Metal material fatigue testing device for corrosion environment

Abstract

The invention discloses a metal material fatigue testing device for a corrosion environment. The metal material fatigue testing device comprises an upper supporting cylinder, a lower supporting base, an upper fixing part, a lower fixing part, a circulating water pump, an overflow valve, a liquid box and a corrosion vessel, the bottom end of the lower fixing piece is connected with the lower supporting base, and the upper portion of the lower fixing piece penetrates through the lower end face of the corrosion vessel. The top end of the upper fixing piece is connected with the upper supporting cylinder through an internal thread cylindrical pin, and the lower part of the upper fixing piece penetrates through a sealing cover of the corrosion vessel; a lower short pin and an upper short pin are respectively arranged at the upper part of the lower fixing piece and the lower part of the upper fixing piece; the overflow valve, the circulating water pump and the liquid box are sequentially communicated through the sleeve; and the overflow valve and the liquid box are communicated with the corrosion vessel. The corrosion environment sealing stability durability is good, the corrosion solution injection and drainage alternation is simple, the electrochemical corrosion environment can be achieved, it can be guaranteed that the metal material is stably tested under the dual effects of electrochemical corrosion and mechanics, and the testing accuracy and safety are guaranteed.

Description

Technical Field

[0001] The invention relates to a fatigue testing device, in particular to a metal material fatigue testing device used in a corrosive environment. Background Art

[0002] In the current field of material testing, in order to test the fatigue performance of metals, the specimens are usually fixed by two holding mechanisms on the fatigue testing machine for reciprocating tension and compression tests. The fixing device of the fatigue testing machine is usually composed of components such as a base, a column, a holding mechanism, fasteners, etc., and is basically made of metal materials, such as carbon steel or aluminum alloy, and uses basic surface treatment technologies, such as galvanizing or painting, to provide a certain degree of corrosion protection. If you want to study the fatigue performance of metals in a corrosive environment, you need to create a stable and long-term corrosion environment while conducting fatigue tests. The current corrosion fatigue test is divided into two types. One is to corrode the test sample to a certain extent and then directly install it on the fatigue testing machine for testing. It cannot simulate the actual working conditions where corrosion and fatigue of metal materials occur simultaneously; the other is to directly spray the corrosive solution while fatigue testing, which has problems such as uneven corrosion, uncontrollable corrosion condition parameters, and easy corrosion of the test machine parts. Summary of the invention

[0003] In view of the problems existing in the above-mentioned prior art, the present invention provides a metal material fatigue testing device for use in a corrosive environment, which has stable and durable sealing in the corrosive environment, is easy to inject and discharge the corrosive solution, and has various functions.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: it includes an upper support tube and a lower support base, the top surface of the upper support tube is connected to the serial platform of the testing machine, and also includes an upper fixing member, a lower fixing member, a circulating water pump, an overflow valve, a liquid tank and a corrosion vessel, the corrosion vessel is a cylindrical structure with a sealing cover on the top, and an electrode hole is provided on the sealing cover; the bottom end of the lower fixing member is connected to the top surface of the lower support base, and the upper part of the lower fixing member passes through the lower end surface of the corrosion vessel; the top end of the upper fixing member is connected to the bottom surface of the upper support tube through an internal threaded cylindrical pin, and the lower part of the upper fixing member passes through the sealing cover of the corrosion vessel; the upper part of the lower fixing member and the lower part of the upper fixing member are respectively provided with a lower short pin and an upper short pin for connecting the two ends of the sample; the overflow valve, the circulating water pump and the liquid tank are connected in sequence through a sleeve, the overflow valve is connected to the bottom surface of the corrosion vessel, and the liquid tank is connected to the upper side of the corrosion vessel.

[0005] Furthermore, the lower fixing member and the lower end surface of the corrosion vessel, and the upper fixing member and the sealing cover of the corrosion vessel are all sealed and connected via sealing rings.

[0006] Furthermore, a sleeve is provided outside the portion of the lower fixing member below the corrosion vessel, and the upper and lower sections of the sleeve are respectively connected to the bottom surface of the corrosion vessel and the top surface of the lower support base.

[0007] Furthermore, the upper short pin is made of chrome-plated carbon steel, which ensures both corrosion resistance and good electrical conductivity.

[0008] Furthermore, the lower short pin is made of a glass fiber reinforced epoxy resin composite material, has certain tensile strength and corrosion resistance, and is suitable for electrochemical corrosion environments, and can avoid the influence caused by mutual conductivity between metal materials.

[0009] Furthermore, an anti-corrosion coating is sprayed on the surface of the upper support tube to avoid the adverse effects of corrosive gases produced by electrochemistry.

[0010] Furthermore, the upper fixing part and the lower fixing part are made of glass fiber reinforced epoxy resin composite material and the surface is frosted, so they have corrosion resistance and impact resistance, can remain unaffected in a corrosive environment for a long time, and are non-conductive and suitable for electrochemical corrosion scenarios.

