Sealing method and sealing component for stress corrosion test of steel strand

Abstract

The invention provides a sealing method and a sealing component for a stress corrosion test of a steel strand, and relates to the field of stress corrosion tests. Comprising the following steps: 1) determining two sealing areas matched with a stress corrosion testing machine for sealing on a steel strand to be tested; 2) sealing a gap in the sealing area of the steel strand to be detected by using sealing glue; (3) filling a surface gap of the to-be-detected steel strand sealing area with an organic silicon sealant, and tightly wrapping the to-be-detected steel strand sealing area with the surface filled with the organic silicon sealant with a sealing tape to form a spindle structure in the length direction of the to-be-detected steel strand sealing area; 4) assembling the to-be-tested steel strand on a stress corrosion testing machine, connecting the to-be-tested steel strand with a sealing component in a penetrating manner, and matching the sealing component with a spindle structure in a sealing area of the to-be-tested steel strand to realize sealing; the problem that the steel strand is not tightly sealed in a stress corrosion test is effectively solved by designing the sealing component and combining with sealing treatment on the to-be-tested steel strand, and mechanical property research of the steel strand under the corrosion working condition is completed.

Description

Technical Field

[0001] The invention relates to the technical field of stress corrosion experiments, and in particular to a sealing method and a sealing component for a stress corrosion test of a steel strand. Background Art

[0002] Steel strand for prestressed concrete is an important load-bearing material widely used in national infrastructure. Its mechanical properties must meet national standards, especially the study of mechanical properties under corrosive conditions.

[0003] Stress corrosion test is used to measure the time taken for a specimen to break when immersed in a given constant temperature thiocyanate solution under a constant tensile force; for example, the time taken for a steel strand to break when immersed in a 50°C ammonium thiocyanate solution under a breaking tensile force of 80%. GB / T 5224-2023 "Steel Strand for Prestressed Concrete" clearly states that stress corrosion test can be carried out on steel strands after negotiation between the supply and demand parties; GB / T 21839-2019 "Test Methods for Steel for Prestressed Concrete" introduces stress corrosion test in thiocyanate solution. In stress corrosion test, corrosion test and stress test of steel strand are carried out at the same time. The corrosion test requires a sealed test kettle, and the stress test requires the steel strand to be stretched by external tension to deform the steel strand in the test kettle. The sealing effect of this kind of corrosion test under external tensile stress is a thorny issue, especially for steel strands, which are specimens that are made of multiple steel wires and do not have regular surfaces. Because the diameter of the central steel wire of the steel strand is slightly larger than that of the six side wires, the central wire and the side wires, as well as the adjacent side wires, are tightly connected, but there are still gaps. This gap and the irregularity of the surface will lead to the failure of the entire test seal.

[0004] In view of the common phenomenon of poor sealing in stress corrosion tests of steel strands, the existing technology mainly focuses on the sealing of the overall test machine. For example, patent application CN114563335A discloses a wire material testing device and a testing method. The wire material testing device disclosed in this embodiment is used for performance testing of wire materials under stress and corrosive media. A sealing plug is used for sealing, and the sealing problem of special samples such as steel strands is not involved. Another example is the sealed corrosion test structure for testing steel strands disclosed in patent CN220854439U, which uses an extruded seal to seal the parts involving the steel strands; the stress corrosion test device for horizontal steel wire or steel strand disclosed in patent CN220854440U uses a sealing sleeve to seal the parts involving the steel strands, and both cannot solve the problem of sealing leakage of special samples such as steel strands. Therefore, it is necessary to propose a structure or method that can effectively solve the problem of test failure caused by leakage due to poor sealing in stress corrosion tests of steel strands. Summary of the invention

[0005] The purpose of the present invention is to provide a sealing method and a sealing component for stress corrosion testing of steel strands. The sealing component and the sealing method proposed in the scheme can effectively solve the problem of test failure of steel strands due to leakage caused by poor sealing in stress corrosion testing, and have great value for promotion and use.

