CN113869708A - State evaluation method for high-pressure steam guide pipe of steam turbine - Google Patents

State evaluation method for high-pressure steam guide pipe of steam turbine Download PDF

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CN113869708A
CN113869708A CN202111124399.0A CN202111124399A CN113869708A CN 113869708 A CN113869708 A CN 113869708A CN 202111124399 A CN202111124399 A CN 202111124399A CN 113869708 A CN113869708 A CN 113869708A
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王大鹏
杜保华
吴智群
黄廷辉
何新
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Xian Thermal Power Research Institute Co Ltd
Xian TPRI Power Station Information Technology Co Ltd
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Abstract

A state evaluation method of a high-pressure steam guide pipe of a steam turbine comprises the following steps; 1) determining a high-pressure steam guide pipe of a steam turbine to be evaluated and confirming basic information; 2) clearly evaluating the stage of the full operation life cycle of the object; 3) finally selecting evaluation points from the straight pipe, the elbow and the welding line; 4) calculating a basic state factor according to the defect condition found in the full operation life cycle stage and the design, manufacture and installation stage; 5) calculating a correction factor according to the feedback of the evaluation result of the evaluation object; 6) selecting executable projects to formulate and implement an offline detection scheme aiming at the selected evaluation points; 7) obtaining an off-line detection state parameter result; 8) performing state evaluation on the selected straight pipe, the elbow and the welding seam evaluation point; 9) performing state evaluation on the evaluation object by integrating the state evaluation result of the evaluation point; 10) the feedback is used to calculate a correction factor for the next evaluation. The invention can help thermal power plant steam turbines or metal professional technicians to better make maintenance strategies.

Description

State evaluation method for high-pressure steam guide pipe of steam turbine
Technical Field
The invention belongs to the technical field of state evaluation of equipment of a thermal power plant, and particularly relates to a state evaluation method of a high-pressure steam guide pipe of a steam turbine.
Background
The high-pressure steam guide pipe of the steam turbine is an important part of a steam turbine system of a thermal power plant, in recent years, a thermal power generating unit frequently participates in peak shaving operation of a power grid, so that the high-pressure steam guide pipe of the steam turbine is in a severe working condition in the operation process and is easily influenced by the action of heat exchange variable load, and creep cavities in local areas are connected into a string to easily form microcracks after long-term high-temperature and high-pressure operation. Particularly, under the influence of high temperature and high pressure variable load of a welding seam at the joint of the high pressure steam guide pipe and the high pressure outer cylinder of the steam turbine, the structural state of the welding seam is deteriorated, and the failure risk is increased due to the structural embrittlement. In addition, since the high-pressure steam guide pipe of the steam turbine is located outside the high-pressure cylinder of the platform of the steam turbine, if failure occurs, a major safety accident may be caused, and therefore, it is necessary to evaluate the state of the high-pressure steam guide pipe of the steam turbine more accurately.
For a high-pressure steam guide pipe of a steam turbine, a nondestructive inspection method is reported in the literature, the evaluation of material state and the estimation of creep residual life are carried out on the steam guide pipe of a boiler in a certain power plant, such as the evaluation of the material state and the creep residual life of the steam guide pipe of the boiler in the literature, thermal power generation, 2011(8), the evaluation of high-temperature impact power and the high-temperature endurance strength of the steam guide pipe is reported in the literature based on a laboratory material performance test, the maximum stress of the steam guide pipe in a working state is calculated based on a finite element method, the residual life of the steam guide pipe is predicted, such as the evaluation of the availability and the analysis of the residual life of the steam guide pipe of the boiler in a power station, the university of east China's Ministry of technology, 2002 ', a comprehensive strength analysis method based on material aging factors and a creep damage method are reported in the literature, such as the evaluation of the use state and the life of the high-pressure steam guide pipe in the power plant in Huainan Tian's county, 2000' of the academic conference and argument set of the failure analysis and service life management of the sixth power station metal components in the country, but no report on the state evaluation of the high-pressure steam guide pipe of the steam turbine is found.