[0011] Compared with the prior art, the present invention has good corrosion environment sealing stability and durability, simple injection and discharge rotation of corrosion solution, and electrochemical corrosion environment can be realized, which can ensure the stable testing of metal materials under the dual effects of electrochemical corrosion and mechanics, and ensure the accuracy and safety of the test; the present invention has a simple structure, convenient operation, convenient installation and simple disassembly, and can be used in conventional corrosion environments as well as electrochemical corrosion environments; the structural materials of each part of the present invention are all treated with anti-corrosion, which can simulate the corrosion fatigue test of different metal materials under the influence of different liquid media. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a cross-sectional view of the structure of the present invention; Figure 2 This is a schematic diagram of the external connection structure of the corrosion vessel of the present invention; Figure 3 It is a stereogram of the present invention; In the figure: 0, metal sample; 1, upper support tube; 2, internal thread cylindrical pin; 3, lower support base; 4, upper fixing piece; 5, corrosion vessel; 6, upper short pin; 7, lower fixing piece; 8, lower short pin; 9, sleeve; 10, casing; 11, circulating water pump; 12, testing machine series platform, 13, overflow valve; 14, liquid box; 15, sealing ring. DETAILED DESCRIPTION

[0013] The present invention will be further described below in conjunction with the accompanying drawings.

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] like Figures 1 to 3 As shown, the present invention provides a technical solution: including an upper support cylinder 1, a lower support base 3, an upper fixing member 4, a lower fixing member 7, a circulating water pump 11, an overflow valve 13, a liquid tank 14 and a corrosion vessel 5, wherein the corrosion vessel 5 is a cylinder structure with a sealing cover on the top, and an electrode hole is provided on the sealing cover.

[0016] The bottom end of the lower fixing member 7 is connected to the top surface of the lower supporting base 3, and the upper part of the lower fixing member 7 passes through the lower end surface of the corrosion vessel 5; the lower fixing member 7 and the lower end surface of the corrosion vessel 5 are sealed by a sealing ring 15 to ensure that the solution in the corrosion vessel 5 will not leak; a sleeve 9 is provided on the outside of the portion of the lower fixing member 7 below the corrosion vessel 5, and the upper and lower sections of the sleeve 9 are respectively connected to the bottom surface of the corrosion vessel 5 and the top surface of the lower supporting base 3, and the sleeve 9 is added to ensure the supporting strength of the corrosion vessel 5.

[0017] The top end of the upper fixing member 4 is connected to the bottom surface of the upper support tube 1 through the internal threaded cylindrical pin 2, the top surface of the upper support tube 1 is connected to the serial platform 12 of the testing machine, the lower part of the upper fixing member 4 passes through the sealing cover of the corrosion vessel 5, and the upper fixing member 4 and the sealing cover of the corrosion vessel 5 are sealed and connected through a sealing ring 15; the upper part of the lower fixing member 7 and the lower part of the upper fixing member 4 are respectively provided with a lower short pin 8 and an upper short pin 6 for connecting the two ends of the sample.

[0018] The overflow valve 13, the circulating water pump 11, and the liquid tank 14 are connected in sequence through the sleeve 10. The overflow valve 13 is connected to the bottom surface of the corrosion vessel 5, and the liquid tank 14 is connected to the upper side of the corrosion vessel 5. A drain port is arranged below the liquid tank 14 to facilitate the discharge and replacement of the liquid. The circulating water pump 11 adopts a micro DC water pump, which can adjust the internal pressure of the corrosion vessel 5 by changing the rotation speed of the circulating water pump 11 and the coordinated control of the overflow valve 13, and form a liquid circulation together with the corrosion vessel 5 and the liquid tank 14, so that the residual waste liquid and corrosion residue in the corrosion vessel 5 can be pumped out of the container. It has the functions of adjusting the liquid level, removing waste water and waste residue and circulating the solution to maintain the stability and cleanliness of the test environment. There is no need to disassemble the vessel in a time-consuming and laborious manner, making the operation more convenient and safe.

[0019] When the metal sample 0 is subjected to fatigue test in a corrosive environment, the two ends of the metal sample 0 are first fixed on the lower fixing part 7 and the upper fixing part 4 through the lower short pin 8 and the upper short pin 6, and then the corrosive solution is injected into the corrosion vessel 5 and the sealing cover is closed. Since the upper short pin 6 is made of chrome-plated carbon steel material, it has certain corrosion resistance and good electrical conductivity. Therefore, when the corrosive solution is poured, the liquid level can be located at the bottom of the upper fixing part 4, and the reference electrode of the electrochemical platform is fixed at the upper short pin 6, and the other electrodes are placed in the solution through the electrode holes on the sealing cover. In order to ensure the sealing, the motor hole is provided with a sealing device, and the other electrodes shall not contact the metal sample 0 to form a current closed loop. At this time, the metal sample 0 is completely immersed in the corrosive solution, and then the test machine series platform 12 provides tensile and compressive forces for the upper support cylinder 1, and finally the purpose of fatigue testing the metal sample 0 in a corrosive environment is achieved.

