Method for judging applicability of pipeline welded joint in hydrogen environment

Abstract

The invention relates to the field of pipeline analysis, and particularly provides a method for judging the applicability of a pipeline welding joint in a hydrogen environment. The judgment method comprises the following steps: arranging a plurality of sampling positions which are arranged at intervals on the welding joint along the circumferential direction of the pipeline, obtaining at least two tensile test samples at each sampling position, and respectively carrying out slow strain rate tensile tests on the tensile test samples in an inert environment and a hydrogen environment, at least two toughness test samples are obtained at each sampling position, fracture toughness tests are conducted on the toughness test samples in the inert environment and the hydrogen environment respectively, and when the slow strain rate tensile test and the fracture toughness tests pass, the applicability of the pipeline welding joint in the hydrogen environment is qualified. According to the method for judging the applicability of the pipeline welding joint in the hydrogen environment, an accurate and comprehensive judgment result can be obtained.

Description

Technical Field

[0001] The invention relates to the field of pipeline analysis, and in particular to a method for judging the suitability of a pipeline welding joint for a hydrogen environment. Background Art

[0002] Pipelines in hydrogen-containing environments, such as natural gas hydrogen-blended pipelines, will have hydrogen-induced damage problems. Pipeline welded joints have a higher sensitivity to hydrogen embrittlement under the effects of hydrogen medium pressure, uneven weld structure, and weld residual stress, and are therefore more likely to crack. In related technologies, the methods used to determine the applicability of pipeline welded joints in hydrogen-containing environments cannot obtain accurate and comprehensive results. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, the present invention proposes a method for judging the suitability of a pipeline welding joint for a hydrogen environment.

[0005] The method for judging the suitability of a pipeline welding joint for a hydrogen environment of the present invention comprises: A plurality of sampling positions arranged at intervals are provided at the weld joint along the circumference of the pipeline; At least two tensile test specimens are obtained at each sampling position, and slow strain rate tensile tests are performed on the tensile test specimens in an inert environment and a hydrogen environment, respectively, to obtain the hydrogen embrittlement coefficient of each sampling position. When the hydrogen embrittlement coefficient of each sampling position is less than or equal to 25%, the slow strain rate tensile test is passed; At least two toughness test specimens are obtained at each sampling position, and fracture toughness tests are performed on the toughness test specimens in an inert environment and a hydrogen environment, respectively, to obtain the strength factor of each sampling position in an inert environment and the strength factor in a hydrogen environment, and the strength factor of each sampling position in an inert environment and the strength factor in a hydrogen environment are both greater than or equal to 55 MPa·m 1 / 2 When , the fracture toughness test is passed; When both the slow strain rate tensile test and the fracture toughness test are passed, the suitability of the pipeline weld joint for hydrogen environment is qualified.

[0006] Furthermore, if the slow strain rate tensile test fails, the suitability of the pipeline weld joint for the hydrogen environment is unqualified; If the slow strain rate tensile test passes, continue to obtain the toughness test sample and perform the fracture toughness test. If the fracture toughness test fails, the suitability of the pipeline weld joint for the hydrogen environment fails. If the fracture toughness test passes, the suitability of the pipeline weld joint for the hydrogen environment passes.

[0007] Furthermore, there are at least three sampling positions, wherein the first sampling position is located at the welding arc starting point of the welding joint, the second sampling position is arranged opposite to the first sampling position along the radial direction of the pipeline, and the third sampling position is located in the middle of the first sampling position and the second sampling position along the circumferential direction of the pipeline.

[0008] Further, after setting a plurality of sampling positions, the weld center and the heat-affected zone center of the weld joint are obtained at each sampling position; Among the at least two tensile test specimens obtained at each sampling position, at least one tensile test specimen is located at the center of the weld, and at least one tensile test specimen is located at the center of the heat-affected zone; Among the at least two toughness test specimens obtained at each sampling position, at least one toughness test specimen is located at the center of the weld, and at least one toughness test specimen is located at the center of the heat affected zone.

[0009] Furthermore, after setting a plurality of the sampling positions, an observation sample is obtained at each of the sampling positions along a weld direction perpendicular to the weld joint, and two fusion lines of the observation sample located on the outer surface of the pipe are observed, wherein a center line of the two fusion lines is the weld center, and a positioning line is set on the observation sample along the wall thickness direction of the pipe, wherein the positioning line passes through the heat affected zone of the weld joint at a maximum proportion along the wall thickness direction of the pipe, and the midpoint of a line segment where the positioning line coincides with the heat affected zone is the center of the heat affected zone.

[0010] Further, after obtaining the center of the weld and the center of the heat-affected zone on the observation sample, measuring the distance L1 between the center of the heat-affected zone and the center of the weld, and measuring the distance L2 between the center of the heat-affected zone and the outer surface of the pipe on the observation sample; When at least two tensile test specimens and / or at least two toughness test specimens are obtained at each sampling position, the center of the weld at the sampling position is obtained according to the two fusion lines on the outer surface of the pipe at the sampling position, and then the center of the heat affected zone at the sampling position is obtained according to the distance L1 and the distance L2 measured by the observation specimen obtained at the sampling position, so as to obtain the tensile test specimen and / or the toughness test specimen located at the center of the weld at each sampling position, and the tensile test specimen and / or the toughness test specimen located at the center of the heat affected zone.

[0011] Furthermore, the tensile test specimens include notched tensile specimens, and the notched tensile specimens obtained at each sampling position are at least two types, wherein the notch of the first type of notched tensile specimen is located at the center of the weld corresponding to the sampling position, and the notch of the second type of notched tensile specimen is located at the center of the heat affected zone corresponding to the sampling position.

[0012] Further, the tensile test specimen also includes a smooth round rod specimen, and the smooth round rod specimen includes a cross-weld specimen and / or a full-weld specimen, the length direction of the cross-weld specimen is perpendicular to the weld direction corresponding to the sampling position, and the center position of the gauge section of the cross-weld specimen is located at the center of the weld corresponding to the sampling position, the length direction of the full-weld specimen is parallel to the weld direction corresponding to the sampling position, and the full-weld specimen is obtained from the weld corresponding to the sampling position.

