阅读说明：本技术 一种铁磁性材料壁厚缺陷扫查装置和扫查方法 (Ferromagnetic material wall thickness defect scanning device and method ) 是由 向安 来园凯 于 2020-05-07 设计创作，主要内容包括：本发明公开了一种铁磁性材料壁厚缺陷扫查装置和扫查方法,本发明所述装置包括中低频电磁涡流主机、带增量式计步器或打点式计步器的传感器总成、数据处理终端及电缆等。中低频电磁涡流主机对传感器总成发出信号并接收反馈信号,接收到的反馈信号经蓝牙或电缆传输到数据处理终端,数据处理终端利用针对铁磁性材料信号处理的特殊算法,在无需拆除包覆层和无需进行表面处理的情况下,实现对铁磁性材料管道或设备的连续扫查,并实现对缺陷的半定量计算。本发明适合在役铁磁性管线和设备腐蚀缺陷的检测,可快速发现和定位安全隐患位置,检测精度高、速度快,并可以穿透保温层和保护层对管道或设备的壁厚进行检测,是良好的无损检测方法。(The invention discloses a ferromagnetic material wall thickness defect scanning device and a ferromagnetic material wall thickness defect scanning method. The medium-low frequency electromagnetic eddy current host sends signals to the sensor assembly and receives the feedback signals, the received feedback signals are transmitted to the data processing terminal through Bluetooth or a cable, the data processing terminal utilizes a special algorithm aiming at ferromagnetic material signal processing, continuous scanning of ferromagnetic material pipelines or equipment is achieved under the condition that a coating layer does not need to be removed and surface processing does not need to be carried out, and semi-quantitative calculation of defects is achieved. The method is suitable for detecting corrosion defects of in-service ferromagnetic pipelines and equipment, can quickly find and position potential safety hazard positions, has high detection precision and high speed, can penetrate through the heat-insulating layer and the protective layer to detect the wall thickness of the pipeline or the equipment, and is a good nondestructive detection method.)

1. A ferromagnetic material wall thickness defect scanning method is characterized by comprising the following steps:

s1: selecting a proper sensor assembly according to the material and the pipe diameter of the pipeline to be detected, whether a coating layer is coated, the thickness of the coating layer and the like;

s2: selecting a proper excitation electromagnetic signal according to the material and the wall thickness of the pipeline to be detected, whether a cladding layer is coated or not, the thickness of the cladding layer and the sensor assembly selected in the step S1, wherein the frequency of the electromagnetic signal is between 1 and 32HZ, and the voltage value is between 2 and 20V;

s3: placing the sensor assembly selected in the step S1 on the outer surface of the pipeline to be detected or the outer surface of the coating layer, sending the electromagnetic signal selected in the step S2 by adopting a medium-low frequency electromagnetic eddy current host, continuously moving the sensor assembly, and collecting a detection signal of the pipeline to be detected, wherein the detection signal comprises an induced voltage value attenuated along with time and a step-counting positioning value which are generated in the conduction process of an electromagnet;

s4: the detection signal in the step S2 is transmitted to a data processing terminal through Bluetooth or a cable after being preprocessed by a medium-low frequency electromagnetic eddy current host;

s5: the data processing terminal performs batch processing on data and extracts characteristic values related to wall thickness, and the method comprises the following steps:

s5.1, each piece of preprocessed detection position data received by the data processing terminal comprises 20-31 time windows distributed according to time, each time window comprises response time T and a corresponding induction voltage value V, and the first 0-5 time windows are removed;

s5.2, calculating the response time T of each residual time window and the natural logarithm value of the induction voltage V;

s5.3, calculating the slope K value of a fitting straight line of the response time T and the natural logarithm value of the induced voltage V of each two or three adjacent groups of time windows;

s5.4, comparing the slope K values obtained in the step S5.3, and selecting a maximum K value Kmax;

s5.5, selecting the response time T and the induction voltage V corresponding to the last time window corresponding to Kmax, and selecting the data of the time window and the data of the first three time windows as a selection interval;

s5.6, calculating the ' response time T, the natural logarithm value ' of the induction voltage V ' of the four time windows of the selection interval to fit the slope of the straight line, and solving the absolute value of the slope, wherein the absolute value of the slope is the characteristic value S;

s6: calculating a value of the wall thickness of the ferromagnetic material using the characteristic value S obtained in step S5, the steps including:

s6.1, measuring the standard test blocks with different wall thicknesses to obtain a group of characteristic values corresponding to known wall thickness values;

s6.2, fitting the known wall thickness value and the characteristic value in the step S6.1 to obtain a relational expression of the wall thickness and the characteristic value;

s6.3, substituting the characteristic value obtained in the step S5.5 into the relational expression in the step S6.2 to obtain the wall thickness value of the corresponding position;

s7: obtaining a wall thickness value of a certain point of the pipeline to be measured by using an ultrasonic thickness gauge, and comparing the wall thickness value with the wall thickness value obtained in the step S6.3 to obtain a calibration coefficient;

s8: and displaying the real-time imaging result of the detection position and the wall thickness.

2. A ferromagnetic material wall thickness defect scanning device comprises a medium-low frequency electromagnetic eddy current host, a sensor assembly, a data processing terminal and a cable, and is characterized in that,

the medium-low frequency electromagnetic eddy current host is used for transmitting electromagnetic signals to the sensor assembly and receiving feedback signals; the sensor assembly is used for acquiring a detection signal of a detection part of a ferromagnetic pipeline or equipment to be detected and sending the detection signal to the data processing terminal through the medium-low frequency electromagnetic eddy current host; and the data processing terminal is used for processing the detection signal, extracting the characteristic value of the wall thickness of the ferromagnetic pipeline or equipment in the detection signal and displaying the real-time imaging result of the wall thickness value of the ferromagnetic pipeline or equipment.