Therefore, a universal method is needed to be found, evaluators do not need to have abundant basic knowledge of mathematical analysis, basic knowledge of metal materials, knowledge of mechanical calculation, knowledge and experience of service life evaluation, extra cost of test cost is not needed, and the state of the high-pressure steam guide pipe of the steam turbine can be evaluated only by obtaining existing off-line detection data, so that technicians of a thermal power plant are directly helped to make maintenance strategies.
Disclosure of Invention
In order to overcome the technical problems, the invention aims to provide a state evaluation method for a high-pressure steam guide pipe of a steam turbine, which helps a professional of the steam turbine of a thermal power plant or a metal professional to make a maintenance strategy better.
In order to achieve the purpose, the technical scheme adopted by the invention and the beneficial effects of the invention are as follows:
a state evaluation method of a high-pressure steam guide pipe of a steam turbine comprises the following steps;
1) determining an evaluation object and basic information of the evaluation object, wherein the evaluation object is a high-pressure steam guide pipe of a steam turbine, such as a left high-pressure steam guide pipe of the steam turbine and a right high-pressure steam guide pipe of the steam turbine, and the basic information comprises a design drawing, a design diameter, a design wall thickness, a design material, design and manufacture data and previous maintenance record files;
2) clearly evaluating the four stages of the front stage, the middle stage, the end stage and the final stage of the full operation life cycle of the object;
3) based on the principle of comprehensive consideration of key parts of equipment, easiness in detection and operation, lowest maintenance cost and controllable maintenance plan, detailed evaluation points are selected from straight pipes, elbows and welding lines in a targeted manner;
4) calculating a basic state factor according to the defect condition found in the full operation life cycle stage and the design, manufacture and installation stage;
5) calculating a correction factor according to the feedback of the last three evaluation results of the evaluation object;
6) selecting proper items from macroscopic inspection, surface flaw detection, nondestructive flaw detection, metallographic inspection, pipe diameter inspection, ovality measurement, hardness inspection and wall thickness measurement according to the selected evaluation points to formulate and implement an offline detection scheme;
7) obtaining an off-line detection state parameter result;
8) performing state evaluation on the selected straight pipe, the elbow and the welding seam evaluation point;
9) integrating the state evaluation results of all the evaluation points, and carrying out state evaluation on the evaluation object;
10) the state of the subject is evaluated for the next evaluation feedback for calculating the correction factor.
The step 2) comprises the following specific operation steps:
the definite evaluation object is in a specific stage of the full-operation life cycle, and the early stage is (0, 0.1L)c]The middle stage is (0.1L)c,0.8Lc]The final phase is (0.8L)c,0.9Lc]The final stage is (0.9L)c,Lc]，LcFor design life, LcTypically 30 years.
The specific operation steps of the step 3) are as follows:
based on the principle comprehensive consideration of key parts of equipment, easy detection operation, lowest maintenance cost, controllable maintenance plan and the like, assessment points are determined in a targeted manner and are divided into three categories: straight tubes, elbows and welds, distinguished by the following corner marks st, et and wb, respectively.
The specific operation steps of calculating the basic state factor in the step 4) are as follows:
determining a basic state factor C according to the formula (1) based on the stage of the full operation life cycle of the specific evaluation object in the step 2) and the defect condition found in the stage of design, manufacture and installationS；
CS＝α·S (1)
In the formula, the values of the parameters alpha and S are searched from the following table according to the basic information collected in the step 1);
Figure BDA0003278172650000041
the specific operation steps of calculating the correction factor in the step 5) are as follows:
determining the correction factor C according to the formula (2) based on the feedback of the last three evaluation results of the evaluation objectC；
Figure BDA0003278172650000042
In the formula, the parameter δ is an evaluation target running time (unit: year);
and C1、C2、C3The values of the correction coefficients corresponding to the last three evaluation results are shown in the following table.
