CN104880400A - High pressure hydrogen penetration test device and method - Google Patents

Abstract

The invention discloses a high-pressure hydrogen permeation test device and a test method; the invention measures the hydrogen permeation amount in the process of stretching a sample, and measures the relationship between the fatigue load state and the hydrogen permeation amount under different high-pressure hydrogen environments on-line and in situ The quantitative relationship between the stress and the segregation and diffusion of hydrogen can be intuitively shown, and the indirect analysis shows that the hydrogen diffusion coefficient, acceleration amount, and hydrogen acceleration amount of the material under different conditions are directly related to the dislocation movement. , so as to improve the reliable data basis for the determination of dislocation density. The invention has the characteristics of reducing the test amount and the test time of a single test.

Description

High pressure hydrogen permeation test device and test method

technical field

The invention relates to the technical field of high-pressure hydrogen permeation testing, in particular to a high-pressure hydrogen permeation testing device and testing method capable of testing the critical fatigue load of materials in a short time and measuring the hydrogen permeation amount under different temperatures, hydrogen pressures and fatigue loads .

Background technique

With the rapid development of my country's economy, the contradiction between energy supply and demand has become increasingly prominent, posing a serious threat to energy security and sustainable economic development. The development and utilization of hydrogen energy and the processing and upgrading of traditional fossil fuels have become important ways to solve energy supply and environmental problems. Hydrogenation reactors in petroleum hydrocracking, hydrofining, hydroreforming, coal hydrogenation liquefaction processes and ultra-high pressure hydrogen storage containers in hydrogen energy storage, etc. Core equipment in the economic pillar field. High-pressure hydrogen-facing equipment is heavy-duty equipment characterized by harsh service environments, complex failure mechanisms, and serious accident consequences. In the high-pressure hydrogen environment, the materials of high-pressure hydrogen-facing equipment can often maintain good use in a short period of time, but as time goes on, cracking problems often occur; after research, it is found that the cracking of the above-mentioned materials is due to fatigue load and hydrogen damage The result of a double action.

In a high-pressure _H2 environment, _H2 molecules can be adsorbed on the metal surface and further dissociate into the interior of the metal, and interact with the material under load, causing various forms of hydrogen damage such as hydrogen-induced cracking, stress corrosion cracking, and hydrogen-induced fatigue cracking. , Seriously endanger the safe service of equipment. On the one hand, the immersion of hydrogen into the metal will reduce the mechanical properties of the material, especially the fatigue resistance of the material. On the other hand, the material will affect the diffusion process of hydrogen into the metal under different loads. Under the influence of hydrogen pressure, the three interact to form a complex coupling mechanism. Therefore, the research on the degradation of mechanical properties of materials under high-pressure H ₂ environment has become an important and difficult point in the promotion and utilization of hydrogen energy.

China Invention Authorization Publication No.: CN202693457U, authorized publication date January 23, 2013, discloses a high temperature and high pressure hydrogen sulfide environment hydrogen permeation detection device, the high temperature and high pressure hydrogen sulfide environment hydrogen permeation detection device includes: a high temperature and high pressure cathode Reactor, the side wall on one side is radially provided with a sealing sleeve, one end of the sealing sleeve is located at the reaction chamber of the high temperature and high pressure cathode reactor, and the other end protrudes from the high temperature and high pressure cathode The outer wall of the reactor, and form a sealed connection with the outer wall of the high-temperature and high-pressure cathode reactor; the disadvantage of this invention is that it cannot detect the amount of hydrogen permeation while stretching the sample.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a high-pressure hydrogen permeation test that can test the critical fatigue load of materials in a short time and measure the hydrogen permeation amount under different temperatures, hydrogen pressures and fatigue loads Device and test method.

In order to achieve the above object, the present invention adopts the following technical solutions:

A high-pressure hydrogen permeation testing device, the high-pressure hydrogen permeation testing device is respectively connected with an electrochemical workstation, an oil bath controller and a fatigue testing machine, and the fatigue testing machine is provided with an upper clamp and a lower clamp for connecting two ends of a sample; comprising A controller, a hydrogen tank, a nitrogen tank, an ion pump, a hydrogen buffer tank, and a reactor on a fatigue testing machine; The first kettle cover that is sealed and connected with the body, the peripheral surface of the first kettle body is provided with a heating chamber surrounding the first kettle body, and the heating chamber is connected with the oil bath controller; the first kettle cover and the first kettle body are respectively provided with There are an upper sealing structure and a lower sealing structure for sealing and limiting the hollow rod-shaped sample vertically penetrating through the reactor; Trachea; the reaction kettle is provided with a first pressure gauge for detecting the nitrogen pressure in the first kettle body; the two ends of the sample are respectively connected to the hydrogen buffer kettle through the ventilation pipe, and the ion pump is connected to the hydrogen buffer kettle;