[0013] Further, the slow strain rate tensile test is performed on the first notched tensile specimen, the second notched tensile specimen, the cross-weld specimen and the full-weld specimen obtained at each sampling position in the inert environment to obtain the cross-sectional shrinkage of the first notched tensile specimen, the second notched tensile specimen, the cross-weld specimen and the full-weld specimen at each sampling position in the inert environment; Performing the slow strain rate tensile test on the first notched tensile specimen, the second notched tensile specimen, the cross-weld specimen and the full-weld specimen obtained at each sampling position in the hydrogen environment to obtain the cross-sectional shrinkage of the first notched tensile specimen, the second notched tensile specimen, the cross-weld specimen and the full-weld specimen at each sampling position in the hydrogen environment; Obtaining the hydrogen embrittlement coefficient of the first notched tensile specimen, the second notched tensile specimen, the cross-weld specimen and the full weld specimen at each sampling position according to the cross-sectional reduction ratios of the first notched tensile specimen, the second notched tensile specimen, the cross-weld specimen and the full weld specimen at each sampling position in an inert environment and a hydrogen environment, respectively; The hydrogen embrittlement coefficients of the first notch tensile specimen, the second notch tensile specimen, the cross-weld specimen and the full-weld specimen at the same sampling position are averaged to obtain the hydrogen embrittlement coefficient corresponding to the sampling position, thereby obtaining the hydrogen embrittlement coefficient of each sampling position.

[0014] Furthermore, the tensile rate of the notched tensile specimen in the slow strain rate tensile test is less than 2×10 -6 s -1 The tensile rate of the smooth round bar specimen in the slow strain rate tensile test is less than 2×10 -5 s-1 .

[0015] Furthermore, the fracture toughness test is a fracture toughness resistance curve test.

[0016] Furthermore, the toughness test specimen is a straight-through specimen or a step-type specimen, the length direction of the toughness test specimen is parallel to the weld direction corresponding to the sampling position, and the thickness of the toughness test specimen is more than 85% of the wall thickness of the pipeline, and the toughness test specimens obtained at each sampling position are at least two types, wherein the notch of the first type of the toughness test specimen is located at the center of the weld corresponding to the sampling position, and the notch of the second type of the toughness test specimen is located at the center of the heat affected zone corresponding to the sampling position.

[0017] Further, the fracture toughness resistance curve test is performed on the first toughness test specimen and the second toughness test specimen obtained at each sampling position in the inert environment to obtain the fracture toughness of the first toughness test specimen and the second toughness test specimen at each sampling position in the inert environment; Obtaining the strength factor of the first toughness test specimen at each sampling position in an inert environment according to the fracture toughness of the first toughness test specimen at each sampling position in an inert environment, and obtaining the strength factor of the second toughness test specimen at each sampling position in an inert environment according to the fracture toughness of the second toughness test specimen at each sampling position in an inert environment; The intensity factor of the first toughness test specimen in the inert environment and the intensity factor of the second toughness test specimen in the inert environment at the same sampling position are averaged to obtain the intensity factor of the corresponding sampling position in the inert environment, thereby obtaining the intensity factor of each sampling position in the inert environment; Conducting the fracture toughness resistance curve test on the first toughness test specimen and the second toughness test specimen obtained at each sampling position in the hydrogen environment to obtain the fracture toughness of the first toughness test specimen and the second toughness test specimen at each sampling position in the hydrogen environment; Obtaining the strength factor of the first toughness test sample at each sampling position in the presence of hydrogen according to the fracture toughness of the first toughness test sample at each sampling position in the presence of hydrogen, and obtaining the strength factor of the second toughness test sample at each sampling position in the presence of hydrogen according to the fracture toughness of the second toughness test sample at each sampling position in the presence of hydrogen; The strength factor of the first toughness test specimen in the hydrogen environment and the strength factor of the second toughness test specimen in the hydrogen environment at the same sampling position are averaged to obtain the strength factor of each sampling position in the hydrogen environment, thereby obtaining the strength factor of each sampling position in the hydrogen environment.

[0018] Furthermore, the tensile rate of the toughness test specimen for the fracture toughness resistance curve test is 0.1 MPa·m 1 / 2 / min~1MPa·m 1 / 2 / min.

[0019] Furthermore, the inert environment is an atmospheric environment or an inert gas environment.

[0020] Furthermore, before the tensile test specimen is subjected to the slow strain rate tensile test, the tensile test specimen needs to be maintained in the hydrogen environment for more than 24 hours, and before the toughness test specimen is subjected to the fracture toughness test, the toughness test specimen needs to be maintained in the hydrogen environment for more than 24 hours.

[0021] Furthermore, the hydrogen environment is consistent with the internal environment of the pipeline during transportation operation, or the natural gas in the internal environment of the pipeline during transportation operation is replaced by inert gas to serve as the hydrogen environment.

[0022] Furthermore, the method for judging the suitability of the pipeline welded joint for a hydrogen environment also includes: performing a basic performance test on the pipeline; if the basic performance test is passed, setting a plurality of sampling positions arranged at intervals at the welded joint along the circumference of the pipeline; if the basic performance test is not passed, the suitability of the pipeline welded joint for a hydrogen environment is unqualified.

[0023] Furthermore, the basic performance test includes testing whether the pipeline meets the preset basic performance requirements of chemical composition, metallographic structure, non-metallic inclusions, hardness, notch sensitivity, tensile strength, toughness and non-destructiveness. When all the basic performance requirements are met, the basic performance test of the pipeline passes.

[0024] The method for judging the suitability of a pipeline welded joint for a hydrogen environment of the present invention sets a plurality of sampling positions for sampling on the pipeline welded joint along the circumference of the pipeline, so as to fully sample the pipeline welded joint, thereby obtaining a comprehensive judgment result. At least two tensile test specimens are obtained at each sampling position for performing slow strain rate tensile tests in an inert environment and a hydrogen environment, respectively, and at least two toughness test specimens are obtained for performing fracture toughness tests in an inert environment and a hydrogen environment, respectively. The suitability of the pipeline welded joint for a hydrogen environment is judged by the slow strain rate tensile test and the fracture toughness test in the two environments, thereby obtaining an accurate judgment result. Therefore, the method for judging the suitability of a pipeline welded joint for a hydrogen environment of the present invention can obtain an accurate and comprehensive judgment result. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic cross-sectional view of a pipeline in an embodiment of the present invention; Figure 2 This is a first surface schematic diagram of an observation sample in an embodiment of the present invention; Figure 3 1 is a second surface schematic diagram of the sample observed in the embodiment of the present invention.

[0026] Reference numerals: 10. Pipeline; 1. Observation specimen. DETAILED DESCRIPTION

[0027] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0028] Reference below Figure 1-Figure 3 A method for judging the suitability of a pipeline welded joint for a hydrogen environment according to an embodiment of the present invention is described.