Figure BDA0003278172650000043
Figure BDA0003278172650000051
The step 6) comprises the following specific operation steps:
and (3) selecting executable items from the macroscopic inspection, the surface flaw detection, the nondestructive flaw detection, the metallographic inspection, the pipe diameter inspection, the ellipticity measurement, the hardness inspection and the wall thickness measurement according to the evaluation points determined in the step 3), making an offline detection scheme and implementing the offline detection scheme.
The specific operation steps of the step 7) are as follows:
and acquiring various off-line detection state parameter results of the evaluation points according to the off-line detection items determined in the step 6), and dividing the off-line detection state parameter results into a rating type and a measurement type.
The state parameters corresponding to the four off-line detection items of macroscopic inspection, surface flaw detection, nondestructive flaw detection and metallographic inspection are collectively called rating type state parameters, and the state parameters and the weights of the rating type state parameters are respectively used as CPG1、CPG2、CPG3、CPG4And WG1、WG2、WG3、WG4And (4) showing.
The state parameters corresponding to four off-line detection items of pipe diameter inspection, ovality measurement, hardness inspection and wall thickness measurement are collectively called rating state parameters, and the state parameters and the weights of the rating state parameters are respectively used as CPM1、CPM2、CPM3、CPM4And WM1、WM2、WM3、WM4And (4) showing.
The step 8) comprises the following specific operation steps:
performing state evaluation on a single evaluation point according to the off-line detection state parameter result obtained in the step 7), and defining the state of the single evaluation point as CjThe evaluation model is shown as formula (3);
Figure BDA0003278172650000052
state C of evaluation pointjThe value of (A) normally falls within [0,1 ]]In the interval range, CjWhen the value of (a) is changed from 0 to 1, the state of the evaluation point becomes worse and worse;
weight W of two types of state parameters in the formula (3)Gi、WMiGiving the rule of formula (4);
Figure BDA0003278172650000061
the specific operation steps in the step 9) are as follows:
counting all the evaluation points obtained in the step 8) according to the classification of straight pipes, elbows and welding lines (the lower corner marks are st, et and wb respectively), counting the number x of the evaluation points of the straight pipes, the number y of the evaluation points of the elbows and the number z of the evaluation points of the welding lines, then carrying out overall evaluation on the evaluation object, and finally, obtaining an evaluation model of the state value as shown in the formula (13).
Figure BDA0003278172650000062
If the C value of the state of the evaluation object is 0, the state of the evaluation object is considered to be optimal, and when the C value changes from 0 to 1, the state of the evaluation object gradually becomes worse; when the C value is larger than 0.8, the state of the evaluation object is poor, a plurality of evaluation points are poor in state, particularly in the final stage and the final stage of the full operation life cycle, if three evaluations are carried out continuously, the C value of the state of the evaluation object is larger than 0.8, the poor state of the evaluation object is proved, and the enterprise needs to make preparations for overall replacement of the evaluation object.
The specific operation steps in the step 10) are as follows:
and 9) feeding back a state evaluation result of the evaluation object for the next evaluation to calculate the correction factor of the step 5).