The first kettle cover is provided with a reference electrode and an auxiliary anode extending into the first kettle body; the electrochemical workstation is electrically connected with the reference electrode, the auxiliary anode and the sample;

The hydrogen buffer tank includes a second tank body with an open upper end and a second tank cover sealed with the second tank body, and the hydrogen tank communicates with the inside of the second tank body through two hydrogen conduits; the hydrogen buffer tank A second pressure gauge for detecting the hydrogen pressure in the second still body is provided on the top;

The controller is respectively connected with the electrochemical workstation, the oil bath controller, the fatigue testing machine, the first electromagnetic valve located on the hydrogen tank, the second electromagnetic valve located on the nitrogen tank, and the third electromagnetic valve located on the exhaust pipe. The electromagnetic valve, the ion pump, the first pressure gauge and the second pressure gauge are electrically connected.

In the traditional hydrogen environment mechanical system, only the indirect relationship between the hydrogen pressure in the external environment and the degradation of the mechanical properties of the material can only be characterized, and the internal relationship between the intrusion of hydrogen and the interaction between the load and the mechanical properties of the material cannot be characterized in a deeper level, which restricts the Quantitative study of mechanical property degradation of materials in high pressure _H2 environment.

As for the measurement method of hydrogen intrusion, the widely used method is the D-S hydroxide method. The principle of this method is to coat a layer of nickel or palladium on the metal surface and apply an oxidation potential to the metal surface. It is exactly the passivation potential of the coating and is the oxidation potential of hydrogen. When no hydrogen emerges from the metal surface, the metal surface is in a passivated state and there is no charge transfer. When hydrogen atoms diffuse from the other end of the metal to the surface of this end , Hydrogen atoms are re-oxidized to become hydrogen ions, and charge transfer occurs. Electrochemical testing equipment is used to collect the generated current. The transfer of an electron represents the diffusion of a hydrogen atom, and the formed current represents the diffusion amount of hydrogen. Currently, only To measure under a high-pressure hydrogen environment without load, or under a load without a high-pressure environment, there is a lack of a device that can perform mechanical loading and in-situ measurement of hydrogen permeation in a high-pressure hydrogen environment.

The conventional experimental method considers that the base material has not broken after 1×10 ⁶ cycles, and the load is considered to be lower than the fatigue limit of the material, but for the weld metal, 2×10 ⁶ cycles are required, and a large number of experiments are required to determine the fatigue limit. Each experiment often lasts for several days and requires more than 10 samples. The experiment is time-consuming, labor-intensive and labor-intensive. As we all know, the essence of material fatigue fracture is the directional movement of dislocations caused by fatigue load, resulting in the final fracture of the material;

The present invention can measure the quantitative relationship between the fatigue load state and the hydrogen permeation amount under different high-pressure hydrogen environments on-line and in situ, and establish the correlation of various data, and the present invention can shorten the fatigue limit load (the When the changing load acts, the stress produced will also change alternately with time. This alternating stress exceeds a certain limit strength and will lead to the destruction of the material after long-term repeated action. This limit is called the fatigue limit of the material) workload.

When the present invention performs fatigue limit measurement, under a given hydrogen pressure condition, after the hydrogen permeation current is stabilized, a step fatigue load from small to large is applied to the material, when the hydrogen permeation current begins to increase with the increase of the load It indicates that the load caused dislocation movement inside the material, and the load is considered to be the fatigue limit of the material in this environment.

Therefore, the present invention has the following advantages:

(1) The traditional test method needs 10-12 samples, but the present invention only needs one sample, which reduces the amount of experiments and overcomes the influence of the performance fluctuation of the commercial material itself on the experiment;

(2) The traditional experimental method to measure the fatigue limit needs to carry out more than 1x10 ⁶ cycles on the material, especially at low frequency cycles (frequency < 1 Hz), a sample (under a certain load) needs to be tested for more than 270 hours, and By using the invention, it only takes two hours to judge the experimental results under the load, which shortens the test time.

As preferably, the first kettle cover and the bottom of the first kettle body are respectively provided with an upper through hole and a lower through hole for penetrating the sample, and the upper sealing structure is located between the upper through hole and the sample; The sealing structure is located between the lower through hole and the sample; the upper through hole is in the shape of a stepped hole with a large cross-sectional area at the upper part, and the upper sealing structure includes two O-rings arranged in the upper part of the upper through hole and a Compress the compression nuts of the two O-rings in the upper through hole and downward;

The lower through hole is in the shape of a stepped hole with a large cross-sectional area at the lower part, and the lower sealing structure includes two O-shaped sealing rings arranged in the lower part of the lower through hole and two O-shaped sealing rings located in the lower through hole and pressed upwards. Compression nut for sealing ring.