[0029] like Figure 1-Figure 3 As shown, the method for judging the suitability of a pipeline welding joint for a hydrogen environment according to an embodiment of the present invention includes: A plurality of sampling positions arranged at intervals are provided at the weld joints along the circumference of the pipeline 10 .

[0030] At least two tensile test specimens are obtained at each sampling location. Slow strain rate tensile tests are performed on the tensile test specimens in an inert environment and a hydrogen environment, respectively. In other words, a slow strain rate tensile test is performed on a portion of the tensile test specimens at each sampling location in an inert environment, and a slow strain rate tensile test is performed on another portion of the tensile test specimens at each sampling location in a hydrogen environment. The hydrogen embrittlement coefficient of each sampling location is obtained. When the hydrogen embrittlement coefficient at each sampling location is less than or equal to 25%, the slow strain rate tensile test is passed.

[0031] At least two toughness test specimens are obtained at each sampling location. Fracture toughness tests are performed on the toughness test specimens in an inert environment and a hydrogen environment, respectively. In other words, a fracture toughness test is performed on a portion of the toughness test specimens at each sampling location in an inert environment, and a fracture toughness test is performed on another portion of the toughness test specimens at each sampling location in a hydrogen environment. In order to obtain the strength factor of each sampling location in an inert environment and the strength factor in a hydrogen environment, in other words, the strength factor of each sampling location in an inert environment is obtained by performing a fracture toughness test on a portion of the toughness test specimens at each sampling location in an inert environment, and the strength factor of each sampling location in a hydrogen environment is obtained by performing a fracture toughness test on another portion of the toughness test specimens at each sampling location in a hydrogen environment. The strength factor in an inert environment and the strength factor in a hydrogen environment at each sampling location are both greater than or equal to 55 MPa·m 1 / 2 The fracture toughness test passed.

[0032] When both the slow strain rate tensile test and the fracture toughness test are passed, the suitability of the welded joint of the pipeline 10 for the hydrogen environment is qualified.

[0033] It should be noted that the inert environment is an environment in which the material of the pipeline 10 is relatively insensitive to the hydrogen environment.

[0034] The method for judging the suitability of a pipeline welded joint for a hydrogen environment of the present invention sets a plurality of sampling positions for sampling on the pipeline welded joint along the circumference of the pipeline, so as to fully sample the pipeline welded joint, thereby obtaining a comprehensive judgment result. At least two tensile test specimens are obtained at each sampling position for performing slow strain rate tensile tests in an inert environment and a hydrogen environment, respectively, and at least two toughness test specimens are obtained for performing fracture toughness tests in an inert environment and a hydrogen environment, respectively. The suitability of the pipeline welded joint for a hydrogen environment is judged by the slow strain rate tensile test and the fracture toughness test in the two environments, thereby obtaining an accurate judgment result. Therefore, the method for judging the suitability of a pipeline welded joint for a hydrogen environment of the present invention can obtain an accurate and comprehensive judgment result.

[0035] In some embodiments, if the slow strain rate tensile test fails, the suitability of the weld joint of the pipeline 10 for a hydrogen environment is unqualified. In other words, if the hydrogen embrittlement coefficient of at least one sampling position among all the multiple sampling positions is greater than 25%, the suitability of the weld joint of the pipeline 10 for a hydrogen environment is unqualified.

[0036] If the slow strain rate tensile test is passed, the toughness test specimen is obtained and the fracture toughness test is performed. If the fracture toughness test is unqualified, the hydrogen environment suitability of the welded joint of the pipeline 10 is unqualified. In other words, if the strength factor of at least one sampling position in the inert environment and / or the strength factor of the hydrogen environment is less than 55 MPa·m 1 / 2 , the suitability of the welded joint of pipeline 10 for hydrogen environment is unqualified. If the fracture toughness test is qualified, the suitability of the welded joint of pipeline 10 for hydrogen environment is qualified.

[0037] By first conducting a slow strain rate tensile test and then conducting a fracture toughness test after the slow strain rate tensile test is passed, the complexity of the method for determining the suitability of pipeline welded joints for hydrogen environments can be reduced during implementation, and the efficiency of obtaining determination results can be improved.

[0038] It is understandable that in other embodiments, both the slow strain rate tensile test and the fracture toughness test may be performed, or the fracture toughness test may be performed first, and then the slow strain rate tensile test may be performed after the fracture toughness test passes.

[0039] In some embodiments, there are at least three sampling positions, wherein the first sampling position is located at the welding arc starting point of the welding joint, the second sampling position is arranged opposite to the first sampling position along the radial direction of the pipeline 10, and the third sampling position is located between the first sampling position and the second sampling position along the circumference of the pipeline 10.

[0040] like Figure 1 As shown, it is preferred but not limited to obtain position points A, B, C and D at the weld joint along the circumference of the pipeline 10. Position point A is located at the welding arc starting point of the weld joint. Position point B and position point A are arranged relative to each other along the radial direction of the pipeline 10. In other words, position point B and position point A are symmetrical with respect to the center line of the pipeline 10. Position point C is located in the middle of the right part of the pipeline 10 between position point A and position point B. Position point D is located in the middle of the left part of the pipeline 10 between position point A and position point B. The angle between the adjacent two of position points A, B, C and D along the circumference of the pipeline 10 is approximately 90°. In other words, position point C is approximately located at the midpoint of the right part of the pipeline 10 between position point A and position point B, and position point D is approximately located at the midpoint of the left part of the pipeline 10 between position point A and position point B. Position point A and position point B are both used as sampling positions, and at least one of position point C and position point D is also used as a sampling position. Preferably, position point A and position point B are both used as sampling positions, and position point C or position point D is also used as a sampling position, so as to fully sample the welding joint of the pipeline 10 and obtain a comprehensive judgment result.

[0041] In some embodiments, after setting a plurality of sampling positions, the weld center and the heat affected zone center of the weld joint are obtained at each sampling position. Preferably, after setting a plurality of sampling positions, the distribution characteristics of the weld, fusion zone and heat affected zone of the weld joint are obtained at each sampling position, thereby obtaining the weld center and the heat affected zone center of the weld joint.

[0042] Among the at least two tensile test specimens obtained at each sampling position, at least one tensile test specimen is located at the center of the weld, and at least one tensile test specimen is located at the center of the heat affected zone, so that the test results of the slow strain rate tensile test are more accurate and comprehensive, thereby obtaining more accurate and comprehensive judgment results.

[0043] Among the at least two toughness test specimens obtained at each sampling position, at least one toughness test specimen is located at the center of the weld, and at least one toughness test specimen is located at the center of the heat affected zone, so that the test results of the fracture toughness test are more accurate and comprehensive, thereby obtaining more accurate and comprehensive judgment results.