[0006] To achieve the above object, the present invention proposes the following technical solutions:

[0007] In a first aspect, a sealing method for a stress corrosion test of a steel strand is proposed, comprising the following steps:

[0008] 1) According to the structure of the stress corrosion testing machine, two sealing areas are determined on the steel strand to be tested, wherein the sealing area is a steel strand section on the steel strand to be tested that cooperates with the stress corrosion testing machine for sealing;

[0009] 2) Use sealing glue to apply the internal gap of the sealing area of ​​the steel strand to be tested multiple times to achieve sealing of the internal gap of the sealing area of ​​the steel strand to be tested;

[0010] 3) Use organic silicon sealant to fill the surface gaps of the sealed area of ​​the steel strand to be tested, use a sealing tape to tightly wrap the sealed area of ​​the steel strand to be tested with the organic silicon sealant on the surface, and form a spindle structure along the length direction of the sealed area of ​​the steel strand to be tested;

[0011] 4) After assembling the steel strand to be tested on the stress corrosion testing machine, a sealing component is connected through it, and the sealing component realizes sealing in the sealing area of ​​the steel strand to be tested;

[0012] The sealing component is configured as a cylindrical structure, and a thread is circumferentially arranged on one side of the outer wall of the cylindrical structure, and the thread is adapted to the thread on the inner side of the elastic sealing tube of the stress corrosion testing machine; two sections of connected stepped holes are arranged through the inside of the cylindrical structure, and the two sections of connected stepped holes are respectively a truncated cone hole and a cylindrical hole, and the cylindrical hole is connected to the small aperture end of the truncated cone hole and is coplanar; one end of the sealing component is sealed and connected to the elastic sealing tube, the steel strand to be tested passes through the stepped hole of the sealing component, and the spindle structure of the sealing area of ​​the steel strand to be tested is interference fit with the cylindrical hole to achieve sealing.

[0013] Furthermore, the process of determining the sealing area on the steel strand to be tested in step 1) is as follows:

[0014] Determine the maximum distance L on both sides of the stress corrosion testing machine after the sealing components are symmetrically installed, and mark two starting points of the sealing area on the steel strand to be tested according to the end point position of the maximum distance;

[0015] A preset distance D is extended toward each other from the starting points of the two sealing areas along the length direction of the steel strand to be tested to determine the end points of the two sealing areas; wherein L>2D.

[0016] Furthermore, the viscosity of the sealing glue used in step 2) is 100-200 cps.

[0017] Furthermore, the organic silicone sealant used in step 3) is 704N organic silicone sealant.

[0018] Furthermore, the process of step 2) using sealing glue to repeatedly apply the internal gaps of the sealed area of ​​the steel strand to be tested is: infiltrate and apply the sealing glue between each gap in the sealed area of ​​the steel strand to be tested, let it stand for 5-10 minutes, then apply it again, and repeat 3-5 times.

[0019] Furthermore, the threads of the outer wall of the sealing member are arranged flush with the outer wall of the truncated cone hole;

[0020] The ratio of the length of the partial cylindrical structure corresponding to the truncated cone hole of the sealing component to the length of the partial cylindrical structure corresponding to the cylindrical hole is 8-10:1.

[0021] Furthermore, the diameter of the steel strand to be tested is defined as R, and the diameter of the cylindrical hole is defined as R1, and the diameter R1 is 1-1.5 mm larger than the diameter R.

[0022] Further, in step 3), the maximum diameter of the middle part of the spindle structure formed in the sealing area of ​​the steel strand to be tested is defined as R3, and the diameter R3 is 1-2 mm larger than the diameter R1.

[0023] Furthermore, the preset distance D has a value of 25-35 mm.

[0024] In a second aspect, a sealing component is provided, wherein the sealing component is connected to an elastic sealing tube of a stress corrosion testing machine, is used for stress corrosion testing of steel strands, and is sealed and connected to the steel strands to be tested;

[0025] The sealing component is set as a cylindrical structure, and a thread is circumferentially arranged on one side of the outer wall of the cylindrical structure, and the thread is adapted to the thread on the inner side of the elastic sealing tube of the stress corrosion testing machine; two sections of connected stepped holes are arranged through the inside of the cylindrical structure, and the two sections of connected stepped holes are respectively a truncated cone hole and a cylindrical hole, and the cylindrical hole is connected to the small-diameter end of the truncated cone hole and is coplanar.

