Multi-axis creep-fatigue test system for connecting pipe test piece

Abstract

The invention provides a multi-axis creep-fatigue test system for a connecting pipe test piece, which comprises a clamp assembly and a positioning adjustment mechanism, and is characterized in that the clamp assembly comprises a first clamp and a second clamp, and two opposite ends of a to-be-tested test piece are clamped between the first clamp and the second clamp; the positioning adjusting mechanism comprises a connecting mechanism and a supporting mechanism, one end of the connecting mechanism is connected with a connecting pipe on the to-be-tested test piece, the other end of the connecting mechanism is connected with an equivalent balance block, and one end of the supporting mechanism movably acts on the connecting mechanism so that the connecting mechanism can always apply loads in the direction perpendicular to the axial direction of the to-be-tested test piece. According to the multi-axis creep-fatigue test system for the connecting pipe test piece, the positioning adjusting mechanism is arranged on one side of the clamp assembly, so that an additionally introduced connecting pipe load is a passive load, a driving motor does not need to be additionally arranged, the economical efficiency is better, the structure is simpler, and the multi-axis stress characteristics of the connecting pipe position are fully and accurately reflected; the method can be directly used as a reference for the creep fatigue analysis and evaluation method of the container connecting pipe area.

Description

Technical Field

[0001] The invention relates to the technical field of creep fatigue testing, and in particular to a multi-axial creep-fatigue testing system for a nozzle test piece. Background Art

[0002] Under cyclic loads and high temperature environments, structures have creep-fatigue failure problems. To solve the above problems, a large number of studies have been conducted on creep-fatigue tests based on uniaxial fatigue specimens, and creep-fatigue failure curves for different materials have been obtained. However, real structures are often under complex multiaxial stress state loading conditions, so multiaxial creep-fatigue tests are needed to compensate for the differences in structural creep-fatigue failure under multiaxial effects.

[0003] According to engineering experience, the local area of ​​the container shell and top cover including the nozzle is a high-incidence area of ​​creep-fatigue failure. In the nozzle area, the shell side structure needs to bear the cyclic load generated by the periodic changes of internal pressure and temperature, and the nozzle side needs to bear the nozzle load.

[0004] Compared with fatigue testing machines, traditional creep-fatigue testing machines have added insulation boxes, electric heating and temperature control systems. They are similar in mechanical force application systems, so their design features and shortcomings can be explained with reference to multi-axis fatigue testing machines.

[0005] At present, multi-axial fatigue testing machines can be divided into two categories: the first category is based on the application of internal and external pressure loads on the tubular test piece; the second category is to create a new load application direction by setting up an additional force application system to achieve multi-axial load application. However, the force application method of the test device in the second category is inconsistent with the multi-axial stress state, which is not suitable for the pipe test piece, and the measurement results cannot accurately reflect the multi-axial stress characteristics at the pipe position.

[0006] Based on this, the inventor of the present application proposes a multi-axial creep-fatigue test system for a pipe test piece in order to solve the above technical problems. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the defect that the multi-axial test device in the prior art is not suitable for a pipe test piece, and to provide a multi-axial creep-fatigue test system for a pipe test piece.

[0008] The present invention solves the above technical problems through the following technical solutions:

[0009] The present invention provides a multi-axial creep-fatigue test system for a nozzle test piece, which is characterized by comprising:

[0010] A fixture assembly, comprising a first fixture and a second fixture, wherein the first fixture and the second fixture are used to clamp two opposite ends of the test piece to be tested;

[0011] The positioning and adjustment mechanism includes a connecting mechanism and a supporting mechanism. One end of the connecting mechanism is connected to the connecting pipe on the test piece to be tested, and the other end is connected to an equivalent balancing block. One end of the supporting mechanism movably acts on the connecting mechanism so that the connecting mechanism always applies a load in a direction perpendicular to the axial direction of the test piece to be tested.

[0012] According to one embodiment of the present invention, the first clamp is located above the second clamp;

[0013] The clamp assembly also includes an insulation box, in which the clamping ends of the first clamp and the second clamp are located.

