Hydrogen compatibility simulation test method under high-pressure environment based on hydrogen diffusion

Abstract

The invention discloses a hydrogen compatibility simulation test method in a high-pressure environment based on hydrogen diffusion. The method comprises the following steps: S1, preparing a sample; s2, performing a hydrogen permeation test in a high-pressure hydrogen environment; s3, preparing a hydrogen permeation cathode hydrogen filling solution; s4, performing a hydrogen permeation test in a simulated high-pressure hydrogen environment; s5, applying and adjusting cathode hydrogen charging current under simulated high-pressure hydrogen permeation; s6, determining a dynamic hydrogen charging current; s7, performing a smooth slow tensile simulation test in a high-pressure hydrogen environment; s8, carrying out a notch slow tensile simulation test in a high-pressure hydrogen environment; s9, carrying out a fracture toughness test; and S10, performing high-pressure hydrogen embrittlement evaluation based on the results of the smooth slow tensile simulation test and the fracture toughness test. According to the method, the hydrogen embrittlement performance of the material under different hydrogen pressure environments can be obtained, and the influence of the influence factors on the high-pressure hydrogen embrittlement performance of the steel can be analyzed in combination with the process, alloy components and stress states of the steel.

Description

Technical Field

[0001] The present invention relates to a method for evaluating hydrogen embrittlement of metal materials in a high-pressure hydrogen environment, and more specifically, to a method for simulating hydrogen compatibility test in a high-pressure environment based on hydrogen diffusion. Background Art

[0002] As a clean energy source, hydrogen energy has a wide range of sources and has the advantages of high energy conversion efficiency, pollution-free, zero emissions, storable, renewable, etc. It is an important direction for energy transformation and upgrading and an important path to achieve carbon neutrality and carbon peak, with huge market potential. The whole life cycle of the hydrogen energy system includes links such as hydrogen production, storage, transportation, and utilization. Among them, hydrogen storage, transportation, and pipelines connect the upstream production and downstream end users, which are the key intermediate links. Hydrogen storage, transportation, and pipeline containers and pipelines work in a high-pressure and high-purity hydrogen environment for a long time, which is likely to cause local plasticity reduction, accelerated crack propagation speed, and durability decline, resulting in problems such as hydrogen-induced cracking, hydrogen embrittlement, or fatigue damage. Solving the problem of high-pressure hydrogen embrittlement of materials is a prerequisite for the safe use of high-pressure hydrogen storage containers. In principle, various conventional material mechanics performance methods can be used for hydrogen embrittlement tests, but the more common test methods are as follows, which are also the test methods required by relevant standards or specifications (Table 1).

[0003] Table 1 Test Methods Required by Standards

[0004]

[0005] The hydrogen embrittlement test methods for metal materials can be roughly divided into two categories: one is used for preliminary screening of materials to quickly evaluate whether the materials can be used to manufacture hydrogen-containing parts, such as disc tests, threshold value tests of stress intensity factors for hydrogen-induced cracking, etc.; the other is used for in-situ testing of material mechanics properties to provide performance data for the design of hydrogen-containing parts or the evaluation of material applicability, such as slow strain rate tensile tests, fatigue crack propagation rate tests, fatigue life tests, etc. In the above standards, the test environment is a high-pressure hydrogen environment, and the test is difficult. Since hydrogen atoms are small and the explosion limit range is wide, the test risk is relatively large, especially the test risk in a high-pressure and ultra-high-pressure hydrogen environment is very high. This is also an important reason restricting the application of hydrogen storage and transportation metal materials. There is an urgent need to develop a test hydrogen embrittlement evaluation method with low risk that can replace the high-pressure hydrogen environment. Whether in a high-pressure hydrogen environment or an electrochemically charged hydrogen environment, the hydrogen embrittlement mechanism is basically similar. The main mechanism is that after hydrogen atoms are adsorbed and dissolved in the material, they diffuse and accumulate at defects, reducing the grain boundary bonding force, forming local hydrogen partial pressure, etc., leading to crack initiation, and finally resulting in fracture under the action of stress. Summary of the Invention

[0006] Aiming at the defects existing in the prior art, the purpose of the present invention is to provide a method for simulating hydrogen compatibility test under high-pressure environment based on hydrogen diffusion, which can obtain the hydrogen embrittlement performance of materials under different hydrogen pressure environments, and can analyze the influence of these influencing factors on the high-pressure hydrogen embrittlement performance of steel in combination with the process, alloy composition and stress state of steel.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for simulating hydrogen compatibility test under high-pressure environment based on hydrogen diffusion, comprising the following steps:

[0009] S1, sample preparation;

[0010] S2, performing hydrogen permeation test under high-pressure hydrogen environment;

[0011] S3, preparing a hydrogen permeation cathode hydrogen charging solution;

[0012] S4, performing hydrogen permeation test under simulated high-pressure hydrogen environment;

[0013] S5, simulating the application and adjustment of cathode hydrogen charging current under high-pressure hydrogen permeation;

[0014] S6, determining the dynamic hydrogen charging current;

[0015] S7, performing smooth slow tensile simulation test under high-pressure hydrogen environment;

[0016] S8, performing notched slow tensile simulation test under high-pressure hydrogen environment;

[0017] S9, fracture toughness test;

[0018] S10, performing high-pressure hydrogen embrittlement evaluation based on the results of smooth slow tensile simulation test and fracture toughness test.

[0019] Preferably, in the step S1, the samples include hydrogen permeation specimens, smooth slow tensile specimens, notched slow tensile specimens and CT specimens;

[0020] All the samples need to be ultrasonically treated in alcohol for 15 minutes.

[0021] Preferably, the hydrogen permeation specimen is a circular specimen with a diameter of 30 mm and a surface roughness of 0.4 μm.

