CN113295313B - Pipeline welded junction stress monitoring and evaluating method - Google Patents
Pipeline welded junction stress monitoring and evaluating method Download PDFInfo
- Publication number
- CN113295313B CN113295313B CN202110549501.5A CN202110549501A CN113295313B CN 113295313 B CN113295313 B CN 113295313B CN 202110549501 A CN202110549501 A CN 202110549501A CN 113295313 B CN113295313 B CN 113295313B
- Authority
- CN
- China
- Prior art keywords
- stress
- pipeline
- welding
- measuring point
- welding seam
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
Abstract
The invention relates to a pipeline crater stress monitoring and evaluating method, which adopts the technical scheme that measuring point groups are arranged on two sides of a welding line to be measured and one side of an adjacent welding line, the internal pressure reduced stress of the welding line and the adjacent welding line pipeline is monitored in real time, and the internal pressure reduced stress sigma in all measuring points is monitored simultaneously eq The position of the point with the maximum value, and converting the internal pressure of each measuring point into stress and allowable stress value [ sigma ] at the design temperature of the pipeline] t The real-time state of the weld joint to be detected or the adjacent weld joint is obtained through comparison, the defect finding efficiency is improved, a theoretical basis is provided for maintenance, the problem of processed weld joint stress monitoring and evaluation is effectively solved, online real-time monitoring can be achieved, the processed weld joint is effectively monitored for stress, the problem that new cracking occurs in the processed weld joint during operation due to overhigh local stress is avoided, innovation in processed weld joint monitoring is achieved, and safe and stable operation of a thermal power plant is guaranteed.
Description
Technical Field
The invention relates to a thermal power plant pipeline welded junction stress monitoring and evaluating method.
Background
During the overhaul period of a thermal power plant, the weld crater with problems is subjected to girdling and repair welding treatment, but effective stress monitoring is not carried out after the treatment, local overhigh stress can occur in the running process of a pipeline, and the excessive stress can easily cause new cracking of the treated weld crater during the running process. Currently, no measures are taken in power systems to monitor the stress of the processed weld. Therefore, improvement and innovation thereof are imperative.
Disclosure of Invention
In view of the above situation, the present invention provides a method for monitoring and evaluating the stress of a weld joint of a pipeline, which can effectively solve the problem of monitoring and evaluating the stress of a processed weld joint.
The technical scheme of the invention is as follows:
a pipeline crater stress monitoring and evaluating method comprises the following steps:
step 1: two sides of a welding seam to be detected are respectively provided with two groups of measuring point groups for monitoring the wall thickness of pipelines at two sides of the welding seam, namely a first measuring point group A and a second measuring point group B, two welding seams adjacent to the welding seam to be detected on a pipeline are respectively a front-end welding seam and a rear-end welding seam, a third measuring point group C for monitoring the wall thickness of the pipeline at one side of the front-end welding seam close to the welding seam to be detected is arranged on the pipeline at one side of the rear-end welding seam close to the welding seam to be detected, a fourth measuring point group D for monitoring the wall thickness of the pipeline at one side of the rear-end welding seam close to the welding seam to be detected is arranged on the pipeline, and each measuring point group comprises a plurality of measuring points which are arranged on the pipeline at the corresponding side of the welding seam along the circumferential direction of the pipeline;
step 2: the wall thickness of the pipeline at the corresponding position is monitored in real time through the measuring points arranged in the step 1, and the internal pressure conversion stress of each measuring point is calculated through the following formula 1:
wherein:
σ eq -internal pressure reduced stress, MPa;
p- -design pressure, MPa;
D 0 -a pipe design outer diameter;
s- -measured wall thickness measured by measuring points;
y-correction coefficient of temperature to pipe wall thickness;
eta-correction factor of allowable stress;
α - -additional thickness in terms of corrosion, wear and mechanical strength, mm;
and 3, step 3: converting the calculated internal pressure of each measuring point into stress sigma eq And the steel to be testedAllowable stress value [ sigma ] of pipe steel at pipeline design temperature] t And comparing to evaluate the weld joint stress, wherein the specific evaluation criteria are as follows:
A. in all measurement points, the internal pressure reduced stress σ eq The point of the maximum value is positioned on the measuring points of the first measuring point group A or the second measuring point group B at the two sides of the welding line to be measured, and the internal pressure conversion stress sigma of the maximum value eq Allowable stress value [ sigma ] at design temperature of pipeline] t Judging that the welding line to be detected is in a first early warning state, wherein the welding line to be detected has defect risk and needs surface flaw detection; the welding line to be detected in the first early warning state is likely to have a defect, flaw detection is needed to detect whether the welding line has the defect, and the defect needs to be mainly checked near a measuring point where the maximum value of the internal pressure reduction stress is located;