Preferably, the reaction kettle is connected with the fatigue testing machine through a support structure, the support structure includes a support ring surrounding the heating chamber and two horizontal support arms arranged on both sides of the support ring, the two horizontal support arms are respectively connected to the It is connected to two vertical bars on the fatigue testing machine.

The inner sides of the two vertical bars facing the supporting structure are provided with a pair of semicircular tubes extending horizontally. The pair of semicircular tubes includes two corresponding semicircular tubes up and down. The circular tube is centered, according to the depth of the two horizontal support arms inserted into the two semicircular tubes, the left and right positions of the support ring can be adjusted, thereby adjusting the left and right positions of the reactor placed on the support ring, so that the sample can be aligned with the The upper and lower clamps are positioned and connected.

As a preference, the support ring is provided with several vertical holes distributed along the circumference of the support ring, each vertical hole is provided with internal threads; the support ring is also provided with several vertical holes along the circumference of the support ring. Distributed connection holes for inserting screws connected to the reactor.

Each vertical hole is used to penetrate the horizontal adjustment screw, and the upper end of the horizontal adjustment screw is used to push the lower end of the reactor, so that the reactor is placed horizontally, and the connection between the sample and the upper and lower fixtures is in line.

As a preference, the two ends of the sample are respectively provided with hollow ferrule joints connected with the cavity in the sample, and the two ventilation pipes are respectively connected with the two ferrule joints; the bottom of the first kettle body is provided with a liquid leakage hole, A sealing plug is arranged on the leakage hole. The setting of the leakage hole facilitates the discharge of the alkaline conductor from the first still body after the test.

A test method suitable for a high-pressure hydrogen permeation test device, comprising the steps of:

(6-1) Use the electrochemical workstation to plate a nickel layer on the outer surface of the sample; insert the hollow rod-shaped sample into the first kettle body and make the lower end of the sample pass through the bottom of the first kettle body. The lower sealing structure is installed between them;

(6-2) Install the reference electrode and the auxiliary anode on the first kettle cover, pour the alkaline conductive liquid into the first kettle body, cover the first kettle cover on the first kettle body, and make the upper end of the sample Pass through the first kettle cover, and install a sealing structure between the upper end of the sample and the first kettle cover; both the reference electrode and the lower part of the auxiliary anode extend into the alkaline conductive liquid;

(6-3) Connect the upper and lower ends of the sample to the hydrogen buffer tank with two soft stainless steel vent pipes;

(6-4) Install the reaction kettle on the fatigue testing machine, and connect the upper end of the sample to the upper fixture, and connect the lower end of the sample to the lower fixture;

(6-5) The lower end of the nitrogen inlet pipe extends into the alkaline conductive liquid, and the lower end of the exhaust pipe is close to the lower surface of the first kettle cover; the controller controls the opening of the second solenoid valve and the third solenoid valve, so that the nitrogen gas flows between the nitrogen cylinder and the first kettle cover. Under the action of the pressure difference between the first kettle body, enter the first kettle body, make the nitrogen gas deoxygenate the alkaline conductive liquid, and after 10 to 20 minutes, the controller controls the second solenoid valve to close;

(6-6) The controller controls the oil bath controller to feed heating oil into the heating chamber, so that the temperature of the heating chamber is stabilized within 45°C to 55°C;

(6-7) Start the electrochemical workstation, set the electrochemical workstation in the constant potential mode, and set the potential to the potential of 0V relative to the saturated calomel electrode; when the current density captured by the electrochemical workstation is less than 5×10 ^-7A , Go to step (6-8);

(6-8) The controller controls the ion pump to evacuate the connected hydrogen buffer tank and the sample, and when the vacuum reaches 0.5 Pascal, the ion pump is controlled to stop working;

The controller controls the opening of the first solenoid valve, and under the action of the pressure difference between the hydrogen tank and the hydrogen buffer tank, hydrogen enters the hydrogen buffer tank and the sample;

While filling the hydrogen buffer tank and the sample with hydrogen, the controller controls the opening of the second solenoid valve to allow nitrogen gas to enter the first tank body;

(6-9) When both the nitrogen pressure detected by the first voltmeter and the hydrogen pressure detected by the second voltmeter are within the pressure range preset in the controller, and when the sample current detected by the electrochemical workstation is stable at 10 ^- When the order of magnitude is ⁵ A, the controller controls the fatigue testing machine to apply a step-type fatigue load from small to large to the sample, and the time for each load is M hours until the sample breaks; The hydrogen permeation current curve.

The invention measures the amount of hydrogen permeation in the process of stretching the sample, and measures the quantitative relationship between the fatigue load state and the amount of hydrogen permeation for the in-situ samples under different high-pressure hydrogen environments, which can intuitively show the stress Intrinsic connection between the segregation and diffusion of hydrogen, establishing the interrelationship of various data.

