CN114910362A - Testing method of electric pulse creep testing machine capable of detecting and repairing damage - Google Patents

Abstract

The invention provides a testing method of an electric pulse creep testing machine capable of detecting and repairing damage, which comprises an electric pulse detecting and repairing system and a multi-sample creep testing system. Wherein the electric pulse detection and repair system is used for detecting and evaluating the damage condition in the material and repairing the damage according to the damage condition. A multi-sample fixing system is arranged in a high-temperature box of the multi-sample creep test system, and the independence of testing of all parallel samples can be realized. The invention can better monitor the internal damage condition of the metal in the creep high-temperature creep process, carry out in-situ repair aiming at the damage grade and compare and analyze the repair effect. The device has compact structure, and can realize multifunctional integrated test of creep test, damage detection, damage repair and effect evaluation.

Description

Test method for electrical impulse creep testing machine capable of damage detection and repair

technical field

The invention belongs to the field of metal material testing and testing and analysis, and particularly relates to a testing method of a device for pulse current-assisted creep testing capable of performing damage detection and repair.

Background technique

With the rapid development of modern industry, the requirements for the service performance of materials are getting higher and higher. Defects such as holes and micro-cracks may appear inside metal structural materials during service under complex working conditions such as high temperature and load, which seriously affect the service safety and life of the structure. In recent years, many scholars at home and abroad have introduced electrical pulses into the repair of internal cracks in metal materials. Through pulse current treatment, metal cracks can be healed in a solid state. The principle is that the higher temperature generated when the current passes through the cracks makes It has a relatively large amount of expansion, and the confinement of the surrounding lower temperature matrix leads to compression into the crack, so that the atoms on the crack face re-bond. In the existing pulse repairing crack experimental device, conductive electrodes and pulse current transmitters are respectively fixed at both ends of the sample. A current loop is formed between the current transmitter, the sample, the conductive wire and the conductive electrode; at the same time, a high-temperature furnace for providing the temperature required for the test is fixed on the testing machine; the sample is also provided with a temperature measuring device and an extension rod for real-time Monitor the test temperature and monitor the deformation of the specimen. Although the problem of current pulse density has been initially solved, the experimental device is too cumbersome and easily damaged.

There are few practical applications of electrical pulses in creep damage repair, and most pulse current devices are independent of creep devices. For example, Application No. 202110465132.1 discloses a treatment method for improving the wear and corrosion resistance of Al-Mg-Si alloy, which can improve the structure of the alloy and reduce the dendrite in the solidification structure of the alloy by performing electric pulse treatment on the alloy. segregation, thereby improving the wear and corrosion resistance of the alloy. Application No. 202010095608.2 discloses an electric pulse-assisted micro-stretching process for ultra-fine-grained metal foils, which utilizes the action of pulsed current to make the obtained product have ultra-fine grains, which greatly improves the toughness of ultra-fine-grained metals. The above patents all use electric pulses to improve the metal structure, but they do not involve the detection and repair of the internal structure defects of the metal during use or service. In terms of creep testing machine, application No. 201910186273.2 discloses a multi-sample tensile-compression creep testing device, which can stretch the sample by adjusting the oil pressure difference in the two sub-cavities in the device Or compression creep test, so that the stress magnitude and stress time of each sample can be kept relatively independent, which greatly improves the efficiency of the creep test. However, the horizontal arrangement of the samples in the multi-sample fixing device will lead to differences in the force of each sample under large load conditions due to the difference in the moment of each sample, which affects the accuracy and accuracy of the test. Therefore, in the prior art, there is still a need for a solution that can perform electrical pulse detection and repair on each sample and accurately control the loading of each sample, so as to compare and verify the effect of material performance recovery after electrical pulse repair.

SUMMARY OF THE INVENTION

1. Technical problems to be solved:

Electric pulses are rarely used in creep damage detection and repair, and most pulsed current devices are independent of creep devices.