[0044] It should be noted that the sample being located at the center of the weld means that at least a portion of the sample is located at the center of the weld, and the sample being located at the center of the heat-affected zone means that at least a portion of the sample is located at the center of the heat-affected zone.

[0045] It should be noted that the weld of the weld joint in the embodiment of the present invention is preferably but not limited to a girth weld.

[0046] In some embodiments, after setting multiple sampling positions, an observation sample 1 is obtained at each sampling position along a weld direction perpendicular to the weld joint, and two fusion lines of the observation sample 1 located on the outer surface of the pipe 10 are observed. The center line of the two fusion lines is the weld center, and a positioning line is set on the observation sample 1 along the wall thickness direction of the pipe 10. The positioning line passes through the heat affected zone of the weld joint at the maximum proportion along the wall thickness direction of the pipe 10, and the midpoint of the line segment where the positioning line coincides with the heat affected zone is the center of the heat affected zone.

[0047] like Figure 2 and Figure 3 As shown, after the sampling position is determined, an observation sample 1 is obtained at each sampling position along a weld direction perpendicular to the weld joint. In other words, an observation sample 1 is obtained at each sampling position roughly along the axial direction of the pipeline 10. In other words, the length direction of the observation sample 1 is roughly the axial direction of the pipeline 10.

[0048] The observation sample 1 is subjected to surface treatment, preferably but not limited to, the surface of the observation sample 1 is ground to 2000# by sandpaper step by step, then polished, and then cleaned with 4% nitric acid alcohol, so as to facilitate observation of the surface of the observation sample 1.

[0049] Observe and obtain the observation sample 1 located on the outer surface of the pipe 10 (such as Figure 2 and Figure 3 The top surface shown in Figure 2 shows two weld lines ( Figure 2 and Figure 3 The line formed by the points J1 and J2 shown on the outer surface of the pipe 10) is the center line of the two fusion lines and is the weld center F.

[0050] On the surface of the observation sample 1, along the wall thickness direction of the pipe 10 (such as Figure 2 and Figure 3 The positioning line G is set along the wall thickness direction of the pipe 10 (as shown in the upper and lower directions). Figure 2 and Figure 3 The maximum proportion of the positioning line G in the up and down directions shown in the figure passes through the heat affected zone H of the weld joint, and the midpoint of the line segment where the positioning line G coincides with the heat affected zone H is the center O of the heat affected zone. In other words, the midpoint of the line segment where the positioning line G is located in the heat affected zone H is the center O of the heat affected zone.

[0051] By observing the sample 1, the weld center F and the heat affected zone center O at each sampling position can be easily and accurately obtained to ensure accurate sampling of the tensile test sample and the toughness test sample, thereby ensuring accurate judgment results.

[0052] It can be understood that the weld center F and the heat-affected zone center O are not limited to being obtained from the surface of the observation sample 1 , and in other embodiments, they can also be obtained from the cross section of the pipe 10 after the observation sample 1 is taken out.

[0053] In some embodiments, Figure 2 and Figure 3 As shown, after obtaining the weld center F and the heat affected zone center O on the observation sample 1, the distance L1 between the heat affected zone center O and the weld center F is measured, and the distance between the heat affected zone center O and the outer surface of the pipe 10 on the observation sample 1 (such as Figure 2 and Figure 3 Each sampling position has a corresponding distance L1 and distance L2, and the distance L1 of all the multiple sampling positions can be the same or different, and the distance L2 of all the multiple sampling positions can be the same or different.

[0054] When at least two tensile test specimens and / or at least two toughness test specimens are obtained at each sampling position, the weld center F at the sampling position is obtained according to the two fusion lines on the outer surface of the pipe 10 at the sampling position, and then the heat affected zone center O at the sampling position is obtained according to the distance L1 and the distance L2 measured by the observation specimen 1 obtained at the sampling position, thereby obtaining a tensile test specimen and / or toughness test specimen located at the weld center F at each sampling position, and a tensile test specimen and / or toughness test specimen located at the center O of the heat affected zone.

[0055] Specifically, when obtaining at least two tensile test specimens at each sampling position, firstly, the weld center F of the sampling position is obtained according to the two fusion lines on the outer surface of the pipe 10 at the sampling position, and then the heat affected zone center O of the sampling position is obtained through the distance L1 and the distance L2 obtained by the observation specimen 1 at the sampling position, so as to obtain the tensile test specimen according to the weld center F and the heat affected zone center O of the sampling position, so that at least one tensile test specimen is located at the weld center F, and at least one tensile test specimen is located at the heat affected zone center O.

[0056] When obtaining at least two toughness test specimens at each sampling position, firstly, the weld center F of the sampling position is obtained according to the two fusion lines on the outer surface of the pipe 10 at the sampling position, and then the heat affected zone center O of the sampling position is obtained through the distance L1 and the distance L2 obtained by the observation specimen 1 at the sampling position, so as to obtain the toughness test specimen according to the weld center F and the heat affected zone center O of the sampling position, so that at least one toughness test specimen is located at the weld center F, and at least one toughness test specimen is located at the heat affected zone center O.

[0057] By observing the sample 1 to obtain the distance L1 and the distance L2, the tensile test sample and the toughness test sample located at the center O of the heat affected zone at each sampling position can be quickly and accurately obtained through the distance L1 and the distance L2, which facilitates the sampling efficiency of the tensile test sample and the toughness test sample, so that the method for judging the suitability of the welded joint of the pipeline 10 in a hydrogen environment can be quickly implemented.

[0058] It is understandable that, in some embodiments, the weld center F and the heat-affected zone center O on the observed sample 1 may be marked at the corresponding sampling positions, and then the tensile test sample and the toughness test sample may be obtained based on the marks.

[0059] In some embodiments, the tensile test specimen includes a notched tensile specimen, and at least two notched tensile specimens are obtained at each sampling position, wherein the notch of the first notched tensile specimen is located at the center of the weld at the corresponding sampling position, that is, the first notched tensile specimen is located at the center of the weld, and the notch of the second notched tensile specimen is located at the center of the heat affected zone at the corresponding sampling position, that is, the second notched tensile specimen is located at the center of the heat affected zone. The slow strain rate tensile test is performed on the first notched tensile specimen and the second notched tensile specimen to obtain a comprehensive and accurate judgment result.

[0060] In some embodiments, the tensile test specimens further include smooth round bar specimens, which include cross-weld specimens and / or full-weld specimens. It is preferred, but not limited to, to obtain both cross-weld specimens and full-weld specimens at each sampling position.

