阅读说明：本技术 一种基于截止频率测量的锅炉管老化程度快速评估方法 (Boiler tube aging degree rapid evaluation method based on cut-off frequency measurement ) 是由 安志彤 杜双明 刘长福 谌康 王庆峰 于 2021-05-20 设计创作，主要内容包括：本发明涉及一种基于截止频率测量的锅炉管老化程度快速评估方法,采用截止频率测量器测量信号流经管子后的信号频散衡量锅炉耐热管子长时间受热载荷的老化程度,包括：步骤一：以1m长度待测的锅炉受热老化管子接入截止频率测量电路,触点做处理,保证电接触良好；步骤二：使用专用信号测试仪,以正弦扫频信号测试该锅炉管的截止频率上、下限；步骤三：对同规格材质长度为1m的不同老化程度的锅炉管重复步骤二进行测量,形成数据库；步骤四：将老化锅炉管测得的结果和所建数据库中不同损伤程度的管子的高低截止频率结果进行比较；步骤五：通过结果比较,评定该锅炉管子的材质劣化程度。本发明提高了锅炉管老化程度检测效率,降低了检测成本。(The invention relates to a method for quickly evaluating the aging degree of a boiler tube based on cut-off frequency measurement, which measures the aging degree of a heat-resisting boiler tube under long-time heating load by measuring the signal frequency dispersion of a signal flowing through the tube by using a cut-off frequency measurer, and comprises the following steps: the method comprises the following steps: a boiler heated aging pipe with the length of 1m to be measured is connected into a cut-off frequency measuring circuit, and a contact is processed to ensure good electric contact; step two: testing the upper limit and the lower limit of the cut-off frequency of the boiler tube by using a special signal tester and a sine frequency sweeping signal; step three: measuring boiler pipes with the same specification, material length of 1m and different aging degrees by repeating the second step to form a database; step four: comparing the result measured by the aging boiler tube with the high and low cut-off frequency results of the tubes with different damage degrees in the built database; step five: and evaluating the deterioration degree of the material of the boiler pipe through result comparison. The invention improves the efficiency of detecting the aging degree of the boiler tube and reduces the detection cost.)

1. A boiler tube aging degree rapid evaluation method based on cut-off frequency measurement is characterized in that a cut-off frequency measurer is adopted to measure the aging degree of a boiler heat-resisting tube under long-time heating load by measuring signal frequency dispersion after a signal flows through the tube, and the method comprises the following steps:

the method comprises the following steps: a boiler heated aging pipe with the length of 1m to be measured is connected into a cut-off frequency measuring circuit, and contacts are processed to ensure good electric contact;

step two: testing the upper limit and the lower limit of the cut-off frequency of the boiler tube by using a special signal tester and a sine frequency sweeping signal;

step three: measuring boiler pipes with the same specification, material length of 1m and different aging degrees by repeating the second step to form a database;

step four: comparing the result measured by the aging boiler tube with the high and low cut-off frequency results of the tubes with different damage degrees in the built database;

step five: and evaluating the deterioration degree of the material of the boiler pipe through result comparison.

2. A boiler tube aging degree rapid evaluation method based on cut-off frequency measurement is characterized in that a cut-off frequency measurer is adopted to measure the aging degree of a boiler heat-resisting tube under long-time heating load by measuring signal frequency dispersion after a signal flows through the tube, and the method comprises the following steps:

step 1, connecting a boiler heated aging pipe with a certain length into a cut-off frequency measuring circuit, and processing a contact to ensure good electric contact;

step 2, using a special signal tester to test the upper limit and the lower limit of the cutoff frequency of the boiler tube by sine frequency sweeping signals;

step 3, measuring the high and low cut-off frequencies of boiler tubes made of other similar specifications;

and 4, comparing the batch of measurement data, and judging that the aging degree of the pipe is different from other aging degrees when abnormal data exists.

Technical Field

The invention belongs to the technical field of thermal power generation, and particularly relates to a boiler tube aging degree rapid evaluation method based on cut-off frequency measurement.

Background

In the long-term service process of the boiler tube in a high-temperature environment, the internal organization structure is changed, so that the strength of the tube is reduced, the high-temperature oxidation resistance is poor, even tube explosion is generated to cause furnace shutdown, and the like. The aging degree of the material is usually detected by methods such as metallographic phase and mechanical property tests, but the methods usually require tube cutting, have low detection efficiency and have higher cost.

Disclosure of Invention

The invention aims to provide a method for rapidly evaluating the aging degree of a boiler tube based on cut-off frequency measurement, which considers that the aging of an internal organization structure of a metal material directly affects the electrical characteristics of the material, such as the frequency bandwidth, the frequency dispersion effect, the change of electrical conductivity and the like of an electrical signal, and indirectly evaluates the aging degree of the boiler tube by detecting the change of the electrical characteristics.

