Compact tensile sample clamp for testing stress corrosion strength factor

Abstract

The utility model provides a compact tensile sample fixture for testing stress corrosion strength factor, which comprises a plurality of pins, an upper chuck, a lower chuck and a corrosion container, the upper end of the upper chuck is provided with a hydraulic servo testing machine fixing part, and the lower end of the lower chuck is provided with a hydraulic servo testing machine fixing part. Compact tensile sample grooves are formed in the lower end of the upper chuck and the upper end of the lower chuck, pin through holes are formed in the side wall of the compact tensile sample groove of the upper chuck and the side wall of the compact tensile sample groove of the lower chuck, and pins can be inserted and fixed into the pin through holes. The compact tensile sample groove of the upper chuck and the compact tensile sample groove of the lower chuck are both arranged in the corrosion container cavity, a magnet is arranged on the side wall of the side, away from the pin through hole, of the compact tensile sample groove of the upper chuck, and a magnet is arranged on the side wall of the side, away from the pin through hole, of the compact tensile sample groove of the lower chuck. A lower chuck connecting hole is formed in the bottom of the corrosion container, the lower chuck connecting hole is a threaded hole, external threads are arranged on the outer side wall of the lower chuck, and the lower chuck connecting hole is in threaded connection with the outer side wall of the lower chuck. According to the utility model, a scientific and reasonable structural design is adopted, and the sample is fixed by the pin, so that the physical damage of the sample in the fixing process is reduced, and the load is uniformly and accurately applied to the compact tensile sample in the stress corrosion strength factor test.

Description

TECHNICAL FIELD

[0001] The utility model relates to material mechanics test technical field especially relates to stress corrosion strength factor test uses compact tension specimen fixture. BACKGROUND

[0002] Stress corrosion cracking (Stress Corrosion Cracking, SCC) is a kind of material destruction phenomenon under the joint action of stress and corrosion medium, and many engineering materials, such as stainless steel, aluminum alloy, magnesium alloy and high-strength low-alloy steel, are sensitive to SCC, therefore, accurately evaluating the behavior of material under stress and corrosion environment has important significance for improving the service life and safety of material. In the field of material science and engineering, stress corrosion intensity factor (Stress Intensity Factor, K) test is an important means to evaluate the stress corrosion resistance of material. At present, stress corrosion intensity factor test needs to use hydraulic servo testing machine, and the hydraulic servo testing machine is usually connected with a chuck for clamping the sample during the test, and a small sample constant load stress corrosion test device is recorded in publication No. CN103926146A, including displacement sensor, loading screw, fixed screw, base, stress ring, stress measurement sample, corrosion test cavity, sample and experimental medium;The stress ring is fixed on the base by the fixed screw and fixed nut, the stress ring has a corrosion test cavity inside, the corrosion test cavity is provided with experimental medium and sample, the U-shaped clamp end of the fixed screw passes through the bottom of the corrosion test cavity and fixes the lower part of the sample, and the lower sealing ring is arranged between the fixed screw and the corrosion test cavity;The loading screw is connected with the upper part of the stress ring and one end of the stress measurement sample through the loading nut, the other end of the stress measurement sample is a U-shaped clamp end, the U-shaped clamp end of the stress measurement sample passes through the upper part of the corrosion test cavity and fixes the upper part of the sample, and the upper sealing ring is arranged between the loading screw and the corrosion test cavity, the size of the stress measurement sample is the same as that of the sample, and a strain gauge is installed in the middle of the stress measurement sample;The base has a support, and the displacement sensor is installed on the support and located on the upper part of the stress ring.

[0003] A method for corrosion test using the small sample constant load stress corrosion test device as described above, comprising the following steps:

[0004] Step one, according to the required simulation field working condition design experimental corrosion medium, sample loading load size;

[0005] Step two, install the sample, load stress through the loading screw, and determine the load through the displacement sensor and strain gauge;

[0006] Step three, the corrosion medium is added into the corrosion experiment cavity, and the gas inlet and the gas outlet are connected to the H2S, CO2 or N2 gas cylinder and the waste gas treatment system respectively;

[0007] Step four, after the corrosion medium in the corrosion experiment cavity is fully deoxygenated, H2S or CO2 and other corrosive gases are introduced, and the experiment is started, and the test time is 720h.