2. Technical solution:

In order to solve the above problems, the present invention provides a creep test method for damage and repair after non-destructive testing, using an electric pulse creep testing machine that can perform damage detection and repair. In the creep testing machine, a plurality of the samples are located in a high temperature box, and the samples are electrically connected to the pulse current transmitter through wires. The sample fixing system includes a first support beam and a second support beam arranged in parallel, the first support beam is connected by the first column and the lower surface of the upper part of the high temperature box, and the second support beam is connected by the second column and the high temperature box The upper surface of the lower part is connected, and a plurality of evenly distributed sample fixing devices are arranged between the first support beam and the second support beam. Each sample fixing device includes a first sealing cavity arranged on the first support beam and a The second sealing chamber is arranged in the second supporting beam, the connecting line between the first sealing chamber and the second sealing chamber is perpendicular to the bottom surface, the first sealing chamber is divided into two sub-chambers by the piston, and the two The sub-chambers are respectively connected to the two working oil ports of the hydraulic system through pipelines. One end of the first tension and compression rod is connected to the piston, the other end is connected to the sample, and the other end of the sample is connected to the second tension rod. The pressing rod is connected, and the other end of the second pulling and pressing rod is arranged in the second sealing cavity. The specific steps of the test method are: the first step: install and connect the sample between the first tension and compression rod and the second tension and compression rod; the second step: seal the high temperature furnace, connect and start the heating device, and make the sample heat up to After the target temperature, start the heat preservation; the third step: start the hydraulic system and the strain measurement device, control the oil pressure difference in the two sub-cavities corresponding to each sample as needed, and perform tensile or compressive creep on the sample At the same time, the strain measurement device measures the strain amount of the sample in real time; Step 4: After the creep test is completed, the sample is subjected to non-destructive testing by the pulse current transmitter to evaluate the internal damage of the material; Step 5: The pulse current transmitter The sample is repaired by electrical impulse damage, and the unrepaired sample group is reserved for comparison. After the repair is completed, non-destructive testing is carried out, and the repair is not achieved. The creep comparison test is used to check the electric pulse repair and compare and analyze the repair effect.

The first pulling and pressing rod and the second pulling and pressing rod are both provided with a connection terminal for connecting the positive or negative pole of the pulse current transmitter, and the first pulling and pressing rod and the second pulling and pressing rod are electrically connected to each other through the connection terminal. Connect to the positive and negative poles of the pulsed current transmitter.

The first sealing cavity and the second sealing cavity are provided with openings corresponding to one end away from the sample, and the openings are closed by sealing screw plugs.

The testing machine also includes a first stress-sensing element and a second stress-sensing element, the first stress-sensing element is arranged between the second tension and compression rod and the shoulder of the second sealing cavity, the second stress-sensing element It is arranged between the second pulling and pressing rod and the nut.

One end of the first tension and compression rod and the second tension and compression rod for connecting the sample is connected with an insulating ring.

The two sub-chambers included in each first sealing chamber are connected to the working oil circuit of the same hydraulic system, and the pressure difference between the two sub-chambers included in each first sealing chamber is adjusted by a set of hydraulic control valves with control.

The testing machine further includes a strain measurement device including a mounting frame, a light source, a DIC camera, and a computer connected to the DIC camera, the mounting frame being fixed on the frame and located outside the high temperature box , the DIC camera and the light source are both arranged on the mounting frame, and the lens of the DIC camera and the illumination direction of the light source are both directed toward the sample in the high temperature box.

The computer is integrated with the PC control machine that comes with the testing machine itself.

A transparent window is provided on one side of the high temperature box corresponding to the DIC camera.

A creep test method for damage repair after non-destructive testing, using the above-mentioned electric pulse creep testing machine capable of damage detection and repair to conduct the test, including the following steps: Step 1: Install and connect the sample on the first Between the tension and compression rod and the second tension and compression rod; the second step: seal the high temperature furnace, connect and start the heating device, and make the sample warm to the target temperature and then start to keep warm; the third step: start the hydraulic system and the strain measurement device, according to the It is necessary to control the oil pressure difference in the two sub-cavities corresponding to each sample, conduct tensile or compressive creep tests on the samples, and at the same time, the strain measuring device measures the strain of the samples in real time; the fourth step: creep At the end of the test, use the pulse current transmitter to apply pulse current for non-destructive testing to judge the damage of the sample; the fifth step: use the pulse current transmitter to repair the damage of the sample by electric pulse, and keep the unrepaired sample group for comparison. After the repair is completed, carry out non-destructive testing, and repair again if the repair purpose is not achieved; the sixth step: carry out a creep comparison test between the repaired sample and the comparison sample group to check the electric pulse repair and compare and analyze the repair effect.