[0014] According to one embodiment of the present invention, the connection mechanism is a steel wire rope, one end of which is connected to the connecting pipe in the middle of the test piece to be tested, and the other end of which is connected to the balance block;

[0015] A fixed pulley is disposed at one end of the support mechanism, and the fixed pulley supports the steel wire rope so that the balance block applies a load to the connecting pipe in the middle of the test piece through the steel wire rope.

[0016] According to one embodiment of the present invention, a waist-shaped hole is provided on the heat preservation box, and one end of the steel wire rope is passed through the waist-shaped hole to the heat preservation box and connected to the pipe in the middle of the test piece to be tested;

[0017] The waist-shaped hole is filled with a dynamic sealing ring.

[0018] According to an embodiment of the present invention, the support mechanism includes a connecting rod, a vertical rod and an inclined rod, one end of the connecting rod is connected to the second clamp, and the other end is connected to the vertical rod, one end of the inclined rod is rotatably connected to the vertical rod, and the other end is provided with the fixed pulley; wherein,

[0019] The connecting rod is vertically arranged with the vertical rod, and the vertical rod is arranged at an angle with the oblique rod.

[0020] According to an embodiment of the present invention, a base is provided at the lower end of the second clamp, and one end of the vertical rod is elastically connected to the base.

[0021] According to an embodiment of the present invention, a receiving groove is provided on the base, an elastic member is provided in the receiving groove, and one end of the vertical rod extends into the receiving groove and abuts against the elastic member.

[0022] According to an embodiment of the present invention, a displacement sensor is further provided on the base, and the displacement sensor is used to detect the displacement of the second clamp along the axial direction.

[0023] According to one embodiment of the present invention, the fixed pulley divides the steel wire rope into a horizontal portion and a vertical portion;

[0024] One end of the horizontal portion is connected to a connecting pipe in the middle of the test piece to be tested, and the vertical portion is arranged perpendicular to the horizontal portion.

[0025] According to one embodiment of the present invention, a first protrusion is provided at one end of the first clamp facing the second clamp, and a second protrusion is provided at one end of the second clamp facing the first clamp;

[0026] The first protrusion and the second protrusion are threadedly matched with opposite ends of the test piece to be tested or fixedly connected by means of a latch.

[0027] The positive and progressive effects of the present invention are:

[0028] The multi-axis creep-fatigue test system of the pipe test piece of the present invention is provided with a positioning adjustment mechanism on one side of the fixture assembly, so that the additional pipe load introduced is a passive load, and there is no need to add a driving motor, which has better economy and simpler structure.

[0029] Moreover, during the test, the supporting mechanism can ensure that the load applied by the balancing block to the nozzle of the test piece is always in a horizontal state, which fully and accurately reflects the multi-axial stress characteristics of the nozzle position and can be directly used as a reference for the creep fatigue analysis and assessment method of the nozzle area of ​​the container. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0031] Figure 1 It is a structural schematic diagram of a multi-axial creep-fatigue test system for a nozzle test piece of the present invention;

[0032] Figure 2 It is a structural schematic diagram of a test piece to be tested according to the present invention;

[0033] Figure 3 It is a partial structural schematic diagram of the clamp assembly of the present invention;

[0034] Figure 4 It is a structural schematic diagram of the positioning adjustment mechanism of the present invention.

[0035] 1. Clamp assembly; 11. First clamp; 111. First protrusion; 12. Second clamp; 121. Second protrusion; 13. Insulation box; 131. Waist-shaped hole; 132. Dynamic sealing ring;

[0036] 2. Components to be tested; 21. Take over;

[0037] 3. Positioning adjustment mechanism; 31. Connecting mechanism; 311. Horizontal part; 312. Vertical part; 32. Support mechanism; 321. Fixed pulley; 322. Connecting rod; 323. Vertical rod; 324. Diagonal rod; 33. Equivalent balancing block; 4. Base; 41. Accommodating groove; 42. Elastic member; 43. Displacement sensor. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with specific embodiments and drawings. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description herein. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0040] Please refer to Figures 1 to 4 The present invention proposes a multi-axial creep-fatigue test system for a pipe test piece, including a fixture assembly 1 and a positioning adjustment mechanism 3. The fixture assembly 1 includes a first fixture 11 and a second fixture 12. The first fixture 11 and the second fixture 12 are used to clamp the opposite ends of the test piece 2 to be tested.