[0022] Preferably, in the step 2, the hydrogen permeation test under high-pressure hydrogen environment specifically includes:

[0023] Performing hydrogen permeation test by using a high-pressure hydrogen environment hydrogen permeation test device, and applying a voltage of 0.2 V vs SCE on the hydrogen measurement side by using an electrochemical workstation before the hydrogen permeation test to reduce the background current to 0.1 μA / cm 2, subsequently, a hydrogen-containing gas is introduced on the hydrogen permeation side, and the test pressure ranges from 0.1 to 25 MPa, and the steady-state hydrogen permeation current Ig is recorded under different pressure environments.

[0024] Preferably, in the step 3, the hydrogen permeation cathode hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea.

[0025] Preferably, in the step 4, the hydrogen permeation test under a simulated high-pressure hydrogen environment specifically includes:

[0026] The hydrogen permeation test is carried out using a conventional hydrogen permeation test device. Before the hydrogen permeation test, a voltage of 0.2 V vs SCE is applied on the hydrogen measurement side by an electrochemical workstation to reduce the background current to 0.1 μA / cm 2 , then 300 ml of the hydrogen permeation cathode hydrogen charging solution is added to the hydrogen permeation side, and then a cathode current It is applied by a constant current source to obtain the steady-state hydrogen permeation current Im under different cathode currents.

[0027] Preferably, in the step 5, the cathode hydrogen charging current is applied by a constant current, and the current is 0.1 μA to 10 mA. Each time the current is applied, it is maintained for at least 30 min, and the next adjustment can be continued only after the current of the cathode hydrogen charging current is stable.

[0028] Preferably, in the step 6, determining the dynamic hydrogen charging current specifically includes:

[0029] According to the method of adjusting the cathode hydrogen charging current in step S5, the cathode current It in step S4 is adjusted until the value of the steady-state hydrogen permeation current Im reaches 1 to 1.1 times the steady-state hydrogen permeation current Ig in step S2, that is, 1.1Ig ≥ Im ≥ Ig.

[0030] Preferably, in the step S7, the smooth slow-stretching simulation test under a high-pressure hydrogen environment specifically includes:

[0031] The smooth slow-stretching simulation test is carried out using a slow-stretching test device. Before the test, the smooth slow-stretching specimen is degreased with alcohol. During the test, the cathode hydrogen charging current is applied by a constant current source for dynamic hydrogen charging, and the current magnitude is Id. The hydrogen permeation cathode hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea, and the slow-stretching rate is 5*10 -7 / s - 1*10 -5 / s, and the data is recorded.

[0032] Preferably, in the step S8, the notched slow-stretching simulation test under a high-pressure hydrogen environment specifically includes:

[0033] A slow tensile simulation test with a notch is carried out using a slow tensile test device. Before the test, the notch slow tensile specimen is degreased with alcohol. During the test, a cathodic charging current is applied using a constant current source for dynamic hydrogen charging. The current magnitude is Id, and the hydrogen permeation cathodic charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea. The slow tensile rate is 5*10 -6 / s - 1*10 -4 / s, and the data is recorded.

[0034] Preferably, in the step S9, the fracture toughness test specifically includes:

[0035] The fracture toughness test of the CT specimen is carried out by the displacement-increasing method. During the test, hydrogen charging is carried out simultaneously. The hydrogen charging current is Id, the hydrogen permeation cathodic charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea, and the displacement rate is 0.01 - 0.5 mm / min to obtain the fracture toughness K IH .

[0036] Preferably, in the step S10, the high-pressure hydrogen embrittlement evaluation based on the results of the smooth slow tensile simulation test specifically includes:

[0037] Compare the results of the two slow tensile tests in steps S7 and S8, obtain the relevant data ratio, and compare the ratio changes. If the ratio reaches more than 0.9, the sample has no hydrogen embrittlement in this high-pressure environment; if the ratio is between 0.75 and 0.9, it is mild hydrogen embrittlement; if the ratio is between 0.5 and 0.75, it is moderate hydrogen embrittlement; if the ratio is below 0.5, it is severe hydrogen embrittlement;

[0038] The sorting of the above three data ratios is as follows:

[0039] The ratio of the reduction of area has the highest priority, the ratio of the tensile strength is the second, and the ratio of the elongation is the third. When there is a conflict in the ratios, the ratio of the reduction of area shall prevail;

[0040] The high-pressure hydrogen embrittlement evaluation based on the results of the fracture toughness test specifically includes:

[0041] Compare the fracture toughness K IH under different hydrogen content conditions. According to the ASTM B31.12 standard, if K IH ≥55 MPa*m 1 / 2 it means that the sample passes the anti-hydrogen embrittlement performance test in this environment, and thus it can be obtained whether the anti-hydrogen performance of the material under the corresponding simulated high-pressure environment is qualified.

[0042] A method for simulating hydrogen compatibility test under high - pressure environment based on hydrogen diffusion provided by the present invention combines with existing high - pressure hydrogen embrittlement evaluation methods and standards to enhance the accuracy and rationality of the test. Using the present invention, different high - pressure hydrogen environments can be simulated under normal temperature and pressure conditions, enabling the evaluation of the hydrogen embrittlement performance of metal materials in high - pressure hydrogen environments and clarifying the hydrogen embrittlement risk of metal materials in high - pressure hydrogen embrittlement environments. Using the present invention, the hydrogen embrittlement resistance performance of steel under different hydrogen pressure conditions can be simulated, clarifying the applicability and hydrogen embrittlement risk of steel under different hydrogen pressure conditions, and at the same time providing guidance and direction for the improvement of the hydrogen embrittlement resistance performance and safe use of steel. Brief Description of the Drawings

[0043] Figure 1 is a schematic flow chart of the method for simulating hydrogen compatibility test under high - pressure environment of the present invention;