[0061] The length direction of the cross-weld sample is perpendicular to the weld direction of the corresponding sampling position. In other words, the length direction of the cross-weld sample is substantially the axial direction of the pipeline 10. The center position of the gauge section of the cross-weld sample is located at the center of the weld at the corresponding sampling position.

[0062] The length direction of the full weld sample is parallel to the weld direction of the corresponding sampling position. In other words, the length direction of the full weld sample is substantially the circumferential direction of the pipeline 10, and the full weld sample is obtained from the weld at the corresponding sampling position.

[0063] Slow strain rate tensile tests were performed on both smooth round bar specimens and notched tensile specimens to obtain more accurate judgment results.

[0064] In some embodiments, a slow strain rate tensile test is performed on the first notch tensile specimen, the second notch tensile specimen, the cross-weld specimen, and the full weld specimen obtained at each sampling position in an inert environment to obtain the cross-sectional reduction ratio of the first notch tensile specimen, the second notch tensile specimen, the cross-weld specimen, and the full weld specimen at each sampling position in an inert environment.

[0065] In a hydrogen environment, slow strain rate tensile tests were performed on the first notch tensile specimens, the second notch tensile specimens, the cross-weld specimens and the full-weld specimens obtained at each sampling position to obtain the cross-sectional shrinkage of the first notch tensile specimens, the second notch tensile specimens, the cross-weld specimens and the full-weld specimens at each sampling position in a hydrogen environment.

[0066] The hydrogen embrittlement coefficient of the first notch tensile specimen, the second notch tensile specimen, the cross-weld specimen and the full weld specimen at each sampling position is obtained according to the cross-sectional reduction rates of the first notch tensile specimen, the second notch tensile specimen, the cross-weld specimen and the full weld specimen at each sampling position in an inert environment and a hydrogen environment respectively.

[0067] Specifically, according to Calculate the cross-sectional shrinkage, where S is the fracture cross-sectional area of ​​the tensile test specimen after the slow strain rate tensile test, S 0 is the fracture cross-sectional area of ​​the tensile test specimen before the slow strain rate tensile test, is the cross-sectional shrinkage of the tensile test specimen, S, S 0 and More specifically, taking the first notched tensile specimen as an example, the fracture cross-sectional area of ​​the first notched tensile specimen after the slow strain rate tensile test in the inert environment is substituted into S, and the fracture cross-sectional area of ​​the first notched tensile specimen before the slow strain rate tensile test in the inert environment is substituted into S. 0 , calculated is the cross-sectional shrinkage of the first notched tensile specimen in an inert environment. The cross-weld specimens and full weld specimens at each sampling position have their cross-sectional reduction ratios in an inert environment, as well as the cross-sectional reduction ratios in a hydrogen environment for the first notch tensile specimen, the second notch tensile specimen, the cross-weld specimen and the full weld specimen at each sampling position.

[0068] according to Calculate the hydrogen embrittlement coefficient, where is the cross-sectional shrinkage of the tensile test specimen in an inert environment, is the cross-sectional shrinkage of the tensile test specimen in a hydrogen environment, Z is the hydrogen embrittlement coefficient of the tensile test specimen, and More specifically, taking the first notched tensile specimen as an example, the cross-sectional shrinkage of the first notched tensile specimen in an inert environment is substituted into , substitute the cross-sectional shrinkage of another first type notched tensile specimen in the hydrogen environment at the same sampling position into , the calculated Z is the hydrogen embrittlement coefficient of the first notched tensile specimen. The hydrogen embrittlement coefficients of the first notch tensile specimen, the second notch tensile specimen, the cross-weld specimen and the full weld specimen at each sampling position were calculated.

[0069] The hydrogen embrittlement coefficients of the first notch tensile specimen, the second notch tensile specimen, the cross-weld specimen and the full-weld specimen at the same sampling position are averaged to obtain the hydrogen embrittlement coefficient of the corresponding sampling position, thereby obtaining the hydrogen embrittlement coefficient of each sampling position, and the obtained hydrogen embrittlement coefficient is accurate, so that accurate judgment results can be obtained.

[0070] Preferably, the number of the first notched tensile specimen, the second notched tensile specimen, the cross-weld specimen and the full-weld specimen at the same sampling position when the slow strain rate tensile test is carried out in an inert environment and a hydrogen environment is multiple. Taking the first notched tensile specimen as an illustrative example, the average value of the cross-sectional reduction rates of the multiple first notched tensile specimens in an inert environment is used as the cross-sectional reduction rate of the first notched tensile specimen in an inert environment, and the average value of the cross-sectional reduction rates of the multiple first notched tensile specimens in a hydrogen environment is used as the cross-sectional reduction rate of the first notched tensile specimen in a hydrogen environment, thereby calculating the hydrogen embrittlement coefficient of the first notched tensile specimen, so that the hydrogen embrittlement coefficient of the first notched tensile specimen obtained is more accurate.

[0071] In some embodiments, the elongation rate of the slow strain rate tensile test of the notched tensile specimen is less than 2×10 - 6 s -1The tensile rate of the slow strain rate tensile test on the smooth round bar specimen is less than 2×10 -5 s -1 .

[0072] In other words, during the slow strain rate tensile test, the tensile rate of the first notched tensile specimen and the second notched tensile specimen is less than 2×10 -6 s -1 The tensile rate of the cross-weld specimen and the full-weld specimen is less than 2×10 - 5 s -1 . To ensure that the fracture cross-sectional area of ​​the tensile test specimen after the slow strain rate tensile test is qualified, so as to obtain accurate cross-sectional shrinkage rate.

[0073] During the slow strain rate tensile test, the tensile rates of the first notched tensile specimen and the second notched tensile specimen are preferably kept constant.

[0074] In some embodiments, the fracture toughness test is preferably, but not limited to, a fracture toughness resistance curve test, so as to facilitate the implementation of the method for determining the suitability of the pipeline welding joint for a hydrogen environment and obtain accurate determination results.

[0075] In some embodiments, the toughness test specimen is a straight-through specimen or a step-type specimen.

[0076] The length direction of the toughness test sample is parallel to the weld direction of the corresponding sampling position. In other words, the length direction of the toughness test sample is substantially the circumferential direction of the pipeline 10. And the thickness of the toughness test sample is more than 85% of the wall thickness of the pipeline 10. This ensures that the test results of the fracture toughness resistance curve test are accurate.