[0008] Step five, after the experiment is completed, the sample is unloaded after being fully deoxygenated, and whether the sample is broken is observed, and crack detection, sample surface corrosion morphology and corrosion product analysis are performed.

[0009] The method and device can be used to determine the stress corrosion cracking resistance of thin-walled pipes and small-size components which cannot be processed into standard samples, and the applicability of the material of the components can be obtained according to the test results, so that the thin-walled pipes and small-size components can be selected and the applicability can be evaluated. Technical problems solved by the utility model

[0010] The utility model solves the technical problems that a stress corrosion intensity factor test compact tensile specimen clamp is provided, and the clamp can reduce the displacement of the compact tensile specimen in the stress corrosion intensity factor test.

[0011] The utility model adopts the technical scheme that:

[0012] The stress corrosion intensity factor test compact tensile specimen clamp, including a plurality of pins, upper chuck, lower chuck and corrosion container, the upper chuck and the lower chuck are vertically placed and the positions are opposite, the upper end of the upper chuck is equipped with hydraulic servo testing machine fixed part, the lower end of the lower chuck is equipped with hydraulic servo testing machine fixed part, the lower end of the upper chuck and the upper end of the lower chuck are all opened compact tensile specimen groove, the compact tensile specimen groove lateral wall of the upper chuck and the compact tensile specimen groove lateral wall of the lower chuck are all equipped with pin through hole, the pin can be inserted and fixed in the pin through hole, the compact tensile specimen groove of the upper chuck and the compact tensile specimen groove of the lower chuck are all placed in the corrosion container cavity, the compact tensile specimen groove lateral wall of the upper chuck is equipped with magnet on the side away from the pin through hole, the compact tensile specimen groove lateral wall of the lower chuck is equipped with magnet on the side away from the pin through hole, the bottom of the corrosion container is equipped with lower chuck connecting hole, the lower chuck connecting hole is screw hole, the outer lateral wall of the lower chuck has outer thread, and the lower chuck connecting hole and the outer lateral wall of the lower chuck are screw connected.

[0013] Further, the compact tension specimen groove of the upper clamp and the compact tension specimen groove of the lower clamp are two grooves with the same opening size and coaxial central axes.

[0014] Further, the compact tension specimen groove of the upper clamp is marked with alignment marks on the side, and the compact tension specimen groove of the lower clamp is also marked with alignment marks at the corresponding position.

[0015] Further, the upper pin through hole and the lower pin through hole are in corresponding positions and have the same hole diameter.

[0016] Further, the plurality of pins are cylindrical pins, and when the pins are inserted into the upper pin through hole or the lower pin through hole, the pins and the upper pin through hole or the lower pin through hole are in interference fit.

[0017] Further, a waterproof sealing ring is fixedly arranged on the outer surface of the bottom of the corrosion container, and the inner side wall of the waterproof sealing ring is tightly combined with the outer side wall of the lower clamp.

[0018] Further, the waterproof sealing ring is at least two, and the outer surface and the inner surface of the bottom of the corrosion container each has at least one waterproof sealing ring.

[0019] Further, the corrosion container is a box body, the top of the corrosion container is provided with an upper clamp connecting hole, the upper clamp can pass through the upper clamp connecting hole and be sealingly connected with the top of the corrosion container through the upper clamp connecting hole, the side wall of the corrosion container is provided with a specimen inlet and outlet, the top of the corrosion container is provided with a corrosion liquid inlet, and the bottom of the corrosion container is provided with a corrosion liquid discharge port.

[0020] Further, the magnet of the upper clamp and the magnet of the lower clamp are both ferrite magnets.

[0021] The utility model discloses the beneficial effect is:

[0022] The compact tension specimen clamp for stress corrosion intensity factor test adopts scientific and reasonable structure design,

[0023] The pin is used for fixing the specimen, and the physical damage of the specimen in the fixing process is reduced. Meanwhile, the corrosion container and the lower clamp are connected in a matched mode, the sealing property and stability of the corrosion solution are ensured, and a constant corrosion environment is provided for the specimen. In addition, the upper clamp and the lower clamp of the clamp are fixed through the hydraulic clamp of the hydraulic servo testing machine, and the uniformity and accuracy of load application in the testing process are ensured. This design not only improves the precision and repeatability of the test, but also greatly simplifies the operation steps, and facilitates the rapid replacement of the specimen and the maintenance of the equipment.

[0024] The compact tension specimen grooves of the upper clamp and the lower clamp have the same opening size and coaxial central axes, the specimen can always be centered during the testing process, the eccentric load phenomenon is avoided, and the accuracy and reliability of the test result are improved.

[0025] The compact tensile specimen groove of the upper clamp head and the lower clamp head is marked with alignment marks on the side, which facilitates the operator to quickly align when installing the specimen, simplifies the operation steps, and reduces human error.

[0026] The upper clamp head and the lower clamp head are connected to the top and the bottom of the corrosion container through threaded connection respectively, which is convenient and fast to install and disassemble, does not need additional tools, and saves operation time.

[0027] The top of the corrosion container is provided with a corrosion liquid water inlet, and the bottom is provided with a corrosion liquid discharge port, which facilitates the injection and discharge of the corrosion liquid, and ensures the uniformity and controllability of the corrosion environment in the test process.

[0028] Through the water inlet and the discharge port, the concentration and temperature of the corrosion liquid can be adjusted at any time to adapt to the requirements of different materials and test conditions.

[0029] The sidewall of the corrosion container is provided with a specimen inlet and outlet, which facilitates the loading and unloading of the specimen and improves the experimental efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments.

[0031] Figure 1 is a structural schematic view of a compact tensile specimen clamp for stress corrosion strength factor test.

[0032] Figure 2 is a structural sectional view of a compact tensile specimen clamp for stress corrosion strength factor test.

[0033] Figure 3 is a structural schematic view of a pin.

[0034] In the figure, 1 is an upper clamp head, 2 is a lower clamp head, 3 is a pin, 4 is a corrosion container, and 5 is a waterproof sealing ring. DETAILED DESCRIPTION

[0035] The present application will be further described below in combination with the drawings.

[0036] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be further described in detail below in combination with the drawings and embodiments, and it should be understood that the specific embodiments described below are only used to explain the present application, and are not used to limit the present application.

[0037] In the description in the utility model, it needs to be understood that the orientation or position relation indicated by the terms "upper", "lower", "inner", "outer" and the like in the utility model should be understood in a broad sense, and should not be used to limit the protection scope of the utility model, and for ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0038] The compact tension specimen clamp for stress corrosion strength factor test comprises an upper clamp head 1, a lower clamp head 2 and a corrosion container 4, the upper end of the upper clamp head 1 is provided with a hydraulic servo testing machine fixing part, the lower end of the lower clamp head 2 is provided with a hydraulic servo testing machine fixing part, the lower end of the upper clamp head 1 and the upper end of the lower clamp head 2 are located in the cavity of the corrosion container 4, a plurality of pins 3 are included, the lower end of the upper clamp head 1 is provided with a compact tension specimen groove with downward opening, the side wall of the compact tension specimen groove of the upper clamp head 1 is provided with an upper pin through hole, the pin 3 can be inserted and fixed in the upper pin through hole, the upper end of the lower clamp head 2 is provided with a compact tension specimen groove with upward opening, the side wall of the compact tension specimen groove of the lower clamp head 2 is provided with a lower pin through hole, the pin 3 can be inserted and fixed in the lower pin through hole, the side wall of the compact tension specimen groove of the upper clamp head 1 away from the pin through hole is provided with a magnet, the side wall of the compact tension specimen groove of the lower clamp head 2 away from the pin through hole is provided with a magnet, the bottom of the corrosion container 4 is provided with a lower clamp connecting hole, the lower clamp connecting hole is a threaded hole, the outer side wall of the lower clamp head 2 is provided with external threads, and the lower clamp connecting hole and the outer side wall of the lower clamp head 2 are screw-connected.