[0041] The fixture assembly 1 is integrated on a uniaxial creep-fatigue testing machine. The first fixture 11 and the second fixture 12 are used to clamp the test piece 2 to be tested. The test piece 2 to be tested in this application adopts a flat plate-tube test piece. The flat plate-tube test piece can be integrally cast, machined, or connected by welding with a seamless steel pipe after a hole is opened in a rolled flat plate. This is not limited here. The structural form is composed of a tube set on the flat plate, and can also be in the form of a round tube and a tube, which is not limited here. Among them, the length direction of the flat plate is set perpendicular to the axial direction of the tube.

[0042] Specifically, according to relevant specifications, the design should avoid setting the connecting weld at the discontinuity of the structure. Therefore, it is recommended to reserve an area when opening a hole in the plate, bend it into a nozzle transition area, and weld it to the connecting pipe 21 outside the transition area.

[0043] The stress of the flat plate-tube test piece during the manufacturing process can be eliminated by overall heat treatment after processing.

[0044] The two ends of the plate can be connected to the first clamp 11 and the second clamp 12 by means of threaded fastening or by opening holes to set pins, and the specific form is not limited here.

[0045] The positioning adjustment mechanism 3 includes a connecting mechanism 31 and a supporting mechanism 32. One end of the connecting mechanism 31 is connected to the connecting pipe 21 on the test piece 2 to be tested, and the other end is connected to an equivalent balancing block 33. One end of the supporting mechanism 32 movably acts on the connecting mechanism 31 so that the connecting mechanism 31 always applies a load in a direction perpendicular to the axial direction of the test piece 2 to be tested.

[0046] The connection mechanism 31 can act on the connecting pipe 21 on the test piece 2 as a passive load through the equivalent balancing block 33 without adding a driving motor, which makes the test system structure simpler and saves test costs.

[0047] Moreover, one end of the support mechanism 32 movably acts on the connection mechanism 31, so that the load of the connection mechanism 31 acting on the pipe 21 is always perpendicular to the axial direction of the test piece 2 to be tested, and also perpendicular to the tensile load on the axial direction of the test piece 2 to be tested. In this way, the multi-axial stress characteristics of the pipe 21 position are fully and accurately reflected, and the test results are more accurate, which can be directly used as a reference for the creep-fatigue analysis and evaluation method of the pipe 21 area of ​​the container.

[0048] Please continue to refer to Figure 1 and Figure 3 , the first clamp 11 is located above the second clamp 12; the clamp assembly 1 also includes an insulation box 13, and the clamping ends of the first clamp 11 and the second clamp 12 are located in the insulation box 13.

[0049] Specifically, a first protrusion 111 is provided at one end of the first clamp 11 facing the second clamp 12, and a second protrusion 121 is provided at one end of the second clamp 12 facing the first clamp 11; the first protrusion 111 and the second protrusion 121 are threadedly matched with the opposite ends of the test piece 2 to be tested or fixedly connected by a pin.

[0050] That is, the first protrusion 111 and the second protrusion 121 are located in the heat preservation box 13. Through holes are respectively provided on the top plate and the floor of the heat preservation box 13, and one end of the first protrusion 111 of the first fixture 11 and one end of the second protrusion 121 of the second fixture 12 extend into the heat preservation box 13 through the through holes.

[0051] Furthermore, the connecting mechanism 31 is a steel wire rope, one end of which is connected to the connecting pipe 21 in the middle of the test piece 2 to be tested, and the other end is connected to the balancing block; a fixed pulley 321 is provided at one end of the supporting mechanism 32, and the fixed pulley 321 supports the steel wire rope so that the balancing block applies a load to the connecting pipe 21 in the middle of the test piece 2 to be tested via the steel wire rope.