[0077] At least two toughness test specimens are obtained at each sampling position, wherein the notch of the first toughness test specimen is located at the center of the weld at the corresponding sampling position, i.e., the first toughness test specimen is located at the center of the weld, and the notch of the second toughness test specimen is located at the center of the heat affected zone at the corresponding sampling position, i.e., the second toughness test specimen is located at the center of the heat affected zone. The fracture toughness resistance curve test is conducted on the first toughness test specimen and the second toughness test specimen to obtain a comprehensive and accurate judgment result.

[0078] In some embodiments, a fracture toughness resistance curve test is performed on the first toughness test specimen and the second toughness test specimen obtained at each sampling position in an inert environment to obtain the fracture toughness of the first toughness test specimen and the second toughness test specimen at each sampling position in an inert environment.

[0079] The strength factor of the first toughness test specimen at each sampling position in an inert environment is obtained according to the fracture toughness of the first toughness test specimen at each sampling position in an inert environment, and the strength factor of the second toughness test specimen at each sampling position in an inert environment is obtained according to the fracture toughness of the second toughness test specimen at each sampling position in an inert environment.

[0080] The strength factor of the first toughness test specimen in an inert environment and the strength factor of the second toughness test specimen in an inert environment at the same sampling position are averaged to obtain the strength factor of the corresponding sampling position in an inert environment, thereby obtaining the strength factor of each sampling position in an inert environment.

[0081] A fracture toughness resistance curve test is performed on the first toughness test specimen and the second toughness test specimen obtained at each sampling position in a hydrogen environment to obtain the fracture toughness of the first toughness test specimen and the second toughness test specimen at each sampling position in a hydrogen environment.

[0082] The strength factor of the first toughness test specimen at each sampling position in the hydrogen environment is obtained according to the fracture toughness of the first toughness test specimen at each sampling position in the hydrogen environment, and the strength factor of the second toughness test specimen at each sampling position in the hydrogen environment is obtained according to the fracture toughness of the second toughness test specimen at each sampling position in the hydrogen environment.

[0083] The strength factor of the first toughness test specimen in the hydrogen environment and the strength factor of the second toughness test specimen in the hydrogen environment at the same sampling position are averaged to obtain the strength factor of each sampling position in the hydrogen environment, thereby obtaining the strength factor of each sampling position in the hydrogen environment.

[0084] Specifically, according to Calculate the intensity factor, where is the fracture toughness of the toughness test sample, E is the material elastic modulus of the toughness test sample, and is also the material elastic modulus of the pipeline 10, is the material yield strength of the toughness test specimen, and is also the material yield strength of the pipeline 10, is the intensity factor, and More specifically, taking the first toughness test specimen as an example, a fracture toughness resistance curve test is performed on the first toughness test specimen in an inert environment to obtain the fracture toughness of the first toughness test specimen in an inert environment, and then the fracture toughness of the first toughness test specimen in an inert environment is substituted into , calculate the strength factor of the first toughness test sample in an inert environment. Perform a fracture toughness resistance curve test on another first toughness test sample at the same sampling position in a hydrogen environment and obtain the fracture toughness of the first toughness test sample in a hydrogen environment. Then substitute the fracture toughness of the first toughness test sample in a hydrogen environment into , the strength factor of the first toughness test specimen in the presence of hydrogen is calculated. Thus, the strength factor of the first toughness test specimen in the inert environment and the strength factor in the presence of hydrogen at each sampling position, as well as the strength factor of the second toughness test specimen in the inert environment and the strength factor in the presence of hydrogen at each sampling position can be calculated.

[0085] Then, the strength factor of the first toughness test specimen in an inert environment and the strength factor of the second toughness test specimen in an inert environment at the same sampling position are averaged to obtain the strength factor of the corresponding sampling position in an inert environment. The strength factor of the first toughness test specimen in a hydrogen environment and the strength factor of the second toughness test specimen in a hydrogen environment at the same sampling position are averaged to obtain the strength factor of the corresponding sampling position in a hydrogen environment. Thus, the strength factors of each sampling position in an inert environment and a hydrogen environment are obtained.

[0086] Preferably, the number of the first toughness test specimens and the second toughness test specimens at the same sampling position when conducting the fracture toughness resistance curve test in the inert environment and the hydrogen environment is multiple. Taking the first toughness test specimen as an illustrative example, the average value of the fracture toughness of multiple first toughness test specimens in the inert environment is used as the fracture toughness of the first toughness test specimen in the inert environment, and the average value of the fracture toughness of multiple first toughness test specimens in the hydrogen environment is used as the fracture toughness of the first toughness test specimen in the hydrogen environment, thereby calculating the strength factors of the first toughness test specimens in the inert environment and the hydrogen environment, respectively, so that the obtained strength factors are more accurate.

[0087] In some embodiments, the tensile rate of the fracture toughness resistance curve test of the toughness test specimen is 0.1 MPa·m 1 / 2 / min~1MPa·m 1 / 2 / min.

[0088] In other words, during the fracture toughness resistance curve test, the tensile rate of the first toughness test specimen and the second toughness test specimen was 0.1 MPa·m 1 / 2 / min~1MPa·m 1 / 2 / min, for example 0.1MPa·m 1 / 2 / min, 0.5MPa·m 1 / 2 / min、1MPa·m 1 / 2 / min. To ensure that qualified and accurate fracture toughness is obtained.

[0089] During the fracture toughness resistance curve test, the tensile rates of the first toughness test specimen and the second toughness test specimen are preferably kept constant.

[0090] In some embodiments, the inert environment is an atmospheric environment or an inert gas environment. In other words, the inert environment is an atmospheric environment formed by air or atmosphere, or the inert environment is an inert gas environment formed by an inert gas such as nitrogen, helium, argon, etc.

[0091] It should be noted that the inert gas in the inert gas environment may be one type or multiple types.

[0092] In some embodiments, before the tensile test specimen is subjected to a slow strain rate tensile test, the tensile test specimen needs to be maintained in a hydrogen environment for more than 24 hours, such as 48 hours or 36 hours. Before the toughness test specimen is subjected to a fracture toughness test, the toughness test specimen needs to be maintained in a hydrogen environment for more than 24 hours, such as 48 hours or 36 hours. This ensures that the test results obtained from the slow strain rate tensile test and the fracture toughness test are accurate.

[0093] In some embodiments, the hydrogen environment is consistent with the internal environment of the pipeline 10 during the transportation operation, or the natural gas in the internal environment of the pipeline 10 during the transportation operation is replaced with an inert gas to serve as the hydrogen environment.