[0039] As Figure 1As shown, in actual use, the upper chuck 1 and the lower chuck 2 that are adapted to the size and shape of the compact tensile specimen should be carefully checked to ensure that the fixture can firmly fix the specimen. Clean all parts of the fixture, especially the upper chuck 1, the lower chuck 2 and the corrosion container 4, to ensure that no contaminants affect the test results during the test. Place the tight tensile specimen in the compact tensile specimen slot between the upper chuck 1 and the lower chuck 2, and use the magnet in the compact tensile specimen slot to adsorb the compact tensile specimen to ensure that the specimen is in the correct position. A pin through hole is provided on the side of the compact tensile specimen slot away from the magnet. Several pins 3 are inserted into the pin through holes to support the specimen, and finally fixed in the pin through holes by interference fit to fix the specimen. Ensure that the pin 3 is firmly installed to prevent the specimen from moving or falling off during the test. Place the corrosion container 4 around the tightened tensile specimen, ensuring that the specimen is within the corrosion container 4. Then, install the lower chuck 4 and secure it to the lower chuck 4 using the external threads on the lower chuck 4. Then, secure the upper end of the upper chuck 1 and the lower end of the lower chuck 2 to the hydraulic servo fatigue testing machine using the hydraulic chucks of the hydraulic servo testing machine, ensuring that the fixture and specimen are securely fixed. Confirm the securement of the hydraulic chucks to prevent the fixture from loosening or specimen displacement during the test. According to the test requirements, add an appropriate amount of corrosive medium to the corrosion container 4 to ensure that the specimen is immersed in the corrosive solution. Start the hydraulic servo fatigue testing machine and perform the stress corrosion test according to the preset load conditions. Monitor data changes during the test to ensure the accuracy and reliability of the test results. After the test is completed, shut down the hydraulic servo fatigue testing machine and remove the fixture and specimen. Clean and maintain the fixture, especially the corrosion container 4, to ensure it is in good condition for the next use.

[0040] like Figure 1 As shown, the compact tensile specimen slot of the upper chuck 1 and the compact tensile specimen slot of the lower chuck 2 are two slots with the same opening size and coaxial central axes.

[0041] The compact tensile specimen slots of the upper chuck 1 and the lower chuck 2 have the same opening size and coaxial center axes, ensuring that the specimen remains centered during the test, avoiding eccentric loading and improving the accuracy and reliability of the test results.

[0042] Furthermore, an alignment mark is engraved on the side of the compact tensile specimen slot of the upper chuck, and an alignment mark is also engraved on the corresponding position of the side of the compact tensile specimen slot of the lower chuck.

[0043] The compact tensile specimen slots of the upper chuck 1 and the lower chuck 2 are engraved with alignment marks on their sides, which facilitates the operator to quickly align the specimens when installing them, simplifies the operating steps, and reduces human errors.

[0044] Furthermore, the upper pin through hole and the lower pin through hole are positioned correspondingly and have the same hole diameter, so as to evenly apply the load and facilitate processing.

[0045] Further, the plurality of pins 3 are cylindrical pins, and when the pins 3 are inserted into the upper pin through holes or the lower pin through holes, the pins 3 are in an interference fit with the upper pin through holes or the lower pin through holes.

[0046] The pins 3 themselves are elastic and can be compressed and then inserted into the holes, and then restored to their original state, and fixed by elastic force. The interference fit means that the diameter of the pins 3 is slightly larger than the diameter of the holes, and the pins 3 are fixed in the holes by knocking or pressing, and here the pins can also be fixed by additional mechanical components such as nuts, bolts, etc., but considering the cost and complexity of the device, the preferred solution is to use an interference fit between the cylindrical pins and the holes.

[0047] As shown in Figure 1 , Figure 2 , a waterproof sealing ring 5 is fixed to the outer surface of the bottom of the corrosion container 4, and the inner side wall of the waterproof sealing ring 5 is tightly fitted with the outer side wall of the lower chuck 2.

[0048] The design of the waterproof sealing ring 5 can effectively prevent the leakage of the corrosion solution and protect the safety of the experimental environment and personnel.

[0049] Further, the waterproof sealing ring 5 is at least two, and the outer surface and the inner surface of the bottom of the corrosion container 4 each has at least one waterproof sealing ring 5.

[0050] The arrangement of at least two waterproof sealing rings 5 further improves the sealing performance, which can effectively prevent the leakage of the corrosion medium even in high pressure or high temperature environment.

[0051] Further, the corrosion container 4 is a box, the top of the corrosion container 4 is provided with an upper chuck connecting hole, the upper chuck 1 can pass through the upper chuck connecting hole and be sealingly connected with the top of the corrosion container 4 through the upper chuck connecting hole, the side wall of the corrosion container 4 is provided with a sample inlet and outlet, the top of the corrosion container 4 is provided with a corrosion liquid inlet, and the bottom of the corrosion container 4 is provided with a corrosion liquid outlet.

[0052] The top of the corrosion container 4 is provided with a corrosion liquid inlet, and the bottom is provided with a corrosion liquid outlet, which facilitates the injection and discharge of the corrosion liquid and ensures the uniformity and controllability of the corrosion environment during the test.