[0052] The height of the fixed pulley 321 corresponds to the height of the connecting pipe 21 of the test piece 2 to be tested, so that the load of the steel wire rope acting on the connecting pipe 21 of the test piece 2 to be tested is a horizontal load.

[0053] Optionally, a waist-shaped hole 131 is opened on the insulation box 13, and one end of the steel wire rope is passed through the waist-shaped hole 131 to the insulation box 13 and connected to the connecting pipe 21 in the middle of the test piece 2 to be tested; the waist-shaped hole 131 is filled with a dynamic sealing ring 132.

[0054] Steel wire rope is selected as the medium for applying load because the steel wire rope is small in size, and thus the size of the waist-shaped hole 131 opened on the insulation box 13 can also be as small as possible, thus avoiding the insulation box 13 opening a hole and reducing its insulation effect.

[0055] The length extension direction of the waist-shaped hole 131 is consistent with the axial direction of the first clamp 11, and the width dimension corresponds to the diameter of the steel wire rope.

[0056] Specifically, the waist-shaped hole 131 is filled with a dynamic sealing ring 132, so that when the test piece 2 is pulled by the second clamp 12, the steel wire rope will move downward along the waist-shaped hole 131, and the dynamic sealing ring 132 can ensure that the thermal insulation performance of the thermal insulation box 13 does not change during the movement of the steel wire rope.

[0057] Specifically, the material of the dynamic sealing ring 132 can be asbestos or thermal insulation wool, which is not limited here. The dynamic sealing ring 132 is formed by filling asbestos or thermal insulation wool into the waist-shaped hole 131. During the up and down movement of the wire rope, the wire rope moves along the asbestos or thermal insulation wool. Due to the elastic expansion of the asbestos or thermal insulation wool itself, there will not be too large a gap during the movement process, thereby achieving dynamic sealing and reducing the leakage rate of hot air in the thermal insulation box 13.

[0058] Please refer to Figure 4 The supporting mechanism 32 includes a connecting rod 322, a vertical rod 323 and an oblique rod 324. One end of the connecting rod 322 is connected to the second clamp 12, and the other end is connected to the vertical rod 323. One end of the oblique rod 324 is rotatably connected to the vertical rod 323, and the other end is provided with a fixed pulley 321; wherein the connecting rod 322 and the vertical rod 323 are vertically arranged, and the vertical rod 323 and the oblique rod 324 are arranged at an angle.

[0059] Specifically, one end of the connecting rod 322 is fixed to the second clamp 12 by sleeve sleeve, and the other end is fixed to the vertical rod 323 by sleeve sleeve.

[0060] One end of the vertical rod 323 is connected to the diagonal rod 324 through a three-way fastener. When the three-way fastener is not fastened, the angle between the diagonal rod 324 and the vertical rod 323 is adjustable. For example, in the initial state, the angle between the diagonal rod 324 and the vertical rod 323 can be adjusted so that the end of the wire rope connected to the pipe 21 of the test piece 2 to be tested remains horizontal.

[0061] After the adjustment is completed, the three-way fastener can be locked by a locking member to prevent relative rotation between the vertical rod 323 and the diagonal rod 324. The form of the three-way fastener is not limited here, for example, an arc groove is set inside the fastener, and one end of the diagonal rod 324 is rotatably connected to the arc groove.

[0062] Please continue to refer to Figure 1 and Figure 4 A base 4 is provided at the lower end of the second clamp 12 , and one end of the vertical rod 323 is elastically connected to the base 4 .

[0063] Specifically, a receiving groove 41 is formed on the base 4 , and an elastic member 42 is provided in the receiving groove 41 of the base 4 . One end of the vertical rod 323 extends into the receiving groove 41 and abuts against the elastic member 42 .

[0064] One end of the elastic member 42 is in contact with the ground, so that the elastic member 42 can buffer ground vibration and avoid the influence of ground vibration on the load of the wire rope.