B. in all measurement points, the internal pressure reduced stress σ eq Are all smaller than allowable stress value [ sigma ] at the design temperature of the pipeline] t When the welding seam to be detected is in a good state, the defect detection is not needed;
C. in all measurement points, the internal pressure reduced stress σ eq The point of the maximum value falls on the third measuring point group C on the side of the front end welding seam or the fourth measuring point group D on the side of the rear end welding seam, and the internal pressure of the maximum value is converted into stress sigma eq Allowable stress value [ sigma ] at design temperature of pipeline] t When the welding line to be detected is judged to be in the second early warning state, the front-end welding line and the rear-end welding line have cracking risks and need to be subjected to stress monitoring or flaw detection, the front-end welding line and the rear-end welding line in the second early warning state are likely to have micro cracks and cracks or even have defects, the stress monitoring or flaw detection needs to be carried out, whether the welding line has cracks or defects is further confirmed, and the positions of the cracks or the defects are likely to be subjected to internal pressure reduction to calculate the positions near a measuring point where the maximum stress value is located, and key investigation is needed;
meanwhile, when the stress does not reach the allowable stress value of the material (when the welding line to be measured is in a good state), the stress borne by the welding line can be estimated by drawing a relation curve of the stress along with the change of the wall thickness at each operating temperature.
Preferably, the distance L1 between the welding line to be detected and the welding line at the front end is smaller than 8m, and the distance L1 between the welding line to be detected and the welding line at the rear end is smaller than 8m.
Preferably, the distance between the measuring points of the first measuring point group A and the second measuring point group B and the edge of the side close to the welding line to be measured is smaller than 20mm, the distance between the measuring point of the third measuring point group C and the edge of the side close to the welding line at the front end is smaller than 20mm, and the distance between the measuring point of the fourth measuring point group D and the edge of the side close to the welding line at the rear end is smaller than 20mm.
A pipeline thickness monitoring device for a pipeline weld stress monitoring and evaluating method comprises a thickness detector, wherein a probe of the thickness detector is fixed on a hoop, the hoop is clamped on the outer wall of a pipeline to be detected, the detection end of the probe is in contact with the surface of the pipeline, a contact point is used as a measurement point, a buffer spring which is suitable for high-temperature expansion of the pipeline is arranged on the hoop, the surface of the probe is ensured to be attached to the surface of the pipeline, meanwhile, the probe is prevented from being damaged due to expansion of the pipeline in a high-temperature state, and the thickness detector is connected with a controller;
the thickness detector monitors the real-time wall thickness of the pipeline through a probe, and simultaneously transmits the monitored wall thickness data to a controller for calculating the internal pressure conversion stress;
the controller is used for receiving the wall thickness data of the pipeline transmitted by the thickness detector, substituting the wall thickness data into a formula to calculate the internal pressure converted stress of each measuring point, and simultaneously calculating the calculated internal pressure converted stress and the allowable stress value [ sigma ] of the measured steel pipe at the design temperature of the pipeline, which is input in advance] t And comparing, and evaluating the weld stress according to the evaluation standard.
The invention provides a pipeline crater stress monitoring and evaluating method and a pipeline thickness monitoring device for the method, the method is simple, the internal pressure reduced stress of a welding seam and an adjacent welding seam pipeline is monitored in real time by arranging measuring point groups on two sides of the welding seam to be measured and one side of the adjacent welding seam, and the internal pressure reduced stress sigma in all measuring points is monitored simultaneously eq The position of the point with the maximum value, and converting the internal pressure of each measuring point into stress and allowable stress value [ sigma ] at the design temperature of the pipeline] t The method has the advantages that comparison is carried out, the real-time state of the welding line to be detected or the adjacent welding line is obtained, the defect finding efficiency is improved, the theoretical basis is provided for maintenance, meanwhile, the pipeline thickness monitoring device is further provided, the probe of the thickness detector is fixed on the clamp with the spring, the device can adapt to free expansion of a pipeline, the measurement result can be more accurate, the problem of stress monitoring and evaluation of the processed welding line is effectively solved, online real-time monitoring can be carried out, effective stress monitoring is carried out on the processed welding line, the problem that new cracking occurs to the processed welding opening in the operation period due to overhigh local stress is avoided, the use is convenient, the effect is good, innovation in the processed welding line monitoring is achieved, safe and stable operation of a thermal power plant is guaranteed, and good social and economic benefits are achieved.