[0026] It can be seen from the above technical solutions that the technical solutions of the present invention have the following beneficial effects:

[0027] The present invention discloses a sealing method and sealing component for stress corrosion testing of steel strands, which comprises: 1) determining two sealing areas on the steel strand to be tested that cooperate with the stress corrosion testing machine for sealing; 2) using sealing glue to seal the internal gaps of the sealing areas of the steel strand to be tested; 3) using organic silicon sealant to fill the surface gaps of the sealing areas of the steel strand to be tested, and using a sealing tape to tightly wrap the sealing areas of the steel strand to be tested filled with organic silicon sealant to form a spindle structure along its length direction; 4) after assembling the steel strand to be tested on the stress corrosion testing machine, the sealing component is connected through it, and the sealing component cooperates with the spindle structure to achieve sealing in the sealing areas of the steel strand to be tested; wherein, the sealing The sealing component is arranged as a cylindrical structure, and a thread which is adapted to the inner thread of the elastic sealing tube of the stress corrosion testing machine is arranged circumferentially on one side of the outer wall thereof, and two sections of connected stepped holes are arranged through the inside thereof, and the two sections of connected stepped holes are respectively a truncated cone hole and a cylindrical hole, and the cylindrical hole is connected to the small aperture end of the truncated cone hole and are coplanar; the present invention utilizes one end of the sealing component to be sealedly connected with the elastic sealing tube, the steel strand to be tested passes through the stepped hole of the sealing component, and the spindle structure of the sealing area of ​​the steel strand to be tested is interference fit with the cylindrical hole to achieve sealing, thereby effectively solving the problem of poor sealing of the steel strand in the stress corrosion test, and completing the study of the mechanical properties of the steel strand under corrosion conditions.

[0028] In addition, the sealing component of the present invention is obtained by improving the sealing plug structure on the basis of a general stress corrosion tester. It is not only simple in structure, but also does not require modification of other components of the stress corrosion tester, is low in cost, and does not affect the normal use of the original equipment. At the same time, the sealing method of the present invention solves the leakage problem of samples with irregular surface, loose structure and internal gaps in the stress corrosion test of steel strands, has good sealing effect, takes less time, and is convenient for assembly and disassembly.

[0029] It should be appreciated that all combinations of the foregoing concepts, as well as additional concepts described in greater detail below, may be considered to be part of the inventive subject matter of the present disclosure, provided such concepts are not mutually inconsistent.

[0030] The foregoing and other aspects, embodiments and features of the present invention can be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the present invention, such as the features and / or beneficial effects of the exemplary embodiments, will be apparent from the following description or learned from the practice of the specific embodiments according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are not intended to be drawn to scale. In the accompanying drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings, in which:

[0032] Figure 1 The schematic diagram of the installation of the steel strand for testing in the stress corrosion testing machine of the prior art;

[0033] Figure 2 The figure is a cross-sectional view of a sealing component used in a stress corrosion testing machine;

[0034] Figure 3 Schematic diagram of the installation of steel strands and sealing components for testing in a stress corrosion testing machine.

[0035] In the figure, the specific meaning of each mark is as follows:

[0036] 1-horizontal tensile testing machine, 2-environmental chamber, 3-liquid filling port, 4-liquid discharge port, 5-elastic sealing tube, 6-sealing plug, 7-steel strand to be tested, 8-sealing component. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment 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. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meaning understood by people with general skills in the field to which the present invention belongs.