[0094] Specifically, the method for judging the suitability of a pipeline welded joint for a hydrogen environment according to an embodiment of the present invention further includes obtaining the internal environment of the pipeline 10 during the transportation operation before performing the slow strain rate tensile test and the fracture toughness test. The internal environment of the pipeline 10 during the transportation operation is preferably, but not limited to, a natural gas hydrogen-doped environment. The hydrogen environment in the slow strain rate tensile test and the fracture toughness test is set to be consistent with the natural gas hydrogen-doped environment, or the natural gas in the natural gas hydrogen-doped environment is replaced with an inert gas as the hydrogen environment.

[0095] It should be noted that the environmental parameters of the hydrogen environment are consistent with the operating parameters of the pipeline 10 during the transportation operation, including the total transportation pressure, such as O 2 , CO 2 , component content of impurities such as CO, water dew point, etc.

[0096] In some embodiments, the method for judging the suitability of a pipe weld joint for a hydrogen environment in an embodiment of the present invention further includes performing a basic performance test on the pipe 10. If the basic performance test is passed, a plurality of sampling positions arranged at intervals are set at the weld joint along the circumference of the pipe 10 to perform a subsequent slow strain rate tensile test and / or fracture toughness test. If the basic performance test is not passed, the suitability of the pipe 10 weld joint for a hydrogen environment is unqualified.

[0097] In some embodiments, the basic performance test includes testing whether the pipeline 10 meets the preset basic performance requirements of chemical composition, metallographic structure, non-metallic inclusions, hardness, notch sensitivity, tensile strength, toughness and non-destructiveness. When all the basic performance requirements are met, the basic performance test of the pipeline 10 passes. When at least one of the basic performance requirements is not met, the basic performance test of the pipeline 10 fails.

[0098] Basic performance testing includes but is not limited to Charpy impact test, steel pipe drop weight tear test, non-destructive testing, etc.

[0099] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for distinction, and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0100] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0101] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for judging the suitability of a pipeline welding joint for a hydrogen environment, characterized in that: include: A plurality of sampling positions arranged at intervals are provided at the weld joint along the circumference of the pipeline; At least two tensile test specimens are obtained at each sampling position, and slow strain rate tensile tests are performed on the tensile test specimens in an inert environment and a hydrogen environment, respectively, to obtain the hydrogen embrittlement coefficient of each sampling position. When the hydrogen embrittlement coefficient of each sampling position is less than or equal to 25%, the slow strain rate tensile test is passed; At least two toughness test specimens are obtained at each sampling position, and fracture toughness tests are performed on the toughness test specimens in an inert environment and a hydrogen environment, respectively, to obtain the strength factor of each sampling position in an inert environment and the strength factor in a hydrogen environment, and the strength factor of each sampling position in an inert environment and the strength factor in a hydrogen environment are both greater than or equal to 55 MPa·m 1 / 2 When , the fracture toughness test is passed; When both the slow strain rate tensile test and the fracture toughness test are passed, the suitability of the pipeline weld joint for hydrogen environment is qualified.

2. The method for judging the suitability of a pipeline welded joint for a hydrogen environment according to claim 1, characterized in that: If the slow strain rate tensile test fails, the suitability of the pipeline weld joint for hydrogen environment is unqualified; If the slow strain rate tensile test passes, continue to obtain the toughness test sample and perform the fracture toughness test. If the fracture toughness test fails, the suitability of the pipeline weld joint for the hydrogen environment fails. If the fracture toughness test passes, the suitability of the pipeline weld joint for the hydrogen environment passes.

3. The method for judging the suitability of a pipeline welded joint for a hydrogen environment according to claim 1, characterized in that: There are at least three sampling positions, wherein the first sampling position is located at the welding arc starting point of the welding joint, the second sampling position is arranged opposite to the first sampling position along the radial direction of the pipeline, and the third sampling position is located in the middle of the first sampling position and the second sampling position along the circumferential direction of the pipeline.

4. The method for judging the suitability of a pipeline welded joint for a hydrogen environment according to claim 1, characterized in that: After setting a plurality of sampling positions, obtaining the weld center and the heat-affected zone center of the weld joint at each sampling position; Among the at least two tensile test specimens obtained at each sampling position, at least one tensile test specimen is located at the center of the weld, and at least one tensile test specimen is located at the center of the heat-affected zone; Among the at least two toughness test specimens obtained at each sampling position, at least one toughness test specimen is located at the center of the weld, and at least one toughness test specimen is located at the center of the heat affected zone.

5. The method for judging the suitability of a pipeline welded joint for a hydrogen environment according to claim 4, characterized in that: After setting a plurality of the sampling positions, an observation sample is obtained at each of the sampling positions along a weld direction perpendicular to the weld joint, and two fusion lines of the observation sample located on the outer surface of the pipe are observed, the center line of the two fusion lines is the weld center, and a positioning line is set on the observation sample along the wall thickness direction of the pipe, the positioning line passes through the heat affected zone of the weld joint at the maximum proportion along the wall thickness direction of the pipe, and the midpoint of the line segment where the positioning line and the heat affected zone coincide with each other is the center of the heat affected zone.

6. The method for judging the suitability of a pipeline welded joint for a hydrogen environment according to claim 5, characterized in that: After obtaining the center of the weld and the center of the heat-affected zone on the observation sample, measuring the distance L1 between the center of the heat-affected zone and the center of the weld, and measuring the distance L2 between the center of the heat-affected zone and the outer surface of the pipe on the observation sample; When at least two tensile test specimens and / or at least two toughness test specimens are obtained at each sampling position, the center of the weld at the sampling position is obtained according to the two fusion lines on the outer surface of the pipe at the sampling position, and then the center of the heat affected zone at the sampling position is obtained according to the distance L1 and the distance L2 measured by the observation specimen obtained at the sampling position, so as to obtain the tensile test specimen and / or the toughness test specimen located at the center of the weld at each sampling position, and the tensile test specimen and / or the toughness test specimen located at the center of the heat affected zone.

7. The method for judging the suitability of a pipeline welded joint for a hydrogen environment according to claim 4, characterized in that: The tensile test specimens include notched tensile specimens, and the notched tensile specimens obtained at each sampling position are at least two types, wherein the notch of the first type of notched tensile specimen is located at the center of the weld corresponding to the sampling position, and the notch of the second type of notched tensile specimen is located at the center of the heat affected zone corresponding to the sampling position.

8. The method for judging the suitability of a pipeline welding joint for a hydrogen environment according to claim 7, characterized in that: The tensile test specimen also includes a smooth round rod specimen, which includes a cross-weld specimen and / or a full-weld specimen, the length direction of the cross-weld specimen is perpendicular to the weld direction corresponding to the sampling position, and the center position of the gauge section of the cross-weld specimen is located at the center of the weld corresponding to the sampling position, the length direction of the full-weld specimen is parallel to the weld direction corresponding to the sampling position, and the full-weld specimen is obtained from the weld corresponding to the sampling position.