[0044] Figure 2 is a schematic diagram of the sample in the method for simulating hydrogen compatibility test under high - pressure environment of the present invention. (a) is a hydrogen permeation specimen, (b) is a smooth slow - tensile specimen, (c) is a notched slow - tensile specimen, and (d) is a CT specimen;

[0045] Figure 3 is a schematic diagram of the hydrogen permeation test device for high - pressure hydrogen environment in the method for simulating hydrogen compatibility test under high - pressure environment of the present invention;

[0046] Figure 4 is a schematic diagram of the conventional hydrogen permeation test device in the method for simulating hydrogen compatibility test under high - pressure environment of the present invention;

[0047] Figure 5 is a schematic diagram of the slow - tensile test device in the method for simulating hydrogen compatibility test under high - pressure environment of the present invention. Detailed Embodiments

[0048] In order to better understand the above - mentioned technical solutions of the present invention, the technical solutions of the present invention will be further described below with reference to the drawings and embodiments.

[0049] Combined with Figure 1 as shown, a method for simulating hydrogen compatibility test under high - pressure environment based on hydrogen diffusion provided by the present invention includes the following steps:

[0050] S1, sample preparation:

[0051] The samples are divided into 4 types. The first type is a hydrogen permeation specimen, which is a circular specimen with a diameter of 30 mm and a surface roughness of 0.4 um, as shown in Figure 2 (a). The second type is a smooth slow - tensile specimen. To ensure the accuracy of the test, the size of the slow - tensile sample is manufactured with reference to the ASTM G142 standard, as shown in Figure 2 (b). The third type is a notched slow - tensile specimen, and the sample size is also manufactured with reference to the ASTM G142 standard, as shown inFigure 3 as shown in (c) of No. 4. The fourth type is a CT specimen, such as Figure 4 shown in (d) of No. 4. All samples were ultrasonically treated in alcohol for 15 min before the test.

[0052] S2. Hydrogen permeation test was carried out under a high-pressure hydrogen environment:

[0053] The hydrogen permeation test was carried out using a high-pressure hydrogen environment hydrogen permeation test device (such as Figure 3 shown). The double electrolytic cell structure was adopted. The left side was the hydrogen-measuring electrolytic cell with the test solution being 0.1 mol / L NaOH. The right side was the hydrogen-permeating electrolytic cell composed of a small high-pressure cylinder made of nickel-based alloy with a volume of 0.8 L and a maximum pressure of up to 30 MPa. Before the hydrogen permeation test, a voltage of 0.2 V vs SCE was applied on the hydrogen-measuring side using an electrochemical workstation to reduce the background current to 0.1 μA / cm 2 . Subsequently, a hydrogen-containing gas was introduced into the hydrogen-permeating side. The test pressure range was 0.1 - 25 MPa, and the steady-state hydrogen permeation current Ig was recorded under different pressure environments.

[0054] S3. Prepare the hydrogen permeation cathode hydrogen charging solution:

[0055] The hydrogen permeation cathode hydrogen charging solution was a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea and was placed at room temperature for 24 h.

[0056] S4. Simulate the hydrogen permeation test under a high-pressure hydrogen environment:

[0057] The hydrogen permeation test was carried out using a conventional hydrogen permeation test device (such as Figure 4 shown). The left side was the hydrogen-measuring electrolytic cell with the test solution being 0.1 mol / L NaOH, and the right side was the hydrogen-permeating electrolytic cell. Before the hydrogen permeation test, a voltage of 0.2 V vs SCE was applied on the hydrogen-measuring side using an electrochemical workstation to reduce the background current to 0.1 μA / cm 2 . Subsequently, 300 ml of the hydrogen permeation cathode hydrogen charging solution (a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea) was added to the hydrogen-permeating side. Then, a cathode current It was applied using a constant current source to obtain the steady-state hydrogen permeation current Im under different cathode currents.

[0058] S5. Simulate applying and adjusting the cathode hydrogen charging current under high-pressure hydrogen permeation:

[0059] A cathode hydrogen charging current was applied using a constant current. The current was 0.1 μA - 10 mA. Each time the current was applied, it was maintained for at least 30 min. The next adjustment could only be carried out after the cathode hydrogen charging current was stable.

[0060] S6. Determine the dynamic hydrogen charging current:

[0061] Adjust the cathode hydrogen charging current according to step S5 to adjust the cathode current It in step S4 until the steady-state hydrogen permeation current Im reaches 1 to 1.1 times the steady-state hydrogen permeation current Ig in step S2, that is, 1.1Ig ≥ Im ≥ Ig. At this time, It is the cathode current required to simulate the high-pressure hydrogen-containing environment in step S2, and this current can be used as the dynamic hydrogen charging current for the dynamic hydrogen charging test, denoted as Id.

[0062] S7. Conduct a smooth slow-stretching simulation test under a high-pressure hydrogen environment:

[0063] Use a slow-stretching test device (such as Figure 5 shown) to conduct a smooth slow-stretching simulation test. The slow-stretching test device consists of a slow-stretching testing machine and a constant current source. The slow-stretching test refers to ASTM G129 for dynamic hydrogen charging slow-stretching. Before the test, degrease the smooth slow-stretching specimen with alcohol. During the test, apply a cathode hydrogen charging current using the constant current source for dynamic hydrogen charging. The current magnitude is Id, the hydrogen permeation cathode hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea, and the slow-stretching rate is 5×10 -7 / s - 1×10 -5 / s. Record the reduction of area, elongation, and tensile strength. Subsequently, conduct a smooth slow-stretching test under an inert gas environment for comparison. The slow-stretching rate is the same as that of the simulation test, and at the same time, record data such as the shrinkage rate, elongation, and tensile strength.

