CN113591348A - Three-dimensional stress calculation method for weld joint of in-service steam-water pipeline of thermal power plant - Google Patents

Three-dimensional stress calculation method for weld joint of in-service steam-water pipeline of thermal power plant Download PDF

Info

Publication number
CN113591348A
CN113591348A CN202110797829.9A CN202110797829A CN113591348A CN 113591348 A CN113591348 A CN 113591348A CN 202110797829 A CN202110797829 A CN 202110797829A CN 113591348 A CN113591348 A CN 113591348A
Authority
CN
China
Prior art keywords
stress
pipeline
power plant
thermal power
water pipeline
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.)
Granted
Application number
CN202110797829.9A
Other languages
Chinese (zh)
Other versions
CN113591348B (en
Inventor
刘明
李海洋
白佳
乔立捷
陈志荣
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huadian Electric Power Research Institute Co Ltd
Original Assignee
Huadian Electric Power Research Institute Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Huadian Electric Power Research Institute Co Ltd filed Critical Huadian Electric Power Research Institute Co Ltd
Priority to CN202110797829.9A priority Critical patent/CN113591348B/en
Publication of CN113591348A publication Critical patent/CN113591348A/en
Application granted granted Critical
Publication of CN113591348B publication Critical patent/CN113591348B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/14—Pipes
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Evolutionary Computation (AREA)
  • Geometry (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)

Abstract

The invention discloses a method for calculating three-dimensional stress of a weld joint of an in-service steam-water pipeline of a thermal power plant, which belongs to the technical field of pipeline stress analysis. The method comprises the steps of taking hanger hoisting points adjacent to two ends of a welding line as starting end points, selecting a long straight pipe section containing a target welding line as a research object, compiling a pipeline stress calculation program, obtaining actual thermal displacement data of the hoisting points at the two ends through a high-precision three-way displacement indicator, inputting test data into the calculation program through a visual interface, obtaining three-dimensional stress data of any position of the section of the welding line, and calculating the position of the maximum stress. The invention has the advantages of rapid and convenient measurement and calculation and low requirement on operators, the calculation precision can meet the requirement of engineering application, and the development of field detection work can be better guided.