The rating class state parameter in the step 7): macroscopic State parameter CPG1-jFrom the results of the macroscopic examination OSG1-j: { no defect found, few suspected defects found, inventive defect evident } definition, as shown in equation (5):
Figure BDA0003278172650000071
the rating class state parameter in the step 7): surface state parameter CPG2-jResults of surface inspection OSG2-j: { no defect found, surface defect found but eliminated after sanding, surface defect found but still present after sanding } is defined as shown in equation (6):
Figure BDA0003278172650000072
the rating class state parameter in the step 7): lossless State parameter CPG3-jFrom results of non-destructive inspection OSG3-j: { stage I, stage II, stage III, stage IV } definition, as shown in equation (7):
Figure BDA0003278172650000073
the steps areRating class status parameter in step 7): tissue state parameter CPG4-jFrom results of metallographic examination OSG4-j: { level 1, level 2, level 3, level 4, level 5 } definition, as shown in equation (8):
Figure BDA0003278172650000081
the measurement of the class state parameters in the step 7): pipe diameter state parameter CPM1-jResults of inspection of pipe diameter OSM1-jAs defined by formula (9):
Figure BDA0003278172650000082
in the formula (9), D0The design pipe diameter is in mm; e is the ultimate creep expansion rate, and the unit is percent, for the high-pressure steam guide pipe of the steam turbine, the value of the ultimate creep expansion rate is shown in the following table:
material of Alloy steel Carbon steel
Value of e 2.5％ 3.5％
The measurement of the class state parameters in the step 7): ovality state parameter CPM2-jResult of ovality check OSM2-jDefinition, as shown in formula (10):
Figure BDA0003278172650000083
in the formula (10), DmaxTo measure the maximum outer diameter, in mm; dminTo measure the minimum outer diameter, in mm; beta is an ovality limiting value, the unit is percent, for the high-pressure steam guide pipe of the steam turbine, the ovality limiting value is shown in the following table:
material of R/D0≥4 2.5≥R/D0＞4 R/D0＜2.5
Value of beta 10％ 12％ 14％
Wherein R is the bending radius and the unit is mm; d0For design pipe diameter, the unit is mm.
The measurement of the class state parameters in the step 7): hardness State parameter CPM3-jResults from hardness test OSM3-jAs defined by formula (11):
Figure BDA0003278172650000091
the hardness in the formula (11) is Brinell hardness, HBLAnd HBHMinimum and ultimate hardness, respectivelyMaximum value, HB of common material for high-pressure steam guide pipe of steam turbineLAnd HBHValues are summarized in the following table:
material of P91 P92 P122 …
HBL 185 185 185 …
HBH 270 270 270 …
The measurement of the class state parameters in the step 7): wall thickness State parameter CPM4-jResults of wall thickness inspection OSM4-jDefinitions, as shown in equation (12):
Figure BDA0003278172650000092
in the formula (12), d0To design forWall thickness in mm.
The invention has the beneficial effects that:
according to the invention, on the basis of conventional metal inspection data aiming at the high-pressure steam guide pipe of the steam turbine, the state of the high-pressure steam guide pipe of the steam turbine is evaluated through correction of basic state factors and correction factors without the need that an evaluator has abundant basic knowledge of metal materials, mechanics calculation knowledge, service life evaluation knowledge and experience and the need of bearing extra test cost, so that a technician of a thermal power plant is directly helped to make a next maintenance strategy, if the evaluation is carried out for three times continuously, the state value of the high-pressure steam guide pipe of the steam turbine is gradually increased, the state is increasingly poor, and an enterprise needs to make preparation for overall replacement of an evaluation object.
By adopting the technical scheme, the state of the high-pressure steam guide pipe of the steam turbine is obtained through evaluation, so that a thermal power plant technician can be helped to know the actual state of the high-pressure steam guide pipe of the steam turbine, the change trend of the state of the high-pressure steam guide pipe of the steam turbine can be predicted through multiple state evaluation results aiming at the same evaluation point, the state results of all the evaluation points can be integrated to evaluate the overall state of the high-pressure steam guide pipe of the steam turbine, and the method has important significance for making a maintenance plan and replacing strategies.
Drawings
FIG. 1 is a schematic diagram of a state estimation process according to the present invention.
Detailed Description
The invention is further described below with reference to the drawings and two specific embodiments.
The first embodiment is as follows:
taking the result of overhauling a steam guide pipe of a high-pressure cylinder of a steam turbine of a certain 300MW subcritical unit in 2019 in 12 months, carrying out state evaluation according to the method disclosed by the invention:
1) the explicitly evaluated objects are: the high-pressure cylinder of the steam turbine leads the steam pipe. Basic information: design diameter and wall thickness: phi 413.8 multiplied by 69.6mm, design material P22 and bending radius 1050 mm.