[0064] S8. Conduct a notched slow-stretching simulation test under a high-pressure hydrogen environment:

[0065] Use a slow-stretching test device (such as Figure 5 shown) to conduct a notched slow-stretching simulation test. The slow-stretching test device consists of a slow-stretching testing machine and a constant current source. Before the test, degrease the notched slow-stretching specimen with alcohol. The slow-stretching test refers to ASTM G129 for dynamic hydrogen charging slow-stretching. During the test, apply a cathode hydrogen charging current using the constant current source for dynamic hydrogen charging. The current magnitude is Id, the hydrogen permeation cathode hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea, and the slow-stretching rate is 5×10 -6 / s - 1×10 -4 / s. Record the reduction of area and tensile strength. Subsequently, conduct a notched slow-stretching test under an inert gas environment for comparison. The slow-stretching rate is the same as that of the simulation test, and at the same time, record data such as the reduction of area and tensile strength.

[0066] S9. Fracture toughness test:

[0067] Refer to GB / T 21143-2014, the fracture toughness test of CT specimens is carried out by the incremental displacement method. During the test, hydrogen charging is carried out simultaneously. The hydrogen charging current is Id, and the hydrogen permeation cathode hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea. The displacement rate is 0.01 - 0.5 mm / min, and the fracture toughness K is obtained. IH .

[0068] S10, based on the results of smooth slow tensile simulation tests and fracture toughness tests, evaluate high-pressure hydrogen embrittlement:

[0069] Compare the results of the two slow tensile tests in steps S7 and S8, obtain the relevant data ratio, and compare the ratio changes. If the ratio reaches more than 0.9, there is no hydrogen embrittlement in the sample under this high-pressure environment; if the ratio is between 0.75 - 0.9, it is mild hydrogen embrittlement; if the ratio is between 0.5 - 0.75, it is moderate hydrogen embrittlement; if the ratio is below 0.5, it is severe hydrogen embrittlement.

[0070] The sorting of the above three data ratios is as follows:

[0071] The priority of the reduction of area ratio is the first, the tensile strength ratio is the second, and the elongation ratio is the third. When there is a conflict in the ratios, the reduction of area ratio shall prevail.

[0072] The evaluation of high-pressure hydrogen embrittlement based on the results of the fracture toughness test specifically includes:

[0073] Compare the fracture toughness K under different hydrogen content conditions IH , and according to the standard of ASTM B31.12, if K IH ≥55 MPa*m 1 / 2 it means that the sample passes the anti-hydrogen embrittlement performance test in this environment, and thus the anti-hydrogen performance of the material under the corresponding simulated high-pressure environment can be obtained.

[0074] Example 1

[0075] In this Example 1, X52 is used as the test sample, and the specific steps are as follows:

[0076] S1, sample preparation: The samples are divided into 4 types. The first type is the hydrogen permeation specimen, which is a circular specimen with a diameter of 30 mm and a surface roughness of 0.4 um, as shown in (a) of Figure 2 . The second type is the smooth slow tensile specimen. To ensure the accuracy of the test, the size of the slow tensile sample is manufactured with reference to the ASTM G142 standard, as shown in (b) of Figure 2 . The third type is the notched slow tensile specimen, and the sample size is also manufactured with reference to the ASTM G142 standard, as shown in (c) of Figure 2 . The fourth type is the CT specimen, as shown in (d) of Figure 2 . All samples are ultrasonically treated in alcohol for 15 minutes before the test.

[0077] S2, high pressure hydrogen environment hydrogen permeation test: using high pressure hydrogen environment hydrogen permeation test equipment (such as Figure 3 The hydrogen permeation test was conducted using a dual electrolytic cell structure. The left side is the hydrogen measurement electrolytic cell, and the test solution is 0.1 mol / L NaOH. The right side is the hydrogen permeation electrolytic cell, which is made of a small high-pressure cylinder made of nickel-based alloy. The volume is 0.8L and the maximum pressure can reach 30MPa. Before the hydrogen permeation test, an electrochemical workstation was used to apply a 0.2VvSCE voltage on the hydrogen measurement side to reduce the background current to 0.1uA / cm 2 Then, pure hydrogen gas is introduced into the hydrogen permeation side, the test pressure is 7MPa, and the steady-state hydrogen permeation current Ig is recorded.

[0078] S3, simulated high-pressure hydrogen permeation cathode charging solution: a mixture of 0.01 mol / L acetic acid and 0.2 g / L thiourea was used as a hydrogen permeation cathode charging solution and placed at room temperature for 24 hours.

[0079] S4, simulated high pressure hydrogen environment hydrogen permeation test: the test uses a conventional hydrogen permeation device such as Figure 4 As shown, the left side is the hydrogen measurement electrolytic cell, the test solution is 0.1 mol / L NaOH, and the right side is the hydrogen permeation electrolytic cell. Before the hydrogen permeation test, an electrochemical workstation was used to apply a 0.2 V vs SCE voltage on the hydrogen measurement side to reduce the background current to 0.1 uA / cm 2 Then, a simulated high-pressure hydrogen permeation cathode hydrogen charging solution (0.01 mol / L acetic acid + 0.2 g / L thiourea mixture) was added to the hydrogen permeation, 300 ml was taken, and then a cathode current It was applied using a constant current source to obtain a steady-state hydrogen permeation current Im under different cathode currents.

[0080] S5, simulate the application and adjustment of high-pressure hydrogen permeation cathode current: use constant current to apply cathode hydrogen charging current, the current is 1uA ~ 10mA, each application of current is maintained for at least 30min, and the next adjustment can be continued after the hydrogen permeation current is stable.