Drawings
FIG. 1 is a schematic view of the arrangement of the measuring point groups according to the present invention.
Fig. 2 is a side view of the pipe thickness monitoring apparatus of the present invention.
FIG. 3 is a graph showing the stress as a function of wall thickness according to the present invention.
Detailed Description
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
As shown in FIGS. 1 to 3, the method for monitoring and evaluating the stress of the welded junction of the pipeline comprises the following steps:
step 1: two groups of measuring point groups for monitoring the wall thickness of pipelines at two sides of a welding seam to be measured are respectively arranged at two sides of the welding seam 7a to be measured, as shown in figure 1, a first measuring point group A and a second measuring point group B are respectively arranged, two welding seams adjacent to the welding seam to be measured on a pipeline are respectively a front end welding seam 7B and a rear end welding seam 7C, a third measuring point group C for monitoring the wall thickness of the pipeline at the front end welding seam 7B is arranged on the pipeline at one side close to the welding seam 7a to be measured, a fourth measuring point group D for monitoring the wall thickness of the pipeline at the rear end welding seam 7C is arranged on the pipeline at one side close to the welding seam 7a to be measured, and each measuring point group comprises a plurality of measuring points which are arranged on the pipeline 1 at the corresponding side of the welding seam along the circumferential direction of the pipeline; as shown in fig. 1 and 2, each group of measuring point groups comprises 4 measuring points which are uniformly distributed along the circumferential direction of the pipeline, the measuring point of the first measuring point group a is a first measuring point 6a, the measuring point of the second measuring point group B is a second measuring point 6B, the measuring point of the third measuring point group C is a third measuring point 6C, the measuring point of the fourth measuring point group D is a fourth measuring point 6D, and the included angle between adjacent measuring points is 90 degrees +/-10 degrees;
step 2: monitoring the wall thickness of the pipeline at the corresponding position in real time through the measuring points arranged in the step 1, and calculating the internal pressure converted stress of each measuring point through the following formula 1:
wherein:
σ eq -internal pressure reduced stress, MPa;
p- -design pressure, MPa;
D 0 -a pipe design outer diameter;
s- -measured wall thickness measured by measuring points;
y-correction coefficient of temperature to pipe wall thickness;
eta-correction factor of allowable stress;
α - -additional thickness in terms of corrosion, wear and mechanical strength, mm;
(the additional thickness, not considering corrosion, abrasion and mechanical strength, is 0 in the present application)
And step 3: converting the calculated internal pressure of each measuring point into stress sigma eq Allowable stress value [ sigma ] of steel and steel pipe to be tested at pipeline design temperature] t And comparing to evaluate the weld joint stress, wherein the specific evaluation criteria are as follows:
A. in all measurement points, the internal pressure reduced stress σ eq The point of the maximum value falls on the measuring points of the first measuring point group A or the second measuring point group B at the two sides of the welding line 7a to be measured, and the internal pressure conversion stress sigma of the maximum value eq Allowable stress value [ sigma ] at design temperature of pipeline] t When the welding line to be detected 7a is judged to be in the first early warning state, the welding line to be detected has defect risk, and surface flaw detection is required; the welding line to be detected in the first early warning state is likely to have defects, flaw detection is needed to detect whether the welding line has the defects, and the calculated stress of the defects in internal pressure isKey investigation is needed near the measuring point where the maximum value is located;
B. in all measurement points, the internal pressure reduced stress σ eq Are all smaller than allowable stress value [ sigma ] at the design temperature of the pipeline] t When the weld joint 7a to be detected is in a good state, the defect detection is not needed;
C. in all measurement points, the internal pressure reduced stress σ eq The point of the maximum value falls on the third measuring point group C on the front end weld 7b side or the fourth measuring point group D on the rear end weld 7C side, and the internal pressure of the maximum value is converted into the stress sigma eq Allowable stress value [ sigma ] at design temperature of pipeline] t When the welding line 7a to be detected is in the second early warning state, the front end welding line 7b and the rear end welding line 7c have the risk of cracking, and stress monitoring or flaw detection needs to be carried out on the front end welding line 7b and the rear end welding line 7 c. The front end welding seam 7b and the rear end welding seam 7c which are in the second early warning state are likely to have micro cracks and cracks, even have defects, and need to be subjected to stress monitoring or flaw detection, so as to further confirm whether the welding seam has cracks or defects, and the positions of the cracks or the defects are likely to need to be subjected to key investigation near a measuring point where the internal pressure is calculated to be the maximum stress value;
the defects comprise linear defects and circular defects;
linear defects: the linear defect length is greater than 1.5mm;
circular defect: in the evaluation box with the size of 35mm multiplied by 100mm, the major diameter of the circular defects is more than 2mm, and the number is more than 1.
