Device for detecting hydrogen embrittlement sensitivity of metal material in pure hydrogen and hydrogen-doped environments
By designing a device for detecting hydrogen embrittlement sensitivity of metal materials, using upper and lower fixture structures and atmosphere control, the high cost and safety hazards of gas-phase hydrogen filling experiments are solved, and the effect of simplifying operation and improving sample utilization is achieved.
Patent Information
- Application Number
- CN202421378989.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-17
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2034-06-17
AI Technical Summary
The existing gas-phase hydrogen filling experiments have high cost, safety hazards and complex operation problems in the research on hydrogen embrittlement sensitivity of metal materials. The traditional tensile samples are cumbersome and expensive to process, resulting in waste of materials.
Design a device for detecting the sensitivity of hydrogen embrittlement of metal materials in pure hydrogen and hydrogen doped environments. It adopts an upper and lower clamp structure, clamps the sample through O-type sealing ring and screw connection, and combines high-pressure needle valve and gas cylinder to achieve atmosphere control, simulate the contact working conditions between gas-phase hydrogen and metal materials, and simplifies the operation process.
It reduces experimental costs, improves safety, simplifies operating procedures, improves the utilization rate and experimental efficiency of samples, and enhances the credibility of experimental results.
Smart Images
Figure CN223154640U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of research on hydrogen embrittlement sensitivity of metal materials, and specifically relates to a device for detecting hydrogen embrittlement sensitivity of metal materials in a pure hydrogen and hydrogen-doped environment. Background Technique
[0002] The research on hydrogen embrittlement of metal materials is usually carried out by experiments or simulation calculations. In experiments, hydrogen atoms are mainly introduced into the material through electrochemical hydrogen charging or gas-phase hydrogen charging. Compared with gas-phase hydrogen charging, the experimental results of electrochemical hydrogen charging usually have better repeatability. However, in reality, the inner wall of the metal pipeline in service will be in direct contact with gaseous hydrogen, and electrochemical hydrogen charging cannot simulate this actual working condition, but gas-phase hydrogen charging can. Therefore, most current researchers generally use slow strain rate tensile tests in a gas-phase hydrogen environment to study the hydrogen embrittlement sensitivity of rod-shaped or sheet-shaped metal specimens. In order to make the specimens in an environment full of hydrogen, pressure vessels are generally required, which greatly increases the experimental cost and potential safety hazards. In addition, some researchers have also tried to process the tensile specimens into a tubular structure and inject hydrogen into the tubular specimens to carry out hydrogen embrittlement research, so as to solve the problems of experimental cost and safety. However, the processing process of the specimens used in tensile experiments is generally cumbersome and expensive, and the analysis of the specimens after fracture is usually only focused on the fracture surface, and other parts have little research value, resulting in waste of materials. Content of the Utility Model
[0003] The purpose of the utility model is to provide a device for detecting hydrogen embrittlement sensitivity of metal materials in a pure hydrogen and hydrogen-doped environment, so as to solve the problems of equipment requirements faced by gas-phase hydrogen charging experiments and the cost problems and potential safety hazards brought by specimen processing, thereby reducing the experimental cost, improving the safety of the experiment, and simplifying the operation process of the experiment.