[0081] S6, determine the dynamic hydrogen charging current: continuously adjust the cathode current It applied on the hydrogen permeation side in step S4. The adjustment method is performed with reference to step S5 until the steady-state hydrogen permeation current Im value reaches 1 to 1.1 times of the steady-state hydrogen permeation current Ig in step S2, that is, 1.1Ig≥Im≥Ig. At this time, It is the cathode current required to simulate the high-pressure hydrogen-containing environment in step S2. This current can be used as the dynamic hydrogen charging current for the dynamic hydrogen charging test, recorded as Id.

[0082] S7, high pressure hydrogen environment smooth slow tensile simulation test: slow tensile test device such as Figure 5As shown in the figure, the test device consists of a slow tensile testing machine and a constant current source. Before the test, the slow tensile sample is degreased with alcohol. The specimen is a smooth slow tensile specimen. The slow tensile test refers to ASTM G129 for dynamic hydrogen charging slow tensile test. During the test, a cathodic hydrogen charging current is applied by the constant current source for dynamic hydrogen charging. The current magnitude is Id, and the hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea. The slow tensile rate is 7*10 -6 / s, the number of specimens is 3, and the reduction of area, elongation and tensile strength are recorded. Subsequently, a smooth slow tensile test is carried out in an inert gas environment for comparison. The slow tensile rate is the same as that of the simulation test, and data such as shrinkage rate, elongation and tensile strength are recorded at the same time.

[0083] S8, Simulation test of slow tensile with a notch in a high-pressure hydrogen environment: The slow tensile test device is as Figure 5 shown. The test device consists of a slow tensile testing machine and a constant current source. Before the test, the slow tensile sample is degreased with alcohol. The specimen is a notched slow tensile specimen. The slow tensile test refers to ASTM G129 for dynamic hydrogen charging slow tensile test. During the test, a cathodic hydrogen charging current is applied by the constant current source for dynamic hydrogen charging. The current magnitude is Id, and the hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea. The slow tensile rate is 7*10 -5 / s, and the reduction of area and tensile strength are recorded. Subsequently, a notched slow tensile test is carried out in an inert gas environment for comparison. The slow tensile rate is the same as that of the simulation test, and data such as the reduction of area and tensile strength are recorded at the same time. The number of specimens is 3.

[0084] S9, Fracture toughness test: Refer to GB / T21143-2014 to conduct a fracture toughness test on CT specimens using the increased displacement method. Hydrogen charging is carried out during the test. The hydrogen charging current is Id, and the hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea. The displacement rate is 0.04 mm / min, and the fracture toughness K IH is obtained. The number of specimens is 3.

[0085] S10, Evaluation of high-pressure hydrogen embrittlement based on the results of smooth slow tensile test: Comparing the results of slow tensile test after hydrogen charging with those of the test in an inert gas environment, the test results show that all ratios reach more than 0.9, and there is no hydrogen embrittlement of the sample in this high-pressure environment.

[0086] S11, Evaluation of high-pressure hydrogen embrittlement based on fracture toughness: The obtained fracture toughnesses K IH are all ≥ 55 MPa*m 1 / 2 , and the hydrogen embrittlement resistance of the test materials is qualified in a 7 MPa hydrogen environment.

[0087]

[0088] Example 2

[0089] In this Example 2, X52 is used as the test sample, and the specific steps are as follows:

[0090] S1. Sample preparation: The samples are divided into 4 types. The first type is the hydrogen permeation specimen, which is a circular specimen with a diameter of 30 mm and a surface roughness of 0.4 um, as shown in (a) of Figure 2 . The second type is the smooth slow tensile specimen. To ensure the accuracy of the test, the size of the slow tensile sample is manufactured with reference to the ASTM G142 standard, as shown in (b) of Figure 2 . The third type is the notched slow tensile specimen, and the sample size is also manufactured with reference to the ASTM G142 standard, as shown in (c) of Figure 2 . The fourth type is the CT specimen, as shown in (d) of Figure 2 . All samples are ultrasonically treated in alcohol for 15 min before the test.

[0091] S2. Hydrogen permeation test in a high-pressure hydrogen environment: The hydrogen permeation test is carried out using the high-pressure hydrogen environment hydrogen permeation test device (as shown in Figure 3 ). A double electrolytic cell structure is adopted. The left side is the hydrogen-measuring electrolytic cell, and the test solution is 0.1 mol / L NaOH. The right side is the hydrogen-permeating electrolytic cell, which consists of a small high-pressure cylinder made of nickel-based alloy with a volume of 0.8 L and a maximum pressure of up to 30 MPa. Before the hydrogen permeation test, a voltage of 0.2 V vs SCE is applied on the hydrogen-measuring side using an electrochemical workstation to reduce the background current to 0.1 uA / cm 2 , and then pure hydrogen gas of 7 Mpa + CH4 of 1 MPa is introduced into the hydrogen-permeating side, and the test pressure is 8 MPa. Record the steady-state hydrogen permeation current Ig at this time.

[0092] S3. Simulating the hydrogen permeation cathode hydrogen charging solution in a high-pressure hydrogen environment: A mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea is used as the hydrogen permeation cathode hydrogen charging solution for standby and is placed at room temperature for 24 h.

[0093] S4. Simulating the hydrogen permeation test in a high-pressure hydrogen environment: The test uses a conventional hydrogen permeation device as shown in Figure 4 . The left side is the hydrogen-measuring electrolytic cell, and the test solution is 0.1 mol / L NaOH. The right side is the hydrogen-permeating electrolytic cell. Before the hydrogen permeation test, a voltage of 0.2 V vs SCE is applied on the hydrogen-measuring side using an electrochemical workstation to reduce the background current to 0.1 uA / cm 2 , and then the simulated high-pressure hydrogen permeation cathode hydrogen charging solution (a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea) is added to the hydrogen-permeating side, taking 300 ml. Then, a cathode current It is applied using a constant current source to obtain the steady-state hydrogen permeation current Im at different cathode currents.

[0094] S5. Simulation of high-pressure hydrogen permeation cathode current application and adjustment: Apply the cathode hydrogen charging current using a constant current. The current is 1 μA to 10 mA, and each time the current is applied, it should be maintained for at least 30 min. The next adjustment can only be carried out after the hydrogen permeation current stabilizes.

[0095] S6. Determine the dynamic hydrogen charging current: Continuously adjust the cathode current It applied on the hydrogen permeation side in step S4. The adjustment method follows step S5 until the steady-state hydrogen permeation current Im reaches 1 to 1.1 times the steady-state hydrogen permeation current Ig in step S2, that is, 1.1Ig ≥ Im ≥ Ig. At this time, It is the cathode current required to simulate the high-pressure hydrogen-containing environment in step S2. This current can be used as the dynamic hydrogen charging current for the dynamic hydrogen charging test and is denoted as Id.

[0096] S7. Smooth slow-stretching simulation test in a high-pressure hydrogen environment: The slow-stretching test device is as Figure 5 shown. The test device consists of a slow-stretching testing machine and a constant current source. Before the test, degrease the slow-stretching sample with alcohol. The specimen is a smooth slow-stretching specimen. The slow-stretching test refers to ASTM G129 for dynamic hydrogen charging slow-stretching. During the test, apply the cathode hydrogen charging current using the constant current source for dynamic hydrogen charging. The current magnitude is Id, and the hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea. The slow-stretching rate is 7×10 -6 / s, and the number of specimens is 3. Record the reduction of area, elongation, and tensile strength. Subsequently, conduct a smooth slow-stretching test in an inert gas environment for comparison. The slow-stretching rate is the same as that of the simulation test, and at the same time, record data such as the shrinkage rate, elongation, and tensile strength.

[0097] S8. Notched slow-stretching simulation test in a high-pressure hydrogen environment: The slow-stretching test device is as Figure 5 shown. The test device consists of a slow-stretching testing machine and a constant current source. Before the test, degrease the slow-stretching sample with alcohol. The specimen is a notched slow-stretching specimen. The slow-stretching test refers to ASTM G129 for dynamic hydrogen charging slow-stretching. During the test, apply the cathode hydrogen charging current using the constant current source for dynamic hydrogen charging. The current magnitude is Id, and the hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea. The slow-stretching rate is 7×10 -5 / s. Record the reduction of area and tensile strength. Subsequently, conduct a notched slow-stretching test in an inert gas environment for comparison. The slow-stretching rate is the same as that of the simulation test, and at the same time, record data such as the reduction of area and tensile strength. The number of specimens is 3.

[0098] S9, Fracture Toughness Test: The fracture toughness test of CT specimens was carried out by the increasing displacement method with reference to GB / T 21143-2014. Hydrogen charging was carried out during the test. The hydrogen charging current was Id, and the hydrogen charging solution was a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea. The displacement rate was 0.04 mm / min, and the fracture toughness K was obtained. IH The number of specimens was 3.

[0099] S10, High-pressure Hydrogen Embrittlement Evaluation Based on Smooth Slow Tensile Test Results: By comparing the results of the slow tensile test after hydrogen charging with those of the test in an inert gas environment, the test results showed that all ratios reached above 0.9, and there was no hydrogen embrittlement in the samples under this high-pressure environment.

[0100] S11, High-pressure Hydrogen Embrittlement Evaluation Based on Fracture Toughness: The fracture toughness K obtained from the test IH ≥55 MPa*m 1 / 2 The hydrogen embrittlement resistance of the test material was qualified under the environment of 7 MPa pure hydrogen gas + 1 MPa CH4.

[0101]

[0102] Example 3

[0103] In this Example 3, X70 was used as the test sample, and the specific steps were as follows:

[0104] S1, Sample Preparation: The samples were divided into 4 types. The first type was the hydrogen permeation specimen, which was a circular specimen with a diameter of 30 mm and a surface roughness of 0.4 um, as shown in Figure 2 (a). The second type was the smooth slow tensile specimen. To ensure the accuracy of the test, the dimensions of the slow tensile specimen were manufactured with reference to the ASTM G142 standard, as shown in Figure 2 (b). The third type was the notched slow tensile specimen, and the sample dimensions were also manufactured with reference to the ASTM G142 standard, as shown in Figure 2 (c). The fourth type was the CT specimen, as shown in Figure 2 (d). All samples were ultrasonically treated in alcohol for 15 min before the test.

[0105] S2, Hydrogen Permeation Test in High-pressure Hydrogen Environment: The test device was as shown in Figure 3 . A double electrolytic cell structure was adopted. The left side was the hydrogen measurement electrolytic cell, and the test solution was 0.1 mol / L NaOH. The right side was the hydrogen permeation electrolytic cell, which consisted of a small high-pressure cylinder made of nickel-based alloy with a volume of 0.8 L and a maximum pressure of up to 30 MPa. Before the hydrogen permeation test, a voltage of 0.2 V vs SCE was applied on the hydrogen measurement side using an electrochemical workstation to reduce the background current to 0.1 uA / cm 2 . Subsequently, 22 MPa pure hydrogen gas was introduced on the hydrogen permeation side, the test pressure was 22 MPa, and the steady-state hydrogen permeation current Ig was recorded at this time.

[0106] S3, simulated high-pressure hydrogen permeation cathode charging solution: a mixture of 0.01 mol / L acetic acid and 0.2 g / L thiourea was used as a hydrogen permeation cathode charging solution and placed at room temperature for 24 hours.

[0107] S4, simulated high pressure hydrogen environment hydrogen permeation test: the test uses a conventional hydrogen permeation device such as Figure 4 As shown, the left side is the hydrogen measurement electrolytic cell, the test solution is 0.1 mol / L NaOH, and the right side is the hydrogen permeation electrolytic cell. Before the hydrogen permeation test, an electrochemical workstation was used to apply a 0.2 V vs SCE voltage on the hydrogen measurement side to reduce the background current to 0.1 uA / cm 2 Then, a simulated high-pressure hydrogen permeation cathode hydrogen charging solution (0.01 mol / L acetic acid + 0.2 g / L thiourea mixture) was added to the hydrogen permeation, 300 ml was taken, and then a cathode current It was applied using a constant current source to obtain a steady-state hydrogen permeation current Im under different cathode currents.

[0108] S5, simulate the application and adjustment of high-pressure hydrogen permeation cathode current: use constant current to apply cathode hydrogen charging current, the current is 1uA ~ 10mA, each application of current is maintained for at least 30min, and the next adjustment can be continued after the hydrogen permeation current is stable.

[0109] S6, determine the dynamic hydrogen charging current: continuously adjust the cathode current It applied on the hydrogen permeation side in step S4. The adjustment method is performed with reference to step S5 until the steady-state hydrogen permeation current Im value reaches 1 to 1.1 times of the steady-state hydrogen permeation current Ig in step S2, that is, 1.1Ig≥Im≥Ig. At this time, It is the cathode current required to simulate the high-pressure hydrogen-containing environment in step S2. This current can be used as the dynamic hydrogen charging current for the dynamic hydrogen charging test, recorded as Id.

[0110] S7, high pressure hydrogen environment smooth slow tensile simulation test: slow tensile test device such as Figure 5 As shown, the test device consists of a slow tensile testing machine and a constant current source. Before the test, the slow tensile sample was degreased with alcohol. The sample was a smooth slow tensile sample. The slow tensile test referred to ASTM G129 for dynamic hydrogen charging and slow stretching. During the test, a constant current source was used to apply a cathode hydrogen charging current for dynamic hydrogen charging. The current size was Id. The hydrogen charging solution was a mixture of 0.01 mol / L acetic acid and 0.2 g / L thiourea. The slow tensile rate was 3*10 -6 / s, 3 samples were collected, and the section shrinkage, elongation and tensile strength were recorded. Then, as a comparison, a smooth slow tensile test was carried out under an inert gas environment. The slow tensile rate was the same as that of the simulation test, and the shrinkage, elongation and tensile strength data were recorded at the same time.

[0111] S8, high pressure hydrogen environment notch slow tensile simulation test: slow tensile test device such asFigure 5 As shown in Figure 5 , the test device consists of a slow tensile testing machine and a constant current source. Before the test, the slow tensile sample is degreased with alcohol. The specimen is a notched slow tensile specimen. The slow tensile test refers to ASTM G129 for dynamic hydrogen charging slow tensile test. During the test, a cathodic hydrogen charging current is applied by the constant current source for dynamic hydrogen charging. The current magnitude is Id, and the hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea. The slow tensile rate is 3×10 -5 / s, and the reduction of area and tensile strength are recorded. Subsequently, a notched slow tensile test is carried out in an inert gas environment for comparison. The slow tensile rate is the same as that of the simulation test, and data such as the reduction of area and tensile strength are recorded simultaneously. The number of specimens is 3.

[0112] S9, fracture toughness test: Referring to GB / T21143-2014, the crack tip opening displacement method is used to conduct the fracture toughness test on the CT specimen. Hydrogen charging is carried out simultaneously during the test. The hydrogen charging current is Id, and the hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea. The displacement rate is 0.04 mm / min, and the fracture toughness K IH is obtained. The number of specimens is 3.

[0113] S10, evaluation of high-pressure hydrogen embrittlement based on the results of smooth slow tensile test: Comparing the results of the slow tensile test after hydrogen charging with the test results in an inert gas environment, the test results show that all ratios reach and some are below 0.9, and the sample has a risk of mild hydrogen embrittlement in this high-pressure environment.

[0114] S11, evaluation of high-pressure hydrogen embrittlement based on fracture toughness: The fracture toughness K IH obtained from the test is ≥55 MPa*m 1 / 2 , and the hydrogen embrittlement resistance of the test material is qualified in a 22 MPa hydrogen environment.

[0115]

[0116] Those of ordinary skill in the art in this technical field should recognize that the above embodiments are only used to illustrate the present invention, rather than to limit the present invention. As long as within the scope of the essential spirit of the present invention, changes and modifications to the above-described embodiments will fall within the scope of the claims of the present invention.

Claims

1. A method for simulating hydrogen compatibility test under high-pressure environment based on hydrogen diffusion, characterized in that, It includes the following steps: S1, sample preparation; S2, perform a hydrogen permeation test under a high-pressure hydrogen environment; S3, configure a hydrogen permeation cathode hydrogen charging solution; S4, simulate a hydrogen permeation test under a high-pressure hydrogen environment; S5, simulate applying and adjusting the cathode hydrogen charging current under high-pressure hydrogen permeation; S6, determine the dynamic hydrogen charging current; S7, perform a smooth slow tensile simulation test under a high-pressure hydrogen environment; S8, perform a notched slow tensile simulation test under a high-pressure hydrogen environment; S9, fracture toughness test; S10, conduct a high-pressure hydrogen embrittlement evaluation based on the results of the smooth slow tensile simulation test and the fracture toughness test.

2. The hydrogen compatibility simulation test method under high-pressure environment based on hydrogen diffusion according to claim 1, wherein: In the step S1, the samples include hydrogen permeation specimens, smooth slow tensile specimens, notched slow tensile specimens, and CT specimens; All the said samples need to be ultrasonically treated in alcohol for 15 minutes.

3. The method for simulating hydrogen compatibility under high-pressure environment based on hydrogen diffusion according to claim 2, wherein: The hydrogen permeation specimen is a circular specimen with a diameter of 30 mm and a surface roughness of 0.4 μm.