Description

Three-dimensional stress calculation method for weld joint of in-service steam-water pipeline of thermal power plant
Technical Field
The invention relates to a three-dimensional stress calculation method for a weld joint of an in-service steam-water pipeline of a thermal power plant, belongs to the technical field of pipeline stress analysis, and can be widely applied to the fields of steam-water pipeline systems and related equipment of the thermal power plant.
Background
The pipeline stress level is an important index for judging whether the pipeline can run safely, a simplified beam model is generally adopted for calculation (CAESAR II, AUTO PIPE and other software) in the design of the steam-water pipeline of the thermal power plant at present, the flexibility and the integral stress level of the pipeline system are mainly analyzed, the stress analysis result is not consistent with the actual stress distribution, the primary stress is the pipeline axial stress under the action of continuous load, and the secondary stress is the maximum tensile stress of the pipeline section under the action of displacement load. The detailed three-dimensional stress distribution condition of the pipeline section cannot be inquired through conventional design files, and the actual stress condition and the theoretical design state of the in-service pipeline may have differences.
The pipeline welding seam is an important object for metal supervision of a thermal power plant, once defects or material performance degradation exist in the in-service pipeline welding seam, safety evaluation needs to be carried out according to the actual stress state of the position, and meanwhile, the actual stress state of the welding seam is also an important parameter for service life evaluation of the in-service pipeline.
At present, only finite element analysis software can be adopted for detailed stress analysis, the calculation process is complicated and time-consuming, certain requirements are required for the technical capability of operators, and the method cannot be quickly applied to field detection guidance.
Disclosure of Invention
The invention aims to overcome the defects in the existing heat-engine plant in-service pipeline weld stress calculation, and provides an in-service steam-water pipeline weld three-dimensional stress calculation method which is simple in operation, quick in calculation and high in precision and meets the requirements of practical engineering application.
The technical scheme adopted by the invention for solving the problems is as follows: a three-dimensional stress calculation method for a weld joint of an in-service steam-water pipeline of a thermal power plant is characterized by comprising the following specific steps of:
the first step is as follows: when detailed three-dimensional stress of a straight pipe section welding line needs to be analyzed in detail, a hanger lifting point adjacent to two ends of the welding line is taken as an initial end point, the long straight pipe section containing the target welding line is selected as a research object, the length L from the end face of a lifting point A to the end face of a lifting point B and the length L from the end face of the lifting point A to the end face of the welding line are measured1Recording the specification of the pipeline, wherein the outer diameter is Do, the wall thickness is S, and the thickness of the heat-insulating layer is t.
The second step is that: three-way displacement indicators are arranged on the end surface of the lifting point A and the end surface of the lifting point B to record the thermal expansion displacement (x) of the lifting point A1、y1、z1) Recording the thermal expansion displacement (x) of the suspension point B2、y2、z2)。
The third step: a software package of a heat-engine plant in-service steam-water pipeline weld joint three-dimensional stress calculation system is compiled by adopting Python language, measurement data are input by using a visual interface mode, and a detailed stress value is calculated. The stress calculation formula is as follows:
hoop stress (MPa):
Figure BDA0003163431920000021
radial stress (MPa):
Figure BDA0003163431920000022
horizontal pipe axial stress (MPa):
Figure BDA0003163431920000023
vertical pipe axial stress (MPa):
Figure BDA0003163431920000024
wherein: r and theta are position parameters of the stress solution point under the polar coordinate condition; doIs the outer diameter (mm) of the pipeline; s is the pipe wall thickness (mm); l, L1Is the length (mm) of the pipe section; t is the thickness (mm) of the heat preservation layer; (x)1、y1、z1) And (x)2、y2、z2) The thermal displacement value (mm) of the hanging points at the two ends is shown; di＝Do-2S is the inner diameter (mm) of the pipe;
Figure BDA0003163431920000025
is the pipe section moment of inertia (mm)4) (ii) a E is the elastic modulus (MPa) of the pipeline material at the working temperature; q is 24.6615X 10-2(Do-S)S+4.7124×10-2(Do+ t) t is the intermediate calculation parameter.
The fourth step: according to the stress solving formula, the axial maximum tensile stress position of the section of the welding seam can be calculated. The calculation formula is as follows:
Figure BDA0003163431920000026
for a horizontal pipe:
Figure BDA0003163431920000027
Figure BDA0003163431920000028
for a vertical pipe:
a＝x2-x1
b＝y2-y1。
preferably, the stress calculation process assumes that the axial displacement of the pipeline caused by thermal expansion is completely absorbed in the pipeline system based on the flexible design characteristics of the steam-water pipeline of the thermal power plant.
Preferably, on the basis of the stress characteristics of the steam-water pipeline structure of the thermal power plant, the pipeline stress caused by the torque action is not considered in the stress calculation process.
Preferably, the three-way displacement indicator in the second step has high reading precision, can adopt a mechanical type or a photoelectric type, and has a reading error of less than 0.1 mm.
Preferably, in the case that the actual thermal expansion of the pipeline is normal, the thermal expansion displacement of the hoisting point measured by the three-way thermal expansion indicator in the second step can also adopt the value of the thermal displacement of the hoisting point obtained by theoretical calculation.
Preferably, the program for solving the equation in the third step can be written in Python language or C, C + +, Fortran, and other calculation and languages.
Preferably, the calculation method can also be applied to three-dimensional stress calculation of any section of the straight pipe section.
Compared with the prior art, the invention has the following advantages and effects: (1) the three-dimensional stress of any position of the section of the welding seam and the position of the maximum stress can be obtained, and the development of field detection work can be guided better; (2) the measurement and calculation are quick and convenient, and the requirement on operators is low.
Drawings
FIG. 1 is a schematic diagram of horizontal pipeline test data in an embodiment of the present invention.
FIG. 2 is a schematic diagram of vertical pipe test data in an embodiment of the present invention.
FIG. 3 is a three-dimensional stress calculation software interface diagram of a weld of an in-service steam-water pipeline of a thermal power plant in an embodiment of the invention.
Fig. 4 is a graph comparing the stress calculation results at each radial position where θ is 130 ° in the embodiment of the present invention.
Detailed Description
The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not to be construed as limiting the present invention.
Examples are given.
Referring to fig. 1 to 3, in the process of overhauling a main steam pipeline of a 660MW ultra-supercritical thermal power generating unit, a linear defect is found in a group of welding seams on a horizontal pipe section of the main steam pipeline, the three-dimensional stress calculation method for the welding seams of the steam-water pipeline in service of the thermal power plant in the embodiment is adopted to calculate the three-dimensional stress at the position of the defect, and the operation steps are as follows:
the specification of the main steam pipe section is phi 472.8mm multiplied by 86.8mm, the material is A335P 92, the design temperature is 610 ℃, the design pressure is 29.67MPa, the thickness t of the aluminum silicate heat-preservation cotton is 300mm, and the query standard shows that the elastic modulus E of the material at the design temperature is 168.8 multiplied by 103MPa, measured in situ as L6000 mm, L13000mm, the thermal expansion displacement of the A end of the lifting point is recorded by a three-way displacement indicator arranged as (x)1＝118.3mm、y1＝-17.8mm、z1-75.4mm) and the thermal expansion displacement at the B-end of the suspension point is (x)2＝162.4mm、y2＝-68.5mm、z2＝-136.7mm)。
Inputting the data into an in-service steam-water pipeline welding seam three-dimensional stress calculation system at a defect position where r is 195mm and theta is 130 degrees, and calculating to obtain the three-dimensional stress of the position as follows: sigmar＝-9.31MPa、σθ＝48.95MPa、σL20.87 MPa; and the axial maximum tensile stress is between 122 and 130 degrees in the azimuth angle theta at different radial depths.
In order to verify the correctness of the calculation result of the invention, finite element software is adopted to carry out three-dimensional stress simulation analysis on the whole main steam pipeline, the stress calculation results of corresponding welding seams are extracted and compared, the stress calculation results of all radial positions at the position where theta is 130 degrees are shown in figure 4, the comparison result shows that the error between the two is within 10 percent, the calculation precision basically can meet the requirement of engineering application, and the calculation method and the assumed conditions adopted by the invention are reasonable and can be used for engineering field application.
Those not described in detail in this specification are well within the skill of the art.
Although the present invention has been described with reference to the above embodiments, it should be understood that the scope of the present invention is not limited thereto, and that various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the present invention.