The steam guide pipe of the high-pressure cylinder of the steam turbine has no abnormity in the design and manufacturing stage, no replacement and maintenance record is generated during the operation, and the state evaluation results of the last 3 times are respectively as follows: better, general and normal.
2) The steam turbine high pressure cylinder steam guide has been in operation for 27.5 years at the end of the full operating life cycle.
3) Considering the maintenance condition of nearly three times, 4 straight pipe evaluation points, 2 elbow evaluation points and 4 welding seam evaluation points are selected.
4) The steam guide pipe of the high-pressure cylinder of the steam turbine is in the final stage of the full operation life cycle, the parameter alpha is 5, a small amount of abnormity exists during design, manufacture and installation, but normal use is not influenced, S is 0.01, and the value of the basic state factor is calculated to be 0.05.
5) And (3) state evaluation results of a steam guide pipe of a high-pressure cylinder of the steam turbine for the last 3 times: better, general, worse, the calculated correction factor value is 0.117;
6) selecting items of macroscopic inspection, surface flaw detection, nondestructive flaw detection, metallographic inspection, pipe diameter inspection, hardness inspection and wall thickness measurement aiming at an evaluation point selected by a steam guide pipe of a high-pressure cylinder of the steam turbine, and formulating and implementing an off-line detection scheme;
7) acquiring the off-line detection state parameter result of a steam guide pipe of a high-pressure cylinder of the steam turbine, as shown in the following;
Figure BDA0003278172650000111
8) the state evaluation is carried out on 4 straight pipe evaluation points, 2 elbow evaluation points and 4 welding seam evaluation points selected by a high-pressure steam guide pipe of the steam turbine, and the state evaluation is as follows:
Figure BDA0003278172650000121
9) and integrating the state evaluation results of all the evaluation points to evaluate the state of the evaluation object, wherein the evaluated state value of the high-pressure steam guide pipe is 0.72, compared with the state evaluation value of 0.69 of the latest 1 time, the state of the high-pressure steam guide pipe has a trend of deterioration, and the real-time state monitoring of the high-pressure steam guide pipe is required to be well done.
Figure BDA0003278172650000122
10) And finally, filing the state evaluation result of the high-pressure steam guide pipe, feeding back the state evaluation result for the next evaluation, and calculating a correction factor.
The second embodiment:
taking the result of A-repair of a left high-pressure upper cylinder steam guide pipe and a right high-pressure upper cylinder steam guide pipe of a steam turbine of a certain 600MW supercritical unit in 10 months in 2020 as an example, the method is used for implementing state evaluation:
1) the explicitly evaluated objects are: the high-pressure steam guide pipe on the left side of the steam turbine and the high-pressure steam guide pipe on the right side of the steam turbine.
The high pressure steam guide pipe on the left side of the steam turbine and the high pressure steam guide pipe on the right side of the steam turbine are distributed in a bilateral symmetry mode, basic information is basically consistent, and the diameter and the wall thickness are designed: 392.2mm by 65.9mm, design material P122, bending radius 1450 mm.
The high-pressure steam guide pipe on the left side of the steam turbine and the high-pressure steam guide pipe on the right side of the steam turbine are not abnormal in the design and manufacturing stage, the replacement and maintenance records are not carried out during the operation, and the state evaluation results of the last 3 times are respectively as follows: generally, worse.
2) The left high-pressure steam guide pipe and the right high-pressure steam guide pipe of the steam turbine have been operated for 25 years and are in the final stage of the full operation life cycle.
3) Considering the maintenance condition of nearly three times, aiming at each steam guide pipe, 3 straight pipe evaluation points are selected at the upper, middle and lower parts of the straight pipe, 1 elbow evaluation point is selected at the upper elbow part, and 2 welding seam evaluation points are selected at the welding seam parts of the elbow and the straight pipe.
