Creep life prediction method of heat-resistant steel welded joint and related device

Abstract

The invention discloses a creep life prediction method of a heat-resistant steel welded joint and a related device, and relates to the field of metal material high-temperature mechanical property research, and the creep life prediction method comprises the following steps: acquiring creep test data of a plurality of heat-resistant steel welded joint samples, and grouping to obtain creep test data under different cracking forms; the threshold stress of cracking form transformation is determined through creep test data; the creep test data under each cracking form is used for determining all coefficients in a Marson-Miller equation corresponding to each cracking form; determining the cracking form according to the comparison of the loading stress applied by the to-be-tested heat-resistant steel welding joint in the creep test and a threshold value; and predicting the creep life of the to-be-tested heat-resistant steel welded joint by using the Marson-Miller equation of the cracking form corresponding to the to-be-tested heat-resistant steel welded joint. The method can accurately predict the creep life of the heat-resistant steel welded joint.

Description

Technical Field

[0001] The present application relates to the research field of high-temperature mechanical properties of metal materials, and in particular to a creep life prediction method and related devices for heat-resistant steel welded joints. Background Art

[0002] Ferrite / martensite heat-resistant steel is the most commonly used type of heat-resistant metal in supercritical and ultra-supercritical units. It has good high-temperature mechanical properties, and creep resistance is one of the most important performance indicators of related materials. Welded joints are indispensable structures in the production process of high-temperature components. Their creep performance is affected by the production process and organizational characteristics. Their performance is significantly lower than that of homogeneous heat-resistant steel, and they are weak areas in high-temperature and high-pressure units. Accurately predicting the creep life of ferrite / martensite heat-resistant steel welded joints is of great engineering significance for ensuring the normal operation of the unit and maintaining high production efficiency. At present, in academic research and engineering practice, the commonly used life prediction methods are mainly divided into three types: one is the study of creep life consumption, such as Robinson linear fracture law, creep deformation fraction method and resistance method; the second is the method based on creep strain analysis, such as Omega parameter method, θ parameter method, CDM model, time-minimum creep rate model, necking model, creep rate prediction method under minimum stress, etc.; the third is the study of creep life extrapolation, such as isothermal extrapolation method and time-temperature parameter method. The third method is widely used in the prediction of creep life of various heat-resistant alloys due to its simplicity and high accuracy. The equation used by the isotherm extrapolation method to describe the relationship between creep life and stress can be expressed as: σ = A (t r ) m ; where σ is the loading stress, t r is the fracture time, A and m are constants related to the material. This formula has a simple structure and few parameters. It can quickly evaluate the material life at a single temperature. However, in practical applications, its application range is narrow and the prediction accuracy is insufficient. The commonly used time-temperature parameter methods are mainly Orr-Sherby-Dorn method (OSD method for short), Manson-Haferd parameter method (MHP method for short) and Larson-Miller method. Taking OSD method and MHP method as examples, their main equations are: Where Q is the activation energy, R is the gas constant, T is the absolute temperature; logt a and T a is a constant term. a0, a1, a2, a n is the regression coefficient, n is the order of the regression equation, e nis the error term. Compared with other creep life test methods, this type of time-temperature parameter method has a simple operation process, relatively easy data acquisition, and relatively accurate life prediction results. It has always been the most popular life prediction method. However, it has been verified by engineering and experiments that the traditional time-temperature parameter method can maintain a high accuracy when used for homogeneous materials, but when applied to heterogeneous materials such as welded joints, it will produce a large prediction error. In engineering, welded joints are one of the indispensable structures in steel structure production. The microstructure is affected by the production process and inevitably has heterogeneous structural characteristics, which determines that the joints will have more complex stress and strain responses when serving at high temperatures, making their creep behavior and life prediction more complicated. During the use of the unit, the failure of traditional life prediction methods and the frequent occurrence of early failure accidents of joints that do not exceed the expected life bring challenges to the safe operation of the unit. Summary of the invention

[0003] The purpose of this application is to provide a method and related device for predicting the creep life of a heat-resistant steel welded joint, which can accurately predict the creep life of a heat-resistant steel welded joint.