3. Beneficial effects:

The test method of the electric pulse creep testing machine for damage detection and repair provided by the present invention can better monitor the internal damage of the metal in the high-temperature creep process of creep, perform in-situ repair according to the damage level, and compare and analyze the repair effect . The device of the invention has a compact structure and can realize multifunctional integrated testing of creep testing, damage detection, damage repair and effect evaluation.

Description of drawings

FIG. 1 is a flow chart of the method of the present invention.

Fig. 2 is the overall shape of the testing machine of the present invention, and the electrical pulse device and the pulse current transmitter are connected by wires (24).

Fig. 3 is the internal result of the test machine in which the high temperature box is removed according to the present invention.

FIG. 4 is a schematic diagram of the multi-sample fixing system of the present invention.

FIG. 5 is a schematic diagram of the sample fixing device of the present invention.

Description of reference numerals: 1-frame, 2-high temperature box, 3-transparent window, 4-mounting frame, 5-DIC camera, 6-light source, 7-sample, 8-first column, 9-first support Beam, 10-Second support beam, 11-Second column, 12-Terminal, 13-Sealing plug, 14-Piston, 15-Insulation ring, 16-First tension rod, 17-Second tension rod , 18-first sealed cavity, 19-temperature detection element, 20-first stress sensing element, 21-second stress sensing element, 22-nut, 23-second sealed cavity, 24-wire, 25-pulse current launcher.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

As shown in Figure 1, a method for performing damage repair and creep testing after non-destructive testing, the specific steps are as follows: Step 1: install and connect the sample between the first tension and compression rod 16 and the second tension and compression rod 17; Step 2: Close the high-temperature furnace 2, connect and start the heating device, and heat the sample 7 to the target temperature and then start to keep warm; Step 3: Start the hydraulic system and the strain measurement device, and control the corresponding The oil pressure difference in the two sub-chambers is used to perform tensile or compressive creep tests on sample 7, and the strain measuring device measures the strain amount of the sample in real time; the fourth step: the creep test is completed, and the pulse current transmitter 25 Perform non-destructive testing on the sample to evaluate the internal damage of the material; the fifth step: perform electrical pulse damage repair on the sample through the pulse current transmitter 25, in which the unrepaired sample group is reserved for comparison, and the non-destructive testing is performed after the repair is completed. If the repairing purpose is not achieved, repair it again; the sixth step: carry out a creep comparison test between the repaired sample and the comparison sample group to check the electric pulse repairing condition and compare and analyze the repairing effect.

As shown in FIG. 2 , the method of the present invention uses an electric pulse creep testing machine that can perform damage detection and repair, including a plurality of samples 7 , and the plurality of samples 7 are located in the high temperature box 2 , and the samples 7 Electrically connected to the pulse current transmitter 25 through the wire 24 , wherein the high temperature box 2 is arranged on the frame 1 . As shown in FIG. 3 and FIG. 4 , the high temperature box 2 is provided with a multi-sample fixing system. The multi-sample fixing system includes a first support beam 9 and a second support beam 10 arranged in parallel. The first support beam 9 passes through the first support beam 9 . The column 8 is connected to the lower surface of the upper part of the high temperature box 2, the second support beam 10 is connected to the upper surface of the lower part of the high temperature box 2 through the second column 9, and a plurality of the first support beam 9 and the second support beam 10 are arranged between Evenly distributed specimen holder. In the present invention, 6 sample fixing devices are provided, and 6 samples can be fixed at the same time.

As shown in FIG. 5 , each sample fixing device includes a first sealing cavity 18 provided on the first support beam 9 and a second sealing cavity provided on the second supporting beam 10 , the first sealing cavity 18 and the second sealing cavity 18 The connection line between the chambers 23 is perpendicular to the bottom surface. The first sealing chamber 18 is divided into two sub-chambers by the piston 14, and the two sub-chambers are respectively connected to the two working oil ports of the hydraulic system through pipelines. , one end of the first tension and compression rod 16 is connected with the piston 14, the other end is connected with the sample 7, and the other end of the sample 7 is connected with the second tension and compression rod 17, the second tension and compression rod 17 The other end is arranged in the second sealing cavity. By adjusting the oil pressure difference in the two sub-chambers and changing the moving tendency or direction of the first tension-compression rod 16 , the tensile or compression creep test is performed on the sample 7 .