Meanwhile, when the stress does not reach the allowable stress value of the material (when the welding line to be measured is in a good state), the stress borne by the welding line can be estimated by drawing a relation curve of the stress along with the change of the wall thickness at each operating temperature.
In order to ensure the using effect, the distance L1 between the welding line 7a to be detected and the welding line 7b at the front end is smaller than 8m, and the distance L1 between the welding line 7a to be detected and the welding line 7c at the rear end is smaller than 8m.
The distance between the measuring points of the first measuring point group A and the second measuring point group B and the edge of the side close to the welding line 7a to be measured is less than 20mm, the distance between the measuring point of the third measuring point group C and the edge of the side close to the front end welding line 7B is less than 20mm, and the distance between the measuring point of the fourth measuring point group D and the edge of the side close to the rear end welding line 7C is less than 20mm.
The value principle of the correction coefficient Y of the temperature to the wall thickness of the pipe in the step 2 is as follows:
when the working temperature is less than or equal to 480 ℃, the value is 0.4;
when the working temperature is between 480 ℃ and 510 ℃, the value is 0.5;
when the working temperature is less than or equal to 480 ℃, the value is 0.4;
the value principle of the correction coefficient eta of the allowable stress in the step 2 is as follows:
when the pipeline is a seamless steel pipe, eta is 1;
when the pipeline is a longitudinal seam welded steel pipe and the welding mode is manual electric welding or gas welding, if the welding seam is in a double-sided welding groove butt welding mode, eta is 1, if the welding seam is in a single-sided welding groove butt welding mode with argon arc welding bottoming, eta is 0.9, and if the welding seam is in a single-sided welding groove butt welding mode without argon arc welding bottoming, eta is 0.75;
when the pipeline is a longitudinal seam welded steel pipe and the welding mode is automatic welding under a solvent, if the welding seam is a double-sided welding butt welding seam, eta is 1, if the welding seam is a single-sided welding groove butt welding seam, eta is 0.85, and if the welding seam is a single-sided welding groove-free butt welding seam, eta is 0.80.
The details are shown in the following table:
a pipeline thickness monitoring device for a pipeline weld joint stress monitoring and evaluating method comprises a thickness detector, wherein a probe 5 of the thickness detector is fixed on a clamp 2, the clamp is clamped on the outer wall of a pipeline to be detected, the detection end of the probe is in contact with the surface of the pipeline, a contact point is used as a measurement point, a buffer spring 4 for adapting to high-temperature expansion of the pipeline is arranged on the clamp, the surface of the probe is ensured to be attached to the surface of the pipeline, meanwhile, the probe is prevented from being damaged by expansion of the pipeline in a high-temperature state, and the thickness detector is connected with a controller;
the thickness detector monitors the real-time wall thickness of the pipeline through a probe, and simultaneously transmits the monitored wall thickness data to a controller for calculating the internal pressure conversion stress; the thickness detector is the prior art, such as an electromagnetic ultra-high temperature corrosion-resistant detector with the model number of ETG-100;
the controller is used for receiving the wall thickness data of the pipeline transmitted by the thickness detector, substituting the wall thickness data into a formula to calculate the internal pressure converted stress of each measuring point, and simultaneously calculating the calculated internal pressure converted stress and the allowable stress value [ sigma ] of the measured steel pipe at the design temperature of the pipeline, which is input in advance] t And comparing, and evaluating the weld stress according to the evaluation standard. The controller is the prior art, such as a PLC controller, a single chip microcomputer controller with the model of STC89C51 and the like;
the temperature sensor can be arranged on the clamp and used for detecting the temperature of the pipeline, the temperature of the pipeline can be the temperature of the working medium under the common condition, the temperature sensor is used for rechecking the operation temperature, and if the deviation is within a certain range, the operation temperature of the pipeline can be considered to be normal, if the deviation is within +/-5 ℃.
