and a three-dimensional geometric model of the soft zone of the target pipe fitting are respectively constructed, and finite element mesh division is performed to obtain a three-dimensional geometric model of the target pipe fitting; based on the three-dimensional geometric model of the target pipe fitting, the creep parameters of the normal zone, the creep parameters of the soft zone, and the creep damage constitutive model, numerical simulation of the high-temperature creep behavior of the normal zone and the soft zone of the target pipe fitting is performed to obtain a numerical simulation result of the high-temperature creep behavior of the target pipe fitting; based on the numerical simulation result, stress analysis is performed on the target pipe fitting to obtain a first stress and a second stress; the first stress is the peak stress of the maximum principal stress in the soft zone of the target pipe fitting at creep steady state, and the second stress is the peak stress of the Von Mises equivalent stress in the soft zone of the target pipe fitting; based on the first stress and the second stress, the soft zone damage stress of the target pipe fitting is determined; based on the soft zone damage stress, the safety level of the target pipe fitting is determined. In this way, through soft zone division and separate model construction for numerical simulation, the obtained soft zone damage stress can reflect the true stress level of the pipe fitting, improving the accuracy of the safety performance evaluation of the P91 pipe fitting with a soft zone.

[0025] To make the above objects, features, and advantages of the present application more obvious and understandable, the following provides preferred embodiments in conjunction with the accompanying drawings and describes them in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] To more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can be obtained based on these drawings.

[0027] Figure 1 Shows a flowchart of a safety performance evaluation method for a P91 pipe fitting with a soft zone provided by an embodiment of the present application;

[0028] Figure 2 Shows one of the functional module diagrams of a safety performance evaluation device for a P91 pipe fitting with a soft zone provided by an embodiment of the present application;

[0029] Figure 3 Shows another functional module diagram of a safety performance evaluation device for a P91 pipe fitting with a soft zone provided by an embodiment of the present application;

[0030] Figure 4 Shows a schematic structural diagram of an electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] To make the objects, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all of them. Usually, the components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application to be protected, but only represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0032] In order to enable those skilled in the art to use the content of the present application, in combination with the specific application scenario of "safety performance evaluation of P91 pipe fittings with soft zones", the following embodiments are given. For those skilled in the art, without departing from the spirit and scope of the present application, the general principles defined here can be applied to other embodiments and application scenarios.

[0033] It is worth noting that before the present application was filed, there were two common schemes for evaluating the safety performance of P91 pipe fittings in the prior art, namely, a pipe cutting sampling scheme and a numerical simulation scheme.

[0034] Among them, the pipe cutting sampling scheme requires pipe cutting and sampling when evaluating the safety performance of pipe fittings, and conducts long-term creep endurance tests to obtain relevant test data. This method is time-consuming and labor-intensive, and the test conditions cannot reflect the complex actual working conditions of the equipment operation; in addition, the creep process is a multi-factor coupling process related to temperature, time, stress, and the internal microstructure of the material. The use of mathematical theory alone will produce large errors, and the equation solving process is also extremely difficult. In addition, the unevenness of the structural shape of engineering equipment will also lead to uneven stress distribution, and the numerical calculation accuracy of the creep damage behavior of the material is not high; at the same time, in actual applications, the conditions for pipe cutting and sampling are often not available, the economy is not high, and the safety performance evaluation of pipe fittings is difficult.

[0035] For numerical simulation schemes, the existing numerical simulation schemes regard the geometric network model of pipe fittings as a continuous, uniform, and single medium when evaluating the safety performance of pipe fittings, and use a unified creep damage constitutive model to perform numerical simulation and stress analysis of high-temperature creep behavior. These schemes cannot accurately reflect the stress level of pipe fittings containing soft areas, and the analysis results have large deviations, which in turn affects the evaluation results of the safety performance of pipe fittings.

[0036] In response to the above problems, an embodiment of the present application provides a method and device for evaluating the safety performance of P91 pipe fittings containing soft zones. By accurately dividing the soft zones of the pipe fittings, a three-dimensional finite element model of the normal zone and the soft zone is constructed. The high-temperature creep behavior of the normal zone and the soft zone of the pipe fittings is numerically simulated and stress analyzed respectively through the creep damage constitutive model. The obtained soft zone damage stress can reflect the actual stress level of the pipe fittings, thereby improving the accuracy of the safety performance assessment of P91 pipe fittings containing soft zones.

[0037] To facilitate the understanding of the present application, the technical solution provided by the present application is described in detail below in conjunction with specific embodiments.

[0038] See also Figure 1 , Figure 1 This is a flow chart of a method for evaluating the safety performance of a P91 pipe with a soft zone provided in an embodiment of the present application. Figure 1 As shown, the safety performance assessment method of the P91 pipe fitting containing a soft zone provided in the embodiment of the present application comprises the following steps:

[0039] S101, performing hardness testing on a target pipe at a first number of testing points to determine whether there is a soft area in the target pipe.

[0040] In the embodiments of the present application, taking the P91 pipe fittings of the main steam pipeline of an in-service electric field unit with a specification of 229×41 mm and steam parameters of 25.50 MPa / 570 °C under the condition of the boiler maximum continuous rating (BMCR) as the target pipe fittings, before evaluating the safety performance of the target pipe fittings, it is first necessary to determine whether there are soft zones in the target pipe fittings. Specifically, hardness tests are carried out on the target pipe fittings at the positions of the first number of detection points to determine whether there are soft zones in the target pipe fittings. Among them, the positions of the first number of detection points can be specifically set according to actual needs and are not specifically limited here.

[0041] S102, if so, perform a hardness test on the target pipe fittings at the positions of the second number of detection points to determine the soft zone boundary of the target pipe fittings; the second number is greater than the first number, and the positions of the second number of detection points are arranged in a grid pattern on the surface of the target pipe fittings.