[0004] The technical solution of the utility model is as follows:
[0005] A device for detecting the hydrogen embrittlement sensitivity of metal materials in a pure hydrogen and hydrogen-doped environment. The entire device is split into two parts: an upper fixture main body and a lower fixture main body that are arranged opposite to each other vertically. The upper fixture main body is provided with an upper through-hole on the upper side of the fixture, a lower through-hole on the lower side of the fixture, a left through-hole on the left side of the fixture, a right through-hole on the right side of the fixture, and a pressure rod insertion hole. The left through-hole on the left side of the upper fixture, the upper through-hole on the upper side of the upper fixture, the right through-hole on the right side of the upper fixture, and the lower through-hole on the lower side of the upper fixture are evenly distributed along the circumference of the upper fixture main body, and the pressure rod insertion hole is located at the center of the upper fixture main body; the lower fixture main body is provided with a specimen fixing groove, a sealing groove, an air cavity, a left ventilation channel on the lower side of the fixture, a right ventilation channel on the lower side of the fixture, an upper screw hole on the lower side of the fixture, a lower screw hole on the lower side of the fixture, a left screw hole on the lower side of the fixture, and a right screw hole on the lower side of the fixture. A specimen fixing groove, a sealing groove, and an air cavity are successively opened downward along the axis from the upper end of the lower fixture main body. The air cavity is connected to the center of the bottom of the specimen fixing groove, the annular sealing groove is connected to the circumference of the bottom of the specimen fixing groove, the left ventilation channel on the lower side of the fixture and the right ventilation channel on the lower side of the fixture are opened on the side wall of the lower fixture main body and are vertically connected to the air cavity, and the left screw hole on the lower side of the fixture, the upper screw hole on the lower side of the fixture, the right screw hole on the lower side of the fixture, and the lower screw hole on the lower side of the fixture are evenly distributed along the circumference of the lower fixture main body and are respectively corresponding to the left through-hole on the left side of the upper fixture main body, the upper through-hole on the upper side of the upper fixture main body, the right through-hole on the right side of the upper fixture main body, and the lower through-hole on the lower side of the upper fixture main body.
[0006] For the device for detecting the hydrogen embrittlement sensitivity of metal materials in a pure hydrogen and hydrogen-doped environment, both the upper fixture main body and the lower fixture main body are of cylindrical structure, and the diameters of the two end circular surfaces are exactly the same; the lower fixture is a coaxial integrated structure of a cylindrical fixed section and the lower fixture main body from bottom to top, and the cylindrical fixed section of the lower fixture is fitted into the fixed groove on the electronic universal testing machine.
[0007] For the device for detecting the hydrogen embrittlement sensitivity of metal materials in a pure hydrogen and hydrogen-doped environment, an O-ring is placed in the sealing groove of the lower fixture main body, a circular specimen is placed in the specimen fixing groove of the lower fixture main body, and the upper and lower sides of the O-ring are in close contact with the circular specimen and the lower fixture main body respectively.
[0008] For the device for detecting the hydrogen embrittlement sensitivity of metal materials in a pure hydrogen and hydrogen-doped environment, the material of the O-ring is fluororubber.
[0009] For the device for detecting hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments, four screws respectively pass through the four through holes of the upper part of the fixture main body and are connected to the four screw holes of the lower part of the fixture main body, so that the upper part of the fixture main body and the lower part of the fixture main body are firmly connected and clamp the disc-shaped specimen. A spherical indenter is placed in the indenter insertion hole and the indenter is inserted. The spherical indenter is located between the lower end of the indenter and the center of the upper end of the disc-shaped specimen.
[0010] For the device for detecting hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments, the left gas pipe is inserted horizontally into the left gas passage of the lower part of the fixture and is connected to the left gas passage on the side wall of the lower part of the fixture main body by welding. The end of the left gas pipe is equipped with a left high-pressure needle valve. The gas cylinder is connected to the left high-pressure needle valve through a matching gas pipe and fixture; the right gas pipe is inserted horizontally into the right gas passage of the lower part of the fixture and is connected to the right gas passage on the side wall of the lower part of the fixture main body by welding. The right gas pipe is connected to a pressure gauge through a ferrule tee joint. The end of the right gas pipe is equipped with a right high-pressure needle valve.