[0004] To achieve the above objectives, this application provides the following solutions:

[0005] In a first aspect, the present application provides a method for predicting the creep life of a heat-resistant steel welded joint, comprising:

[0006] Acquire creep test data of multiple heat-resistant steel welded joint samples, and group the creep test data according to the cracking forms of the heat-resistant steel welded joint samples to obtain creep test data under different cracking forms; the creep test data includes test temperature, loading stress, creep life and cracking form;

[0007] The creep test data is used to determine the threshold stress for cracking form transition; the threshold stress is used to determine the cracking form generated in the heat-resistant steel welded joint in the creep test;

[0008] The creep test data under each cracking form are used to determine the coefficients in the Larson-Miller equation corresponding to each cracking form;

[0009] Determining the cracking form corresponding to the heat-resistant steel weld joint to be tested according to the comparison between the loading stress applied to the heat-resistant steel weld joint to be tested during the creep test and the threshold value; the heat-resistant steel weld joint to be tested has the same type and characteristics as the heat-resistant steel weld joint sample;

[0010] The creep life of the heat-resistant steel welded joint to be tested is predicted using the Larson-Miller equation corresponding to the cracking form of the heat-resistant steel welded joint to be tested.

[0011] In a second aspect, the present application provides a creep life prediction device for a heat-resistant steel welded joint, comprising:

[0012] A data acquisition module, used to acquire creep test data of multiple heat-resistant steel welded joint specimens, and group the creep test data according to the cracking forms of the heat-resistant steel welded joint specimens to obtain creep test data under different cracking forms; the creep test data includes test temperature, loading stress, creep life and cracking form;

[0013] A threshold stress determination module, used to determine the threshold stress of cracking form transition using the creep test data; the threshold stress is used to determine the cracking form generated by the heat-resistant steel welded joint in the creep test;

[0014] A coefficient fitting module is used to determine the coefficients of the Larson-Miller equation corresponding to each cracking form using creep test data under each cracking form;

[0015] A cracking form determination module, used to determine the cracking form corresponding to the heat-resistant steel welded joint to be tested according to the comparison between the loading stress applied to the heat-resistant steel welded joint to be tested during the creep test and the threshold value; the heat-resistant steel welded joint to be tested has the same type and characteristics as the heat-resistant steel welded joint sample;

[0016] The creep life prediction module is used to predict the creep life of the heat-resistant steel welded joint to be tested by using the Larson-Miller equation corresponding to the cracking form of the heat-resistant steel welded joint to be tested.

[0017] In a third aspect, the present application provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-mentioned creep life prediction method for heat-resistant steel welded joints.

[0018] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned creep life prediction method for heat-resistant steel welded joints.

[0019] In a fifth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the above-mentioned creep life prediction method for heat-resistant steel welded joints.

[0020] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0021] The present application provides a method and related device for predicting the creep life of heat-resistant steel welded joints, which introduces possible cracking modes and threshold stresses of welded joints at different measuring temperatures as parameters into the method for predicting the life of welded joints, and increases the accuracy of life prediction of welded joints based on theoretical foundations such as cracking modes and failure mechanisms, and also increases the judgment of cracking forms. The present invention improves the accuracy of creep life prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is an application environment diagram of a creep life prediction method for a heat-resistant steel welded joint in one embodiment of the present application;

[0024] Figure 2 A schematic flow chart of a method for predicting the creep life of a heat-resistant steel welded joint provided in one embodiment of the present application;

[0025] Figure 3 A schematic diagram of a fitting curve of the traditional Larson-Miller method provided in one embodiment of the present application;

[0026] Figure 4 The use of a single constant C provided in an embodiment of the present application LM Schematic diagram of the fitting results of the life prediction curves for different cracking forms;

[0027] Figure 5 A schematic diagram of a life prediction curve fitted by the method of the present invention provided in one embodiment of the present application;