Claims (4)

1. A three-dimensional stress calculation method for a weld joint of an in-service steam-water pipeline of a thermal power plant is characterized by comprising the following specific steps of:
the first step is as follows: when the detailed three-dimensional stress of the welding line of the straight pipe section is analyzed in detail, the hanging points of the hanging bracket adjacent to the two ends of the welding line are taken as starting end points, the long straight pipe section containing the target welding line is selected as a research object, the length L from the end face of the hanging point A to the end face of the hanging point B and the length L from the end face of the hanging point A to the end face of the welding line are measured1Recording the specification of the pipeline, wherein the outer diameter is Do, the wall thickness is S, and the thickness of the heat-insulating layer is t;
the second step is that: three-way displacement indicators are arranged on the end surface of the lifting point A and the end surface of the lifting point B to record the thermal expansion displacement (x) of the lifting point A1、y1、z1) Recording the thermal expansion displacement (x) of the suspension point B2、y2、z2)；
The third step: compiling a software package of a three-dimensional stress calculation system of the in-service steam-water pipeline welding line of the thermal power plant, inputting measurement data by using a visual interface mode, and calculating a detailed stress value; the stress calculation formula is as follows:
hoop stress (MPa):
Figure FDA0003163431910000011
radial stress (MPa):
Figure FDA0003163431910000012
horizontal pipe axial stress (MPa):
Figure FDA0003163431910000013
vertical pipe axial stress (MPa):
Figure FDA0003163431910000014
wherein: r and theta are position parameters of the stress solution point under the polar coordinate condition; doIs the outer diameter (mm) of the pipeline; s is the pipe wall thickness (mm); l, L1Is the length (mm) of the pipe section; t is the thickness (mm) of the heat preservation layer; (x)1、y1、z1) And (x)2、y2、z2) The thermal displacement value (mm) of the hanging points at the two ends is shown; di＝Do-2S is the inner diameter (mm) of the pipe;
Figure FDA0003163431910000015
is the pipe section moment of inertia (mm)4) (ii) a E is the elastic modulus (MPa) of the pipeline material at the working temperature; q is 24.6615X 10-2(Do-S)S+4.7124×10-2(Do+ t) t is an intermediate calculation parameter;
the fourth step: calculating the axial maximum tensile stress position of the section of the welding seam according to the stress solving formula; the calculation formula is as follows:
Figure FDA0003163431910000016
for a horizontal pipe:
Figure FDA0003163431910000021
Figure FDA0003163431910000022
for a vertical pipe:
a＝x2-x1
b＝y2-y1。
2. the method for calculating the three-dimensional stress of the weld joint of the in-service steam-water pipeline of the thermal power plant according to claim 1, wherein the axial displacement of the pipeline caused by thermal expansion is assumed to be completely absorbed in a pipeline system in the stress calculation process based on the flexible design characteristics of the steam-water pipeline of the thermal power plant.
3. The method for calculating the three-dimensional stress of the weld joint of the in-service steam-water pipeline of the thermal power plant according to claim 1, wherein the stress of the pipeline caused by the action of torque is not considered in the stress calculation process based on the stress characteristics of the steam-water pipeline structure of the thermal power plant.
4. The method for calculating the three-dimensional stress of the weld joint of the in-service steam-water pipeline of the thermal power plant according to claim 1, wherein in the second step, the three-way displacement indicator is in a mechanical or photoelectric type, and the reading error is less than 0.1 mm.
CN202110797829.9A 2021-07-14 2021-07-14 Method for calculating three-dimensional stress of weld joint of steam-water pipeline in service of thermal power plant Active CN113591348B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110797829.9A CN113591348B (en) 2021-07-14 2021-07-14 Method for calculating three-dimensional stress of weld joint of steam-water pipeline in service of thermal power plant

