CN218937292U - Structure suitable for high temperature bolt creep measurement - Google Patents

Abstract

The utility model discloses a structure suitable for creep measurement of a high-temperature bolt, which comprises a high-temperature bolt and creep measuring points, wherein the number of the creep measuring points is 4, the creep measuring points are distributed on the end surfaces of two sides of the high-temperature bolt and are positioned in a plane, and each measuring point is positioned in the middle position between the edge of the end surface of the bolt and a central hole of the bolt and is distributed in a central symmetry way with the central hole of the bolt; the 4 creep measuring points are of cylindrical structures and are equally divided into an upper layer and a lower layer, the upper layer of the measuring points is made of stainless steel, and the lower layer of the measuring points is made of the same material as the high-temperature bolts; the upper layer of the measuring point is connected with the lower layer of the measuring point through welding, and the lower layer of the measuring point is connected with the end face of the bolt through welding; the utility model has simple and reasonable structure and is not easy to generate measurement errors. The measuring operation is simple and quick, the measuring result has high precision and small error, the creep deformation of the high-temperature bolt can be accurately measured by the micrometer, the popularization in the industry is facilitated, and the development of creep supervision work of the high-temperature bolt is facilitated.

Description

Structure suitable for high temperature bolt creep measurement

Technical Field

The utility model relates to creep monitoring of a high-temperature bolt of a thermal power plant, in particular to a structure suitable for creep measurement of the high-temperature bolt.

Background

The high-temperature bolt is one of important parts in the turbine equipment of the thermal power plant, and is connected with a high-temperature part such as a turbine cylinder, a main valve, an adjusting valve, a steam guide pipe and the like, so that leakage accidents are avoided in the running process of the unit. The rod part of the bolt bears axial tensile stress, creep deformation can occur under high-temperature and high-pressure operation conditions, and creep rupture failure is one of main failure modes of the high-temperature bolt. Therefore, creep supervision of high-temperature bolts is an important content of metal technical supervision of thermal power plants.

At present, regarding creep measurement of high-temperature bolts, the electric power industry standard DL/T439-2018, the technical guidelines for high-temperature fasteners of thermal power plants, prescribes: the creep deformation monitoring measurement is carried out on the high-pressure inner cylinder bolt, and the measurement method is to punch sample punching holes on the end surfaces of the two sides of the screw rod respectively before use, and the creep deformation condition of the high-temperature bolt is measured by measuring the distance change between the sample punching holes. The measuring method has two problems, firstly, the surface of the sample punching hole is oxidized in a high-temperature environment, and the generated oxide scale is easy to fall off, so that the sample punching hole is deformed, and the measurement of the distance between the sample punching holes at two sides is influenced. Secondly, the measuring tool commonly used for creep measurement is a micrometer, the measuring surface of the measuring tool is a circular plane, the sample punching hole is inwards concave on the end surface of the bolt, the inner surface of the measuring tool is a spherical surface, the measuring tool and the sample punching hole cannot be attached, and the measuring tool with high precision in other conventional measuring tools can be used for measuring the sample punching hole spacing. In view of this, in actual operation, creep measurement of high-temperature bolts is less and less, and inspection personnel often remain to be in the spotlight.

Disclosure of Invention

The utility model aims to overcome the defects in the prior art and provide a structure suitable for creep measurement of a high-temperature bolt.

The utility model solves the problems by adopting the following technical scheme: the structure suitable for creep measurement of the high-temperature bolt is characterized by comprising the high-temperature bolt and creep measurement points, wherein 4 creep measurement points are arranged, 4 creep measurement points are of a cylindrical structure and are equally divided into an upper layer and a lower layer, the upper layer of the measurement point is made of stainless steel, and the lower layer of the measurement point is made of the same material as the high-temperature bolt; the 4 creep measurement points are a first measurement point, a second measurement point, a third measurement point and a fourth measurement point respectively, wherein the first measurement point and the third measurement point are a group of creep measurement points, and the second measurement point and the fourth measurement point are a group of creep measurement points; the first measuring point and the second measuring point are arranged on the first end face of one side of the high-temperature bolt, and the third measuring point and the fourth measuring point are arranged on the second end face of the other side of the high-temperature bolt; the first measuring point, the second measuring point, the third measuring point and the fourth measuring point are in a plane, the first measuring point and the second measuring point are symmetrically distributed on two sides of the central hole of the bolt, the third measuring point and the fourth measuring point are symmetrically distributed on two sides of the central hole of the bolt, the first measuring point and the third measuring point are coaxially arranged, and the second measuring point and the fourth measuring point are coaxially arranged.