[0028] Figure 6 A schematic diagram showing a comparison between the prediction results of the method of the present invention based on two cracking modes and the prediction results of the traditional method provided in one embodiment of the present application;

[0029] Figure 7 A schematic diagram of functional modules of a creep life prediction device for a heat-resistant steel welded joint provided in one embodiment of the present application;

[0030] Figure 8 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0032] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0033] The creep life prediction method of the heat-resistant steel welded joint provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown, the terminal 102 communicates with the server 104 through a network. The data storage system can store data that the server 104 needs to process. The data storage system can be set up separately, integrated on the server 104, or placed on the cloud or other servers. The terminal 102 can send the creep test data of the heat-resistant steel welded joint sample to the server 104. The server 104 receives the creep test data, and groups the creep test data according to the cracking form and strength matching form of the heat-resistant steel welded joint sample to obtain creep test data under different cracking forms; the threshold stress of the cracking form transition is determined by using the creep test data; the threshold stress is used to judge the cracking form generated by the heat-resistant steel welded joint in the creep test, and the creep test data under each cracking form are used to determine the coefficients in the Larson-Miller equation corresponding to each cracking form, and the cracking form corresponding to the heat-resistant steel welded joint to be tested is determined by comparing the loading stress applied to the heat-resistant steel welded joint to be tested during the creep test with the threshold value, and the creep life of the heat-resistant steel welded joint to be tested is predicted by using the Larson-Miller equation of the cracking form corresponding to the heat-resistant steel welded joint to be tested. The server 104 can feed back the obtained creep life of the heat-resistant steel welded joint to be tested to the terminal 102. In addition, in some embodiments, the creep life prediction method of the heat-resistant steel weld joint can also be implemented independently by the server 104 or the terminal 102. For example, the terminal 102 can directly perform the creep life prediction of the heat-resistant steel weld joint to be tested based on the creep test data of the heat-resistant steel weld joint sample, or the server 104 can obtain the creep test data of the heat-resistant steel weld joint sample from the data storage system and perform the creep life prediction of the heat-resistant steel weld joint to be tested.

[0034] The terminal 102 may be, but is not limited to, various desktop computers, laptop computers, smart phones, tablet computers, IoT devices, and portable wearable devices. The IoT devices may be smart speakers, smart TVs, smart air conditioners, smart vehicle-mounted devices, etc. The portable wearable devices may be smart watches, smart bracelets, head-mounted devices, etc. The server 104 may be implemented as an independent server or a server cluster consisting of multiple servers, or may be a cloud server.

[0035] In an exemplary embodiment, Figure 2 As shown, a method for predicting the creep life of a heat-resistant steel welded joint is provided. The method is executed by a computer device, and can be executed by a computer device such as a terminal or a server alone, or by a terminal and a server together. In the embodiment of the present application, the method is applied to Figure 1 The server 104 in the example is used for explanation, and the steps include the following steps 201 to 205.

[0036] Step 201, obtaining creep test data of multiple heat-resistant steel welded joint specimens, and grouping the creep test data according to the cracking forms of the heat-resistant steel welded joint specimens to obtain creep test data under different cracking forms; the creep test data includes test temperature, loading stress, creep life and cracking form.

[0037] Step 202, using the creep test data to determine a threshold stress for cracking form transition; the threshold stress is used to determine the cracking form generated in the heat-resistant steel welded joint in the creep test.

[0038] Step 203: using the creep test data under each cracking form, determine the coefficients of each item in the Larson-Miller equation corresponding to each cracking form.

[0039] Step 204, determining the cracking form corresponding to the heat-resistant steel weld joint to be tested based on the comparison between the loading stress applied to the heat-resistant steel weld joint to be tested during the creep test and the threshold; the heat-resistant steel weld joint to be tested has the same type and characteristics as the heat-resistant steel weld joint sample.