[0011] The design concept of the present utility model is:
[0012] 1. For the device for detecting hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments of the present utility model, one side of the disc-shaped specimen can be in a gaseous hydrogen environment. The gas cavity of the lower part of the fixture main body is filled with gas, so that one side of the disc-shaped specimen is hydrogen-facing, thus simulating the real working condition of the contact between gaseous hydrogen and metal materials in actual engineering. It realizes the purpose of only needing the cooperation of the disc-shaped specimen and the fixture to achieve gas-phase hydrogen charging, atmosphere change, gas pressure control and monitoring, solves the problems of experimental cost and potential safety hazards brought by the need to use pressure vessels, simplifies the experimental operation process, and greatly reduces the processing cost of the specimen.
[0013] 2. A device for detecting the hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments according to the present utility model. The disc-shaped specimen is clamped between the upper fixture body and the lower fixture body. The upper fixture body and the lower fixture body are connected by screws to ensure the airtightness of the whole device after gas is filled. During the fixture assembly process, the O-ring is placed in the sealing groove of the lower fixture body. Then, the disc-shaped specimen is placed in the specimen fixing groove of the lower fixture body. At this time, one side of the disc-shaped specimen is in contact with the O-ring. Then, the upper fixture body is pressed on the other side of the disc-shaped specimen. Adjust the positions of the four through holes on the upper fixture body so that they are aligned with the positions of the four screw holes on the lower fixture body. After alignment, insert the four screws into the four through holes of the upper fixture body respectively. Finally, use a hex wrench to tighten the four screws into the four screw holes of the lower fixture body respectively. After installation, the upper and lower sides of the disc-shaped specimen are in close contact with the lower surface of the upper fixture body and the O-ring respectively, thus meeting the airtightness requirements.
[0014] 3. A device for detecting the hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments according to the present utility model can regulate the gas pressure and gas atmosphere in the air chamber of the lower fixture body. The air chamber is inflated through the high-pressure needle valves on the left and right sides of the lower fixture body connected to the gas cylinder, and the pressure of the gas in the air chamber is controlled by monitoring the reading on the pressure gauge.
[0015] The advantages and beneficial effects of the present utility model are:
[0016] 1. A device for detecting the hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments according to the present utility model. The disc-shaped specimen is clamped between the upper fixture body and the lower fixture body. The upper fixture body and the lower fixture body are connected by screws. After installation, the upper and lower sides of the disc-shaped specimen are in close contact with the lower surface of the upper fixture body and the O-ring respectively, thus meeting the airtightness requirements.
[0017] 2. A device for detecting the hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments according to the present utility model. The high-pressure needle valves on the left and right sides of the lower fixture body are connected to the gas cylinder. When inflating, the air chamber can be pressurized by closing one of the high-pressure needle valves, and the gas pressure in the air chamber can be regulated by the reading on the pressure gauge.
[0018] 3. A device for detecting the hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments according to the present utility model. The high-pressure needle valves on the left and right sides of the lower fixture body are connected to the gas cylinder. When inflating, the air chamber can be flushed with gas by opening both high-pressure needle valves to ensure the purity of the gas in the air chamber during the subsequent process.
[0019] 4. A device for detecting the hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments. The high-pressure needle valves on the left and right sides of the lower fixture body are connected to gas cylinders, and different gas cylinders can be connected according to experimental requirements to change the gas atmosphere, so as to meet the needs of various experiments.
[0020] 5. A device for detecting the hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments. The high-pressure needle valves on the left and right sides of the lower fixture body are connected to gas cylinders. By filling the gas chamber with gas, one side of the disc-shaped specimen is in a gaseous hydrogen environment, thus simulating the real working condition of gaseous hydrogen contacting metal materials in actual engineering and increasing the credibility of experimental results.
[0021] 6. A device for detecting the hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments. First, install the disc-shaped specimen between the upper fixture body and the lower fixture body, then carry out the processes of gas washing and pressurization. Finally, embed the cylindrical fixed section of the lower fixture into the fixed groove of the electronic universal testing machine. The whole operation process is convenient and fast, and the whole hydrogen charging device is economical and practical.