[0042] Here, after confirming that there are soft zones in the target pipe fittings, in order to confirm the soft zone boundary of the target pipe fittings, the number of detection points is increased. Specifically, a hardness test is carried out on the target pipe fittings at the positions of the second number of detection points to determine the soft zone boundary of the target pipe fittings. Among them, the second number is greater than the first number, and the positions of the second number of detection points are arranged in a grid pattern on the surface of the target pipe fittings. The spacing between each of the second number of detection points is kept the same and is appropriately set and adjusted according to the specification of the pipe fittings to ensure the accurate division of the soft zone boundary. In the embodiments of the present application, the spacing between the positions of each of the second number of detection points is about 10 mm. The division of the soft zone boundary can show the distribution of the soft zone, including the distribution position, size, shape, etc. of the soft zone. Specifically, in the embodiments of the present application, the soft zone is distributed in the arc length of the pipe diameter from 10:00 to 2:00 and the axial length within 200 mm, with an area of about 65102.67 mm 2 , and the circumferential proportion of the area is about 4 / 12.

[0043] S103, based on the specification of the target pipe fittings and the soft zone boundary, respectively construct a three-dimensional geometric model of the normal zone and a three-dimensional geometric model of the soft zone of the target pipe fittings, and perform finite element mesh division to obtain the three-dimensional geometric model of the target pipe fittings.

[0044] Here, after determining the soft zone boundary of the target pipe fitting, a three-dimensional geometric model of the pipe fitting is constructed and finite element mesh division is performed. Specifically, with the aid of finite element analysis software, according to the specifications and soft zone boundary of the target pipe fitting, three-dimensional modeling is respectively carried out on the normal zone and the soft zone to obtain a normal three-dimensional zone geometric model and a soft zone three-dimensional geometric model, and a suitable mesh division method is used to perform finite element mesh division on the normal three-dimensional zone geometric model and the soft zone three-dimensional geometric model to obtain a three-dimensional geometric model of the target pipe fitting. Among them, the finite element mesh division methods include automatic mesh division, tetrahedral mesh division, hexahedral mesh division, sweeping method, multi-zone method, inflation method, etc. The appropriate division method should be adopted according to the specifications of the target pipe fitting to ensure the quality of the divided mesh and the accuracy of the finite element analysis. Among them, the specifications of the target pipe fitting refer to the comprehensive description of the size, shape, material and related standards of the target pipe fitting, which can be determined by on-site actual measurement or by the nominal specifications of the target pipe fitting. In the embodiment of the present application, the mesh element type adopts a standard eight-node hexahedral element, and at the same time, in order to ensure the accuracy of the local stress value and strain gradient of the simulation calculation, the mesh is refined. Finite Element Analysis (FEA) has the advantages and characteristics of convenient and fast operation and saving test time, and has been widely applied in engineering practice. Commonly used finite element analysis software mainly includes ANSYS, ADINA / COMSOL and MSC, etc. It has a rich element library, can simulate any complex geometric structure, and reflect subtle structural phenomena and differences between phenomena; at the same time, the finite element analysis software has a very rich model library, including creep damage constitutive models and criteria for judging material failure, etc. Therefore, the finite element analysis software can be used as a numerical simulation software to simulate complex structural mechanics problems and has advantages in solving non-linear problems such as the creep behavior of metal materials.

[0045] In the embodiment of the present application, the finite element analysis does not consider the phase change process of the pipe fitting material from the soft zone to the normal zone, and the material instantaneously changes from a soft material to a normal material; and in the actual detection process, since the depth of the soft zone cannot be measured, the finite element analysis defines the soft zone as the entire wall thickness penetrating the pipe wall.

[0046] S104, based on the three-dimensional geometric model of the target pipe fitting, the creep parameters of the normal zone, the creep parameters of the soft zone, and the creep damage constitutive model, numerically simulate the high-temperature creep behavior of the normal zone and the soft zone of the target pipe fitting to obtain the numerical simulation results of the high-temperature creep behavior of the target pipe fitting.

[0047] Here, with the help of numerical simulation software, the three-dimensional geometric model of the target pipe fitting, the creep parameters of the normal area, the creep parameters of the soft area, and the creep damage constitutive model are input into the numerical simulation software. The finite element analysis technology is used to numerically simulate the high-temperature creep behavior of the normal area and the soft area of the target pipe fitting, and the numerical simulation results of the high-temperature creep behavior of the target pipe fitting are obtained. Among them, the creep damage constitutive model is a mathematical model used to describe the mutual relationship between creep behavior and damage evolution under high temperature and long-term stress of materials, including any one of the Garofalo model, the Graham model, the Gurson model, the Kachanov-Rabotnov model, and the Norton model. In the embodiment of the present application, the Norton model is used as the creep damage constitutive model. Creep parameters can reflect the characteristics of materials during the creep process. For pipe fittings with soft areas, the soft area materials have different creep parameters from those of the normal area materials, and this inconsistent creep parameter will cause a creep relaxation effect between the soft area and the normal area. During the high-temperature creep process, the soft area is restricted by the surrounding normal materials, and the stress of the soft area materials will be more absorbed by the surrounding normal materials, and the stresses of the two areas are in a state of mutual balance, which will cause the stress level of the soft area materials to always be lower than that of the surrounding normal materials. Therefore, the existence of the soft area will affect the redistribution of creep stress inside the target pipe fitting. At the same time, the degree of influence is also related to factors such as the distribution position, size, shape, and direction of the soft area. Compared with the normal area, although the soft area has a worse creep fracture strength, because the soft area is also at a relatively lower creep steady-state stress level, this does not necessarily mean that it has a short service life. In other words, the soft area may still have a relatively high safety performance. If only simply performing numerical simulation and stress analysis according to normal pipe fittings, the stress level of the soft area of the pipe fitting cannot be accurately reflected, and there are likely to be large deviations in the analysis results. Therefore, different creep parameters should be used for the high-temperature creep behavior numerical simulation of the soft area and the normal area.

[0048] Among them, the creep parameters of the soft area and the normal area can be obtained by conducting high-temperature creep rupture tests on prefabricated matching specimens or by referring to literature materials. The prefabricated matching specimens refer to test samples prepared by different heat treatment systems to match the hardness values of the normal area and the soft area of the target pipe fitting. Since the hardness values are statistical data, hardness value matching refers to the matching of hardness ranges; in addition, since the time for conducting high-temperature creep rupture tests on the matching specimens is relatively long and the acquisition of creep test data is relatively slow, the creep test data of the target pipe fitting with matched hardness values can also be quickly obtained by referring to literature materials, and the creep parameters of the soft area and the normal area corresponding to the creep damage constitutive model can be obtained by substituting the creep test data into the creep constitutive equation for non-linear fitting.

[0049] In the embodiments of the present application, the numerical simulation is further divided into five sub-steps, namely: setting the boundary conditions for finite element analysis, selecting the creep damage constitutive model, selecting the creep parameters for the normal area and the soft area, numerical simulation in the elastic stage, and numerical simulation in the inelastic stage.

[0050] Specifically, first, set the boundary conditions for finite element analysis. To ensure the calculation results are on the safe side, the boundary conditions include the loading conditions of the main steam pipe corresponding to the target pipe fitting. Select the steam pressure and temperature parameters of the unit under the BMCR condition, that is, P = 25.50 MPa and t = 570 °C. The loading process is divided into two steps. The first step is the elastic analysis step, and there is no creep effect within a very small time value (10 -5 hours). During the first loading step of the simulation, the internal pressure rapidly increases from 0 to the defined applied pressure at the specified temperature (570 °C). The second step is the creep analysis step. In the second simulation step, the internal pressure and temperature applied in the first step remain constant, and a sufficient holding time is selected to reach the creep steady state.

[0051] In addition, to perform finite element analysis on the creep behavior of the material at a specific temperature, it is necessary to clarify the performance parameters of the material at the specific temperature. In the embodiments of the present application, the temperature-dependent properties of P91 material can be obtained by looking up the table. Among them, in the first elastic analysis, since the elastic properties (elastic modulus, Poisson's ratio) of the material are independent of hardness, the materials in the normal area and the soft area have the same material properties, and interpolation calculations can be performed by looking up the table: at 570 °C, the elastic modulus E of P91 material is 1.745×105 MPa, and the Poisson's ratio υ is 0.3.

[0052] Next, select the creep damage constitutive model. In the embodiments of the present application, since the creep curve of P91 steel in the second stage has an approximately stable creep rate. This stable or minimum creep strain rate (dε / dt) varies systematically with the applied stress and temperature. Therefore, for the creep test at a given temperature (570 °C), the dependence of the minimum creep strain rate on the applied stress can be described by Norton's law, and the formula is as follows:

[0053] where A and n are creep parameters, and σ is the applied stress.

[0054] Due to its simple implementation and effectiveness in describing creep deformation, Norton's law is widely used in solving practical engineering problems and has been applied to most commercial finite element analysis software, such as ANSYS software, etc. Therefore, in this embodiment, the Norton model (time-hardening creep model) is used as the creep damage constitutive model to simulate the high-temperature creep behavior of the normal area and the soft area of the target pipe fitting.

[0055] Next, the selection of creep parameters for the normal region and the soft region. In the embodiments of the present application, the creep parameters A and n in the Norton formula are usually obtained by conducting tensile creep tests at different stresses and temperatures. In this embodiment, the creep parameters of the normal region and the soft region are obtained by referring to the literature. Since the creep test results of normal P91 material at 600°C conform to the Watanabe relationship; at the same time, NIMS (National Institute for Materials Science, Japan) obtained the test results of normal region P91 material through long-term low-stress creep tests at 550°C. Therefore, the Watanabe data and NIMS data are selected to determine the creep parameter values of A and n for 91 material in the normal region at 600°C and 550°C, as shown in Table 1 below:

[0056] Table 1

[0057]

[0058] The Norton relationship for soft region 91 material below 600°C can be referred to the relevant research of EPRI (Electric Power Research Institute, USA). The Norton relationship of soft region 91 material at 600°C and 550°C is very close to that of T22 material. Based on the Norton relationship of T22 material, EPRI gives the creep parameter values of A and n for soft region 91 material at 600°C and 550°C, as shown in Table 2 below:

[0059] Table 2

[0060]

[0061] According to Table 1 and Table 2, the creep parameter values of A and n for normal region 91 and soft region 91 materials at 570°C can be obtained by interpolation calculation, as shown in Table 3 below:

[0062] Table 3

[0063]

[0064] Therefore, the Norton formula used to describe normal region P91 and soft region P91 in this embodiment can be expressed as follows:

[0065]

[0066] Next, numerical simulation of the elastic stage is carried out. Before simulating the long-term high-temperature creep behavior of the main steam pipeline, it is necessary to conduct elastic analysis first. Elastic analysis not only provides validity verification for the quality of the finite element model establishment, the rationality of the boundary condition setting, and the accuracy of the load applied to the finite element model, but also establishes an accurate initial state for creep analysis.

[0067] Finally, perform numerical simulations in the inelastic stage. Conduct inelastic creep analysis on the main steam pipeline under loading conditions to obtain the numerical simulation results of the high-temperature creep behavior of the target pipe fitting, i.e., the distribution of the maximum principal stress and Von Mises equivalent stress in the normal area and the soft area. Since creep steady state refers to the second stage of the creep process of the pipe fitting, when performing numerical simulations of the high-temperature creep behavior of the pipe fitting, the loading time of the numerical simulation is set to 100,000 hours.

[0068] S105. Based on the numerical simulation results, perform stress analysis on the target pipe fitting to obtain a first stress and a second stress; the first stress is the peak stress of the maximum principal stress in the soft area of the target pipe fitting at creep steady state, and the second stress is the peak stress of the Von Mises equivalent stress in the soft area of the target pipe fitting.

[0069] Here, based on the numerical simulation results obtained in step S104, i.e., the distribution of the maximum principal stress and Von Mises equivalent stress in the normal area and the soft area, perform stress analysis on the pipe fitting to obtain a first stress and a second stress, where the first stress is the peak stress σ of the maximum principal stress in the soft area of the target pipe fitting at creep steady state, that is, when the main steam pipeline reaches creep steady state at about 100,000 hours. θ软max The second stress is the peak stress σ of the Von Mises equivalent stress in the soft area of the target pipe fitting. eqmax Among them, the Von Mises equivalent stress is an equivalent stress index used to describe whether a material will undergo plastic deformation under complex stress states.

[0070] S106. Based on the first stress and the second stress, determine the damage stress of the soft area of the target pipe fitting.

[0071] Here, in most cases, the creep damage of the soft area is caused by the combined action of the first stress σ θ软max and the second stress σ eqmax . Therefore, based on the first stress σ θ软max and the second stress σ eqmax , the damage stress σ of the soft area of the target pipe fitting can be determined. r

[0072] S107. Based on the damage stress of the soft area, determine the safety level of the target pipe fitting.

[0073] Here, according to the damage stress σ of the soft area of the target pipe fitting obtained in S105 r , determine the corresponding safety level for the target pipe fitting. Since the damage stress σ of the soft area r can accurately reflect the stress level of the target pipe fitting, the accurate assessment of the safety performance of the target pipe fitting is thus realized.

[0074] Further, the hardness of the target pipe fitting is detected at the first number of detection point positions to determine whether there is a soft area in the target pipe fitting, including:

[0075] Step a1, use a Leeb hardness tester to detect the hardness of the target pipe fitting at the first number of detection point positions, and determine the first hardness value of the target pipe fitting at each of the detection point positions.

[0076] In the embodiment of the present application, an HT-1000A portable Leeb hardness tester is used to detect the hardness of the target pipe fitting at the first number of detection point positions, and the first hardness value of the target pipe fitting at each detection point position is determined.

[0077] Step a2, if the first hardness value at the first detection point position is less than the preset first hardness threshold, use a Brinell hardness tester to detect the hardness of the target pipe fitting at the first detection point position, and determine the second hardness value of the target pipe fitting at the first detection point position.

[0078] Here, if the first hardness value at the first detection point position is less than the preset first hardness threshold, in order to prevent errors caused by the detection results of the portable Leeb hardness tester, a PHB-200 magnetic Brinell hardness tester is used to check the hardness value at the first detection point position, and the second hardness value of the target pipe fitting at the first detection point position is determined. Among them, the preset first hardness threshold is 180 HBHLD.

[0079] Step a3, if the second hardness value at the first detection point position is less than the preset second hardness threshold, it is determined that there is a soft area in the target pipe fitting.

[0080] Here, if the second hardness value at the first detection point position is less than the preset second hardness threshold after verification, it is determined that there is a soft area in the target pipe fitting. Among them, the preset second hardness threshold is 180 HBW.

[0081] Step a4, if the first hardness values at the first number of detection point positions are all greater than or equal to the first hardness threshold, or the second hardness values at each of the first detection point positions are all greater than or equal to the second hardness threshold, it is determined that there is no soft area in the target pipe fitting.

[0082] Here, if the first hardness values at the first number of detection point positions are all greater than or equal to the first hardness threshold, or the second hardness values at each of the first detection point positions are all greater than or equal to the second hardness threshold, it means that there is no soft area in the target pipe fitting, and it can be directly processed according to the existing pipe fitting safety performance evaluation scheme, without the need to evaluate the safety performance of the pipe fitting with a soft area.

[0083] Further, the hardness inspection of the target pipe fitting at the second number of inspection point positions to determine the soft zone boundary of the target pipe fitting includes:

[0084] Step b1, use a Leeb hardness tester to perform hardness inspection on the target pipe fitting at the second number of inspection point positions to determine the third hardness value of the target pipe fitting at each of the inspection point positions.

[0085] Here, after confirming that there is a soft zone in the target pipe fitting, use a portable Leeb hardness tester to perform hardness inspection at the second number of inspection point positions, and record the third hardness value corresponding to each of the second number of inspection point positions.

[0086] Step b2, if the third hardness value at the second inspection point position is less than the first hardness threshold, use a Brinell hardness tester to perform hardness inspection on the target pipe fitting at the second inspection point position to determine the fourth hardness value of the target pipe fitting at the second inspection point position.

[0087] Here, if the third hardness value at the second inspection point position is less than the first hardness threshold, use a magnetic Brinell hardness tester to check the target pipe fitting at the second inspection point position to determine the fourth hardness value of the target pipe fitting at the second inspection point position.

[0088] Step b3, determine the second inspection point position where the fourth hardness value is less than the second hardness threshold as the third inspection point position corresponding to the soft zone of the target pipe fitting.

[0089] Here, determine the second inspection point position where the fourth hardness value is less than the second hardness threshold as the third inspection point position corresponding to the soft zone of the target pipe fitting.

[0090] Step b4, connect the outermost third inspection point positions among the third inspection point positions to obtain the soft zone boundary of the target pipe fitting.

[0091] Here, connect the outermost third inspection point positions among the third inspection point positions to obtain the soft zone boundary of the target pipe fitting. Among them, the division of the soft zone boundary can show the distribution of the soft zone, including the distribution position, size, shape, etc.

[0092] Further, the determination of the soft zone damage stress of the target pipe fitting based on the first stress and the second stress includes:

[0093] Step c1, determine the first weight of the first stress and the second weight of the second stress according to the creep damage mechanism of the soft zone of the target pipe fitting.

[0094] Here, according to the creep damage mechanism of the soft zone of the target pipe fitting, determine the first stress σ θ软maxThe first weight α and the second stress σ eqmax The second weight β. Specifically, if the creep damage mechanism in the soft zone is mainly dominated by the coarsening of the material structure and there are few creep cavities, the first weight α is 0 and the second weight β is 1, and the second stress σ eqmax is used as the damage stress σ r of the soft zone under the multiaxial stress state; if the creep damage mechanism in the soft zone is mainly dominated by creep cavities and cracks, the failure of the material is controlled by the first stress σ θ软max , the first weight α is 1 and the second weight β is 0, then the first stress σ θ软max is used as the damage stress σ r of the soft zone; in most cases, the creep damage in the soft zone is caused by the combined action of the first stress σ θ软max and the second stress σ eqmax , and can be calculated according to the following formula:

[0095] σ r = ασ θ软max + βσ eqmax ;

[0096] In the embodiments of the present application, for P91 steel, α = β = 0.5.

[0097] Step c2, determine the damage stress of the soft zone of the target pipe fitting according to the first stress, the first weight, the second stress and the second weight.

[0098] Here, according to the above formula σ r = ασ θ软max + βσ eqmax , determine the damage stress σ θ软max of the soft zone of the target pipe fitting according to the first stress σ eqmax , the first weight α, the second stress σ r .

[0099] Further, determining the safety level of the target pipe fitting based on the damage stress of the soft zone includes:

[0100] Step d1, if the damage stress of the soft zone is less than or equal to the first damage stress threshold, determine that the safety level of the target pipe fitting is the first safety level; the first damage stress threshold is the ten-thousand-hour creep rupture strength value of the target pipe fitting.

[0101] Here, if the damage stress σ r of the soft zone is less than or equal to the first damage stress threshold then determine that the safety level of the target pipe fitting is the first safety level; among them, the safety assessment of the pipe fitting at the first safety level is "high", indicating that the pipe fitting can continue to be put into operation. In the embodiments of the present application, the first damage stress threshold is the ten-thousand-hour creep rupture strength value of the target pipe fitting

[0102] Step d2, if the soft zone damage stress is greater than the first damage stress threshold and less than or equal to the second damage stress threshold, determine that the safety level of the target pipe fitting is the second safety level; the second damage stress threshold is the ten-thousand-hour creep rupture strength value of the target pipe fitting.

[0103] Here, if the soft zone damage stress σ r is greater than the first damage stress threshold and less than or equal to the second damage stress threshold then determine that the safety level of the target pipe fitting is the second safety level; among them, the safety assessment of the pipe fitting at the second safety level is "medium", indicating that the life of the pipe fitting should be evaluated and the operation should be supervised. In the embodiments of the present application, the second damage stress threshold is the ten-thousand-hour creep rupture strength value of the target pipe fitting

[0104] Step d3, if the soft zone damage stress is greater than the second damage stress threshold, determine that the safety level of the target pipe fitting is the third safety level.

[0105] Here, if the soft zone damage stress σ r is greater than the second damage stress threshold then determine that the safety level of the target pipe fitting is the third safety level; among them, the safety assessment of the pipe fitting at the third safety level is "low", indicating that the pipe fitting should be replaced.

[0106] Furthermore, the first damage stress threshold and the second damage stress threshold can be determined by referring to the literature. In the embodiments of the present application, when performing the safety assessment, a relatively low value should be taken for the creep rupture strength to ensure that the solution result is on the safe side, that is, the creep rupture strength value of the soft zone of the main steam pipeline at 570 °C for 10 5 h, that is, the first damage stress threshold is 79.7 MPa, and the creep rupture strength value of 10 4 h, that is, the second damage stress threshold is 101.22 MPa.

[0107] Furthermore, the method further includes:

[0108] Step e1, if the safety level of the target pipe fitting is the second safety level, calculate the creep remaining life of the soft zone of the target pipe fitting based on the soft zone damage stress and a preset pipe fitting life calculation method; the pipe fitting life calculation method includes one of the isothermal extrapolation method and the L-M parameter curve method.

[0109] Here, if the safety level of the target pipe fitting is the second safety level, without replacing the pipe fitting with abnormal hardness, in order to ensure the safety and reliability of the unit operation, it is necessary to evaluate the life of the target pipe fitting. Specifically, the life evaluation method generally adopts the isothermal extrapolation method and the L-M parameter curve method. When calculating the life, the damage stress in the soft zone should be selected as the calculation stress. Specifically, when using the isothermal extrapolation method, the damage stress σ r is substituted into the creep life formula for solution, and σ r = σ θ软max = 76.15 MPa is substituted into the above formula. After calculation, the remaining life t r of the P91 pipe fitting with a soft zone in the embodiment of the present application is 155104 h; when using the L-M parameter curve method, since the P91 material in the soft zone has the same L-M parameter curve as the P / T22 material, the L-M parameter curve of the P / T22 steel can be referred to for calculation and solution.

[0110] Step e2: Determine the creep remaining life of the soft zone of the target pipe fitting as the remaining life of the target pipe fitting.

[0111] Here, the creep remaining life of the soft zone of the target pipe fitting is determined as the remaining life of the target pipe fitting to further evaluate the pipe fitting safety performance of the target pipe fitting, help technicians make accurate judgments, and improve the operation reliability and economy of the unit equipment.

[0112] An embodiment of the present application provides a method for evaluating the safety performance of a P91 pipe fitting with a soft zone, including: performing hardness detection on a target pipe fitting at the positions of a first number of detection points to determine whether there is a soft zone in the target pipe fitting; if so, performing hardness detection on the target pipe fitting at the positions of a second number of detection points to determine the boundary of the soft zone of the target pipe fitting; the second number is greater than the first number, and the positions of the second number of detection points are arranged in a grid pattern on the surface of the target pipe fitting; based on the specifications of the target pipe fitting and the soft zone boundary, respectively construct a three-dimensional geometric model of the normal zone and a three-dimensional geometric model of the soft zone of the target pipe fitting, and perform finite element mesh division to obtain a three-dimensional geometric model of the target pipe fitting; based on the three-dimensional geometric model of the target pipe fitting, the creep parameters of the normal zone, the creep parameters of the soft zone, and the creep damage constitutive model, perform numerical simulation on the high-temperature creep behavior of the normal zone and the soft zone of the target pipe fitting to obtain a numerical simulation result of the high-temperature creep behavior of the target pipe fitting; based on the numerical simulation result, perform stress analysis on the target pipe fitting to obtain a first stress and a second stress; the first stress is the peak stress of the maximum principal stress in the soft zone of the target pipe fitting at the creep steady state, and the second stress is the peak stress of the Von Mises equivalent stress in the soft zone of the target pipe fitting; based on the first stress and the second stress, determine the damage stress of the soft zone of the target pipe fitting; based on the damage stress of the soft zone, determine the safety level of the target pipe fitting. In this way, by dividing the soft zone and respectively constructing models for numerical simulation, the obtained damage stress of the soft zone can reflect the true stress level of the pipe fitting, improving the accuracy of the safety performance evaluation of the P91 pipe fitting with a soft zone.

[0113] Based on the same inventive concept, an embodiment of the present application also provides a safety performance evaluation device for a P91 pipe fitting with a soft zone corresponding to the safety performance evaluation method for a P91 pipe fitting with a soft zone provided in the above embodiment. Since the principle of solving problems by the device in the embodiment of the present application is similar to the safety performance evaluation method for a P91 pipe fitting with a soft zone in the above embodiment of the present application, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be described again.

[0114] Please refer to Figure 2 , Figure 2 which is one of the functional module diagrams of a safety performance evaluation device for a P91 pipe fitting with a soft zone provided by an embodiment of the present application. As Figure 2 shown, the safety performance evaluation device 200 for a P91 pipe fitting with a soft zone includes:

[0115] A soft zone judgment module 210, configured to perform hardness detection on a target pipe fitting at the positions of a first number of detection points to determine whether there is a soft zone in the target pipe fitting.

[0116] A boundary division module 220, which is used to, if so, perform hardness detection on the target pipe fitting at the positions of the second number of detection points, and determine the soft zone boundary of the target pipe fitting; the second number is greater than the first number, and the positions of the second number of detection points are arranged in a grid pattern on the surface of the target pipe fitting.

[0117] A model construction module 230, which is used to respectively construct a three-dimensional geometric model of the normal zone and a three-dimensional geometric model of the soft zone of the target pipe fitting based on the specifications of the target pipe fitting and the soft zone boundary, and perform finite element mesh division to obtain a three-dimensional geometric model of the target pipe fitting.

[0118] A numerical simulation module 240, which is used to numerically simulate the high-temperature creep behavior of the normal zone and the soft zone of the target pipe fitting based on the three-dimensional geometric model of the target pipe fitting, the creep parameters of the normal zone, the creep parameters of the soft zone, and the creep damage constitutive model, and obtain the numerical simulation results of the high-temperature creep behavior of the target pipe fitting.

[0119] A stress analysis module 250, which is used to perform stress analysis on the target pipe fitting based on the numerical simulation results to obtain a first stress and a second stress; the first stress is the peak stress of the maximum principal stress in the soft zone of the target pipe fitting at the creep steady state, and the second stress is the peak stress of the Von Mises equivalent stress in the soft zone of the target pipe fitting.

[0120] A first determination module 260, which is used to determine the soft zone damage stress of the target pipe fitting based on the first stress and the second stress.

[0121] A second determination module 270, which is used to determine the safety level of the target pipe fitting based on the soft zone damage stress.

[0122] Further, when the soft zone judgment module 210 is used to perform hardness detection on the target pipe fitting at the positions of the first number of detection points and judge whether there is a soft zone in the target pipe fitting, the soft zone judgment module 210 is specifically used for:

[0123] Use a Leeb hardness tester to perform hardness detection on the target pipe fitting at the positions of the first number of detection points, and determine the first hardness value of the target pipe fitting at each of the detection point positions;

[0124] If there is a first hardness value at the first detection point position that is less than a preset first hardness threshold, then use a Brinell hardness tester to perform hardness detection on the target pipe fitting at the first detection point position, and determine the second hardness value of the target pipe fitting at the first detection point position;

[0125] If there is a second hardness value at the first detection point position that is less than a preset second hardness threshold, then determine that there is a soft zone in the target pipe fitting;

[0126] If the first hardness values at the first quantity of detection point positions are all greater than or equal to the first hardness threshold, or the second hardness values at each of the first detection point positions are all greater than or equal to the second hardness threshold, it is determined that there is no soft zone in the target pipe fitting.

[0127] Further, when the boundary division module 220 is used to perform hardness detection on the target pipe fitting at the second quantity of detection point positions to determine the soft zone boundary of the target pipe fitting, the boundary division module 220 specifically is used for:

[0128] Perform hardness detection on the target pipe fitting at the second quantity of detection point positions using a Leeb hardness tester to determine the third hardness value of the target pipe fitting at each of the detection point positions;

[0129] If there is a third hardness value at a second detection point position that is less than the first hardness threshold, perform hardness detection on the target pipe fitting at the second detection point position using a Brinell hardness tester to determine the fourth hardness value of the target pipe fitting at the second detection point position;

[0130] Determine the second detection point positions where the fourth hardness value is less than the second hardness threshold as the third detection point positions corresponding to the soft zone of the target pipe fitting;

[0131] Connect the outermost third detection point positions among the third detection point positions to obtain the soft zone boundary of the target pipe fitting.

[0132] Further, when the first determination module 260 is used to determine the soft zone damage stress of the target pipe fitting based on the first stress and the second stress, the first determination module 260 specifically is used for:

[0133] Determine the first weight of the first stress and the second weight of the second stress according to the creep damage mechanism of the soft zone of the target pipe fitting;

[0134] Determine the soft zone damage stress of the target pipe fitting according to the first stress, the first weight, the second stress, and the second weight.

[0135] Further, when the second determination module 270 is used to determine the safety level of the target pipe fitting based on the soft zone damage stress, the second determination module 270 specifically is used for:

[0136] If the soft zone damage stress is less than or equal to the first damage stress threshold, determine that the safety level of the target pipe fitting is the first safety level; the first damage stress threshold is the ten - thousand - hour creep - rupture strength value of the target pipe fitting;

[0137] If the soft zone damage stress is greater than the first damage stress threshold and less than or equal to the second damage stress threshold, determine that the safety level of the target pipe fitting is the second safety level; the second damage stress threshold is the ten-thousand-hour endurance strength value of the target pipe fitting.

[0138] If the soft zone damage stress is greater than the second damage stress threshold, determine that the safety level of the target pipe fitting is the third safety level.

[0139] Further, please refer to Figure 3 , Figure 3 which is the second functional module diagram of a safety performance evaluation device for a P91 pipe fitting with a soft zone provided by an embodiment of the present application. As Figure 3 shown, the safety performance evaluation device 200 for a P91 pipe fitting with a soft zone further includes:

[0140] A life calculation module 280, configured to calculate the creep remaining life of the soft zone of the target pipe fitting based on the soft zone damage stress and a preset pipe fitting life calculation method if the safety level of the target pipe fitting is the second safety level; the pipe fitting life calculation method includes one of an isothermal extrapolation method and an L-M parameter curve method.

[0141] A life determination module 290, configured to determine the creep remaining life of the soft zone of the target pipe fitting as the remaining life of the target pipe fitting.

[0142] An embodiment of the present application provides a safety performance evaluation device for P91 pipe fittings with soft zones, including a soft zone judgment module for performing hardness detection on a target pipe fitting at a first number of detection point positions to determine whether there is a soft zone in the target pipe fitting; a boundary division module for, if so, performing hardness detection on the target pipe fitting at a second number of detection point positions to determine the soft zone boundary of the target pipe fitting; the second number being greater than the first number, and the second number of detection point positions being arranged in a grid pattern on the surface of the target pipe fitting; a model construction module for respectively constructing a three-dimensional geometric model of the normal zone and a three-dimensional geometric model of the soft zone of the target pipe fitting based on the specifications of the target pipe fitting and the soft zone boundary, and performing finite element mesh division to obtain a three-dimensional geometric model of the target pipe fitting; a numerical simulation module for performing numerical simulation on the high-temperature creep behavior of the normal zone and the soft zone of the target pipe fitting based on the three-dimensional geometric model of the target pipe fitting, the creep parameters of the normal zone, the creep parameters of the soft zone, and the creep damage constitutive model to obtain a numerical simulation result of the high-temperature creep behavior of the target pipe fitting; a stress analysis module for performing stress analysis on the target pipe fitting based on the numerical simulation result to obtain a first stress and a second stress; the first stress being the peak stress of the maximum principal stress in the soft zone of the target pipe fitting at the creep steady state, and the second stress being the peak stress of the Von Mises equivalent stress in the soft zone of the target pipe fitting; a first determination module for determining the soft zone damage stress of the target pipe fitting based on the first stress and the second stress; a second determination module for determining the safety level of the target pipe fitting based on the soft zone damage stress. In this way, by dividing the soft zone and respectively constructing models for numerical simulation, the obtained soft zone damage stress can reflect the true stress level of the pipe fitting, improving the accuracy of the safety performance evaluation of P91 pipe fittings with soft zones.

[0143] Based on the same inventive concept, please refer to Figure 4 , Figure 4 which is a schematic structural diagram of an electronic device provided by an embodiment of the present application. As Figure 4 shown, the electronic device 400 includes: a processor 410, a memory 420, and a bus 430.

[0144] The memory 420 stores machine-readable instructions executable by the processor 410. When the electronic device 400 runs, the processor 410 communicates with the memory 420 through the bus 430. When the machine-readable instructions are run by the processor 410, they execute the steps of the safety performance evaluation method for P91 pipe fittings with soft zones provided in the above embodiment. The specific implementation manner can be seen in the method embodiment and will not be elaborated here.

[0145] Based on the same application concept, an embodiment of the present application further provides a computer-readable storage medium. A computer program is stored on the computer-readable storage medium. When the computer program is run by a processor, it executes the steps of the safety performance evaluation method for the soft zone P91 pipe fittings provided in the above embodiment. The specific implementation manner can be referred to the method embodiment and will not be elaborated herein.

[0146] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described devices and units can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0147] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there may be other division methods in actual implementation. For another example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed mutual coupling or direct coupling or communication connection can be through some communication interfaces. The indirect coupling or communication connection of the devices or units can be in an electrical, mechanical or other form.

[0148] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0149] In addition, each functional unit in the embodiments provided in the present application can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0150] When the above-mentioned functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of this application. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs.

[0151] It should be noted that: similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0152] Finally, it should be noted that: the above-mentioned embodiments are only specific implementation manners of this application, used to illustrate the technical solution of this application, rather than limiting it. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: any person skilled in the art within the technical scope disclosed in this application can still modify the technical solutions recorded in the foregoing embodiments, or can easily think of changes, or perform equivalent replacements on some of the technical features; and these modifications, changes, or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of this application. All should be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A method for evaluating the safety performance of P91 pipe fittings containing soft areas, characterized in that: The method comprises: Performing hardness testing on a target pipe at a first number of testing points to determine whether there is a soft area in the target pipe; If yes, hardness test is performed on the target pipe at a second number of test points to determine the soft zone boundary of the target pipe; the second number is greater than the first number, and the second number of test points are arranged on the surface of the target pipe in a grid-like distribution; Based on the specifications of the target pipe and the boundary of the soft zone, a three-dimensional geometric model of the normal zone and a three-dimensional geometric model of the soft zone of the target pipe are respectively constructed, and finite element meshing is performed to obtain a three-dimensional geometric model of the target pipe; Based on the three-dimensional geometric model of the target pipe, the creep parameters of the normal zone, the creep parameters of the soft zone, and the creep damage constitutive model, the high-temperature creep behavior of the normal zone and the soft zone of the target pipe is numerically simulated to obtain the numerical simulation result of the high-temperature creep behavior of the target pipe; Based on the numerical simulation results, a stress analysis is performed on the target pipe to obtain a first stress and a second stress; the first stress is a peak stress of the maximum principal stress of the soft zone of the target pipe in the creep steady state, and the second stress is a peak stress of the Von Mises equivalent stress of the soft zone of the target pipe; Determining the soft zone damage stress of the target pipe based on the first stress and the second stress; Based on the soft zone damage stress, the safety level of the target pipe is determined.