The connection between the probe (5) and the hoop is conventional connection, such as bolt connection, buckle connection, flange connection and the like, the hoop is directly buckled on a pipeline after being pulled open through a buffer spring (4), two ends of the hoop are lapped together, the lapped sections are connected through bolts (3), and the hoop can also be designed to be hinged with a left semicircle and a right semicircle and can be clamped on the pipeline; the clip can also be made of deformable material (similar to a watchband structure); the clamp can be according to the different clamps of producing different specification and dimension of pipeline diameter in order to adapt to the pipeline of different sizes simultaneously, and this technique is prior art.
One section has the pipeline of welding seam, because the welding seam can have welding stress in butt joint and welding, lead to the welding seam to be the weakest existence in this section pipeline, when the inside high temperature high pressure working medium that flows through of pipeline, because the pressure that the working medium brought, can give an effort of pipeline inner wall, simultaneously because the corruption that the working medium quality brought to the pipeline, and the scouring action of working medium flow to the pipeline, can cause the thickness of this section pipeline to take place the attenuate, so in this section pipeline that has the welding seam, the welding seam has just become the place that the defect appears most easily. In the current technical means, a method for monitoring the stress of a pipeline opening of a pipeline is not available, the method can accurately measure the real-time wall thickness of a measured point of the pipeline under the working condition by using a designed online monitoring device and a monitoring and evaluating method, can accurately calculate the equivalent stress generated by the internal pressure of a working medium on each measured point of the pipeline at a specific temperature by using a formula 1, and can judge whether a welding line has defects or not by comparing the equivalent stress with the allowable stress of a material at the specific temperature. Meanwhile, when the stress does not reach the allowable stress of the material, the stress borne by the welding seam can be predicted by drawing a wall thickness-stress curve at a specific temperature. The method has the advantages of obtaining the real-time state of the welding line to be detected or the adjacent welding line, improving the defect finding efficiency, providing a theoretical basis for maintenance, effectively solving the problem of stress monitoring and evaluation of the processed welding line, realizing online real-time monitoring, avoiding the problem that the processed welding line is newly cracked during the operation due to overhigh local stress, being convenient to use and good in effect, being an innovation in the processed welding line monitoring, ensuring the safe and stable operation of a thermal power plant, and having good social and economic benefits.
Through practical application, the invention has good technical effect, and concretely comprises the following steps:
the number of a low-temperature reheating steam pipeline of a certain power plant is 31, the outer diameter of the pipeline is 660mm, the design pressure is 5.72MPa, the initial wall thickness is 19.05mm, the temperature of a working medium flowing through the pipeline is 384 ℃, the material of the pipeline is 12Cr2MoG, and the temperature of the pipeline is 20 [ sigma ] at room temperature] t The allowable stress at the design temperature is 123MPa, the cold section pipeline is a seamless steel pipe, the monitored welding seam is a single-side welding groove butt welding seam with argon arc welding bottoming, the welding seam passes through surface flaw detection when shutdown maintenance is carried out, no defect is found, and after a stress monitoring device is installed, the actual measured pipeline data is as follows: (the working temperature is below 480 ℃, Y is 0.4; the additional thickness without considering corrosion, abrasion and mechanical strength, alpha is 0, the steel pipe to be tested is a seamless steel pipe, eta is 1) the data at room temperature are as follows:
in the table, the measuring point number C-1 represents the first measuring point of the third measuring point group C, the measuring point number A-2 represents the second measuring point of the first measuring point group A, and so on.
After 70 days at 384 degrees, the data were:
the test shows that the internal pressure converted stress calculated at the positions of the B-3 measuring point and the B-4 measuring point is overproof and is 123MPa higher than the allowable stress of the material at the operating temperature, the welding seam is inspected in the next shutdown maintenance of the unit, a surface opening crack with the length of 15mm is found near the position B-3 of the welding seam to be detected, a surface opening crack with the length of 2mm is found at the position B-4 measuring point, and the pipe is replaced, so that the pipe section at the thinned position is recovered to be normal.
As the experimental result shows that the internal pressure converted stress value of the D-3 measuring point of the rear-end welding line exceeds the allowable stress of the material, the rear-end welding line beside the section of the fourth measuring point group needs to be subjected to stress measurement in a second early warning state.