4) And the high-pressure steam guide pipe on the left side of the steam turbine and the high-pressure steam guide pipe on the right side of the steam turbine are in the final stage of the full operation life cycle, the parameter alpha is 2, 0 is obtained when no abnormality S is found during design, manufacture and installation, and the calculated basic state factor values are all 0.
5) The state evaluation results of the high-pressure steam guide pipe on the left side of the steam turbine and the high-pressure steam guide pipe on the right side of the steam turbine last 3 times are as follows: generally, worse and worse, the calculated correction factor values are all 0.21;
6) selecting items of macroscopic inspection, surface flaw detection, nondestructive flaw detection, metallographic inspection, pipe diameter inspection, ellipticity measurement, hardness inspection and wall thickness measurement according to evaluation points selected by the left high-pressure steam guide pipe and the right high-pressure steam guide pipe of the steam turbine, and formulating and implementing an offline detection scheme;
7) obtaining the off-line detection state parameter results of the high-pressure steam guide pipe on the left side of the steam turbine and the high-pressure steam guide pipe on the right side of the steam turbine as shown in the following;
Figure BDA0003278172650000141
8) the state evaluation is carried out on the straight pipe, the elbow and the welding seam evaluation point selected by the high-pressure steam guide pipe on the left side of the steam turbine and the high-pressure steam guide pipe on the right side of the steam turbine, and the state evaluation is as follows:
Figure BDA0003278172650000142
9) and integrating the state evaluation results of all the evaluation points to evaluate the state of the evaluation object.
And the state evaluation value of the left high-pressure upper cylinder steam guide pipe reaches the critical limit value of 1.00, and direct replacement is recommended.
Although the right high-pressure upper cylinder steam guide pipe does not reach the critical limit value, the evaluation point state of the welding seam of the elbow and the straight pipe is poor, and the right high-pressure upper cylinder steam guide pipe is required to be processed in time.
Figure BDA0003278172650000151
10) And finally, filing the state evaluation result of the right high-pressure upper cylinder steam guide pipe, feeding back the state evaluation result for the next evaluation, and calculating a correction factor. And the left high-pressure upper cylinder steam guide pipe is replaced by a new pipe, and the calculation is restarted when the evaluation is carried out next time, so that the correction is not needed.

Claims (10)

1. A state evaluation method of a high-pressure steam guide pipe of a steam turbine is characterized by comprising the following steps;
1) determining an evaluation object and basic information of the evaluation object, wherein the evaluation object is a high-pressure steam guide pipe of a steam turbine, such as a left high-pressure steam guide pipe of the steam turbine and a right high-pressure steam guide pipe of the steam turbine, and the basic information comprises a design drawing, a design diameter, a design wall thickness, a design material, design and manufacture data and previous maintenance record files;
2) clearly evaluating the four stages of the pre-stage, the middle stage, the end stage and the final stage of the full operation life cycle of the object
3) Based on the principle of comprehensive consideration of key parts of equipment, easiness in detection and operation, lowest maintenance cost and controllable maintenance plan, detailed evaluation points are selected from straight pipes, elbows and welding lines in a targeted manner;
4) calculating a basic state factor according to the defect condition found in the full operation life cycle stage and the design, manufacture and installation stage;
5) calculating a correction factor according to the feedback of the last three evaluation results of the evaluation object;
6) selecting proper items from macroscopic inspection, surface flaw detection, nondestructive flaw detection, metallographic inspection, pipe diameter inspection, ovality measurement, hardness inspection and wall thickness measurement according to the selected evaluation points to formulate and implement an offline detection scheme;
7) obtaining an off-line detection state parameter result;
8) performing state evaluation on the selected straight pipe, the elbow and the welding seam evaluation point;
9) integrating the state evaluation results of all the evaluation points, and carrying out state evaluation on the evaluation object;
10) the state of the subject is evaluated for the next evaluation feedback for calculating the correction factor.