[0053] Through the inlet and outlet, the concentration and temperature of the corrosion liquid can be adjusted at any time to meet the requirements of different materials and test conditions.

[0054] The side wall of the corrosion container is provided with a sample inlet and outlet, which facilitates the loading and unloading of the sample and improves the experimental efficiency.

[0055] Further, the magnets of the upper chuck 1 and the magnets of the lower chuck 2 are ferrite magnets.

[0056] Compared with common magnets, the ferrite magnet is more corrosion resistant, and the ferrite magnet is preferably adopted in the scheme

[0057] The compact tensile specimen clamp for stress corrosion strength factor test is not limited in preparation process and surface treatment method, and can be variously changed and modified for the person skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A compact tension specimen clamp for stress corrosion strength factor test, comprising a plurality of pins (3), an upper clamp head (1), a lower clamp head (2) and a corrosion container (4), the upper clamp head (1) and the lower clamp head (2) are both vertically placed and oppositely positioned, the upper end of the upper clamp head (1) and the lower end of the lower clamp head (2) are both provided with a hydraulic servo testing machine fixing part, the lower end of the upper clamp head (1) and the upper end of the lower clamp head (2) are both provided with a compact tension specimen groove, the compact tension specimen groove side wall of the upper clamp head (1) and the compact tension specimen groove side wall of the lower clamp head (2) are both provided with a pin through hole, the pin (3) can be inserted and fixed in the pin through hole, the compact tension specimen groove of the upper clamp head (1) and the compact tension specimen groove of the lower clamp head (2) are both placed in the cavity of the corrosion container (4), characterized in that, The compact tensile specimen groove of the upper clamp head (1) is fixed with a magnet on the side wall away from the pin hole, the compact tensile specimen groove of the lower clamp head (2) is fixed with a magnet on the side wall away from the pin hole, the bottom of the corrosion container (4) is provided with a lower clamp head connecting hole, the lower clamp head connecting hole is a threaded hole, the outer side wall of the lower clamp head (2) is externally threaded, and the lower clamp head connecting hole is threadedly connected with the outer side wall of the lower clamp head (2).

2. The compact tension specimen clamp for stress corrosion strength factor testing of claim 1, wherein: The compact tensile specimen groove of the upper clamp head (1) and the compact tensile specimen groove of the lower clamp head (2) are two grooves with the same opening size and coaxial center axes.

3. The compact tension specimen clamp for stress corrosion strength factor testing of claim 1, wherein: The compact tensile specimen groove of the upper clamp head (1) is provided with an alignment mark on the side surface, and the compact tensile specimen groove of the lower clamp head (2) is also provided with an alignment mark at the corresponding position.

4. The compact tension specimen clamp for stress corrosion strength factor testing of claim 1, wherein: The upper pin hole and the lower pin hole are in position correspondence and have the same hole diameter.

5. The compact tension specimen clamp for stress corrosion strength factor testing of claim 1, wherein: The plurality of pins (3) are cylindrical pins, and when the pin (3) is inserted into the upper pin hole or the lower pin hole, the pin (3) is in interference fit with the upper pin hole or the lower pin hole.

6. The compact tension specimen clamp for stress corrosion strength factor testing of claim 1, wherein: The waterproof sealing ring (5) is fixedly arranged on the outer surface of the bottom of the corrosion container (4), and the inner side wall of the waterproof sealing ring (5) is tightly attached to the outer side wall of the lower clamp head (2).

7. The compact tension specimen clamp for stress corrosion strength factor testing of claim 6, wherein: The waterproof sealing ring (5) has at least two, and the outer surface and the inner surface of the bottom of the corrosion container (4) each has at least one waterproof sealing ring (5).

8. The compact tension specimen clamp for stress corrosion strength factor testing of claim 1, wherein: The corrosion container (4) is a box body, the top of the corrosion container (4) is provided with an upper clamp head connecting hole through which the upper clamp head (1) can pass, the side wall of the corrosion container (4) is provided with a specimen inlet and outlet, the top of the corrosion container (4) is provided with a corrosion liquid inlet, and the bottom of the corrosion container (4) is provided with a corrosion liquid discharge port.

9. The compact tension specimen clamp for stress corrosion strength factor testing of claim 1, wherein: The magnet of the upper clamp head (1) and the magnet of the lower clamp head (2) are both ferrite magnets.

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