After the unit is shut down, the surface detection is carried out on the welding seam at the rear end, defects are not found temporarily, but because the welding seam is judged to be in a second early warning state, the stress monitoring is carried out on the welding seam, the welding seam at the rear end is used as a welding seam to be detected, the original welding seam to be detected is used as a front-end welding seam ', the other welding seam connected with the welding seam to be detected is used as a rear-end welding seam', after the equipment is installed at normal temperature, the real-time monitoring is carried out, and the data of the normal temperature of the welding seam to be detected are measured:
after 25 days of measurement, the internal pressure conversion stress value of the' B-3 measuring point of the welding line to be measured exceeds the standard, and the measured values are as follows:
the method is convenient to use and good in effect, is an innovation in the monitoring of the processed welding line, ensures the safe and stable operation of a thermal power plant, and has good social and economic benefits.
Claims (5)
1. A pipeline crater stress monitoring and evaluating method is characterized by comprising the following steps:
step 1: two sides of a welding seam (7 a) to be detected are respectively provided with two groups of measuring point groups for monitoring the wall thickness of pipelines at two sides of the welding seam, namely a first measuring point group A and a second measuring point group B, two welding seams adjacent to the welding seam to be detected on a pipeline are respectively a front end welding seam (7B) and a rear end welding seam (7C), a third measuring point group C for monitoring the wall thickness of the pipeline at one side of the front end welding seam (7B) close to the welding seam (7 a) to be detected is arranged on the pipeline at one side of the rear end welding seam (7C) close to the welding seam (7 a) to be detected, a fourth measuring point group D for monitoring the wall thickness of the pipeline at the position is arranged on the pipeline at one side of the rear end welding seam (7C) close to be detected, and each measuring point group comprises a plurality of measuring points which are arranged on the pipeline (1) at the corresponding side of the welding seam along the circumferential direction of the pipeline;
step 2: the wall thickness of the pipeline at the corresponding position is monitored in real time through the measuring points arranged in the step 1, and the internal pressure conversion stress of each measuring point is calculated through the following formula 1:
wherein:
σ eq -internal pressure reduced stress, MPa;
p- -design pressure, MPa;
D 0 -a pipe design outer diameter;
s- -measured wall thickness measured by measuring points;
y-correction coefficient of temperature to pipe wall thickness;
eta-correction factor of allowable stress;
α - -additional thickness in terms of corrosion, wear and mechanical strength, mm;
and step 3: converting the calculated internal pressure of each measuring point into stress sigma eq Allowable stress value [ sigma ] of steel and steel pipe to be tested at pipeline design temperature] t And comparing to evaluate the weld joint stress, wherein the specific evaluation criteria are as follows:
A. in all measurement points, the internal pressure reduced stress σ eq The point of the maximum value is positioned on the measuring points on the first measuring point group A or the second measuring point group B at the two sides of the welding line (7 a) to be measured, and the internal pressure of the maximum value is converted into stress sigma eq Allowable stress value [ sigma ] at design temperature of pipeline] t When the welding line (7 a) to be detected is judged to be in the first early warning state, the welding line to be detected has defect risks, and surface flaw detection is required;
B. in all measurement points, the internal pressure reduced stress σ eq Are all smaller than allowable stress value [ sigma ] at the design temperature of the pipeline] t When the welding seam (7 a) to be detected is in a good state, the defect detection is not needed;
C. in all measurement points, the internal pressure reduced stress σ eq The point of the maximum value falls on the third measuring point group C on the front end weld (7 b) side or the fourth measuring point group D on the rear end weld (7C) side, and the internal pressure of the maximum value is converted into stress sigma eq Allowable stress value [ sigma ] at design temperature of pipeline] t And then, judging that the welding line (7 a) to be detected is in a second early warning state, and carrying out stress monitoring or flaw detection on the front-end welding line (7 b) and the rear-end welding line (7 c) when the front-end welding line and the rear-end welding line have cracking risks.
2. The pipeline crater stress monitoring and evaluation method according to claim 1, wherein a distance L1 between the weld joint (7 a) to be tested and the front end weld joint (7 b) is less than 8m, and a distance L1 between the weld joint (7 a) to be tested and the rear end weld joint (7 c) is less than 8m.
3. The pipeline crater stress monitoring and evaluation method according to claim 1, wherein the distance between the measuring points of the first measuring point group A and the second measuring point group B and the edge of the weld to be measured (7 a) close to each other is less than 20mm, the distance between the measuring point of the third measuring point group C and the edge of the front end weld (7B) close to each other is less than 20mm, and the distance between the measuring point of the fourth measuring point group D and the edge of the rear end weld (7C) close to each other is less than 20mm.