[0022] 7. A device for detecting the hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments. Using the disc-shaped specimen to conduct hydrogen embrittlement sensitivity detection experiments, compared with traditional tensile specimens, the processing cost is greatly reduced, and the utilization rate of specimens and the efficiency of experiments are both greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 FIG. 1 is a front view schematic diagram of a device for detecting the hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments when the fixture is used on an electronic universal testing machine.
[0024] FIGS. 2(a) and 2(b) are Figure 1 structural schematic diagrams of the upper fixture body in FIG. 1. Among them, FIG. 2(a) is the front view of the upper fixture body, and FIG. 2(b) is the top view of the upper fixture body.
[0025] FIGS. 3(a) and 3(b) are Figure 1 structural schematic diagrams of the lower fixture body in FIG. 1. Among them, FIG. 3(a) is the front view of the lower fixture body, and FIG. 3(b) is the top view of the lower fixture body.
[0026] Figure 4 FIG. 4 is Figure 1 a three-dimensional structure diagram of the position where the upper fixture body and the lower fixture body in FIG. 1 clamp the specimen.
[0027] Figure 1 FIG. 1, FIGS. 2(a), 2(b), 3(a), 3(b) and Figure 4Among them, reference numerals: 1 compression rod; 2 screw; 3 upper part of the fixture body (31 left through hole of the upper part of the fixture, 32 jack for the compression rod, 33 right through hole of the upper part of the fixture, 34 upper through hole of the upper part of the fixture, 35 lower through hole of the upper part of the fixture); 4 spherical indenter; 5 disc-shaped specimen; 6 lower part of the fixture body (61 specimen fixing groove, 62 sealing groove, 63 left screw hole of the lower part of the fixture, 64 air cavity, 65 left air vent passage of the lower part of the fixture, 66 right screw hole of the lower part of the fixture, 67 right air vent passage of the lower part of the fixture, 68 upper screw hole of the lower part of the fixture, 69 lower screw hole of the lower part of the fixture); 7 left air vent pipe; 8 left high-pressure needle valve; 9 cylindrical fixed section; 10, O-ring; 11 pressure gauge; 12 right air vent pipe; 13 right high-pressure needle valve.
[0028] Figure 5 It is the load-displacement curve of the X42 pipeline steel specimen when 4 MPa of N2 and 4 MPa of H2 are respectively filled into the fixture. In the figure, the abscissa Displacement represents displacement (mm), and the ordinate Load represents load (N). Detailed implementation manner
[0029] Next, the present invention will be further described in conjunction with the drawings and embodiments.
[0030] As Figure 1 shown in Fig. 1, Fig. 2(a), Fig. 2(b), Fig. 3(a), Fig. 3(b), Figure 4 A device for detecting the hydrogen embrittlement sensitivity of metal materials in a pure hydrogen and hydrogen-doped environment of the present invention is composed of a compression rod 1, a screw 2, an upper part of the fixture body 3, a spherical indenter 4, a lower part of the fixture body 6, a left air vent pipe 7, a left high-pressure needle valve 8, a cylindrical fixed section 9, an O-ring 10, a pressure gauge 11, a right air vent pipe 12, and a right high-pressure needle valve 13. The specific structure is as follows:
[0031] The whole device can be disassembled into two parts: the upper part fixture body 3 and the lower part fixture body 6 which are arranged opposite to each other up and down. The upper part fixture body 3 is provided with an upper part fixture upper side through hole 34, an upper part fixture lower side through hole 35, an upper part fixture left side through hole 31, an upper part fixture right side through hole 33 and a pressure rod insertion hole 32. The upper part fixture left side through hole 31, the upper part fixture upper side through hole 34, the upper part fixture right side through hole 33 and the upper part fixture lower side through hole 35 are evenly distributed along the circumference of the upper part fixture body 3, and the pressure rod insertion hole 32 is located at the center of the upper part fixture body 3; The lower part fixture body 6 is provided with a specimen fixing groove 61, a sealing groove 62, an air cavity 64, a lower part fixture left side ventilation channel 65, a lower part fixture right side ventilation channel 67, an upper part fixture upper side screw hole 