2. The method for evaluating the condition of the high-pressure steam guide pipe of the steam turbine according to claim 1, wherein the step 2) comprises the following specific operation steps:
the definite evaluation object is in a specific stage of the full-operation life cycle, and the early stage is (0, 0.1L)c]The middle stage is (0.1L)c,0.8Lc]The final phase is (0.8L)c,0.9Lc]The final stage is (0.9L)c,Lc]，LcFor design life, LcTypically 30 years.
3. The method for evaluating the condition of the high-pressure steam guide pipe of the steam turbine according to claim 1, wherein the step 3) comprises the following specific operation steps:
based on the principle comprehensive consideration of key parts of equipment, easy detection operation, lowest maintenance cost, controllable maintenance plan and the like, assessment points are determined in a targeted manner and are divided into three categories: straight tubes, elbows and welds, distinguished by the following corner marks st, et and wb, respectively.
4. The method for evaluating the condition of the high-pressure steam guide pipe of the steam turbine according to claim 1, wherein the specific operation steps in the step 4) are as follows:
determining a basic state factor C according to the formula (1) based on the stage of the full operation life cycle of the evaluation object determined in the step 2)S；
CS＝α·S (1)
In the formula, the values of the parameters alpha and S are searched from the following table according to the basic information collected in the step 1);
Figure FDA0003278172640000021
Figure FDA0003278172640000031
5. the method for evaluating the condition of the high-pressure steam guide pipe of the steam turbine according to claim 1, wherein the step 5) comprises the following specific operation steps:
determining the correction factor C according to the formula (2) based on the feedback of the last three evaluation results of the evaluation objectC；
Figure FDA0003278172640000032
In the formula, the parameter δ is an evaluation target running time (unit: year);
and C1、C2、C3The values of the correction coefficients corresponding to the last three evaluation results are shown in the following table.
Figure FDA0003278172640000033
6. The method for evaluating the condition of the high-pressure steam guide pipe of the steam turbine according to claim 1, wherein the step 6) comprises the following specific operation steps:
and (3) selecting executable items from the macroscopic inspection, the surface flaw detection, the nondestructive flaw detection, the metallographic inspection, the pipe diameter inspection, the ellipticity measurement, the hardness inspection and the wall thickness measurement according to the evaluation points determined in the step 3), making an offline detection scheme and implementing the offline detection scheme.
7. The method for evaluating the condition of the high-pressure steam guide pipe of the steam turbine according to claim 1, wherein the step 7) comprises the following specific operation steps:
acquiring various off-line detection state parameter results of the evaluation points according to the off-line detection items determined in the step 6), and dividing the off-line detection state parameter results into a rating type and a measurement type;
the state parameters corresponding to the four off-line detection items of macroscopic inspection, surface flaw detection, nondestructive flaw detection and metallographic inspection are collectively called rating type state parameters, and the state parameters and the weights of the rating type state parameters are respectively used as CPG1、CPG2、CPG3、CPG4And WG1、WG2、WG3、WG4Represents;
the state parameters corresponding to four off-line detection items of pipe diameter inspection, ovality measurement, hardness inspection and wall thickness measurement are collectively called rating state parameters, and the state parameters and the weights of the rating state parameters are respectively used as CPM1、CPM2、CPM3、CPM4And WM1、WM2、WM3、WM4And (4) showing.