4. The method for monitoring and evaluating the stress of the pipe craters according to claim 1, wherein the temperature-to-pipe wall thickness correction coefficient Y in the step 2 is obtained by the following principle:
when the working temperature is less than or equal to 480 ℃, the value is 0.4;
when the working temperature is between 480 ℃ and 510 ℃, the value is 0.5;
when the working temperature is less than or equal to 480 ℃, the value is 0.4.
5. The pipeline weld crater stress monitoring and evaluating method according to claim 1, wherein the correction coefficient η of the allowable stress in the step 2 is obtained according to a value principle:
when the pipeline is a seamless steel pipe, eta is 1;
when the pipeline is a longitudinal seam welded steel pipe and the welding mode is manual electric welding or gas welding, if the welding seam is in a double-sided welding groove butt welding mode, eta is 1, if the welding seam is in a single-sided welding groove butt welding mode with argon arc welding bottoming, eta is 0.9, and if the welding seam is in a single-sided welding groove butt welding mode without argon arc welding bottoming, eta is 0.75;
when the pipeline is a longitudinal seam welded steel pipe and the welding mode is automatic welding under a solvent, if the welding seam is a double-sided welding butt welding seam, eta is 1, if the welding seam is a single-sided welding groove butt welding seam, eta is 0.85, and if the welding seam is a single-sided welding groove-free butt welding seam, eta is 0.80.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110549501.5A CN113295313B (en) | 2021-05-20 | 2021-05-20 | Pipeline welded junction stress monitoring and evaluating method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110549501.5A CN113295313B (en) | 2021-05-20 | 2021-05-20 | Pipeline welded junction stress monitoring and evaluating method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113295313A CN113295313A (en) | 2021-08-24 |
| CN113295313B true CN113295313B (en) | 2023-02-28 |
Family
ID=77322962
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110549501.5A Active CN113295313B (en) | 2021-05-20 | 2021-05-20 | Pipeline welded junction stress monitoring and evaluating method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113295313B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114197313B (en) * | 2021-12-22 | 2023-05-12 | 中铁七局集团有限公司 | Intelligent monitoring device for construction safety of tower for hoisting river-crossing arch bridge |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5557048A (en) * | 1993-09-28 | 1996-09-17 | Hitachi, Ltd. | Stress evaluation method and apparatus therefor |
| JPH09218195A (en) * | 1996-02-13 | 1997-08-19 | Babcock Hitachi Kk | Method for evaluating damage of boiler pipe collecting stub pipe |
| JP2003080392A (en) * | 2001-09-07 | 2003-03-18 | Mitsubishi Heavy Ind Ltd | Welding repair structure and welding repair method of pipe |
| JP2004028769A (en) * | 2002-06-25 | 2004-01-29 | Tokyo Gas Co Ltd | Stress evaluating method for curved pipe, stress evaluating device, program, and storage medium for the same |
| JP2014052211A (en) * | 2012-09-05 | 2014-03-20 | Mitsubishi Heavy Ind Ltd | Welded part evaluation apparatus and welded part evaluation method |
| UA92921U (en) * | 2014-04-04 | 2014-09-10 | Национальный Университет "Львовская Политехника" | METHOD FOR DETEction of STRESSed STATE IN annular welded joints of PIPELINES |
| CN206583563U (en) * | 2017-03-29 | 2017-10-24 | 罗勇 | One kind is used for the annular scanning equipment of pipe welding seam ultrasonic wave residual stress test |
| CN108168755A (en) * | 2017-12-08 | 2018-06-15 | 燕山大学 | A kind of detection inside pipe wall residual stress drilling equipment and method |
| CN109307568A (en) * | 2018-11-16 | 2019-02-05 | 北京理工大学 | The lossless detection method of welding residual stress and the probe for using this method |
| CN110806191A (en) * | 2018-09-29 | 2020-02-18 | 北京科力华安地质灾害监测技术有限公司 | Circumferential weld defect pipeline safety evaluation method based on strain monitoring |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8186875B2 (en) * | 2008-09-14 | 2012-05-29 | Nuovo Pignone S.P.A. | Method for determining reheat cracking susceptibility |
-
2021
- 2021-05-20 CN CN202110549501.5A patent/CN113295313B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5557048A (en) * | 1993-09-28 | 1996-09-17 | Hitachi, Ltd. | Stress evaluation method and apparatus therefor |