Further, the creep measurement points on each end face of the high-temperature bolt are located at the middle positions between the edges of the end faces and the central holes of the bolts.

Further, the upper layer of the measuring point is connected with the lower layer of the measuring point through welding, and the lower layer of the measuring point is connected with the end face of the bolt through welding.

Compared with the prior art, the utility model has the following advantages and effects: the utility model can realize accurate measurement of the creep deformation of the high-temperature bolt by the micrometer, has simple and reasonable structure, is not easy to generate measurement errors, is convenient for popularization in industry and is beneficial to the development of creep supervision work of the high-temperature bolt.

Drawings

FIG. 1 is a schematic diagram of the overall arrangement of creep measurement points of a high-temperature bolt in an embodiment of the utility model.

FIG. 2 is a schematic diagram of an arrangement structure of an end face of a creep measurement point of a high-temperature bolt in an embodiment of the utility model.

FIG. 3 is a schematic view of the structure of the high temperature bolt in the embodiment of the utility model in the creep deformation measurement.

In the figure: the measuring point comprises a measuring point I1, a measuring point II 2, a measuring point III 3, a measuring point IV 4, an end face I5, an end face II 6, a bolt center hole 7, a measuring point I upper layer 1-1, a measuring point II lower layer 1-2, a measuring point II upper layer 2-1 and a measuring point II lower layer 2-2.

Detailed Description

The present utility model will be described in further detail by way of examples with reference to the accompanying drawings, which are illustrative of the present utility model and not limited to the following examples.

Examples

Referring to fig. 1 and 2, in this embodiment, a structure suitable for creep measurement of a high-temperature bolt includes a high-temperature bolt and creep measurement points, wherein the number of the creep measurement points is 4, the number of the 4 creep measurement points is all in a cylindrical structure, and the two creep measurement points are equally divided into an upper layer and a lower layer, the upper layer of the measurement points is made of stainless steel, and the lower layer of the measurement points is made of the same material as that of the high-temperature bolt; the diameter of the cross section of the upper layer of the measuring point is 5mm, the height is 5mm, the diameter of the cross section of the lower layer of the measuring point is 5mm, and the height is 5mm.

In the embodiment, the 4 creep measurement points are respectively a measurement point 1, a measurement point 2, a measurement point three 3 and a measurement point four 4, wherein the measurement point 1 and the measurement point three 3 are a group of creep measurement points, and the measurement point 2 and the measurement point four 4 are a group of creep measurement points; the first measuring point 1 and the second measuring point 2 are arranged on the first end face 5 of one side of the high-temperature bolt, and the third measuring point 3 and the fourth measuring point 4 are arranged on the second end face 6 of the other side of the high-temperature bolt; the first measuring point 1, the second measuring point 2, the third measuring point 3 and the fourth measuring point 4 are positioned in a plane, the first measuring point 1 and the second measuring point 2 are symmetrically distributed on two sides of the bolt central hole 7, the third measuring point 3 and the fourth measuring point 4 are symmetrically distributed on two sides of the bolt central hole 7, the first measuring point 1 and the third measuring point 3 are coaxially arranged, and the second measuring point 2 and the fourth measuring point 4 are coaxially arranged.

In this embodiment, the creep measurement point on each end face of the high temperature bolt is located at an intermediate position between the end face edge and the bolt center hole 7.

In the embodiment, the upper layer of the measuring point is connected with the lower layer of the measuring point through welding, and the lower layer of the measuring point is connected with the end face of the bolt through welding.

Referring to fig. 3, in this embodiment, creep measurement is specifically performed on a creep measurement point by using a micrometer, and the specific measurement operation steps are as follows:

step 1: the micrometer for measurement was calibrated with a standard rod at a temperature of about 20 ℃, and the zero calibration value of the micrometer was calculated as follows.

Wherein:

b: zero correction value of micrometer;

b ₁ : measuring the zero position value of the micrometer before measuring, and mm;

b ₂ : zero value of micrometer, mm after measurement.

Step 2: creep measurement is carried out before the high-temperature bolt runs, and a micrometer ratchet wheel is slowly rotated to enable the measuring surface of the micrometer to be in contact with the measuring surfaces of the first measuring point 1 and the third measuring point 3; the measurement was performed 3 times, and the measurement results were respectively recorded as: l (L) ₁ 、L ₂ 、L ₃ And taking an arithmetic average

Wherein->

Step 3: similarly, creep measurement is performed on the second measuring point 2 and the fourth measuring point 4, the measurement is performed 3 times, and the measurement results are respectively recorded as follows: l (L) ₁ '、L ₂ '、L ₃ ' and taking an average

Wherein->

The initial length of the high temperature bolt before operation is recorded as L _{Initially, the method comprises} And->

Step 4: the original length of the high-temperature bolt converted to 0 ℃ is recorded as L _{First 1} And calculated as follows.