8. The method for evaluating the condition of the high-pressure steam guide pipe of the steam turbine according to claim 1, wherein the step 8) comprises the following specific operation steps:
performing state evaluation on a single evaluation point according to the off-line detection state parameter result obtained in the step 7), and defining the state of the single evaluation point as CjThe evaluation model is shown as formula (3);
Figure FDA0003278172640000041
state C of evaluation pointjThe value of (A) normally falls within [0,1 ]]In the interval range, CjWhen the value of (a) is changed from 0 to 1, the state of the evaluation point becomes worse and worse;
weight W of two types of state parameters in the formula (3)Gi、WMiGiving the rule of formula (4);
Figure FDA0003278172640000051
the rating class state parameter in the step 7): macroscopic State parameter CPG1-jFrom the results of the macroscopic examination OSG1-j: { no defect found, few suspected defects found, inventive defect evident } definition, as shown in equation (5):
Figure FDA0003278172640000052
the rating class state parameter in the step 7): surface state parameter CPG2-jResults of surface inspection OSG2-j: { no defect found, surface defect found but eliminated after sanding, surface defect found but still present after sanding } is defined as shown in equation (6):
Figure FDA0003278172640000053
the rating class state parameter in the step 7): lossless State parameter CPG3-jFrom results of non-destructive inspection OSG3-j: { stage I, stage II, stage III, stage IV } definition, as shown in equation (7):
Figure FDA0003278172640000054
the rating class state parameter in the step 7): tissue state parameter CPG4-jFrom results of metallographic examination OSG4-j: { level 1, level 2, level 3, level 4, level 5 } definition, as shown in equation (8):
Figure FDA0003278172640000061
the measurement of the class state parameters in the step 7): pipe diameter state parameter CPM1-jResults of inspection of pipe diameter OSM1-jAs defined by formula (9):
Figure FDA0003278172640000062
in the formula (9), D0The design pipe diameter is in mm; e is the ultimate creep expansion rate in%;
the measurement of the class state parameters in the step 7): ovality state parameter CPM2-jResult of ovality check OSM2-jDefinition, as shown in formula (10):
Figure FDA0003278172640000063
in the formula (10), DmaxTo measure the maximum outer diameter, in mm; dminFor measuring the smallest outer diameterThe bit is mm; beta is the ovality limit in%;
the measurement of the class state parameters in the step 7): hardness State parameter CPM3-jResults from hardness test OSM3-jAs defined by formula (11):
Figure FDA0003278172640000071
in the formula (11), HBLAnd HBHRespectively a minimum limit hardness value and a maximum limit hardness value;
the measurement of the class state parameters in the step 7): wall thickness State parameter CPM4-jResults of wall thickness inspection OSM4-jDefinitions, as shown in equation (12):
Figure FDA0003278172640000072
formula (12), d0For design wall thickness, units are mm.
9. The method for evaluating the condition of the high-pressure steam guide pipe of the steam turbine according to claim 1, wherein the specific operation steps in the step 9) are as follows:
counting all the evaluation points obtained in the step 8) according to the classification of straight pipes, elbows and welding lines (the lower corner marks are st, et and wb respectively), counting the number x of the evaluation points of the straight pipes, the number y of the evaluation points of the elbows and the number z of the evaluation points of the welding lines, and then carrying out overall evaluation on an evaluation object, wherein an evaluation model of a final state value is shown as a formula (12);
Figure FDA0003278172640000073
if the C value of the state of the evaluation object is 0, the state of the evaluation object is considered to be optimal, and when the C value changes from 0 to 1, the state of the evaluation object gradually becomes worse; when the C value is larger than 0.8, the state of the evaluation object is poor, a plurality of evaluation points are poor in state, particularly in the final stage and the final stage of the full operation life cycle, if three evaluations are carried out continuously, the C value of the state of the evaluation object is larger than 0.8, the poor state of the evaluation object is proved, and the enterprise needs to make preparations for overall replacement of the evaluation object.
10. The method for evaluating the condition of the high-pressure steam guide pipe of the steam turbine according to claim 1, wherein the specific operation steps in the step 10) are as follows:
and 9) feeding back the state of the evaluation object obtained in the step 9) for next evaluation to calculate the correction factor in the step 5).
CN202111124399.0A 2021-09-24 2021-09-24 State evaluation method for high-pressure steam guide pipe of steam turbine Pending CN113869708A (en)

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