[0038] The words "first", "second" and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "a", "an" or "the" and other similar words do not indicate a quantitative limitation, but indicate the existence of at least one. Words such as "include" or "comprise" mean that the elements or objects appearing before "include" or "comprise" cover the features, wholes, steps, operations, elements and / or components listed after "include" or "comprise", and do not exclude the existence or addition of one or more other features, wholes, steps, operations, elements, components and / or their collections. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0039] The structural design of the sealing end of the stress corrosion testing machine is only applicable to a single specimen with a regular surface and a standard specimen with a dense interior, and can achieve a good sealing effect, such as round steel wire; therefore, when used to measure the mechanical properties of steel strands, that is, the tested samples with irregular surfaces and loose structures under corrosion conditions, leakage occurs from the gaps in the steel strands due to poor sealing; therefore, the present invention aims to solve the problem that steel strands cannot be sealed in stress corrosion tests, and proposes a sealing method and a sealing component for stress corrosion tests of steel strands. The sealing treatment of the steel strands and the sealing component with a special structure can fully solve the leakage problem caused by poor sealing when the stress corrosion testing machine is working.

[0040] like Figure 1 As shown, the stress corrosion testing machine is supported by a horizontal tensile testing machine 1, and the horizontal tensile testing machine 1 is used to provide tension for the stress corrosion test of the steel strand; the stress corrosion testing machine includes an environmental box 2 for providing stress corrosion test, the environmental box 2 is a closed structure, and contains ammonium thiocyanate solution, and is provided with a liquid injection port 3 on the top and a liquid discharge port 4 on the bottom; the left and right ends of the environmental box 2 are respectively sealed and connected to a corrugated elastic sealing tube 5, and the end of the elastic sealing tube 5 away from the environmental box 2 is connected to a sealing plug 6; when working, the steel strand 7 to be tested passes through the interior of the environmental box 2, and the ammonium thiocyanate solution inside it immerses the steel strand 7 to be tested, and the left and right ends of the steel strand 7 to be tested pass through the environmental box 2 and the interior of the sealing plug 6 respectively, and then are stretched by the tensile testing machine 1 to start the test.

[0041] In order to improve the problem that the contact position between the existing sealing plug 6 and the steel strand cannot be sealed, resulting in leakage of the ammonium thiocyanate solution, the present invention improves the mechanical properties of the steel strand under corrosion conditions from two perspectives: the sealing structure and the sealing method.

[0042] Structurally, the present invention replaces the sealing plug 6 with a sealing member 8, which is connected to the elastic sealing tube 5 of the stress corrosion testing machine and is used for stress corrosion testing of steel strands and is sealed and connected to the steel strand 7 to be tested; Figure 2As shown, the sealing member 8 is configured as a cylindrical structure, and a thread is circumferentially arranged on one side of the outer wall of the cylindrical structure, and the thread is adapted to the thread on the inner side of the elastic sealing tube 5 of the stress corrosion testing machine; two sections of connected stepped holes are arranged through the inside of the cylindrical structure, and the two sections of connected stepped holes are respectively a truncated cone hole and a cylindrical hole, and the cylindrical hole is connected to the small-diameter end of the truncated cone hole and is coplanar. The threads of the outer wall of the sealing component 8 are flush with the outer wall of the truncated cone hole, and the ratio of the length of the partial cylindrical structure corresponding to the truncated cone hole of the sealing component 8 to the length of the partial cylindrical structure corresponding to the cylindrical hole is 8-10:1; in the embodiment, the diameter of the steel strand 7 to be tested is defined as R, the diameter of the cylindrical hole is R1, and the diameter of the large aperture end is R2, then the diameter R1 is 1-1.5mm larger than the diameter R, and the diameter R2 of the large aperture end of the truncated cone hole can be moderate; for example, the diameter R of the steel strand is 15mm, the diameter R1 is made into 16.5mm, the length of the partial cylindrical structure corresponding to the truncated cone hole is 80mm, and the length of the partial cylindrical structure corresponding to the cylindrical hole is 10mm.

[0043] In terms of sealing method, the sealing method for stress corrosion test of steel strand proposed by the present invention comprises the following steps:

[0044] 1) According to the structure of the stress corrosion testing machine, two sealing areas are determined on the steel strand 7 to be tested, wherein the sealing areas are steel strand segments on the steel strand 7 to be tested that cooperate with the stress corrosion testing machine for sealing;

[0045] Specifically, determine the maximum distance L (L includes the length of the sealing component) on both sides of the stress corrosion testing machine after the sealing component 8 is symmetrically installed, and mark the starting points of two sealing areas on the steel strand 7 to be tested according to the end point position of the maximum distance, that is, mark the two ends of the middle length L of the steel strand 7 to be tested, and the left and right marks are the starting points of the two sealing areas respectively; then, extend the preset distance D from the starting points of the two sealing areas in the length direction of the steel strand to be tested respectively, to determine the end points of the two sealing areas; wherein, L>2D; in the embodiment, the area 30mm from the starting point of the sealing area to the center direction is the sealing area of ​​the steel strand 7 to be tested.