Wherein:

α _p : the linear expansion coefficient of the high-temperature bolt is mm/(mm. DEG C);

α _ck : linear expansion coefficient of the micrometer bow body, mm/(mm·deg.c);

t _p : surface temperature near creep measurement point, DEG C;

t _ck : temperature of the micrometer bow, DEG C.

Step 5: creep measurement is carried out on the high-temperature bolt after operation, and creep measurement is carried out on the first measuring point 1 and the third measuring point 3 according to the step 2; the measurement was performed 3 times, and the measurement results were respectively recorded as: l (L) _1h 、L _2h 、L _3h And taking an arithmetic average

Wherein->

Step 6: similarly, creep measurement is performed on the second measuring point 2 and the fourth measuring point 4, the measurement is performed 3 times, and the measurement results are respectively recorded as follows: l (L) _1h '、L _2h '、L _3h ' and taking an average

Wherein->

The length of the high-temperature bolt after operation is recorded as L _{Transport and transport} And->

Step 7: the length of the bolt after the high temperature bolt runs at 0 ℃ is converted to L _{Carrying out h} And calculated as follows.

Step 8: the absolute creep deformation of the high temperature bolt was calculated, denoted as Δl, and calculated as follows.

ΔL＝L _{Carrying out h} -L _{First 1}

Step 9: the relative creep strain of the high temperature bolt was calculated, noted epsilon (%), and calculated as follows.

In conclusion, the creep deformation measuring structure of the high-temperature bolt is simple and reasonable, measurement errors are not easy to generate, actual measurement operation is simple and rapid, detection personnel can conveniently master the creep deformation measuring structure, measurement result accuracy is high, errors are small, detection personnel can accurately measure the creep deformation of the high-temperature bolt through a micrometer, the creep deformation measuring structure can be popularized in industry, development of creep supervision work of the high-temperature bolt is facilitated, and the creep deformation measuring structure really becomes an effective ring of metal technical supervision.

What is not described in detail in this specification is all that is known to those skilled in the art.

Furthermore, the foregoing description of the utility model is provided by way of example only. All equivalent changes in construction, features and principles of the utility model according to the inventive concept are intended to be encompassed by the scope of the utility model. Those skilled in the art may make various modifications, additions and substitutions to the described embodiments without departing from the scope of the utility model as defined in the accompanying claims.

Claims (3)

1. The structure suitable for creep measurement of the high-temperature bolt is characterized by comprising the high-temperature bolt and creep measurement points, wherein 4 creep measurement points are arranged, 4 creep measurement points are of a cylindrical structure and are equally divided into an upper layer and a lower layer, the upper layer of the measurement point is made of stainless steel, and the lower layer of the measurement point is made of the same material as the high-temperature bolt; the 4 creep measuring points are respectively a first measuring point (1), a second measuring point (2), a third measuring point (3) and a fourth measuring point (4), wherein the first measuring point (1) and the third measuring point (3) are a group of creep measuring points, and the second measuring point (2) and the fourth measuring point (4) are a group of creep measuring points; the first measuring point (1) and the second measuring point (2) are arranged on the first end face (5) of one side of the high-temperature bolt, and the third measuring point (3) and the fourth measuring point (4) are arranged on the second end face (6) of the other side of the high-temperature bolt; the measuring point I (1), the measuring point II (2), the measuring point III (3) and the measuring point IV (4) are positioned in a plane, the measuring point I (1) and the measuring point II (2) are symmetrically distributed on two sides of a bolt center hole (7), the measuring point III (3) and the measuring point IV (4) are symmetrically distributed on two sides of the bolt center hole (7), the measuring point I (1) and the measuring point III (3) are coaxially arranged, and the measuring point II (2) and the measuring point IV (4) are coaxially arranged.

2. Structure suitable for creep measurement of high temperature bolts according to claim 1, characterized in that the creep measurement point on each end face of the high temperature bolt is located in an intermediate position between the end face edge and the bolt central hole (7).

3. The structure for creep measurement of high temperature bolts according to claim 1 or 2, wherein the upper layer of the measuring point is welded to the lower layer of the measuring point, and the lower layer of the measuring point is welded to the end face of the bolt.

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