[0065] Moreover, the arrangement of the elastic member 42 can keep the force of the steel wire rope acting on the connecting pipe 21 of the test piece 2 to be tested always horizontal during the test of the test piece 2 to be tested.

[0066] Specifically, when the test piece 2 is subjected to the pulling force of the second clamp 12, the height of the connecting pipe 21 in the middle of the test piece 2 decreases accordingly, and then the height of the connecting end of the wire rope and the connecting pipe 21 is adjusted downward, and the wire rope is tilted. During this process, the connecting rod 322 drives the vertical pole 323 to also decrease in height. The descending process compresses the elastic member 42 and causes the wire rope to return to a horizontal state, thereby improving the reliability of the test data.

[0067] Furthermore, a displacement sensor 43 is provided on the base 4 , and the displacement sensor 43 is used to detect the displacement of the second fixture 12 along the axial direction.

[0068] Moreover, the fixed pulley 321 divides the steel wire rope into a horizontal portion 311 and a vertical portion 312 ; one end of the horizontal portion 311 is connected to the connecting pipe 21 in the middle of the test piece 2 to be tested, and the vertical portion 312 is arranged perpendicular to the horizontal portion 311 .

[0069] The fixed pulley 321 provided in the present application adjusts the wire rope portion from a horizontal extension state to a vertical state, and then the equivalent balance block 33 is vertically arranged so that the rated horizontal load can be applied to the connecting pipe 21 of the test piece 2 to be tested through the wire rope.

[0070] In some other embodiments, a certain number of movable pulleys may be provided on the basis of the fixed pulley 321 , thereby reducing the mass of the load required to apply the load to the connecting pipe 21 .

[0071] The equivalent balance block 33 may adopt a structure such as a large-section beam with greater rigidity, so as to maintain the stability of load application.

[0072] The test process is described as follows:

[0073] Before the test, the two ends of the test piece 2 are connected to the first protrusion 111 and the second protrusion 121 through nuts. The installation needs to be aligned. The flat plate part of the test piece 2 (refer to Figure 2 ) is consistent with the axial extension direction of the first clamp 11 and the second clamp 12.

[0074] Then, a cover is provided at the connecting pipe 21, one end of the steel wire rope is fixed on the cover, and the other end is connected to the equivalent balance block 33. The weight of the equivalent balance block 33 can be adjusted according to the weight required for the test, which is not limited here.

[0075] The heat preservation box 13 is closed, and after the temperature reaches the test target temperature, it is kept warm for a certain period of time, such as one hour, and then the test machine connected to the fixture assembly 1 is started to start the test.

[0076] Among them, the first clamp 11 of the test piece is fixed, and the second clamp 12 can move up and down. The second clamp 12 is set to move up and down coaxially, and the tensile and compressive loads are transmitted to the test piece 2 to be tested through the first protrusion 111 and the second protrusion 121. At the same time, a static load is set to transmit a constant tensile load parallel to the horizontal direction to the connecting pipe 21 of the test piece 2 to be tested through the fixed pulley 321, thereby realizing a multi-axial creep-fatigue test of the test piece 2 to be tested.

[0077] In summary, compared with the traditional test system, the present invention has at least the following advantages:

[0078] 1. The positioning adjustment mechanism 3 provided by the present invention is connected to a uniaxial creep-fatigue testing machine. It only needs to make a partial opening in the heat preservation box 13 and lead out the steel wire rope, which is convenient for modification and has lower cost.

[0079] Second, because the connecting mechanism 31 is a steel wire rope, and one end is connected to the equivalent balance block 33 to apply a horizontal load to the connecting pipe 21, no additional driving power supply is required to achieve passive application of a constant load on the connecting pipe 21, the structural stability is good, and the test repeatability is high.

[0080] 3. The additionally introduced load of the pipe 21 is a passive load, and there is no need to add a driving motor. A dynamic sealing structure is also provided at the opening of the insulation box 13, so that the insulation performance of the insulation box 13 is not affected, and there is no need to increase the test cost, which is more economical.

[0081] Fourth, the positioning adjustment mechanism 3 is integrated into the uniaxial creep-fatigue testing machine, and the combined effect of the cyclic load on the container side and the load on the nozzle 21 side is simulated, which fully reflects the multi-axial stress characteristics of the nozzle 21 position and can be directly used as a reference for the creep-fatigue analysis and evaluation method of the nozzle 21 area of ​​the container.

[0082] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "install", "connect", "connect", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be a mechanical connection. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0083] The present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or multiple times in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0084] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A multi-axial creep-fatigue test system for a nozzle test piece, characterized in that: include: A fixture assembly, comprising a first fixture and a second fixture, wherein the first fixture and the second fixture are used to clamp two opposite ends of the test piece to be tested; The positioning and adjustment mechanism includes a connecting mechanism and a supporting mechanism. One end of the connecting mechanism is connected to the connecting pipe on the test piece to be tested, and the other end is connected to an equivalent balancing block. One end of the supporting mechanism movably acts on the connecting mechanism so that the connecting mechanism always applies a load in a direction perpendicular to the axial direction of the test piece to be tested.

2. The multiaxial creep-fatigue test system for nozzle test piece according to claim 1, characterized in that: The first fixture is located above the second fixture; The clamp assembly also includes an insulation box, in which the clamping ends of the first clamp and the second clamp are located.

3. The multiaxial creep-fatigue test system for nozzle test pieces according to claim 2, characterized in that: The connecting mechanism is a steel wire rope, one end of which is connected to the connecting pipe in the middle of the test piece to be tested, and the other end is connected to the balancing block; A fixed pulley is disposed at one end of the support mechanism, and the fixed pulley supports the steel wire rope so that the balance block applies a load to the connecting pipe in the middle of the test piece through the steel wire rope.

4. The multiaxial creep-fatigue test system for nozzle test piece according to claim 3, characterized in that: The heat preservation box is provided with a waist-shaped hole, and one end of the steel wire rope is passed through the waist-shaped hole to the heat preservation box and connected to the pipe in the middle of the test piece to be tested; The waist-shaped hole is filled with a dynamic sealing ring.

5. The multiaxial creep-fatigue test system for nozzle test piece according to claim 3, characterized in that: The supporting mechanism comprises a connecting rod, a vertical rod and an inclined rod, one end of the connecting rod is connected to the second clamp, and the other end is connected to the vertical rod, one end of the inclined rod is rotatably connected to the vertical rod, and the other end is provided with the fixed pulley; wherein, The connecting rod is vertically arranged with the vertical rod, and the vertical rod is arranged at an angle with the oblique rod.

6. The multiaxial creep-fatigue test system for nozzle test piece according to claim 5, characterized in that: A base is provided at the lower end of the second clamp, and one end of the vertical rod is elastically connected to the base.

7. The multiaxial creep-fatigue test system for nozzle test pieces according to claim 6, characterized in that: The base is provided with a receiving groove, the base is provided with an elastic member in the receiving groove, and one end of the vertical rod extends into the receiving groove and abuts against the elastic member.

8. The multiaxial creep-fatigue test system for nozzle test pieces according to claim 6, characterized in that: The base is also provided with a displacement sensor, and the displacement sensor is used to detect the displacement of the second fixture along the axial direction.

9. The multiaxial creep-fatigue test system for nozzle test pieces according to claim 5, characterized in that: The fixed pulley divides the steel wire rope into a horizontal portion and a vertical portion; One end of the horizontal portion is connected to a connecting pipe in the middle of the test piece to be tested, and the vertical portion is arranged perpendicular to the horizontal portion.

10. The multi-axial creep-fatigue test system for nozzle test piece according to claim 1, characterized in that: A first protrusion is provided at one end of the first clamp facing the second clamp, and a second protrusion is provided at one end of the second clamp facing the first clamp; The first protrusion and the second protrusion are threadedly matched with opposite ends of the test piece to be tested or fixedly connected by means of a latch.

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