9. The method for judging the suitability of a pipeline welded joint for a hydrogen environment according to claim 8, characterized in that: Performing the slow strain rate tensile test on the first notched tensile specimen, the second notched tensile specimen, the cross-weld specimen and the full-weld specimen obtained at each sampling position in the inert environment to obtain the cross-sectional shrinkage of the first notched tensile specimen, the second notched tensile specimen, the cross-weld specimen and the full-weld specimen at each sampling position in the inert environment; Performing the slow strain rate tensile test on the first notched tensile specimen, the second notched tensile specimen, the cross-weld specimen and the full-weld specimen obtained at each sampling position in the hydrogen environment to obtain the cross-sectional shrinkage of the first notched tensile specimen, the second notched tensile specimen, the cross-weld specimen and the full-weld specimen at each sampling position in the hydrogen environment; Obtaining the hydrogen embrittlement coefficient of the first notched tensile specimen, the second notched tensile specimen, the cross-weld specimen and the full weld specimen at each sampling position according to the cross-sectional reduction ratios of the first notched tensile specimen, the second notched tensile specimen, the cross-weld specimen and the full weld specimen at each sampling position in an inert environment and a hydrogen environment, respectively; The hydrogen embrittlement coefficients of the first notch tensile specimen, the second notch tensile specimen, the cross-weld specimen and the full-weld specimen at the same sampling position are averaged to obtain the hydrogen embrittlement coefficient corresponding to the sampling position, thereby obtaining the hydrogen embrittlement coefficient of each sampling position.

10. The method for judging the suitability of a pipeline welding joint for a hydrogen environment according to claim 9, characterized in that: The tensile rate of the notched tensile specimen in the slow strain rate tensile test is less than 2×10 -6 s -1 The tensile rate of the smooth round bar specimen in the slow strain rate tensile test is less than 2×10 -5 s -1 .

11. The method for judging the suitability of a pipeline welding joint for a hydrogen environment according to claim 4, characterized in that: The fracture toughness test is a fracture toughness resistance curve test.

12. The method for judging the suitability of a pipeline welding joint for a hydrogen environment according to claim 11, characterized in that: The toughness test specimen is a straight-through specimen or a step-type specimen, the length direction of the toughness test specimen is parallel to the weld direction corresponding to the sampling position, and the thickness of the toughness test specimen is more than 85% of the wall thickness of the pipeline, and the toughness test specimens obtained at each sampling position are at least two types, wherein the notch of the first type of the toughness test specimen is located at the center of the weld corresponding to the sampling position, and the notch of the second type of the toughness test specimen is located at the center of the heat affected zone corresponding to the sampling position.

13. The method for judging the suitability of a pipeline welding joint for a hydrogen environment according to claim 12, characterized in that: Performing the fracture toughness resistance curve test on the first toughness test specimen and the second toughness test specimen obtained at each sampling position in the inert environment to obtain the fracture toughness of the first toughness test specimen and the second toughness test specimen at each sampling position in the inert environment; Obtaining the strength factor of the first toughness test specimen at each sampling position in an inert environment according to the fracture toughness of the first toughness test specimen at each sampling position in an inert environment, and obtaining the strength factor of the second toughness test specimen at each sampling position in an inert environment according to the fracture toughness of the second toughness test specimen at each sampling position in an inert environment; The intensity factor of the first toughness test specimen in the inert environment and the intensity factor of the second toughness test specimen in the inert environment at the same sampling position are averaged to obtain the intensity factor of the corresponding sampling position in the inert environment, thereby obtaining the intensity factor of each sampling position in the inert environment; Conducting the fracture toughness resistance curve test on the first toughness test specimen and the second toughness test specimen obtained at each sampling position in the hydrogen environment to obtain the fracture toughness of the first toughness test specimen and the second toughness test specimen at each sampling position in the hydrogen environment; Obtaining the strength factor of the first toughness test sample at each sampling position in the presence of hydrogen according to the fracture toughness of the first toughness test sample at each sampling position in the presence of hydrogen, and obtaining the strength factor of the second toughness test sample at each sampling position in the presence of hydrogen according to the fracture toughness of the second toughness test sample at each sampling position in the presence of hydrogen; The strength factor of the first toughness test specimen in the hydrogen environment and the strength factor of the second toughness test specimen in the hydrogen environment at the same sampling position are averaged to obtain the strength factor of each sampling position in the hydrogen environment, thereby obtaining the strength factor of each sampling position in the hydrogen environment.

14. The method for judging the suitability of a pipeline welding joint for a hydrogen environment according to claim 12, characterized in that: The tensile rate of the toughness test specimen for the fracture toughness resistance curve test is 0.1 MPa·m 1 / 2 / min~1MPa·m 1 / 2 / min.

15. The method for judging the suitability of a pipeline welding joint for a hydrogen environment according to claim 1, characterized in that: The inert environment is an atmospheric environment or an inert gas environment.

16. The method for judging the suitability of a pipeline welding joint for a hydrogen environment according to claim 1, characterized in that: Before the tensile test specimen is subjected to the slow strain rate tensile test, the tensile test specimen needs to be maintained in the hydrogen environment for more than 24 hours. Before the toughness test specimen is subjected to the fracture toughness test, the toughness test specimen needs to be maintained in the hydrogen environment for more than 24 hours.

17. The method for judging the suitability of a pipeline welding joint for a hydrogen environment according to claim 1, characterized in that: The hydrogen environment is consistent with the internal environment of the pipeline during transportation operation, or the natural gas in the internal environment of the pipeline during transportation operation is replaced by inert gas to serve as the hydrogen environment.

18. The method for judging the suitability of a pipeline welding joint for a hydrogen environment according to claim 1, characterized in that: Also includes: A basic performance test is performed on the pipeline. If the basic performance test is passed, a plurality of sampling positions arranged at intervals are set at the weld joint along the circumference of the pipeline. If the basic performance test is not passed, the suitability of the pipeline weld joint for hydrogen environment is unqualified.

19. The method for judging the suitability of a pipeline welding joint for a hydrogen environment according to claim 18, characterized in that: The basic performance test includes testing whether the pipeline meets the preset basic performance requirements of chemical composition, metallographic structure, non-metallic inclusions, hardness, notch sensitivity, tensile strength, toughness and non-destructiveness. When all basic performance requirements are met, the basic performance test of the pipeline passes.

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