[0046] 2) Use sealing glue to apply the internal gap of the sealing area of ​​the steel strand to be tested multiple times to achieve sealing of the internal gap of the sealing area of ​​the steel strand to be tested;

[0047] In the embodiment, a sealing glue with a viscosity of 100-200cps is selected and applied between each gap of the two sealing areas on the left and right sides of the steel strand 7 to be tested, so that the sealing glue penetrates into the internal gap, and then applied again after standing for 5-10 minutes, and repeated 3 times before use; in the scheme, standing for 5 minutes is selected; in the embodiment, a sealing glue with a viscosity of 100-200cps is selected because the sealing glue with a viscosity lower than 100cps has strong fluidity and is not easy to accumulate, while the sealing glue with a viscosity higher than 200cps has weak fluidity and is not easy to penetrate.

[0048] 3) using organic silicon sealant to fill the surface gaps in the sealed area of ​​the steel strand 7 to be tested, using a sealing tape, such as a raw tape, to tightly wrap the sealed area of ​​the steel strand 7 to be tested with the organic silicon sealant filled on the surface, and forming a spindle structure along the length direction of the sealed area of ​​the steel strand 7 to be tested;

[0049] In the embodiment, 704N organic silicone sealant is used to fill the surface gaps of the left and right sealing areas of the steel strand 7 to be tested, and the sealant is tightly wrapped with raw tape to form a spindle structure; in order to ensure sufficient sealing, the maximum diameter of the middle part of the spindle structure is defined as R3, and the diameter R3 is 1-2mm larger than the diameter R1 of the cylindrical hole inside the sealing member 8, and 1.5mm is selected in the embodiment. In the specific implementation, the winding amount of the raw tape can be repeatedly adjusted according to the tightness of the assembly.

[0050] 4) After the steel strand 7 to be tested is assembled on the stress corrosion testing machine, a sealing member 8 is connected through it, and the sealing member 8 realizes sealing in the sealing area of ​​the steel strand 7 to be tested; that is, according to Figure 3 As shown, the sealed steel strand 7 to be tested is first passed through the environmental chamber 2, and then the sealing components 8 are respectively inserted from the left and right sides and compacted in the sealing area, and then the sealing component 8 is connected to the threaded seal of the elastic sealing tube 5; finally, the external tension is loaded to carry out the stress corrosion test according to the requirements of GB / T 21839-2019.

[0051] The sealing method and sealing component for stress corrosion test of steel strands disclosed in the present invention are based on a general stress corrosion testing machine, and improve the existing sealing plug 6 into a replaceable sealing component 8. The steel strand to be tested that is sealed with sealant is fully sealed at the contact position between the sealing component 8 and the steel strand to be tested 7 through an interference fit. The two-stage stepped hole structure of the sealing component 8 and the spindle structure of the sealing area of ​​the steel strand to be tested are used to ensure that the steel strand to be tested can still remain sealed under the tension provided by the tensile testing machine 1 without leakage. That is, the sealing method of the present application not only does not affect the normal use of the original equipment, but also solves the leakage problem of steel strand samples with irregular surfaces, loose structures, and internal gaps, and has good sealing effect and convenient assembly and disassembly.