68, a lower part fixture lower side screw hole 69, a lower part fixture left side screw hole 63 and a lower part fixture right side screw hole 66. The specimen fixing groove 61, the sealing groove 62 and the air cavity 64 are successively opened downward along the axis from the upper end of the lower part fixture body 6. The air cavity 64 is communicated with the center of the bottom of the specimen fixing groove 61, and the annular sealing groove 62 is communicated with the bottom of the specimen fixing groove 61 along the circumferential direction. The lower part fixture left side ventilation channel 65 and the lower part fixture right side ventilation channel 67 are opened on the side wall of the lower part fixture body 6 and are vertically communicated with the air cavity 64. The lower part fixture left side screw hole 63, the upper part fixture upper side screw hole 68, the lower part fixture right side screw hole 66 and the lower part fixture lower side screw hole 69 are evenly distributed along the circumference of the lower part fixture body 6 and are respectively corresponding to the positions of the upper part fixture left side through hole 31, the upper part fixture upper side through hole 34, the upper part fixture right side through hole 33 and the upper part fixture lower side through hole 35 of the upper part fixture body 3.
[0032] Both the upper part fixture body 3 and the lower part fixture body 6 are cylindrical structures, and the diameters of the two end circular surfaces are exactly the same; The lower part fixture is a coaxial integrated combination structure of a cylindrical fixed section 9 and the lower part fixture body 6 from bottom to top; The cylindrical fixed section 9 is fitted in the fixed groove on the electronic universal testing machine.
[0033] The O-ring 10 is placed in the sealing groove 62 of the lower part fixture body 6, and the circular sheet specimen 5 is placed in the specimen fixing groove 61 of the lower part fixture body 6; The upper and lower sides of the O-ring 10 are in close contact with the circular sheet specimen 5 and the lower part fixture body 6 respectively to ensure the airtightness inside the device. Among them, the material of the O-ring 10 is fluororubber, aiming to prevent gas from leaking through the O-ring 10 and ensure the sealing effect.
[0034] Four screws 2 respectively pass through four through holes of the upper part fixture body 3 and are connected to four screw holes of the lower part fixture body 6, so that the upper part fixture body 3 and the lower part fixture body 6 are firmly connected and clamp the disc-shaped specimen 5. A spherical indenter 4 is placed in the pressure rod insertion hole 32 and the pressure rod 1 is inserted. The spherical indenter 4 is located between the lower end of the pressure rod 1 and the center of the upper end of the disc-shaped specimen 5.
[0035] The left vent pipe 7 is horizontally inserted into the left vent channel 65 on the left side of the lower part fixture and is connected to the left vent channel 65 on the side wall of the lower part fixture body 6 by welding to ensure the firm connection between the left vent pipe 7 and the lower part fixture body 6. The end of the left vent pipe 7 is equipped with a left high-pressure needle valve 8. The gas cylinder is connected to the left high-pressure needle valve 8 through a matching vent pipe and fixture. The right vent pipe 12 is horizontally inserted into the right vent channel 67 on the right side of the lower part fixture and is connected to the right vent channel 67 on the side wall of the lower part fixture body 6 by welding to ensure the firm connection between the right vent pipe 12 and the lower part fixture body 6. The right vent pipe 12 is connected to the pressure gauge 11 through a ferrule tee. The end of the right vent pipe 12 is equipped with a right high-pressure needle valve 13. Gas is filled into the gas cavity 64 through the left vent pipe 7 and the left vent channel 65 of the lower part fixture. The internal gas pressure of the gas cavity 64 is adjusted by changing the opening and closing states of the left high-pressure needle valve 8 and the right high-pressure needle valve 13. The inflation and gas pressure control of the inside of the gas cavity 64 are realized by connecting the gas cylinder through the left high-pressure needle valve 8. The internal gas pressure of the gas cavity 64 is monitored by the pressure gauge 11.