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110797829.9A CN113591348B (en) 2021-07-14 2021-07-14 Method for calculating three-dimensional stress of weld joint of steam-water pipeline in service of thermal power plant

Publications (2)

Publication Number Publication Date
CN113591348A true CN113591348A (en) 2021-11-02
CN113591348B CN113591348B (en) 2023-06-23

Family

ID=78247465

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110797829.9A Active CN113591348B (en) 2021-07-14 2021-07-14 Method for calculating three-dimensional stress of weld joint of steam-water pipeline in service of thermal power plant

Country Status (1)

Country Link
CN (1) CN113591348B (en)

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003028786A (en) * 2001-07-18 2003-01-29 Ishikawajima Harima Heavy Ind Co Ltd Stress corrosion crack forming method and device of tube inner surface
CN102261518A (en) * 2010-05-24 2011-11-30 中国石油天然气集团公司 Restoration construction method for in-service oil gas pipeline which encounters with collapse and destruction of worked-out section
CN109141516A (en) * 2018-07-05 2019-01-04 华电电力科学研究院有限公司 A kind of thermal power plant's high-temperature and pressure pipeline detection data management system and application method
CN109870295A (en) * 2019-02-20 2019-06-11 华电电力科学研究院有限公司 A kind of online service life evaluation system of thermal power plant jet chimney and method
CN110188377A (en) * 2019-04-12 2019-08-30 中国大唐集团科学技术研究院有限公司火力发电技术研究院 It is a kind of fatigue operating condition under steam guiding tube welding line structure damage measurement method
CN110414081A (en) * 2019-07-08 2019-11-05 华电电力科学研究院有限公司 A kind of thermal power plant pipe stress coupling analysis system and analysis method
CN111396676A (en) * 2020-04-27 2020-07-10 南京晨光东螺波纹管有限公司 Displacement compensation device of arc-shaped heat pipe and installation method thereof
CN112149332A (en) * 2020-09-27 2020-12-29 大唐东北电力试验研究院有限公司 Safety state evaluation method for steam-water pipeline supporting and hanging system of thermal power plant
CN112270118A (en) * 2020-10-26 2021-01-26 甘肃蓝科石化高新装备股份有限公司 Method for predicting stress corrosion sensitivity of welded joint of tube and tube plate of shell-and-tube heat exchanger
CN112395801A (en) * 2020-12-08 2021-02-23 中国石油天然气集团有限公司 Method for determining length of B-shaped sleeve for repairing circumferential weld defects of oil and gas pipeline