4. The method for simulating hydrogen compatibility test under high-pressure environment based on hydrogen diffusion according to claim 2, wherein, In the step 2, performing the hydrogen permeation test under a high-pressure hydrogen environment specifically includes: The hydrogen permeation test was carried out using a high-pressure hydrogen environment hydrogen permeation test device. Before the hydrogen permeation test, an electrochemical workstation was used to apply a voltage of 0.2 V vs SCE on the hydrogen measurement side to reduce the background current to 0.1 μA / cm 2 , and then a hydrogen-containing gas was introduced on the hydrogen permeation side. The test pressure range was 0.1 - 25 MPa, and the steady-state hydrogen permeation current Ig under different pressure environments was recorded.

5. The method for simulating hydrogen compatibility under high-pressure environment based on hydrogen diffusion according to claim 4, wherein: In the step 3, the hydrogen permeation cathode hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea.

6. The method for simulating hydrogen compatibility under high-pressure environment based on hydrogen diffusion according to claim 5, wherein In the step 4, simulating the hydrogen permeation test under a high-pressure hydrogen environment specifically includes: Hydrogen permeation tests were carried out using a conventional hydrogen permeation test device. Before the hydrogen permeation test, a voltage of 0.2 V vs SCE was applied on the hydrogen measurement side using an electrochemical workstation to reduce the background current to 0.1 μA / cm 2 , and then 300 ml of the hydrogen permeation cathode hydrogen charging solution was added during hydrogen permeation. Subsequently, a cathode current It was applied using a constant current source to obtain the steady-state hydrogen permeation current Im at different cathode currents.

7. The method for simulating hydrogen compatibility under high-pressure environment based on hydrogen diffusion according to claim 6, wherein: In the step 5, apply the cathode hydrogen charging current by constant current, the current is 0.1 μA to 10 mA, and each time the current is applied, it should be maintained for at least 30 minutes. Only after the current of the cathode hydrogen charging current is stable can the next adjustment be continued.

8. The method for simulating hydrogen compatibility under high-pressure environment based on hydrogen diffusion according to claim 7, characterized in that, In the step 6, determining the dynamic hydrogen charging current specifically includes: Adjust the cathode current It in the step S4 according to the way of adjusting the cathode hydrogen charging current in the step S5 until the value of the steady-state hydrogen permeation current Im reaches 1 to 1.1 times the steady-state hydrogen permeation current Ig in the step S2, that is, 1.1Ig ≥ Im ≥ Ig.

9. The method for simulating hydrogen compatibility under high-pressure environment based on hydrogen diffusion according to claim 8, wherein In the step S7, performing the smooth slow tensile simulation test under a high-pressure hydrogen environment specifically includes: A smooth slow-stretching simulation test is carried out using a slow-stretching test device. Before the test, the smooth slow-stretching specimen is degreased with alcohol. During the test, a cathodic charging hydrogen current is applied using a constant current source for dynamic hydrogen charging, with the current magnitude being Id. The hydrogen permeation cathodic charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea, and the slow-stretching rate is 5*10 -7 / s - 1*10 -5 / s, and the data is recorded.

10. The method for simulating hydrogen compatibility under high-pressure environment based on hydrogen diffusion according to claim 9, wherein In the step S8, performing the notched slow tensile simulation test under a high-pressure hydrogen environment specifically includes: Use a slow tensile test device to conduct a notched slow tensile simulation test. Before the test, degrease the notched slow tensile specimen with alcohol. During the test, apply the cathodic hydrogen charging current using a constant current source for dynamic hydrogen charging. The current magnitude is Id, and the hydrogen permeation cathodic hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea. The slow tensile rate is 5*10 -6 / s - 1*10 -4 / s, and record the data.

11. The method for simulating hydrogen compatibility under high-pressure environment based on hydrogen diffusion according to claim 10, wherein In the step S9, the fracture toughness test specifically includes: The fracture toughness test of the CT specimen is carried out by the incremental displacement method. During the test, hydrogen charging is carried out simultaneously. The hydrogen charging current is Id, and the hydrogen permeation cathode hydrogen charging solution is a mixed solution of 0.01 mol / L acetic acid + 0.2 g / L thiourea. The displacement rate is 0.01 - 0.5 mm / min, and the fracture toughness K is obtained. IH .

12. The method for simulating hydrogen compatibility under high-pressure environment based on hydrogen diffusion according to claim 11, wherein, In the step S10, conducting a high-pressure hydrogen embrittlement evaluation based on the results of the smooth slow tensile simulation test specifically includes: Compare the results of the two slow tensile tests in the step S7 and the step S8, obtain the relevant data ratio, compare the ratio change. If the ratio reaches more than 0.9, there is no hydrogen embrittlement in the sample under this high-pressure environment; if the ratio is between 0.75 and 0.9, it is mild hydrogen embrittlement; if the ratio is between 0.5 and 0.75, it is moderate hydrogen embrittlement; if the ratio is below 0.5, it is severe hydrogen embrittlement; The sorting of the above three data ratios is as follows: The priority of the reduction of area ratio is the first, the priority of the tensile strength ratio is the second, and the priority of the elongation ratio is the third. When there is a conflict in the ratios, the reduction of area ratio shall prevail; Conducting a high-pressure hydrogen embrittlement evaluation based on the results of the fracture toughness test specifically includes: Compare the fracture toughness K under different hydrogen content conditions IH , according to K in ASTM B31.12 standard IH ≥55MPa*m 1 / 2 It indicates that the sample passes the hydrogen embrittlement resistance test in this environment, and thus it can be determined whether the hydrogen resistance of the material under the corresponding simulated high-pressure environment is qualified.

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