Control the oil pressure difference in the two sub-cavities corresponding to each sample 7 as required, and perform tensile or compressive creep tests on the sample 7. The oil pressure in the sub-chambers close to the sample 7 is greater than that far away from the sample 7. The oil pressure in the sub-chamber of sample 7, the sub-chamber close to sample 7 enters oil, and the sub-chamber away from sample 7 returns oil; when sample 7 needs compressive stress, it is close to the sub-chamber of sample 7. The oil pressure in the body is lower than the oil pressure in the sub-chamber away from the sample 7, the sub-chamber far from the sample enters oil, and the sub-chamber close to the sample returns oil. Each component cavity included in each first sealing cavity 18 is connected to the working oil circuit of the same hydraulic system, and the pressure difference between the two sub-cavities included in each sealing cavity is adjusted by a set of hydraulic control valves. control.

Also includes a first stress-sensing element 20 and a second stress-sensing element 21, the first stress-sensing element 20 is disposed between the second tension and compression rod 17 and the shoulder of the second sealing cavity, the second stress-sensing element 21 is arranged between the second pulling and pressing rod 17 and the nut 22 . During the compressive creep test, that is, when the sample is under compressive stress, the second stress sensing element 21 of the compressive stress sensor in the present invention is under compression, and the first stress sensing element 20 of the tensile stress sensor does not work; During the tensile creep test, that is, when the sample is subjected to tensile stress, the stress sensing element 20 of the tensile stress sensor in the present invention is under compression, and the stress sensing element 21 of the compressive stress sensor does not work.

"Tension" and "compression" in the tensile stress sensor and compressive stress sensor described in the present invention are relative to the sample, and "tension" and "compression" refer to the tensile stress and the compressive stress of the sample respectively.

In one embodiment, the first sealing cavity 18 and the second sealing cavity are provided with openings corresponding to one end away from the sample, and the openings are closed by the sealing screw 13 .

An insulating ring 15 is connected to one end of the first tension and compression rod 16 and the second tension and compression rod 17 for connecting the sample, which plays an insulating role, and the piston 14 is a conductor.

In one embodiment, the first tension and compression rod 16 and the second tension and compression rod 17 are both provided with a terminal 12 for connecting the positive or negative pole of the pulse current transmitter 23 . The first tension and compression rod 16 and the second The tension and compression rods 17 are respectively electrically connected to the positive and negative poles of the pulse current transmitter 25 through the connection terminals 12 . The piston 14 and the pulse current transmitter 25 are connected to the connection terminal 12 through a conductive wire wrapped with a high temperature resistant mica material.

The pulse current is injected into the metal or component from the excitation electrode. If there is a defect in the metal, the size, phase and distribution of the current density will be affected by the defect, which will cause the voltage between the measurement electrodes to change. The detection of defects can be realized, and the in-situ electric pulse detection and repair experiments can be carried out while the creep experiment is carried out, so as to improve the efficiency of the experiment.

The present invention also includes a strain measurement device, which includes a mounting frame 4, a light source 6, a DIC camera 5, and a computer connected to the DIC camera 5, and the computer is used to perform a measurement on the sample image collected by the DIC camera. Real-time online analysis, and generate the strain results of the sample, the computer can be integrated with the PC control machine that comes with the creep testing machine itself, the mounting frame is fixed on the frame and is located outside the high temperature box, the DIC camera and the light source All are installed on the mounting frame, and the irradiation direction of the lens of the DIC camera and the light source are all facing the sample in the quasi-high temperature box, and the side of the high temperature box corresponding to the DIC camera is set as a transparent window. The mounting frame 4 is fixed on the rack 1 and is located outside the high temperature box 2 , the DIC camera 5 and the light source 6 are both arranged on the mounting frame 4 , the lens of the DIC camera 5 and the The irradiation directions of the light sources 6 are all directed towards the sample 7 in the high temperature box 2 .