| JPH09218195A (en) * | 1996-02-13 | 1997-08-19 | Babcock Hitachi Kk | Method for evaluating damage of boiler pipe collecting stub pipe |
| JP2003080392A (en) * | 2001-09-07 | 2003-03-18 | Mitsubishi Heavy Ind Ltd | Welding repair structure and welding repair method of pipe |
| JP2004028769A (en) * | 2002-06-25 | 2004-01-29 | Tokyo Gas Co Ltd | Stress evaluating method for curved pipe, stress evaluating device, program, and storage medium for the same |
| JP2014052211A (en) * | 2012-09-05 | 2014-03-20 | Mitsubishi Heavy Ind Ltd | Welded part evaluation apparatus and welded part evaluation method |
| UA92921U (en) * | 2014-04-04 | 2014-09-10 | Национальный Университет "Львовская Политехника" | METHOD FOR DETEction of STRESSed STATE IN annular welded joints of PIPELINES |
| CN206583563U (en) * | 2017-03-29 | 2017-10-24 | 罗勇 | One kind is used for the annular scanning equipment of pipe welding seam ultrasonic wave residual stress test |
| CN108168755A (en) * | 2017-12-08 | 2018-06-15 | 燕山大学 | A kind of detection inside pipe wall residual stress drilling equipment and method |
| CN110806191A (en) * | 2018-09-29 | 2020-02-18 | 北京科力华安地质灾害监测技术有限公司 | Circumferential weld defect pipeline safety evaluation method based on strain monitoring |
| CN109307568A (en) * | 2018-11-16 | 2019-02-05 | 北京理工大学 | The lossless detection method of welding residual stress and the probe for using this method |
Non-Patent Citations (1)
| Title |
|---|
| 某电厂三通焊接接头开裂原因分析;王昊等;《理化检验(物理分册)》;20191231(第007期);501-505 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113295313A (en) | 2021-08-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109781754B (en) | Safety evaluation method for pipeline girth weld defects | |
| CN109992825B (en) | Boiler four-tube real-time service life assessment method considering wall thickness reduction and overheating influence | |
| CN113295313B (en) | Pipeline welded junction stress monitoring and evaluating method | |
| CN104551337A (en) | 30CrMo heat resistant steel pipeline welding construction method | |
| CN101767243B (en) | Method for welding tuyere-cooler casing and blast furnace casing | |
| CN112393969B (en) | Axial surface type crack steel pipe explosion test device and fracture resistance evaluation method thereof | |
| CN111151845A (en) | Main loop of nuclear main pump test bed and inner wall surfacing and circumferential weld butt welding method thereof | |
| CN111077281A (en) | In-service fracturing high-pressure manifold detection method and system | |
| CN201140884Y (en) | Soldering structure of container housing made by zirconium steel composite board | |
| Chen et al. | Research on burst tests of pipeline with spiral weld defects | |
| CN113029075B (en) | Method for rapidly judging aging damage degree of high-temperature austenitic steel furnace tube for thermal power plant on site | |
| CN108682463B (en) | Repair structure for joint sleeve of main pipeline branch pipe of heavy water reactor | |
| CN112475549A (en) | Argon arc welding multilayer multi-channel water wall pipe repairing method | |
| CN102156146B (en) | Method for detecting cracks of heated steel tube welding joint | |
| CN105953018A (en) | Rubber-lining equipment corrosion online monitoring and control system | |
| Bartholomé et al. | Preclusion of double-ended circumferential rupture of the main coolant line | |
| CN205678342U (en) | A kind of rubber-lining equipment on-line corrosion monitoring and control system | |
| Povarov et al. | Analysis of the reasons for damage in the welded assembly joining the hot collector of first-loop coolant to the Du 1200 tube of the steam generators in No. 5 unit of the Novovoronezh NPP | |
| Turner | Flash-Butt welding of large-diameter oil and gas pipelines | |
| CN108597623B (en) | Stress corrosion cracking relieving main pipeline branch pipe joint connecting structure of heavy water reactor | |
| CN217156357U (en) | Ray detection fixing device for pipeline | |
| Alexander et al. | Reinforcement of Planar Defects in Low-Frequency ERW Long Seams Using Composite Reinforcing Materials | |
| CN209589592U (en) | Coke dry quenching furnace recyclegas detects sampling line | |
| Hopkins et al. | Investigation of fatigue-induced socket-welded joint failures for small-bore piping used in power plants | |
| CN113984638A (en) | Boiler flue gas side corrosion detection method based on alternating-current impedance |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |