Tubular sample clamp for testing residual stress

Abstract

The utility model discloses a tubular sample clamp for testing residual stress, and belongs to the technical field of tubular sample residual stress measuring methods. Comprising a clamping unit and an aligning unit, the clamping unit comprises two clamping blocks which are connected together through a connecting piece, the distance between the two clamping blocks is adjusted through the connecting piece, and a tubular sample is placed between the two clamping blocks to be fixed during testing; the alignment unit comprises a centering base which is arranged between the upper portions of the two clamping blocks and fixed to the connecting piece, and a through hole is formed in the centering base. A middle guide seat is fixed on the centering base, and the middle guide seat is a hollow cylinder; the through hole is coaxial with the middle guide seat; according to the utility model, the technical problem of poor positioning stability in the residual stress test process of the tubular sample can be really solved, and the device has a promotion effect on accurate measurement of the residual stress and strength design of the tubular sample.

Description

Technical Field

[0001] The utility model belongs to the technical field of residual stress measurement methods for tubular samples, and relates to a tubular sample clamp for testing residual stress. Background Art

[0002] With the rapid development of oil and gas field development, there are more and more ultra-deep wells, high-temperature wells, high-pressure wells, and oil and gas wells rich in corrosive media such as H2S, CO2 and Cl-. In order to ensure the safety and efficiency of production, it is particularly important to select oil casing with high strength, high toughness and excellent corrosion resistance. Residual stress refers to the self-balanced internal stress remaining in the object after the external force or uneven temperature field is removed. It is one of the important indicators affecting the performance of oil casing. In recent years, there have been many studies on the residual stress of metal plates, and the main test methods are ring cutting method, drilling method, and X-ray method. The drilling method is currently the most commonly used residual stress test method in engineering, and the American ASTM Association has included it in the standard. The research work on the drilling method has been deeply analyzed from various process factors and error sources in actual operation, making it more and more perfect. However, in the drilling process, the residual stress is affected by factors such as strain gauge size, hole diameter, hole depth, drill bit type, drilling speed and distance to the center of the blind hole. At present, the influence of residual stress has not been considered in the design of oil casing and tubing strings, and there is almost no relevant literature on the study of residual stress of oil casing and tubing. To study the influence of residual stress on the performance of oil pipes, the residual stress level of oil casing and tubing must be tested first. The drilling residual stress test equipment on the market currently comes with a positioning pedestal fixture suitable for plate residual stress testing, but the positioning pedestal fixture for tubular specimens such as oil casing and tubing is not accurate enough and the operation is complicated. Utility Model Content

[0003] The utility model aims to solve the technical problems in the prior art that when the drilling method is used to test residual stress, the positioning of the fixture of the positioning seat of tubular samples such as oil casing is not accurate enough and the operation is complicated, and to provide a tubular sample fixture for testing residual stress.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] In a first aspect, the utility model provides a tubular specimen fixture for testing residual stress, comprising a clamping unit and an alignment unit; the clamping unit comprises two clamping blocks connected together by a connecting piece, the distance between the two clamping blocks is adjusted by the connecting piece, and the tubular specimen is placed between the two clamping blocks to be fixed during testing; the alignment unit comprises a centering base arranged between the upper parts of the two clamping blocks and fixed on the connecting piece, and a through hole is arranged on the centering base; a centering guide seat is fixed on the centering base, and the center guide seat is a hollow cylinder; the through hole is coaxial with the centering guide seat; a magnifying glass is installed in the centering guide seat, and after adjusting the position of the tubular specimen so that the center of the strain rosette on the tubular specimen is aligned with the center of the magnifying glass, the connecting piece is adjusted so that the distance between the two clamping blocks is reduced to clamp the tubular specimen; the magnifying glass is taken out, and an electric drill bit is passed through the centering guide seat to drill a hole at the center of the strain rosette.

[0006] The utility model is further improved in that:

[0007] A plurality of first fine-tuning bolts are arranged on the centering base and pass through the centering base from top to bottom; the screw end faces of the first fine-tuning bolts are pressed against the wall surface of the tubular sample to radially position it.

[0008] Two first fine-tuning bolts are provided.

[0009] A plurality of second fine-tuning bolts are symmetrically arranged on the wall surface of the centering guide seat; when the electric drill bit passes through the centering guide seat to drill a hole at the center of the strain flower, the second fine-tuning bolts are used to fix the electric drill and adjust its radial position.

[0010] There are four second fine-tuning bolts.

[0011] The connecting member is two bolts symmetrically arranged at both ends of the upper parts of the two clamping blocks, and nuts are arranged on the bolts.

[0012] The centering base is a transparent acrylic base.

[0013] One end of the centering base extends out from between the two clamping blocks, and the centering guide seat is arranged on the extended end.

[0014] Compared with the prior art, the utility model has the following beneficial effects:

[0015] The utility model discloses a tubular sample clamp for testing residual stress. Two connecting blocks are connected together by a connecting piece. The tubular sample is placed between the two connecting blocks and clamped. A centering base fixed with a middle guide seat is provided. When the clamp is working, a magnifying glass is installed in the middle guide seat. After adjusting the position of the tubular sample so that the center of the strain flower on the tubular sample is aligned with the center of the magnifying glass, the connecting piece is adjusted so that the distance between the two clamping blocks is reduced to clamp the tubular sample. The magnifying glass is taken out, and a drill is passed through the middle guide seat to drill a hole at the center of the strain flower. The utility model can quickly and accurately center and position, is easy to operate, and has strong applicability. The utility model can truly solve the technical problem of poor positioning stability in the process of residual stress testing of tubular samples, and has a driving effect on accurately measuring the residual stress of tubular samples and strength design.

[0016] Furthermore, the material of the centering base is transparent acrylic, which is convenient for observing the position of the strain rosette on the tubular specimen during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a stereoscopic diagram of a tubular sample fixture for testing residual stress in the utility model;

[0019] Figure 2 This is a front view of a tubular sample fixture for testing residual stress in the utility model;

[0020] Figure 3 It is a top view of a tubular sample fixture for testing residual stress in the utility model;

[0021] Figure 4 It is a left view of a tubular sample fixture for testing residual stress in the utility model.

[0022] Among them: 1-clamping block; 2-connecting piece; 3-first fine-tuning bolt; 4-centering base; 5-second fine-tuning bolt; 6-centering guide seat. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. 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.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0026] In the description of the embodiments of the present utility model, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product is usually placed when in use, it is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0027] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0028] In the description of the embodiments of the present utility model, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0029] The utility model is further described in detail below with reference to the accompanying drawings:

[0030] See also Figure 1 and Figure 4 The embodiment of the utility model discloses a tubular specimen fixture for testing residual stress, including a clamping unit and an alignment unit; the clamping unit includes two clamping blocks 1 connected together by a connecting member 2, the distance between the two clamping blocks 1 is adjusted by the connecting member 2, and the tubular specimen is placed between the two clamping blocks 1 to fix it during testing; the connecting member 2 is two bolts symmetrically arranged at both ends of the upper parts of the two clamping blocks 1, and nuts are arranged on the bolts. The alignment unit includes a centering base 4 arranged between the upper parts of the two clamping blocks 1 and fixed on the connecting member, and a through hole is arranged on the centering base 4; a centering guide seat 6 is fixed on the centering base 4, and the centering guide seat 6 is a hollow cylinder; the through hole is coaxial with the centering guide seat 6; the centering base 4 is a transparent acrylic base. One end of the centering base 4 extends out between the two clamping blocks 1, and the centering guide seat 6 is arranged on the extended end.

[0031] When the fixture is working, a magnifying glass is installed in the centering guide seat 6, and the position of the tubular specimen is adjusted so that the center of the strain rosette on the tubular specimen is aligned with the center of the magnifying glass. Then, the connecting piece 2 is adjusted so that the distance between the two clamping blocks 1 is reduced to clamp the tubular specimen. The magnifying glass is taken out, and a drill is passed through the centering guide seat 6 to drill a hole at the center of the strain rosette.

[0032] See also Figure 2 and Figure 3 , two first fine-tuning bolts 3 are arranged on the centering base 4, passing through the centering base 4 from top to bottom; the screw end faces of the first fine-tuning bolts 3 are against the wall of the tubular sample to radially position it. Four second fine-tuning bolts 5 are symmetrically arranged on the same horizontal plane of the wall of the middle guide seat 6; when the magnifying glass is installed in the middle guide seat 6, the second fine-tuning bolts 5 are used to fix the magnifying glass and adjust its radial position.

[0033] The working process of the utility model is as follows:

[0034] Place the tubular specimen between the two clamping blocks 1, install a magnifying glass in the center guide seat 6 so that the centering guide seat 6 is roughly aligned with the center punching point on the strain gauge on the tubular specimen, then adjust the connector 2 according to the specifications of the tubular specimen, check the connection reliability of the probe on the strain gauge, and ensure the stability of the residual stress test instrument and the fixture, then use the second fine-tuning bolt 5 and the first fine-tuning bolt 3 to adjust the centering guide seat 6 so that the center cross mark center of the magnifying glass is aligned with the punching point on the strain gauge, tighten the connector 2 to lock the entire fixture, and remove the magnifying glass. Pass the electric drill bit through the centering guide seat 6 to drill a hole at the center of the strain flower. After the measurement is completed, loosen the connector 2, remove the fixture, wipe all components clean and put them into the equipment box.

[0035] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A tubular specimen fixture for testing residual stress, characterized in that: The invention comprises a clamping unit and an alignment unit; the clamping unit comprises two clamping blocks (1) connected together by a connecting piece (2), the distance between the two clamping blocks (1) being adjusted by the connecting piece (2), and the tubular specimen is placed between the two clamping blocks (1) to be fixed during testing; the alignment unit comprises a centering base (4) arranged between the upper parts of the two clamping blocks (1) and fixed on the connecting piece, and a through hole is arranged on the centering base (4); a centering guide seat (6) is fixed on the centering base (4), and the centering guide seat (6) is a hollow cylinder; the through hole is coaxial with the centering guide seat (6); a magnifying glass is installed in the centering guide seat (6), and after adjusting the position of the tubular specimen so that the center of the strain rosette on the tubular specimen is aligned with the center of the magnifying glass, the connecting piece (2) is adjusted so that the distance between the two clamping blocks (1) is reduced to clamp the tubular specimen; the magnifying glass is taken out, and an electric drill bit is passed through the centering guide seat (6) to drill a hole at the center of the strain rosette.

2. The tubular specimen fixture for testing residual stress according to claim 1, characterized in that: A plurality of first fine-tuning bolts (3) are arranged on the centering base (4) and pass through the centering base (4) from top to bottom; the screw end faces of the first fine-tuning bolts (3) are pressed against the wall surface of the tubular sample to radially position it.

3. The tubular specimen fixture for testing residual stress according to claim 2, characterized in that: Two first fine-tuning bolts (3) are provided.

4. The tubular specimen fixture for testing residual stress according to claim 1, characterized in that: A plurality of second fine-tuning bolts (5) are symmetrically arranged on the wall surface of the centering guide seat (6); when the electric drill bit passes through the centering guide seat (6) to drill a hole at the center of the strain flower, the second fine-tuning bolts (5) are used to fix the electric drill and adjust its radial position.

5. The tubular specimen fixture for testing residual stress according to claim 4, characterized in that: Four second fine-tuning bolts (5) are provided.

6. The tubular specimen fixture for testing residual stress according to claim 1, characterized in that: The connecting member (2) is two bolts symmetrically arranged at both ends of the upper parts of the two clamping blocks (1), and nuts are arranged on the bolts.

7. The tubular specimen fixture for testing residual stress according to claim 1, characterized in that: The centering base (4) is a transparent acrylic base.

8. The tubular specimen fixture for testing residual stress according to claim 1, characterized in that: One end of the centering base (4) extends out from between the two clamping blocks (1), and the centering guide seat (6) is arranged on the extended end.

Images