As a preference, the upper fixture of the fatigue testing machine can move up and down, the upper part of the sample is provided with an annular groove, and the annular groove is provided with a limit ring.

The limit ring is set so that when the sample is broken, the upper part of the sample will not fly out of the reactor under the limit action of the limit ring.

Preferably, the conductive solution is a 0.19 mol/L to 0.23 mol/L KOH solution.

Preferably, the preset pressure range is 4.5 to 5.4 MPa.

Preferably, the cross-sectional area of the sample gradually decreases from both ends to the middle; the thickness of the nickel layer is 1 μm to 4 μm.

Therefore, the present invention has following beneficial effect:

(1) The quantitative relationship between the fatigue load state and hydrogen permeation can be measured in situ on-line and in situ under different high-pressure hydrogen environments, and the internal relationship between stress and hydrogen segregation and diffusion can be intuitively displayed, and a variety of data can be established mutual relationship;

(2) It can measure the quantitative relationship between temperature and hydrogen permeation in different high-pressure hydrogen environments, and the influence of high-pressure hydrogen and temperature factors on the fatigue properties of materials;

(3) It can clearly show the influence of environmental hydrogen on the service life of materials. In addition to analyzing the influence of pure hydrogen environment on the fatigue performance of materials, it is also possible to add other gases into the reactor to analyze the impact of gas competition on hydrogen during the adsorption process. Injury-promoting or inhibiting effects;

(4) The traditional test method needs 10-12 samples, but the present invention only needs one sample, which reduces the amount of experiments and overcomes the influence of the performance fluctuation of the commercial material itself on the experiment;

(5) The traditional experimental method to measure the fatigue limit needs to carry out more than ^1x106 cycles on the material, especially at low frequency cycles (frequency < 1Hz), a sample (under a certain load) needs to be tested for more than 270 hours, and With the present invention, it only takes two hours to judge the experimental results under the load, which shortens the test time.

Description of drawings

Fig. 1 is a kind of structural representation of the present invention;

Fig. 2 is a kind of structural representation of hydrogen buffer tank of the present invention;

Fig. 3 is a kind of structural representation of support structure of the present invention;

Fig. 4 is a kind of structural representation of reactor of the present invention;

Fig. 5 is another kind of structural representation of reactor of the present invention;

Fig. 6 is a kind of flowchart of the embodiment of the present invention;

Fig. 7 is a kind of hydrogen permeation curve figure of the present invention;

Fig. 8 is a curve diagram of fatigue times of a sample in the prior art;

Fig. 9 is a functional block diagram of the present invention.

In the figure: electrochemical workstation 1, oil bath controller 2, fatigue testing machine 3, upper fixture 4, lower fixture 5, hydrogen tank 6, hydrogen conduction pipe 7, hydrogen buffer tank 8, reaction kettle 9, first kettle body 10. First kettle cover 11, heating chamber 12, oil inlet pipe 13, oil outlet pipe 14, sample 15, upper sealing structure 16, lower sealing structure 17, ventilation pipe 18, first pressure gauge 19, reference electrode 20, auxiliary Anode 21, second kettle body 22, second kettle cover 23, second pressure gauge 24, upper through hole 25, O-shaped sealing ring 26, compression nut 27, support structure 28, support ring 29, horizontal support arm 30, Vertical rod 31, vertical hole 32, connecting hole 33, nitrogen gas inlet pipe 34, exhaust pipe 35, limit ring 36, controller 37, first solenoid valve 38, second solenoid valve 39, ferrule joint 40, drain Liquid hole 41 , sealing plug 42 , third solenoid valve 44 .

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

The embodiment shown in Fig. 1, Fig. 4, Fig. 5 is a kind of high-pressure hydrogen permeation testing device, and the high-pressure hydrogen permeation testing device is respectively connected with electrochemical workstation 1, oil bath controller 2 and fatigue testing machine 3, fatigue test The machine is equipped with an upper clamp 4 and a lower clamp 5 for connecting the two ends of the sample; it includes a PLC controller 37, a hydrogen tank 6, a nitrogen tank, an ion pump, a hydrogen buffer tank 8 and a reactor 9 on the fatigue testing machine; the reactor It includes a first kettle body 10 with an open upper end for containing an alkaline conductive liquid and a first kettle cover 11 sealingly connected with the first kettle body, and a heating chamber 12 surrounding the first kettle body is provided on the peripheral surface of the first kettle body , the heating chamber is connected to the oil bath controller through the oil inlet pipe 13 and the oil outlet pipe 14; the first kettle cover and the first kettle body are respectively provided with upper seals for sealing the hollow rod-shaped sample 15 vertically penetrating the reactor. The sealing structure 16 and the lower sealing structure 17; the nitrogen tank communicates with the first still body through the nitrogen inlet pipe 34, and the first still body is provided with an exhaust pipe 35; The first pressure gauge 19; the two ends of the sample are respectively communicated with the hydrogen buffer tank through the vent pipe 18, and the ion pump is connected with the hydrogen buffer tank;