Example

The specific test method is:

The first step. Select the metal round bar sample to keep the smoothness and cleanliness of the surface of the sample as much as possible, otherwise it will affect the effect of subsequent non-destructive testing.

The second step. Carry out multiple sets of parallel creep tests. Specifically, start the hydraulic system and the strain measurement device, and adjust the oil pressure difference in the two sub-chambers to change the moving trend or direction of the first tension and compression rod 16. Sample 7 was tested for tensile or compressive creep. At the same time, the strain measuring device measures the strain amount of the sample in real time, and the temperature detection element 19 detects the temperature change in real time.

Control the oil pressure difference in the two sub-cavities corresponding to each sample 7 as required, and perform tensile or compressive creep tests on the sample 7. The oil pressure in the sub-chambers close to the sample 7 is greater than that far away from the sample 7. The oil pressure in the sub-chamber of sample 7, the sub-chamber close to sample 7 enters oil, and the sub-chamber away from sample 7 returns oil; when sample 7 needs compressive stress, it is close to the sub-chamber of sample 7. The oil pressure in the body is lower than the oil pressure in the sub-chamber away from the sample 7, the sub-chamber far from the sample enters oil, and the sub-chamber close to the sample returns oil. Each component cavity included in the first sealing cavity 18 of each sample is connected to the working oil circuit of the same hydraulic system, and the pressure difference between the two sub-cavities included in each sealing cavity passes through a set of hydraulic control valves to adjust and control.

In the embodiment, the first sealing cavity 18 and the second sealing cavity 23 are provided with openings corresponding to one end away from the sample, and the openings are closed by the sealing screw 13 .

The third step. Use the electric pulse nondestructive testing analysis to measure the change of voltage to evaluate the degree of damage inside the metal to judge the level of damage; for the sample whose test result is nondestructive, creep again to achieve the damage condition;

Step 4. Determine the damage category and carry out damage repair. In particular, it is necessary to retain the control group samples for subsequent creep comparison tests;

Step 5. The main purpose of non-destructive testing of repair effect is to check whether the repair process is fully completed. If there are still problems in metal repair, analyze and judge the damage category again according to the change of voltage, and take corresponding repair measures.

Step 6. Creep comparison test, carry out the creep test on the repaired metal sample and the control sample to compare and analyze the repair effect.

The present invention also includes a strain measurement device, the strain measurement device includes a mounting frame 4, a light source 6, a DIC camera 5, and a computer connected to the DIC camera 5, and the computer is used for real-time online analysis of the sample images collected by the DIC camera, And generate the strain results of the sample, the computer can be integrated with the PC control machine that comes with the creep testing machine itself, the mounting frame is fixed on the frame and is located outside the high temperature box, and the DIC camera and light source are set on the mounting frame. , The lens of the DIC camera and the irradiation direction of the light source are all facing the sample in the quasi-high temperature box, and the side of the high temperature box corresponding to the DIC camera is set as a transparent window 3 . The mounting frame 4 is fixed on the rack 1 and is located outside the high temperature box 2 . The DIC camera 5 and the light source 6 are both arranged on the mounting frame 4 . Sample 7.

The method of the present invention can be used for tensile and compression relaxation aging tests. Moreover, the device of the invention has a compact structure, and can realize multi-functional integrated testing of creep testing, damage detection, damage repair and effect evaluation.

The above descriptions are only preferred embodiments of the present invention, and do not limit the technical content of the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solutions of the present invention.

Claims (9)