[0036] As Figure 1 shown in, Figure 2(a), Figure 2(b), Figure 3(a), Figure 3(b), Figure 4 The usage method of a device for detecting hydrogen embrittlement sensitivity of metal materials in a pure hydrogen and hydrogen-doped environment of the present utility model includes the following steps:
[0037] (1) Place the O-ring 10 in the sealing groove 62 of the lower part fixture body 6;
[0038] (2) Place the disc-shaped specimen 5 in the specimen fixing groove 61 of the lower part fixture body 6;
[0039] (3) Press the upper part of the fixture body 3 onto the upper surface of the disc-shaped specimen 5, and adjust the positions of the four through holes (the left through hole 31 of the upper part of the fixture, the upper through hole 34 of the upper part of the fixture, the right through hole 33 of the upper part of the fixture, and the lower through hole 35 of the upper part of the fixture) on the upper part of the fixture body 3 so that they are directly opposite to the positions of the four screw holes (the left screw hole 63 of the lower part of the fixture, the upper screw hole 68 of the lower part of the fixture, the right screw hole 66 of the lower part of the fixture, and the lower screw hole 69 of the lower part of the fixture) on the lower part of the fixture body 6. After alignment, insert the four screws 2 into the four through holes of the upper part of the fixture body 3 respectively, and then use a hex wrench to tighten the four screws 2 into the four screw holes of the lower part of the fixture body 6 respectively;
[0040] (4) Connect the gas pipe of the gas cylinder to the left high-pressure needle valve 8, open the left high-pressure needle valve 8 and the right high-pressure needle valve 13, and use the gas in the gas cylinder to flush the air chamber 64. After flushing for 20 - 30 minutes, close the right high-pressure needle valve 13 to make the internal gas pressure of the air chamber 64 reach 1 - 4 MPa, close the left high-pressure needle valve 8 and keep it closed for 10 - 20 minutes, then open the right high-pressure needle valve 13, and then open the left high-pressure needle valve 8 to continue flushing for 20 - 30 minutes. The flushing process lasts for 3 - 4 times;
[0041] (5) After the flushing is completed, close the right high-pressure needle valve 13 to pressurize the inside of the air chamber 64, and monitor the internal gas pressure of the air chamber 64 through the pressure gauge 11. When the gas pressure reaches the predetermined value of the experimental plan, close the left high-pressure needle valve 8, then close the gas cylinder switch, and disassemble the gas pipe of the gas cylinder connected to the left high-pressure needle valve 8;
[0042] (6) Place the spherical indenter 4 into the pressure rod insertion hole 32 of the upper part of the fixture body 3, then insert the pressure rod 1 into the pressure rod insertion hole 32 of the upper part of the fixture body 3, fit the cylindrical fixed section 9 of the lower part of the fixture into the fixed slot of the electronic universal testing machine, and start the small punch test after setting parameters such as the loading rate, the downward displacement, and the sampling interval.
[0043] Example 1
[0044] As Figure 1 、Figure 2(a), Figure 2(b), Figure 3(a), Figure 3(b), Figure 4As shown in the figure, a device for detecting the hydrogen embrittlement sensitivity of metal materials in a pure hydrogen and hydrogen-doped environment in this embodiment. The circular sheet specimen 5 is clamped between the upper part fixture body 3 and the lower part fixture body 6. The upper and lower surfaces of the circular sheet specimen 5 are in close contact with the lower surface of the upper part fixture body 3 and the O-ring 10 placed in the sealing groove 62 of the lower part fixture body 6 respectively. The upper part fixture body 3 and the lower part fixture body 6 are connected together by screws 2. Among them, the circular sheet specimen 5 is made of X42 pipeline steel, with a diameter of 9 mm and a thickness of 0.5 mm. Assemble the circular sheet specimen 5 and the fixture together according to the above operation method. After the gas washing and gas charging processes are completed, install the specimen and the fixture as a whole on an electronic universal testing machine and start the test. The test temperature is room temperature, the set loading rate is 0.004 mm / min, and the sampling interval is 1 s.
[0045] As Figure 5 shown, the circular sheet specimen 5 used is made of X42 pipeline steel. After filling 4 MPa of H2 and 4 MPa of N2 into the gas chamber 64 of the lower part fixture body 6 respectively and conducting the small punch test, the load-displacement curves obtained are significantly different. Compared with 4 MPa of N2, the values of the maximum load, failure displacement, and small punch energy obtained from the load-displacement curve under 4 MPa of H2 are all significantly reduced. The failure displacement is generally the displacement value corresponding to 80% of the maximum load in the descending stage of the load-displacement curve, and the small punch energy is generally obtained by integrating the displacement value corresponding to the maximum load on the load-displacement curve.
[0046] The circular sheet specimen 5 used is made of X42 pipeline steel. After filling 4 MPa of H2 and 4 MPa of N2 into the gas chamber 64 of the lower part fixture body 6 respectively and conducting the small punch test, the overall SEM morphology of the surface of the circular sheet specimen is significantly different. When the downward displacement is set to 2.5 mm in both cases, the opening degree of the specimen after rupture under 4 MPa of N2 is small and there are basically no secondary cracks near the rupture area; the opening degree of the specimen after rupture under 4 MPa of H2 is very large and there are secondary cracks all over the area near the rupture area.
[0047] The circular specimen 5 used is made of X42 pipeline steel. After filling 4 MPa of H2 and 4 MPa of N2 into the gas chambers 64 of the lower fixture body 6 respectively, significant differences exist in the SEM microscopic morphology characteristics within the surface rupture area of the circular specimen obtained from the small punch test. Under 4 MPa of N2, shear-type dimples structure appears within the specimen rupture area, belonging to the characteristics of ductile fracture; under 4 MPa of H2, quasi-cleavage structure appears within the specimen rupture area, belonging to the characteristics of brittle fracture. The experimental results are basically consistent with the expected assumptions, indicating that the fixture meets the test and design requirements and proving the effectiveness of this method. The degree of hydrogen embrittlement can be comprehensively judged by the maximum load, failure displacement, small punch energy obtained from the load-displacement curve and combined with the rupture morphology on the surface of the circular specimen.
[0048] The implementation results show that the present utility model obtains a device and a use method for detecting the hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments. It can not only simulate the real working conditions of gas-phase hydrogen contacting metal materials in actual engineering, but also solve the experimental cost problems brought by equipment requirements and specimen processing. At the same time, it greatly simplifies the experimental operation process, which is of great significance for the study of the hydrogen embrittlement sensitivity of metal materials. The actual application process of the device of the present utility model is applicable to specimens of most metal materials, such as: No. 20 steel, X52 pipeline steel, X65 pipeline steel, etc. In this embodiment, the structure of the indenter is spherical. During the actual application of the fixture, the indenter can also be designed into a cylindrical structure according to the situation.
[0049] The above schematically describes the present utility model and its implementation manners. This description is not restrictive, and what is shown in the drawings is only one of the implementation manners of the present utility model. The actual structure is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and design similar structural manners and embodiments without creative efforts without departing from the creative purpose of the present utility model, they all fall within the protection scope of the present utility model.
Claims
1. A device for detecting the hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments, characterized in that, The whole device is split into two parts: an upper part fixture body and a lower part fixture body which are arranged opposite to each other up and down. The upper part fixture body is provided with an upper part fixture upper side through hole, an upper part fixture lower side through hole, an upper part fixture left side through hole, an upper part fixture right side through hole and a pressure rod insertion hole. The upper part fixture left side through hole, the upper part fixture upper side through hole, the upper part fixture right side through hole and the upper part fixture lower side through hole are evenly distributed along the circumference of the upper part fixture body, and the pressure rod insertion hole is located at the center position of the upper part fixture body; The lower part fixture body is provided with a specimen fixing groove, a sealing groove, an air cavity, a lower part fixture left side ventilation channel, a lower part fixture right side ventilation channel, an upper part fixture upper side screw hole, a lower part fixture lower side screw hole, a lower part fixture left side screw hole and a lower part fixture right side screw hole. A specimen fixing groove, a sealing groove and an air cavity are successively opened downward along the axis from the upper end of the lower part fixture body. The air cavity is communicated with the bottom center of the specimen fixing groove, and the annular sealing groove is communicated with the bottom circumference of the specimen fixing groove. The lower part fixture left side ventilation channel and the lower part fixture right side ventilation channel are opened on the side wall of the lower part fixture body and are vertically communicated with the air cavity. The lower part fixture left side screw hole, the upper part fixture upper side screw hole, the lower part fixture right side screw hole and the lower part fixture lower side screw hole are evenly distributed along the circumference of the lower part fixture body and are respectively corresponding to the positions of the upper part fixture left side through hole, the upper part fixture upper side through hole, the upper part fixture right side through hole and the upper part fixture lower side through hole of the upper part fixture body.
2. The device for detecting the hydrogen embrittlement sensitivity of metal materials in a pure hydrogen and hydrogen-doped environment according to claim 1, characterized in that, Both the upper part fixture body and the lower part fixture body are of cylindrical structure, and the diameters of the two end circular surfaces are exactly the same; The lower part fixture is a coaxial integrated combination structure of a cylindrical fixed section and the lower part fixture body from bottom to top. The cylindrical fixed section of the lower part fixture is fitted into the fixed groove on the electronic universal testing machine.
3. The fixture for detecting the hydrogen embrittlement sensitivity of metal materials in a pure hydrogen and hydrogen-doped environment according to claim 1, characterized in that The O-ring is placed in the sealing groove of the lower part fixture body, and the circular specimen is placed in the specimen fixing groove of the lower part fixture body. The upper and lower sides of the O-ring are in close contact with the circular specimen and the lower part fixture body respectively.
4. The device for detecting the hydrogen embrittlement sensitivity of metal materials in a pure hydrogen and hydrogen-doped environment according to claim 3, characterized in that, The material of the O-ring is fluororubber.
5. The device for detecting the hydrogen embrittlement sensitivity of metal materials in a pure hydrogen and hydrogen-doped environment according to claim 3, characterized in that, Four screws pass through the four through holes of the upper part fixture body and are connected to the four screw holes of the lower part fixture body, so that the upper part fixture body and the lower part fixture body are tightly connected and clamp the circular specimen. A spherical indenter is placed in the pressure rod insertion hole and a pressure rod is inserted. The spherical indenter is located between the lower end of the pressure rod and the center of the upper end of the circular specimen.
6. The fixture for detecting the hydrogen embrittlement sensitivity of metal materials in pure hydrogen and hydrogen-doped environments according to claim 1, characterized in that, The left side ventilation pipe is inserted horizontally into the left side ventilation channel of the lower part fixture and is connected to the left side ventilation channel on the side wall of the lower part fixture body by welding. The end of the left side ventilation pipe is equipped with a left side high-pressure needle valve. The gas cylinder is connected to the left side high-pressure needle valve through a supporting ventilation pipe and fixture; The right side ventilation pipe is inserted horizontally into the right side ventilation channel of the lower part fixture and is connected to the right side ventilation channel on the side wall of the lower part fixture body by welding. The right side ventilation pipe is connected to the pressure gauge through a ferrule tee joint, and the end of the right side ventilation pipe is equipped with a right side high-pressure needle valve.