The first kettle cover is provided with a reference electrode 20 and an auxiliary anode 21 extending into the inside of the first kettle body; as shown in Figure 9, the electrochemical workstation is electrically connected to the reference electrode, the auxiliary anode and the sample respectively;

As shown in Figure 2, the hydrogen buffer tank includes a second tank body 22 with an open upper end and a second tank cover 23 that is hermetically connected to the second tank body, and the hydrogen tank is connected to the inside of the second tank body through two hydrogen conduits 7 Pass; The hydrogen buffer tank is provided with a second pressure gauge 24 for detecting the hydrogen pressure in the second tank body. The first and second pressure gauges are both digital voltmeters.

As shown in Figure 9, the controller is respectively connected with the electrochemical workstation, the oil bath controller, the fatigue testing machine, the first electromagnetic valve 38 arranged on the hydrogen tank, the second electromagnetic valve 39 arranged on the nitrogen tank, and the exhaust valve. The third electromagnetic valve 44 on the gas pipe, the ion pump, the first pressure gauge and the second pressure gauge are electrically connected.

As shown in Figure 4, the first kettle cover and the bottom of the first kettle body are respectively provided with an upper through hole 25 and a lower through hole for penetrating the sample, and the upper sealing structure is positioned between the upper through hole and the sample; the lower sealing structure Located between the lower through hole and the specimen.

As shown in Figure 5, the upper through hole is in the shape of a stepped hole with a large cross-sectional area at the upper part, and the upper sealing structure includes two O-shaped sealing rings 26 arranged in the upper part of the upper through hole and located in the upper through hole and pressed downwards. Compression nuts 27 of two O-rings;

The lower through hole is in the shape of a stepped hole with a large cross-sectional area at the lower part, and the lower sealing structure includes two O-shaped sealing rings 26 arranged in the lower part of the lower through hole and a seal located in the lower through hole and pressing the two O-shaped sealing rings upward. Tighten nut 27.

As shown in Figure 1, the reactor is connected with the fatigue testing machine through a support structure 28; as shown in Figure 3, the support structure includes a support ring 29 surrounding the heating chamber and two horizontal support arms 30 located on both sides of the support ring, The two horizontal support arms are respectively connected with the two vertical bars 31 provided on the fatigue testing machine.

The support ring is provided with 3 vertical holes 32 distributed along the circumference of the support ring, and each vertical hole is provided with an internal thread; the support ring is also provided with 3 holes distributed along the circumference of the support ring for insertion and The connection hole 33 of the screw that reactor connects.

As shown in Figure 1 and Figure 5, the two ends of the sample are respectively provided with hollow ferrule joints 40 connected with the cavity in the sample, and the two ventilation pipes are respectively connected with the two ferrule joints; The bottom is provided with a leaking hole 41, and a sealing plug 42 is arranged on the leaking hole.

The present invention utilizes the hydrogen permeation principle to detect the hydrogen permeation current:

The hydrogen is located in the sample and the hydrogen buffer tank, and the outer surface of the sample and the first tank constitute a hydrogen diffusion chamber; the hydrogen molecules are transformed into atomic H through physical adsorption and chemical adsorption on the inner surface of the sample. Specific steps are as follows:

(1) Van der Waals force: Molecular hydrogen randomly migrates to the inner surface of the sample and collides with the adsorption;

(2) Physical adsorption: H ₂ +M→H ₂ ·M;

(3) Chemical adsorption: Covalent atomic hydrogen is formed by reaction: H ₂ ·M+M→ _2Hco ·M or H ₂ ·M→HM+M

(4) Dissolution process: change to adatomic hydrogen: H _co · M → MH _dissolved

(5) Diffusion process: into the interior of the sample:

The hydrogen diffusion chamber is connected to the electrochemical workstation to apply a large potential to ensure that once H diffuses from the inner surface of the sample to the outer surface, it will be completely ionized into H ⁺ immediately, that is

H→H ⁺ +e

Thus the current I is formed; after a period of time, the current I reaches the maximum value, which is called the steady-state current I _∞ ; the outer surface of the sample must be plated with nickel to ensure the reliability of the hydrogen oxidation current. Samples can be made of stainless steel, carbon steel, and pipeline steel.