1. A method for performing damage and repair creep testing after non-destructive testing, using an electric pulse creep testing machine that can perform damage detection and repair for testing, and a plurality of electrical pulse creep testing machines that can perform damage detection and repair are used for testing. The sample (7) is located in the high temperature box (2), the sample (7) is electrically connected to the pulse current transmitter (25) through the wire (24), and the high temperature box (2) is provided with multiple test samples. A sample fixing system, the multi-sample fixing system includes a first support beam (9) and a second support beam (10) arranged in parallel, the first support beam (9) passing through the first column (8) and the high temperature box (2) The lower surface of the upper part is connected, the second support beam (10) is connected to the upper surface of the lower part of the high temperature box (2) through the second column (11), and the first support beam (9) is connected to the second support A plurality of evenly distributed sample fixing devices are arranged between the beams (10), and each sample fixing device includes a first sealing cavity (18) arranged on the first support beam (9) and a first sealing cavity (18) arranged on the second support beam ( 10) The second sealing chamber (23), the connecting line between the first sealing chamber (18) and the second sealing chamber (23) is perpendicular to the bottom surface, and the first sealing chamber (18) is divided by the piston (14) It is divided into two sub-chambers, the two sub-chambers are respectively connected to the two working oil ports of the hydraulic system through pipelines, one end of the first pulling and pressing rod (16) is connected with the piston (14), and the other One end is connected to the sample (7), the other end of the sample (7) is connected to the second tension and compression rod (17), and the other end of the second tension and compression rod (17) is set in the second sealing cavity ( 23), the specific steps of the test method are: the first step: install and connect the sample between the first tension and compression rod (16) and the second tension and compression rod (17); the second step: seal the high temperature furnace (2 ), connect and start the heating device, make the sample (7) warm to the target temperature and then start to keep warm; the third step: start the hydraulic system and the strain measuring device, and control the two corresponding to each sample (7) as needed According to the oil pressure difference in the cavity, the tensile or compressive creep test is performed on the sample (7), and the strain measurement device measures the strain amount of the sample in real time; the fourth step: the creep test is over, and the pulse current transmitter ( 25) Perform non-destructive testing on the sample to evaluate the internal damage of the material; Step 5: Repair the sample with electrical pulse damage through the pulse current transmitter (25), in which the unrepaired sample group is reserved for comparison, and after the repair is completed Carry out non-destructive testing, and repair again if the repair purpose is not achieved; the sixth step: carry out a creep comparison test between the repaired sample and the comparison sample group to check the electric pulse repair and compare and analyze the repair effect. 2. The method according to claim 1, characterized in that: both the first tension and compression rod (16) and the second tension and compression rod (17) are provided with a positive or negative electrode for connecting the pulse current transmitter (25). The connecting terminal (12), the first pulling and pressing rod (16) and the second pulling and pressing rod (17) are respectively electrically connected to the positive and negative poles of the pulse current transmitter (25) through the connecting terminal (12). 3. The method according to claim 1, characterized in that: the first sealing chamber (18) and the second sealing chamber (23) are provided with openings corresponding to one end away from the sample (7), and the openings pass through the sealing screw plugs (13) To be closed. 4. The method according to claim 3, characterized in that: the testing machine further comprises a first stress sensing element (20), a second stress sensing element (21) and a temperature detecting element (19), the first stress sensing element (21) A stress sensing element (20) is arranged between the second tension and compression rod (17) and the shoulder of the second sealing cavity (23), and the second stress sensing element (21) is arranged on the second tension and compression rod (17) ) and the nut (22), the temperature detection element (19) is attached to the surface of the sample to measure the temperature change on the surface of the sample. 5. The method according to any one of claims 1-4, characterized in that: the first tension and compression rod (16) and the second tension and compression rod (17) are used to connect the sample (7) One end is connected with an insulating ring (15). 6. The method according to any one of claims 1-4, characterized in that: the two sub-chambers included in each first sealing chamber (18) are connected to the working oil circuit of the same hydraulic system, and each The pressure difference between the two sub-cavities included in the first sealing chamber (18) is regulated and controlled by a set of hydraulic control valves. 7. The method according to any one of claims 1-4, wherein the testing machine further comprises a strain measuring device, the strain measuring device comprising a mounting frame (4), a light source (6), a DIC A camera (5), and a computer connected to the DIC camera (5), the mounting bracket (4) is fixed on the frame (1) and is located outside the high temperature box (2), the DIC camera (5) ) and the light source (6) are both arranged on the mounting frame (4), and the lens of the DIC camera (5) and the irradiation direction of the light source (6) are both oriented toward the high temperature box (2). of sample 7. 8. The method according to claim 7, wherein the computer is integrated with the PC control machine provided by the testing machine itself. 9 . The method according to claim 7 , wherein a transparent window ( 3 ) is provided on one side of the high temperature box ( 2 ) corresponding to the DIC camera ( 5 ). 10 .

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