The invention provides a method for rapidly evaluating the aging degree of a boiler tube based on cut-off frequency measurement, which measures the aging degree of a heat-resisting boiler tube under long-time heating load by measuring the signal frequency dispersion of a signal flowing through the tube by using a cut-off frequency measurer, and comprises the following steps:

the method comprises the following steps: a boiler heated aging pipe with the length of 1m to be measured is connected into a cut-off frequency measuring circuit, and contacts are processed to ensure good electric contact;

step two: testing the upper limit and the lower limit of the cut-off frequency of the boiler tube by using a special signal tester and a sine frequency sweeping signal;

step three: measuring boiler pipes with the same specification, material length of 1m and different aging degrees by repeating the second step to form a database;

step four: comparing the result measured by the aging boiler tube with the high and low cut-off frequency results of the tubes with different damage degrees in the built database;

step five: and evaluating the deterioration degree of the material of the boiler pipe through result comparison.

The invention also provides a method for rapidly evaluating the aging degree of the boiler tube based on cut-off frequency measurement, which measures the aging degree of the heat-resisting boiler tube under long-time heating load by measuring the signal frequency dispersion after the signal flows through the tube by adopting a cut-off frequency measurer, and comprises the following steps:

step 1, connecting a boiler heated aging pipe with a certain length into a cut-off frequency measuring circuit, and processing a contact to ensure good electric contact;

step 2, using a special signal tester to test the upper limit and the lower limit of the cutoff frequency of the boiler tube by sine frequency sweeping signals;

step 3, measuring the high and low cut-off frequencies of boiler tubes made of other similar specifications;

and 4, comparing the batch of measurement data, and judging that the aging degree of the pipe is different from other aging degrees when abnormal data exists.

By means of the scheme, the boiler tube aging degree rapid evaluation method based on cut-off frequency measurement utilizes the grain structure change of the aged tube to evaluate the aging degree of the tube on the bandwidth change in the signal transmission process, and the aging degree of the heat-resisting boiler tube subjected to long-time heat load is measured by measuring the high and low cut-off frequencies of the tube through a bandwidth testing instrument, so that the boiler tube aging degree detection efficiency is improved, and the detection cost is reduced.

Detailed Description

The following examples are given to further illustrate the embodiments of the present invention. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The embodiment provides a method for rapidly evaluating the aging degree of a boiler tube based on cut-off frequency measurement, and the method is characterized in that a cut-off frequency measurer is adopted to measure the aging degree of a heat-resisting boiler tube under long-time heating load by measuring the signal dispersion after a signal flows through the tube.

The aging of the heat-resistant steel pipe after service mainly has the following effects:

graphitizing carbon steel;

spheroidizing carbide of pearlite steel;

the martensitic steel is ferritized, carbide is coarsened, and carbide and a new phase are precipitated;

martensite transformation of austenitic steel and aggregation of austenite steel dispersoid precipitates

The common points of the above aging conditions are: the uniform structure is gradually and locally uneven in the service process, a new precipitated phase is generated, a new interface is formed, and the grain size is increased.

This change in the material causes a change in its conductive properties: the high and low cut-off frequencies of the signal change during transmission.

By utilizing the influence of the aging of the material on the signal transmission, the aging degree of the boiler tube can be rapidly detected.

The method specifically comprises the following steps:

the method comprises the following steps: a boiler heated aging pipe to be measured with the length of 1m is connected into a cut-off frequency measuring circuit, and a contact is processed to ensure good electric contact;

step two: testing the upper limit and the lower limit of the cut-off frequency of the boiler tube by using a special signal tester and a sine frequency sweeping signal;

step three: measuring boiler pipes which are made of the same specification and have different aging degrees and are 1m in length by repeating the second step to form a database;

step four: comparing the result measured by the aging boiler tube with the high and low cut-off frequency results of the tubes with different damage degrees in the built database;

step five: and evaluating the deterioration degree of the material of the boiler pipe through result comparison.

Sometimes, in order to quickly pick out the tube with abnormal material, the method can be carried out according to the following steps without using a database:

the method comprises the following steps: a certain length of a boiler heated aging pipe is connected into a cut-off frequency measuring circuit, and a contact is processed to ensure good electric contact;

step two: testing the upper limit and the lower limit of the cut-off frequency of the boiler tube by using a special signal tester and a sine frequency sweeping signal;

step three: measuring the high and low cut-off frequencies of boiler tubes made of other similar specifications;

step four: comparing the batch of measurement data, and judging that the aging degree of the pipe is different from other aging degrees when abnormal data exists.

According to the boiler tube aging degree rapid evaluation method based on cut-off frequency measurement, the aging degree of the tube is evaluated by using the crystal grain structure change after the tube is aged to the bandwidth change in the signal transmission process, and the aging degree of the boiler heat-resistant tube under long-time heating load is measured by measuring the high and low cut-off frequencies of the tube by using a bandwidth testing instrument, so that the boiler tube aging degree detection efficiency is improved, and the detection cost is reduced.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, it should be noted that, for those skilled in the art, many modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.