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003028786A (en) * 2001-07-18 2003-01-29 Ishikawajima Harima Heavy Ind Co Ltd Stress corrosion crack forming method and device of tube inner surface
CN102261518A (en) * 2010-05-24 2011-11-30 中国石油天然气集团公司 Restoration construction method for in-service oil gas pipeline which encounters with collapse and destruction of worked-out section
CN109141516A (en) * 2018-07-05 2019-01-04 华电电力科学研究院有限公司 A kind of thermal power plant's high-temperature and pressure pipeline detection data management system and application method
CN109870295A (en) * 2019-02-20 2019-06-11 华电电力科学研究院有限公司 A kind of online service life evaluation system of thermal power plant jet chimney and method
CN110188377A (en) * 2019-04-12 2019-08-30 中国大唐集团科学技术研究院有限公司火力发电技术研究院 It is a kind of fatigue operating condition under steam guiding tube welding line structure damage measurement method
CN110414081A (en) * 2019-07-08 2019-11-05 华电电力科学研究院有限公司 A kind of thermal power plant pipe stress coupling analysis system and analysis method
CN111396676A (en) * 2020-04-27 2020-07-10 南京晨光东螺波纹管有限公司 Displacement compensation device of arc-shaped heat pipe and installation method thereof
CN112149332A (en) * 2020-09-27 2020-12-29 大唐东北电力试验研究院有限公司 Safety state evaluation method for steam-water pipeline supporting and hanging system of thermal power plant
CN112270118A (en) * 2020-10-26 2021-01-26 甘肃蓝科石化高新装备股份有限公司 Method for predicting stress corrosion sensitivity of welded joint of tube and tube plate of shell-and-tube heat exchanger
CN112395801A (en) * 2020-12-08 2021-02-23 中国石油天然气集团有限公司 Method for determining length of B-shaped sleeve for repairing circumferential weld defects of oil and gas pipeline

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
H.V. KRECHKOVS\'KA等: "Diagnostics of the engineering state of steam pipelines of thermal power plants by the hardness and crack resistance of steel" *
刘明等: "火电厂汽水管道热胀位移异常综合评估及处理" *
徐卫仙等: "基于火电厂四大管道图形信息管理***开发与应用" *

Also Published As

Publication number Publication date
CN113591348B (en) 2023-06-23

Similar Documents

Publication Publication Date Title
CN110822294B (en) Submarine pipeline structure bending failure assessment method containing corrosion defects
KR101158250B1 (en) Pipe Line Evaluation and Repair Methods using Measured Linear Coefficient
CN110108455B (en) Method for measuring vibration stress and evaluating fatigue life of small pipeline of nuclear power plant
CN110909505A (en) Transient temperature field calculation method of nuclear power plant fatigue monitoring and life evaluation system
KR101045884B1 (en) Reliability Evaluation and Recovery Method of High Temperature High Pressure Piping and Support System Reflecting Operating Environment
JP5306561B1 (en) Tube leak detection device and tube leak detection method
Kim et al. Investigation on the effects of geometric variables on the residual stresses and PWSCC growth in the RPV BMI penetration nozzles
JP4808110B2 (en) Damage assessment method
CN113591348A (en) Three-dimensional stress calculation method for weld joint of in-service steam-water pipeline of thermal power plant
CN105909910A (en) On-line rubber lining integrality monitoring system
JP3389209B2 (en) Method and system for selecting priority inspection locations for piping
CN110990972B (en) Simplified assessment method for thermal shock resistance of heat exchange tube and tube plate joint of photo-thermal heat exchanger
CN209919140U (en) Dynamic stress testing device for welding seam of steam guide pipe of steam turbine of supercritical unit
KR20100010815U (en) / Plant Pipe Life Evaluation Method Based On Operation History Including Creep and Fatigue
Cho et al. Cyclic plasticity behavior of 90 back-to-back pipe bends under cyclic bending and steady pressure
JP4831624B2 (en) Graphitization damage diagnosis method for carbon steel and Mo steel for boilers
Dewees Grade 11 High Temperature Steam Header Case History and Benchmark
Brodov et al. State of the art and trends in the design and operation of high-and low-pressure heaters for steam turbines at thermal and nuclear power plants in Russia and abroad: Part 2. Heater design and operation peculiarities
Wang et al. Effect of pipe length on the temperature field for 9% Cr heat-resistant steel pipes in local post weld heat treatment
JP2003065984A (en) Method and apparatus for assessing remaining life of furnace heat conduction wall panel
JP4415299B2 (en) Piping equipment design method
Yin et al. Numerical Simulation of Thermal-Mechanical Stress Field of Coke Drum Considering Deformation
Kaushik et al. A Review on Finite Element Modeling and Analysis Of Gasket On Circular Bolted Flange Connection
Yahiaoui et al. Pressurized piping elbows under simulated seismic bending: design code implications
Katsuyama et al. Creep deformation analysis of a pipe specimen based on creep damage evaluation method

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