[0040] Step 205: predicting the creep life of the heat-resistant steel welded joint to be tested by using the Larson-Miller equation of the cracking form corresponding to the heat-resistant steel welded joint to be tested.

[0041] In high-strength matching welded joints, the possible cracking modes are base material tensile cracking and type IV cracking (fine-grained heat-affected zone cracking), and in low-strength matching welded joints, the possible cracking modes are type I cracking (weld nugget zone cracking) and type IV cracking. For any heat-resistant steel welded joint to be tested, after determining its strength matching form, the possible cracking form can be determined, and then the cracking form under the loaded stress is determined by comparing it with the threshold stress, and then the Larson-Miller equation corresponding to the cracking form is selected to predict the creep life.

[0042] For the high-strength matching form, when the loaded stress is greater than the threshold stress, the base material cracks in the weld joint; when the loaded stress is less than the threshold stress, type IV cracking occurs in the weld joint; for the low-strength matching form: when the loaded stress is greater than the threshold stress, type I cracking occurs in the weld joint; when the loaded stress is less than the threshold stress, type IV cracking occurs in the weld joint.

[0043] Implement the above-mentioned steps 201 to 205, by adding the parameters of the joint creep failure form and adding the threshold stress test process, the creep test data is classified and sorted into data sets, and the traditional Larson-Miller equation is refitted to obtain a multi-segment line fitting curve and a corresponding equation different from the traditional form. By comparing the loading stress with the threshold stress, it is determined which segment of the curve and the corresponding equation to be selected, so that the parameters such as the temperature to be measured and the stress are brought into the equation to accurately determine the expected life of the welded joint. In addition, the Larson-Miller equation fitted by the present invention can also be used to input the temperature to be measured and the life data into the equation to obtain the loading stress, and compare it with the threshold stress to determine the possible cracking form. In addition, the heat-resistant steel welded joint life prediction method provided by the present invention has the advantages of being simple, efficient, and having a low error rate. It can predict the creep life and determine the cracking form by performing a small amount of test measurements and threshold stress tests on the same type of materials. It is a practical creep life prediction method. The method of the present invention is applicable to all ferrite or martensitic heat-resistant steel welded joints.

[0044] In another exemplary embodiment of the present application, in order to determine the loading stress to be applied to the welded joint in the creep test, it is necessary to first perform a tensile test on the welded joint to determine the yield strength and tensile strength, and then perform a creep test to obtain the creep test data. Specifically, according to GB / T 228.2-2015 "Tensile testing of metallic materials Part 2: High temperature test methods", before the creep test, the yield strength σ of the heat-resistant steel welded joint at the corresponding temperature of at least three groups of creep tests to be conducted needs to be measured. e And tensile strength σ b, based on the range of 10% above and below the 1 / 2 yield strength at the corresponding temperature, the loading stress in the creep test is selected; according to GB / T2039-2012 "Uniaxial Tension Creep Test Method for Metallic Materials", at the test temperature of the creep test, different loading stresses σ are determined i Creep life tr under (i=1,2,3,4……) i (i=1, 2, 3, 4……); requires no less than 3 groups of creep test data, and includes at least two types of cracking forms; collects all temperature, loading stress, creep life data and all welded joint specimens used in creep tests, and groups all temperature, loading stress and creep life data based on the cracking type of welded joint specimens. Based on the strength matching form and cracking type of welded joints, it can be divided into weld nugget zone cracking data set, fine grain heat affected zone cracking data set, and parent material tensile cracking data set, and further uses these data sets to fit the coefficients of Larson-Miller equation under different cracking forms. Therefore, step 201, obtaining creep test data of heat-resistant steel welded joint specimens, specifically includes:

[0045] (11) The loading stress applied in the creep test is determined based on the yield strength and tensile strength of the heat-resistant steel welded joint specimen at each test temperature measured in the tensile test; at least three loading stresses are included at the same test temperature. The test requires at least two to three test temperatures.

[0046] (12) Obtaining the creep life of the heat-resistant steel weld joint sample to be tested under each loading stress at each test temperature in the creep test; each loading stress corresponds to one creep test; and the creep test at the same test temperature includes at least two types of cracking forms.

[0047] (13) Collect the test temperature, loading stress, creep life and cracking form in each creep test to obtain the creep test data.

[0048] In another exemplary embodiment of the present application, at the corresponding test temperature, two sets of loading stresses corresponding to different cracking forms are selected to determine the stress interval corresponding to the cracking form transition. When the stress interval span is less than a preset value (such as 10 MPa), the stress average value of the stress interval is used as the threshold stress. When the stress interval range is greater than the preset value (such as 10 MPa), the intermediate stress is taken for supplementary testing, so that the threshold stress corresponding to the cracking form transition is determined within the interval with a span less than the preset value. Therefore, step 202, using the creep test data to determine the threshold stress for the cracking form transition, specifically includes:

[0049] (21) For each test temperature in the creep test, the stress interval corresponding to the current transition between the two cracking forms is determined according to the loading stresses corresponding to the two different cracking forms, and is recorded as the cracking form transition stress interval.

[0050] (22) The threshold stress for the transition between the two current cracking forms is determined based on the cracking form transition stress interval.

[0051] Specifically, step (22), determining the threshold stress for the transition between the two current cracking forms according to the cracking form transition stress interval, includes:

[0052] (a) Determine whether the interval span of the current cracking form transition stress interval is greater than a preset value.

[0053] (b) If not, then the stress average value of the cracking form transition stress interval is taken as the threshold stress for the current transition between the two cracking forms.

[0054] (c) If yes, then select the nearest intermediate stress value of the crack form transition stress interval, and obtain the creep test data corresponding to the nearest intermediate stress value, which is recorded as the supplementary creep test data; the nearest intermediate stress value is the intermediate stress value of the crack form transition stress interval or a stress value whose difference with the intermediate stress value is less than a preset difference.

[0055] (d) updating the cracking form transition stress interval whose interval span is greater than a preset value according to the supplementary creep test data, obtaining an updated cracking form transition stress interval, taking the updated cracking form transition stress interval as the current cracking form transition stress interval, and returning to step (a) "determining whether the interval span of the current cracking form transition stress interval is greater than a preset value".

[0056] In another exemplary embodiment of the present application, the creep life prediction method of the present invention is based on the Larson-Miller method, and its main equation is:

[0057] P=a0+a1logσ+a2log 2 σ+…+a n log n σ+e n ;

[0058] P=T(C LM +logt r );

[0059] Where, t r is the creep life, in h, C LM is the Larson-Miller constant, T is the test temperature, unit is K; σ is the applied stress, a0, a1, a2, a nis the regression coefficient, n is the order of the regression equation, generally n=2~4; e n is the error term, and in the present invention, n is 2.

[0060] Based on the Larson-Miller method, the present invention proposes a temperature, stress, time, and cracking type parameter method from the perspective of the failure cracking behavior of the welded joint, which is used to describe and predict several cracking modes that may occur during the creep process of the joint and their corresponding creep life. Under experimental conditions, the creep life prediction method provided by the present invention is simple to operate compared with the traditional life prediction method; the prediction accuracy is higher than other time and temperature parameter methods, and the prediction error is kept within 3%. It can effectively reflect the premature creep failure behavior of the joint during the long-term creep process of the joint, and has higher prediction accuracy and operability than the traditional method.

[0061] The present application also provides an application scenario, which applies the above-mentioned creep life prediction method for heat-resistant steel welded joints. Specifically: The creep life prediction method for heat-resistant steel welded joints provided in this embodiment can be used in scenarios such as strength or life prediction or remaining life evaluation of the same or different steel welded joints in ferrite and martensitic heat-resistant steel pipelines in power plants.

[0062] The following is a case study of a P91 steel welded joint to predict the creep life at three temperature conditions of 550°C, 575°C, and 600°C, and to verify the advantages of the prediction method of the present invention over the traditional method.

[0063] Firstly, according to GB / T 228.2-2015 "Tensile test of metallic materials Part 2: High temperature test method", three temperatures of 550℃, 575℃ and 600℃ were selected for high temperature tensile test. The specimen size was an I-shaped plate specimen, the cross-sectional size of the gauge section was 4mm×8mm, and the length was 64mm. The specimen design required that the joint was located at the center of the gauge section, and the gauge section should contain a complete joint structure and parent material. The martensitic heat-resistant steel welded joint was subjected to tensile test at a tensile rate of 0.0025s-1 at three sets of temperatures, and the yield strength σ at the corresponding temperature was measured. e And tensile strength σ b , the creep stress is selected based on the 1 / 2 yield strength.

[0064] According to GB / T2039-2012 "Metallic Materials Uniaxial Tensile Creep Test Method", the welded joint material is processed into a rod-shaped specimen with the joint located at the center of the gauge length. The creep test uses three temperature conditions of 500℃, 575℃, and 600℃ to measure different stresses σ at the predicted creep temperature. i(Take 575℃ as an example, the stress range is 120~190MPa, and the stress range is selected based on the value within 10% of the measured 1 / 2 yield strength) i .

[0065] During the creep test, according to the test results, the creep test is appropriately supplemented. The supplementary basis is that at a fixed temperature, when the cracking mode changes, the minimum stress span between the two cracking modes should be less than or equal to 10MPa. If it is not satisfied, a compromise value between the two stresses should be taken for supplementary testing to confirm the cracking mode transition threshold. In this embodiment, the threshold stresses corresponding to the three groups of temperatures of 550°C, 575°C, and 600°C are 160MPa, 145MPa, and 140MPa, respectively.

[0066] Collect all temperature, stress, creep life data and fracture specimens used in all creep tests, and group all temperature stress time data based on the fracture type of the fracture specimen. There are two cracking modes in this case, namely base material cracking and type IV cracking. All data are grouped based on the two cracking types.

[0067] The creep life prediction method is based on the Larson-Miller method, and its main equation is:

[0068] P=a0+a1logσ+a2log 2 σ+…+a n log n σ+e n

[0069] P=T(C LM +logt r )

[0070] In the formula, t r is the creep life, in h, C LM is the Larson-Miller constant, T is the test temperature, unit is K; is the applied stress, a0, a1, a2, a n is the regression coefficient, n is the order of the regression equation, and in this example n=2. Based on the traditional method, the cracking data of the parent material and the type IV cracking data, C LM and other constants, among which C LM As shown in Table 1.

[0071] Table 1 C in the fitting process of different data sets LM The fitting results of

[0072]

[0073] Various constants C derived from different data information LMAnd related data fitting curve equations and drawing related curves. By comparing the temperature and stress to be tested with the threshold stress of the corresponding temperature obtained by the test, it can be determined which section of the equation and curve to use for strength prediction, so as to quickly determine its expected cracking form and corresponding effective life. Figure 3 As shown in the figure, the fitting curve of the traditional Larson-Miller method is as follows: Figure 4 As shown, using a single constant C LM The fitting results of the life prediction curves for different cracking forms, such as Figure 5 As shown, a life prediction curve fitted by the method of the present invention is shown.

[0074] In order to prove the prediction accuracy of the method of the present invention, the actual measured strength and life of nearly 10,000 hours were predicted. The corresponding temperature and creep life were respectively introduced into the isotherm extrapolation method, OSD method, traditional Larson-Miller method and new method. The results are shown in Table 2.

[0075] Table 2 Fitting results and errors of various life prediction methods for the same set of data

[0076]

[0077] By comparison, it can be found that when the service temperature is relatively long, when various methods are applied to the creep strength prediction and life prediction of the joint, the accuracy varies greatly, and the difference increases with the increase of creep temperature, and the error increases significantly. Through practice, it can be known that as the creep time increases, the difficulty of evaluating the creep strength and life of the welded joint by various methods becomes higher, and the prediction accuracy of the traditional method becomes worse. In this embodiment, the method of the present invention and test data are used to predict the creep strength required for the P91 steel welded joint with a service time of 30,000 hours to a cumulative service time of 100,000 hours. The comparison results with the traditional life prediction method are shown in Table 3 and Figure 6 shown.

[0078] Table 3 Prediction results of creep strength of P91 steel after cumulative service of 100,000 hours

[0079]

[0080] The results in Table 3 show that the present invention has higher safety in predicting the creep strength and creep life of long-term creep components. This is because the present invention fully considers the reality and possibility of premature failures such as IV-type cracking that may occur during long-term creep. Therefore, compared with traditional methods, the present invention has higher prediction accuracy, more reliable safety, and greater practical value.

[0081] Based on the same inventive concept, the embodiment of the present application also provides a device for predicting the creep life of a heat-resistant steel welded joint for implementing the method for predicting the creep life of a heat-resistant steel welded joint involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in the embodiments of one or more devices for predicting the creep life of a heat-resistant steel welded joint provided below can refer to the limitations of the method for predicting the creep life of a heat-resistant steel welded joint above, and will not be repeated here.

[0082] In an exemplary embodiment, Figure 7 As shown, a creep life prediction device for a heat-resistant steel welded joint is provided, comprising:

[0083] The data acquisition module M1 is used to acquire creep test data of multiple heat-resistant steel welded joint specimens, and group the creep test data according to the cracking form of the heat-resistant steel welded joint specimens to obtain creep test data under different cracking forms; the creep test data includes test temperature, loading stress, creep life and cracking form.

[0084] The threshold stress determination module M2 is used to determine the threshold stress of cracking form transition using the creep test data; the threshold stress is used to judge the cracking form generated in the heat-resistant steel welded joint in the creep test.

[0085] The coefficient fitting module M3 is used to determine the coefficients of each Larson-Miller equation corresponding to each cracking form by using the creep test data under each cracking form.

[0086] The cracking form determination module M4 is used to determine the cracking form corresponding to the heat-resistant steel weld joint to be tested according to the comparison between the loading stress applied to the heat-resistant steel weld joint to be tested during the creep test and the threshold value; the heat-resistant steel weld joint to be tested has the same type and characteristics as the heat-resistant steel weld joint sample.

[0087] The creep life prediction module M5 is used to predict the creep life of the heat-resistant steel welded joint to be tested by using the Larson-Miller equation corresponding to the cracking form of the heat-resistant steel welded joint to be tested.

[0088] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Figure 8As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store creep life prediction data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a creep life prediction method for a heat-resistant steel welded joint is implemented.

[0089] Those skilled in the art will understand that Figure 8 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0090] In an exemplary embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0091] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0092] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0093] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0094] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0095] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0096] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for predicting creep life of heat-resistant steel welded joints, characterized in that: include: Acquire creep test data of multiple heat-resistant steel welded joint samples, and group the creep test data according to the cracking forms of the heat-resistant steel welded joint samples to obtain creep test data under different cracking forms; the creep test data includes test temperature, loading stress, creep life and cracking form; The creep test data is used to determine the threshold stress for cracking form transition; the threshold stress is used to determine the cracking form generated in the heat-resistant steel welded joint in the creep test; The creep test data under each cracking form are used to determine the coefficients in the Larson-Miller equation corresponding to each cracking form; Determining the cracking form corresponding to the heat-resistant steel weld joint to be tested according to the comparison between the loading stress applied to the heat-resistant steel weld joint to be tested during the creep test and the threshold value; the heat-resistant steel weld joint to be tested has the same type and characteristics as the heat-resistant steel weld joint sample; The creep life of the heat-resistant steel welded joint to be tested is predicted using the Larson-Miller equation corresponding to the cracking form of the heat-resistant steel welded joint to be tested.