As shown in Figure 6, a test method of a high-pressure hydrogen permeation test device comprises the following steps:

Step 100, pretreat the sample made of carbon steel material, and install the sample:

The preset pressure range in the controller is 5±0.1MPa; use an electrochemical workstation to plate a nickel layer on the outer surface of the sample; insert a hollow rod-shaped sample into the first kettle and let the lower end of the sample pass through the first kettle At the bottom, a lower sealing structure is installed between the lower end of the sample and the reaction kettle;

Step 200, after installing the sample, make the sample, the reference electrode and the lower part of the auxiliary anode extend into the alkaline conductive liquid:

Install the reference electrode and the auxiliary anode on the first kettle cover, pour the alkaline conductive liquid into the first kettle body, cover the first kettle cover on the first kettle body, and make the upper end of the sample pass through the first kettle cover. Go out, install a sealing structure between the upper end of the sample and the first kettle cover; both the reference electrode and the lower part of the auxiliary anode extend into the alkaline conductive liquid;

Step 300, connecting the sample and the hydrogen buffer tank:

Use 2 soft stainless steel vent pipes to connect the upper and lower ends of the sample with the hydrogen buffer tank respectively;

Step 400, installing the reactor on the fatigue testing machine, connecting the upper end of the sample to the upper fixture, and connecting the lower end of the sample to the lower fixture;

Step 500, deoxidizing the alkaline conductive liquid:

As shown in Figure 1 and Figure 5, the lower end of the nitrogen inlet pipe extends into the alkaline conductive liquid, and the lower end of the exhaust pipe is close to the lower surface of the first kettle cover; the controller controls the opening of the second electromagnetic valve and the third electromagnetic valve, so that the nitrogen gas is Under the effect of the pressure difference between the nitrogen cylinder and the first kettle body, it enters the first kettle body, and the exhaust pipe is connected with the tail gas treatment device equipped with supersaturated NaOH solution, so that the nitrogen gas is an alkaline conductive liquid for deoxygenation after 20 minutes, and the control The controller controls the closing of the second solenoid valve and the third solenoid valve;

Step 600, the controller controls the oil bath controller to feed heating oil into the heating cavity, so that the temperature of the heating cavity is stabilized within 50±0.5°C;

Step 700, start the electrochemical workstation, set the electrochemical workstation in the constant potential mode, and set the potential to the potential of 0V relative to the saturated calomel electrode; when the current density captured by the electrochemical workstation is less than 5×10 ^-7A , switch to Step 800;

Step 800, vacuumize and fill the sample with hydrogen:

The controller controls the ion pump to evacuate the connected hydrogen buffer tank and the sample, and when the vacuum reaches 0.5 Pascal, the ion pump is controlled to stop working;

The controller controls the opening of the first solenoid valve, and under the action of the pressure difference between the hydrogen tank and the hydrogen buffer tank, hydrogen enters the hydrogen buffer tank and the sample;

While filling the hydrogen buffer tank and the sample with hydrogen, the controller controls the opening of the second solenoid valve to allow nitrogen gas to enter the first tank body;

Step 900, stretching the sample and obtaining the hydrogen permeation current curve as a function of time:

When the nitrogen pressure detected by the first voltmeter and the hydrogen pressure detected by the second voltmeter are both within 5±0.1MPa, and the sample current detected by the electrochemical workstation is stable at the order of magnitude of 5×10 ^-5 A, the controller controls The fatigue testing machine applies small to large step fatigue loads on the sample, each load is applied for 2 hours until the sample breaks, and the nitrogen pressure and hydrogen pressure are kept at 5±0.1 during the stretching process. Within MPa; the electrochemical workstation obtains the hydrogen permeation current curve as shown in Figure 7 as a function of time

In this embodiment, the upper fixture of the fatigue testing machine can move up and down, and a limit ring 36 is provided on the sample near the lower surface of the first kettle cover; the conductive solution is 0.2mol/L KOH solution; The cross-sectional area gradually decreases; the thickness of the nickel layer is 2 μm.

As shown in Figure 7, when the nitrogen pressure and hydrogen pressure are in the range of 5±0.1MPa for 3 hours, the hydrogen permeation current flowing through the sample detected by the electrochemical workstation is stable below I _∞ =5×10 ^-5 A, which means , the fatigue testing machine applied small to large step fatigue loads on the sample, and each load was applied for 2 hours until the sample broke; the hydrogen permeation current curve in Figure 7 was obtained by the electrochemical workstation. The hydrogen permeation current is directly proportional to the hydrogen permeation amount, so the present invention obtains the change curve of the hydrogen permeation amount by measuring the hydrogen permeation current. The abscissa in FIG. 7 is time in hours; the ordinate is the detected hydrogen permeation current in μA/cm ² .