[0052] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A sealing method for stress corrosion test of steel strand, characterized in that: The steps include: 1) According to the structure of the stress corrosion testing machine, two sealing areas are determined on the steel strand to be tested, wherein the sealing area is a steel strand section on the steel strand to be tested that cooperates with the stress corrosion testing machine for sealing; 2) Use sealing glue to apply the internal gap of the sealing area of ​​the steel strand to be tested multiple times to achieve sealing of the internal gap of the sealing area of ​​the steel strand to be tested; 3) Use organic silicon sealant to fill the surface gaps of the sealed area of ​​the steel strand to be tested, use a sealing tape to tightly wrap the sealed area of ​​the steel strand to be tested with the organic silicon sealant on the surface, and form a spindle structure along the length direction of the sealed area of ​​the steel strand to be tested; 4) After assembling the steel strand to be tested on the stress corrosion testing machine, a sealing component is connected through it, and the sealing component realizes sealing in the sealing area of ​​the steel strand to be tested; The sealing component is configured as a cylindrical structure, and a thread is circumferentially arranged on one side of the outer wall of the cylindrical structure, and the thread is adapted to the thread on the inner side of the elastic sealing tube of the stress corrosion testing machine; two sections of connected stepped holes are arranged through the inside of the cylindrical structure, and the two sections of connected stepped holes are respectively a truncated cone hole and a cylindrical hole, and the cylindrical hole is connected to the small aperture end of the truncated cone hole and is coplanar; one end of the sealing component is sealed and connected to the elastic sealing tube, the steel strand to be tested passes through the stepped hole of the sealing component, and the spindle structure of the sealing area of ​​the steel strand to be tested is interference fit with the cylindrical hole to achieve sealing.

2. The sealing method for stress corrosion test of steel strand according to claim 1, characterized in that: The process of determining the sealing area on the steel strand to be tested in step 1) is as follows: Determine the maximum distance L on both sides of the stress corrosion testing machine after the sealing components are symmetrically installed, and mark two starting points of the sealing area on the steel strand to be tested according to the end point position of the maximum distance; A preset distance D is extended toward each other from the starting points of the two sealing areas along the length direction of the steel strand to be tested to determine the end points of the two sealing areas; wherein L>2D.

3. The sealing method for stress corrosion test of steel strand according to claim 1, characterized in that: The viscosity of the sealing glue used in step 2) is 100-200 cps.

4. The sealing method for stress corrosion test of steel strand according to claim 1, characterized in that: The organic silicon sealant used in step 3) is 704N organic silicon sealant.

5. The sealing method for stress corrosion test of steel strand according to claim 1, characterized in that: The process of step 2) using sealing glue to repeatedly apply the internal gap of the sealed area of ​​the steel strand to be tested is: Apply sealant between each gap in the sealing area of ​​the steel strand to be tested, let it stand for 5-10 minutes, then apply it again, and repeat 3-5 times.

6. The sealing method for stress corrosion test of steel strand according to claim 1, characterized in that: The threads of the outer wall of the sealing member are flush with the outer wall of the truncated cone hole; The ratio of the length of the partial cylindrical structure corresponding to the truncated cone hole of the sealing component to the length of the partial cylindrical structure corresponding to the cylindrical hole is 8-10:

1.

7. The sealing method for stress corrosion test of steel strand according to claim 1, characterized in that: Define the diameter of the steel strand to be tested as R and the diameter of the cylindrical hole as R1, then the diameter R1 is 1-1.5mm larger than the diameter R.

8. The sealing method for stress corrosion test of steel strand according to claim 7, characterized in that: Definition step 3) The maximum diameter of the middle part of the spindle structure formed in the sealing area of ​​the steel strand to be tested is R3, and the diameter R3 is 1-2 mm larger than the diameter R1.

9. The sealing method for stress corrosion test of steel strand according to claim 2, characterized in that: The preset distance D is set to a value of 25-35 mm.

10. A sealing member, characterized in that: The sealing component is connected to the elastic sealing tube of the stress corrosion testing machine, is used for stress corrosion testing of steel strands, and is sealed and connected to the steel strands to be tested; The sealing component is set as a cylindrical structure, and a thread is circumferentially arranged on one side of the outer wall of the cylindrical structure, and the thread is adapted to the thread on the inner side of the elastic sealing tube of the stress corrosion testing machine; two sections of connected stepped holes are arranged through the inside of the cylindrical structure, and the two sections of connected stepped holes are respectively a truncated cone hole and a cylindrical hole, and the cylindrical hole is connected to the small-diameter end of the truncated cone hole and is coplanar.

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