2. The creep life prediction method of heat-resistant steel welded joint according to claim 1, characterized in that: Obtain creep test data of heat-resistant steel welded joint specimens, including: The loading stress applied in the creep test is determined based on the yield strength and tensile strength of the heat-resistant steel welded joint specimen at each test temperature measured in the tensile test; at least three loading stresses are included at the same test temperature; Obtaining the creep life of the heat-resistant steel welded joint sample to be tested under each loading stress at each test temperature in the creep test; each loading stress corresponds to one creep test; and the creep test under the same test temperature includes at least two types of cracking forms; The test temperature, loading stress, creep life and cracking form in each creep test are collected to obtain the creep test data.

3. The creep life prediction method of heat-resistant steel welded joint according to claim 1, characterized in that: The threshold stress for cracking mode transformation is determined by using the creep test data, specifically including: For each test temperature in the creep test of the heat-resistant steel welded joint sample, according to the loading stresses corresponding to the two different cracking forms, determine the stress interval corresponding to the current transition between the two cracking forms, and record it as the cracking form transition stress interval; The threshold stress for the transition between the two current cracking forms is determined based on the cracking form transition stress interval.

4. The creep life prediction method of heat-resistant steel welded joint according to claim 3, characterized in that: The threshold stress for the transition between the two current cracking forms is determined according to the cracking form transition stress interval, including: Determine whether the interval span of the current cracking form transition stress interval is greater than a preset value; If not, then the stress average value of the cracking form transition stress interval is taken as the threshold stress for the current transition between the two cracking forms; If yes, then select the neighboring intermediate stress value of the cracking form transition stress interval, and obtain the creep test data corresponding to the neighboring intermediate stress value, which is recorded as the supplementary creep test data; the neighboring intermediate stress value is the intermediate stress value of the cracking form transition stress interval or a stress value whose difference with the intermediate stress value is less than a preset difference; According to the supplementary creep test data, the cracking form transition stress interval whose interval span is greater than the preset value is updated, and an updated cracking form transition stress interval is obtained. The updated cracking form transition stress interval is used as the current cracking form transition stress interval, and the process returns to the step of "determining whether the interval span of the current cracking form transition stress interval is greater than the preset value".

5. The creep life prediction method of heat-resistant steel welded joint according to claim 1, characterized in that: The expression of the Larson-Miller equation is: P=a0+a1logσ+a2log 2 s+…+a n log n s+e n ; P=T(C LM +logt r ); Where, t r is the creep life, C LM is the Larson-Miller constant, T is the test temperature; σ is the loading stress, a0, a1, a2, a n is the regression coefficient, n is the order of the regression equation; e n is the error term.

6. A creep life prediction device for heat-resistant steel welded joints, characterized in that: include: A data acquisition module, used to acquire creep test data of multiple heat-resistant steel welded joint specimens, and group the creep test data according to the cracking forms of the heat-resistant steel welded joint specimens to obtain creep test data under different cracking forms; the creep test data includes test temperature, loading stress, creep life and cracking form; A threshold stress determination module, used to determine the threshold stress of cracking form transition using the creep test data; the threshold stress is used to determine the cracking form generated by the heat-resistant steel welded joint in the creep test; A coefficient fitting module is used to determine the coefficients of the Larson-Miller equation corresponding to each cracking form using creep test data under each cracking form; A cracking form determination module, used to determine the cracking form corresponding to the heat-resistant steel welded joint to be tested according to the comparison between the loading stress applied to the heat-resistant steel welded joint to be tested during the creep test and the threshold value; the heat-resistant steel welded joint to be tested has the same type and characteristics as the heat-resistant steel welded joint sample; The creep life prediction module is used to predict the creep life of the heat-resistant steel welded joint to be tested by using the Larson-Miller equation corresponding to the cracking form of the heat-resistant steel welded joint to be tested.

7. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the creep life prediction method for a heat-resistant steel welded joint according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the creep life prediction method for a heat-resistant steel welded joint according to any one of claims 1 to 5 is implemented.

9. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the creep life prediction method for a heat-resistant steel welded joint according to any one of claims 1 to 5 is implemented.

Images