It can be seen from Figure 7 that when the fatigue load is 10kN and 12kN, the hydrogen permeation behavior of the material does not change, indicating that under this load, there is no directional movement of dislocations inside the material; when the load reaches 14kN, the hydrogen permeation behavior The current increased significantly, indicating that under this load, the directional movement of dislocations occurred inside the material, hydrogen accumulated in the dislocations, and directional movement occurred with the dislocations, resulting in an increase in the diffusion flux of hydrogen. Therefore, hydrogen The penetration current also increases accordingly. And as the load increases, the hydrogen permeation current gradually increases, indicating that the increase in the load accelerates the directional movement of dislocations, resulting in an increase in the amount of hydrogen transport, dislocation movement and mutual entanglement can cause the formation of microscopic pores, and further form microscopic pores. Cracks, which eventually lead to fracture failure of the material.

And the traditional fatigue life test of the sample shows that when the load is less than 12kN, the material will not undergo fatigue fracture, but when the load is greater than 14kN, the material will undergo fatigue fracture, and the cycle of fatigue fracture will shorten as the load increases, which is It is consistent with the experimental results obtained by the present invention.

As shown in Figure 8, the traditional experimental method to measure the fatigue limit needs to carry out more than 1×10 ⁶ cycles to the sample material, and a sample (under a certain load) will carry out the experiment of more than 270 hours, and utilize the present invention, only need two The results of experiments under this load can be judged in hours, which shortens the test time. Moreover, the hydrogen permeation current measured by the present invention reflects the total amount of hydrogen passing through the sample. The present invention indirectly analyzes the hydrogen diffusion coefficient, acceleration amount, and hydrogen acceleration of the material under different conditions by analyzing its change process. Quantities are directly related to dislocation motion, thus providing reliable data basis for the determination of dislocation density. The abscissa in Fig. 8 is the maximum load, the unit is kN; the ordinate is the fatigue times, the unit is times.

It should be understood that this embodiment is only used to illustrate the present invention but not to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (10)

1. a High Pressure Hydrogen pervasion test device, described High Pressure Hydrogen pervasion test device is connected with fatigue tester (3) with electrochemical workstation (1), oil bath controller (2) respectively, and fatigue tester is provided with upper fixture (4) for connecting sample two ends and lower clamp (5); It is characterized in that, the reactor (9) comprising controller (37), hydrogen gas tank (6), nitrogen pot, ionic pump, hydrogen buffering still (8) and be located on fatigue tester; Described reactor comprise upper end open for the first kettle (10) of holding alkaline conducting liquid and the first kettle cover (11) be tightly connected with the first kettle, first kettle outer peripheral face is provided with the heating chamber (12) around the first kettle, and heating chamber is connected with oil bath controller; Described first kettle cover and the first kettle are respectively equipped with for carrying out the spacing upper hermetically-sealed construction (16) of sealing and lower seal structure (17) to the hollow rod-shape sample (15) vertically running through reactor; Described nitrogen pot is connected with the first kettle by nitrogen inlet duct (34), and the first kettle is provided with gas outlet (35); Reactor is provided with the first tensimeter (19) for detecting the nitrogen pressure in the first kettle; Sample two ends are connected with hydrogen buffering still respectively by snorkel (18), and ionic pump is connected with hydrogen buffering still;

First kettle cover is provided with the contrast electrode (20) and impressed current anode (21) that stretch into the first kettle inside; Electrochemical workstation is electrically connected with contrast electrode, impressed current anode and sample respectively;

The second kettle (22) that described hydrogen buffering still comprises upper end open and the second kettle cover (23) be tightly connected with the second kettle, described hydrogen gas tank is connected with the second kettle inside by two hydrogen conduction pipes (7); Hydrogen buffering still is provided with the second tensimeter (24) for detecting the Hydrogen Vapor Pressure in the second kettle;

Described controller is electrically connected with electrochemical workstation, oil bath controller, fatigue tester, the first solenoid valve (38) be located in hydrogen gas tank, the second solenoid valve (39) be located on nitrogen pot, the 3rd solenoid valve (44), ionic pump, the first tensimeter and the second tensimeter be located on gas outlet respectively.

2. High Pressure Hydrogen pervasion test device according to claim 1, it is characterized in that, described first kettle cover and the first autoclave body bottom are respectively equipped with upper through hole (25) for penetrating sample and lower through-hole, and described upper hermetically-sealed construction is between upper through hole and sample; Described lower seal structure is between lower through-hole and sample; The ladder that described upper through hole presents cross section area large is poroid, and described upper hermetically-sealed construction comprises two O RunddichtringOs (26) being located in through hole top and is positioned at through hole and compresses the gland nut (27) of two O RunddichtringOs downwards;

It is poroid that described lower through-hole is the large ladder of lower cross section area, and described lower seal structure comprises two O RunddichtringOs (26) being located in lower through-hole bottom and is positioned at lower through-hole and upwards compresses the gland nut (27) of two O RunddichtringOs.

3. High Pressure Hydrogen pervasion test device according to claim 1, it is characterized in that, described reactor is connected with fatigue tester by supporting construction (28), described supporting construction comprise around heating chamber support ring (29) and be located at two horizontal support arms (30) of support ring both sides, two horizontal support arms are connected with two montants (31) be located on fatigue tester respectively.

4. High Pressure Hydrogen pervasion test device according to claim 3, is characterized in that, described support ring is provided with the vertical hole (32) of several circle distribution along support ring, is equipped with internal thread in each vertical hole; Described support ring is also provided with the connecting hole (33) for inserting the screw be connected with reactor of several circle distribution along support ring.

5. the High Pressure Hydrogen pervasion test device according to claim 1 or 2 or 3 or 4, it is characterized in that, sample two ends are respectively equipped with the hollow ferrule fitting (40) be connected with the cavity in sample, two snorkels are connected with two ferrule fittings respectively; First autoclave body bottom is provided with liquid-leaking nozzle (41), and liquid-leaking nozzle is provided with sealing-plug (42).

6. be applicable to a method of testing for High Pressure Hydrogen pervasion test device according to claim 1, it is characterized in that, comprise the steps:

(6-1) utilize electrochemical operation to stand in sample outside surface and plate nickel dam; The bar samples of hollow to be inserted in the first kettle and to make sample lower end pass the first autoclave body bottom, between sample lower end and reactor, loading lower seal structure;

(6-2) contrast electrode and impressed current anode are arranged on the first kettle cover, alkaline conducting liquid is poured in the first kettle, first kettle cover is covered on the first kettle, sample upper end is passed from the first kettle cover, between sample upper end and the first kettle cover, installs hermetically-sealed construction; Contrast electrode and impressed current anode bottom are all stretched in alkaline conducting liquid;

(6-3) 2 soft stainless steel snorkels are utilized to be connected with hydrogen buffering still respectively in sample upper end, lower end;

(6-4) be installed on fatigue tester by reactor, and sample upper end is connected with upper fixture, sample lower end is connected with lower clamp;

(6-5) nitrogen inlet duct lower end is stretched in alkaline conduction liquid, and gas outlet lower end is near the first kettle cover lower surface; Controller controls the second solenoid valve and the 3rd solenoid valve is opened, and enters in the first kettle under making the effect of the pressure differential of nitrogen between nitrogen cylinder and the first kettle, and make nitrogen be alkaline conduction liquid deoxygenation after 10 to 20 minutes, controller controls the second closed electromagnetic valve;

(6-6) controller controls oil bath controller and pass into heating oil in heating chamber, makes the temperature stabilization of heating chamber at 45 DEG C in 55 DEG C;

(6-7) start electrochemical workstation, electrochemical workstation is arranged on potentiostatic mode, potential setting is on the current potential of relative saturation mercurous chloride electrode OV; Treat that the current density that electrochemical workstation catches is less than 5 × 10 ^-7Atime, proceed to step (6-8);

(6-8) controller control ionic pump vacuumizes the hydrogen buffering still be communicated with and sample, after vacuum tightness reaches 0.5 Pascal, controls ionic pump and quits work;

Controller controls the first solenoid valve and opens, and under the effect of the pressure differential between hydrogen gas tank and hydrogen buffering still, hydrogen enters in hydrogen buffering still and sample;

While filling hydrogen to hydrogen buffering still and sample, controller controls the second solenoid valve and opens, and makes nitrogen enter the first kettle inner;

(6-9) Hydrogen Vapor Pressure detected when nitrogen pressure and second voltage table of the first voltage table detection is all positioned at the pressure limit preset in the controller, and when the specimen current of electrochemical workstation detection is stabilized in 10 ^-5during the order of magnitude of A, controller controls the phase step type fatigue load that fatigue tester applies from small to large to sample, and the time of often kind of load applying is M hour, till sample fracture; Electrochemical workstation obtains the hydrogen infiltration current curve along with time variations.

7. the method for testing of High Pressure Hydrogen pervasion test device according to claim 6, is characterized in that, the upper fixture of described fatigue tester can move up and down, and sample top is provided with annular groove, and annular groove is provided with spacing ring (36).

8. the method for testing of High Pressure Hydrogen pervasion test device according to claim 6, is characterized in that, described conducting solution is the KOH solution of 0.19mol/L to 0.23mol/L.

9. the method for testing of the High Pressure Hydrogen pervasion test device according to claim 6 or 7 or 8, is characterized in that, the pressure limit preset is 4.5 to 5.4MPa.

10. the method for testing of the High Pressure Hydrogen pervasion test device according to claim 6 or 7 or 8, is characterized in that, sample is reduced gradually by two ends to middle part cross-sectional area; The thickness of nickel dam is 1 μm to 4 μm.