2. The safety performance assessment method of P91 pipe fittings containing soft areas according to claim 1 is characterized in that: The hardness test of the target pipe is performed at the first number of test points to determine whether there is a soft zone in the target pipe, including: Perform hardness testing on the target pipe at a first number of testing points using a Leeb hardness tester to determine a first hardness value of the target pipe at each of the testing points; If there is a first hardness value at the first detection measuring point position that is less than a preset first hardness threshold, a hardness test is performed on the target pipe at the first detection measuring point position using a Brinell hardness tester to determine a second hardness value of the target pipe at the first detection measuring point position; If the second hardness value at the first detection point is less than a preset second hardness threshold, it is determined that a soft area exists in the target pipe; If the first hardness values ​​of the first number of detection measuring point positions are all greater than or equal to the first hardness threshold, or the second hardness values ​​of each of the first detection measuring point positions are all greater than or equal to the second hardness threshold, it is determined that no soft zone exists in the target pipe.

3. The safety performance assessment method of P91 pipe fittings with soft areas according to claim 2 is characterized in that: The performing hardness testing on the target pipe at the second number of testing points to determine the soft zone boundary of the target pipe includes: Performing hardness testing on the target pipe at a second number of testing points using a Leeb hardness tester to determine a third hardness value of the target pipe at each of the testing points; If there is a third hardness value at the second detection measuring point position that is less than the first hardness threshold, a hardness test is performed on the target pipe at the second detection measuring point position using a Brinell hardness tester to determine a fourth hardness value of the target pipe at the second detection measuring point position; Determine the second detection point position where the fourth hardness value is less than the second hardness threshold as the third detection point position corresponding to the soft zone of the target pipe; The outermost third detection point positions among the third detection point positions are connected to obtain the soft zone boundary of the target pipe.

4. The safety performance assessment method of P91 pipe fittings with soft areas according to claim 1 is characterized in that: The creep damage constitutive model includes any one of the Garofalo model, the Graham model, the Gurson model, the Kachanov-Rabotnov model and the Norton model.

5. The method for evaluating the safety performance of a P91 pipe with a soft zone according to claim 1, characterized in that: The determining the soft zone damage stress of the target pipe based on the first stress and the second stress includes: Determining a first weight of the first stress and a second weight of the second stress according to a creep damage mechanism of the soft zone of the target pipe; The soft zone damage stress of the target pipe is determined according to the first stress, the first weight, the second stress and the second weight.

6. The method for evaluating the safety performance of P91 pipe fittings containing soft areas according to claim 1, characterized in that: The step of determining the safety level of the target pipe based on the soft zone damage stress includes: If the soft zone damage stress is less than or equal to a first damage stress threshold, the safety level of the target pipe is determined to be the first safety level; the first damage stress threshold is the 100,000-hour endurance strength value of the target pipe; If the soft zone damage stress is greater than the first damage stress threshold and less than or equal to the second damage stress threshold, the safety level of the target pipe is determined to be the second safety level; the second damage stress threshold is the 10,000-hour endurance strength value of the target pipe; If the soft zone damage stress is greater than the second damage stress threshold, the safety level of the target pipe is determined to be the third safety level.

7. The method for evaluating the safety performance of a P91 pipe with a soft zone according to claim 6, characterized in that: The method further comprises: If the safety level of the target pipe is the second safety level, the creep residual life of the soft zone of the target pipe is calculated based on the soft zone damage stress and a preset pipe life calculation method; the pipe life calculation method includes one of an isotherm extrapolation method and an LM parameter curve method; The creep remaining life of the soft zone of the target pipe is determined as the remaining life of the target pipe.

8. A safety performance assessment device for P91 pipe fittings with soft zones, characterized in that: The safety performance assessment device for the P91 pipe fittings containing soft areas comprises: A soft zone determination module, configured to perform hardness detection on a target pipe at a first number of detection points to determine whether a soft zone exists in the target pipe; A boundary division module is used for, if the target pipe is subjected to hardness testing at a second number of testing points, to determine the soft zone boundary of the target pipe; the second number is greater than the first number, and the second number of testing points are arranged on the surface of the target pipe in a grid-like distribution; A model building module, for building a normal zone three-dimensional geometric model and a soft zone three-dimensional geometric model of the target pipe respectively based on the specification of the target pipe and the soft zone boundary, and performing finite element meshing to obtain a three-dimensional geometric model of the target pipe; A numerical simulation module, for numerically simulating the high-temperature creep behavior of the normal zone and the soft zone of the target pipe based on the three-dimensional geometric model of the target pipe, the creep parameters of the normal zone, the creep parameters of the soft zone, and the creep damage constitutive model, to obtain the numerical simulation results of the high-temperature creep behavior of the target pipe; A stress analysis module, for performing stress analysis on the target pipe based on the numerical simulation result to obtain a first stress and a second stress; the first stress is a peak stress of the maximum principal stress of the soft zone of the target pipe in a creep steady state, and the second stress is a peak stress of the Von Mises equivalent stress of the soft zone of the target pipe; A first determination module, configured to determine the soft zone damage stress of the target pipe based on the first stress and the second stress; The second determination module is used to determine the safety level of the target pipe based on the soft zone damage stress.

9. An electronic device, characterized in that: include: A processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor and the memory communicate through the bus, and the machine-readable instructions are executed by the processor to execute the steps of the method for assessing the safety performance of P91 pipe fittings containing soft areas as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for evaluating the safety performance of a P91 pipe fitting containing a soft zone as described in any one of claims 1 to 7 are executed.

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