[0020] The lower short pin 8 is made of glass fiber reinforced epoxy resin composite material, which has certain tensile strength, corrosion resistance and non-conductive properties, and can be immersed in the solution. The lower fixing member 7 and the upper fixing member 4 are made of glass fiber reinforced epoxy resin composite material, which has corrosion resistance and impact resistance, and can be unaffected in a long-term corrosive environment. By cooperating with the lower short pin 8 and the upper short pin 6, the metal sample 0 can be firmly fixed. The lower fixing member 7 and the upper fixing member 4 can adapt well to a variety of corrosive environments, and have no conductivity, and can be well used for electrochemical corrosion tests.

[0021] In a chemical corrosion environment, when the metal sample 0 is fatigue-broken, the electrochemical platform should be closed first, the circulating water pump 11 should be turned on and the overflow valve 13 should be adjusted to collect and discharge the waste corrosion solution and waste impurities through the sleeve 10 to ensure water circulation during the experiment; then take out the reference electrode clamped at the upper short pin 6 and the other electrodes placed in the corrosion vessel 5, and then operate the testing machine series platform 12 to lift and take out the metal sample 0 that has been broken.

[0022] Since the present invention can coordinately control and adjust the internal pressure of the corrosion vessel 5 by changing the rotation speed of the circulating water pump 11 and the overflow valve 13, the present invention can not only perform corrosion fatigue performance tests on metal structural materials under conventional conditions, but also simulate corrosion fatigue performance tests on materials for pressure vessels and pressurized pipelines. The present invention is mainly suitable for fatigue performance tests on pressure vessels and ship pipeline basic materials.

[0023] The present invention has certain requirements on the size of the assembled sample. The GB / T 20120.0-2006 standard must be strictly followed, and the sample must be processed into a dumbbell-shaped round bar with a size range of 5-18 mm in diameter. After the processing is completed, the surface of the sample is polished. In addition, before the test, the oil stain on the sample must be removed first, then acetone is used to clean it in an ultrasonic cleaner for 10-15 minutes, and finally the surface of the sample is blown dry with a hair dryer.

[0024] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0025] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any slight modification, equivalent substitution and improvement made to the above embodiment based on the technical essence of the present invention should be included in the protection scope of the technical solution of the present invention.

Claims

1. A metal material fatigue testing device for use in a corrosive environment, comprising an upper support tube (1) and a lower support base (3), wherein the top surface of the upper support tube (1) is connected to a test machine series platform (12), and is characterized in that: It also includes an upper fixing member (4), a lower fixing member (7), a circulating water pump (11), an overflow valve (13), a liquid tank (14) and a corrosion vessel (5), wherein the corrosion vessel (5) is a cylindrical structure with a sealing cover on the top, and an electrode hole is provided on the sealing cover; The bottom end of the lower fixing member (7) is connected to the top surface of the lower supporting base (3), and the upper part of the lower fixing member (7) passes through the lower end surface of the corrosion vessel (5); The top end of the upper fixing member (4) is connected to the bottom surface of the upper supporting cylinder (1), and the lower portion of the upper fixing member (4) passes through the sealing cover of the corrosion vessel (5); The upper part of the lower fixing member (7) and the lower part of the upper fixing member (4) are respectively provided with a lower short pin (8) and an upper short pin (6) for connecting the two ends of the sample; The overflow valve (13), the circulating water pump (11), and the liquid tank (14) are connected in sequence through the sleeve (10); the overflow valve (13) is connected to the bottom surface of the corrosion vessel (5), and the liquid tank (14) is connected to the upper side of the corrosion vessel (5).

2. A metal material fatigue testing device for a corrosive environment according to claim 1, characterized in that: The lower fixing member (7) and the lower end surface of the corrosion vessel (5), and the upper fixing member (4) and the sealing cover of the corrosion vessel (5) are all sealed and connected via a sealing ring (15).

3. The metal material fatigue testing device for a corrosive environment according to claim 1, characterized in that: A sleeve (9) is provided outside the portion of the lower fixing member (7) located below the corrosion vessel (5), and the upper and lower sections of the sleeve (9) are respectively connected to the bottom surface of the corrosion vessel (5) and the top surface of the lower support base (3).

4. The metal material fatigue testing device for a corrosive environment according to claim 1, characterized in that: The upper short pin (6) is made of chrome-plated carbon steel.

5. The metal material fatigue testing device for a corrosive environment according to claim 1, characterized in that: The lower short pin (8) is made of a glass fiber reinforced epoxy resin composite material.

6. The metal material fatigue testing device for a corrosive environment according to claim 1, characterized in that: The surface of the upper support cylinder (1) is sprayed with an anti-corrosion coating.

7. The metal material fatigue testing device for a corrosive environment according to claim 1, characterized in that: The upper fixing member (4) and the lower fixing member (7) are made of glass fiber reinforced epoxy resin composite material and their surfaces are frosted.

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