3. The ferromagnetic material wall thickness defect scanning device of claim 2, wherein the data processing terminal is a general computer or a tablet computer system including a data processing module and a display module, and the data processing terminal is connected to the low-and-medium-frequency electromagnetic eddy current host computer through bluetooth or a cable.

4. The ferromagnetic material wall thickness defect scanning device of claim 2, wherein the medium-low frequency electromagnetic eddy current host is provided with an electromagnetic signal emitting module, a signal collecting module and a signal preprocessing module.

5. The ferromagnetic material wall thickness defect scanning device of claim 2, wherein the sensor assembly is connected with the medium-low frequency electromagnetic eddy current host computer through a cable, and the data processing terminal is connected with the host computer through bluetooth or a cable.

6. The apparatus for scanning defects in the wall thickness of ferromagnetic material according to claim 2, wherein said sensor assembly comprises a transmitter coil, a receiver coil and a pedometer, said pedometer is an incremental pedometer or a dotting pedometer; the sensor assembly is arranged on the outer surface of the pipeline to be detected or the outer surface of the coating and continuously moves; the pedometer is used for positioning the detection position.

Technical Field

The invention belongs to the field of nondestructive detection of ferromagnetic pipelines and equipment in the basic chemical industry and the petroleum refining industry, and particularly relates to a ferromagnetic material wall thickness defect scanning device and a ferromagnetic material wall thickness defect scanning method.

Background

In the operation process of basic chemical industry and petroleum refining devices, ferromagnetic materials are generally adopted as materials of pipelines and equipment. These pipes and equipment are often covered with insulation and protective layers for insulation, moisture protection, etc. When the pipelines and the equipment are in service (on-line) operation, the pipelines and the equipment bear high pressure of gas or liquid, operate in a relatively severe working environment, and are in a high-temperature, high-pressure and corrosive environment for a long time, and are easy to corrode to form defects, thereby causing serious consequences. Therefore, it is necessary to monitor the wall thickness reduction state of pipelines and equipment with high corrosion risk, and the existing pipeline and equipment wall thickness measuring method generally adopts a traditional ultrasonic thickness gauge to perform fixed-point measurement.

On one hand, the ultrasonic thickness gauge can only measure the thickness at a fixed point, and cannot realize continuous scanning, so that missing detection is easy to occur or the region with the most serious defects cannot be detected; on the other hand, the coating (including the heat preservation layer and the protective layer) needs to be removed by adopting ultrasonic thickness measurement, the metal surface also needs to be treated, a coupling agent needs to be adopted in the detection process, and the coating needs to be recovered after the detection is finished, so that firstly, the detection time is long, the cost is high, and secondly, secondary damage is easily caused to pipelines and equipment due to the removal and recovery of the coating and the treatment of the metal surface. Therefore, a detection method which can realize continuous scanning without removing a coating layer and processing the surface of a pipeline is needed. As a branch of the eddy current detection technology, the pulse eddy current detection technology adopts square wave or step mode excitation, contains rich frequency components, belongs to a non-contact nondestructive detection method, and can continuously scan the pipeline and the wall thickness defects without removing a coating layer.

The existing published pulse eddy current detection technology generally adopts differential peak value, differential peak value time, zero crossing point, lift-off intersection point, inflection point time, late signal attenuation rate and the like as characteristic values of wall thickness detection, wherein: the differential peak value, the differential peak value time, the zero crossing point and the lift-off crossing point are more used for detecting the wall thickness of the non-ferromagnetic material, and the inflection point, the inflection point time and the late signal attenuation rate can be used for detecting the wall thickness of the ferromagnetic material.

The induced voltage of the pulse eddy current is attenuated along with the time change in the transfer process of the ferromagnetic material, the attenuation rule of the pulse eddy current accords with the power function relationship at the early stage and accords with the exponential function relationship at the later stage, and therefore, an inflection point which is converted from the power function relationship to the exponential function relationship exists; the thicker the wall thickness is, the larger the induced voltage value of the inflection point is, the later the time of the inflection point appears, and a certain functional relationship exists between the induced voltage value or inflection point time at the inflection point and the wall thickness, so that the induced voltage value or inflection point time at the inflection point can be used as a characteristic value for detecting the wall thickness of the pulse eddy current; however, in field application, the inflection point is affected by the lift-off height and environmental interference, and the detection effect of the inflection point often fluctuates greatly. The late signal attenuation rate or the late signal slope is also a characteristic value of the pulse eddy current detection ferromagnetic material, and is less affected by the lift-off height and environmental interference, but the calculation method is relatively complex, the calculation speed is slow, and the determination of the signal attenuation rate or the signal slope interval is difficult.

Disclosure of Invention

In order to solve the above technical problems, the present invention provides a device and a method for scanning ferromagnetic material wall thickness defects.

The invention is realized according to the following technical scheme:

a ferromagnetic material wall thickness defect scanning method comprises the following steps:

s1: selecting a proper sensor assembly according to the material and the pipe diameter of the pipeline to be detected, whether a coating layer is coated, the thickness of the coating layer and the like;

s2: selecting a proper excitation electromagnetic signal according to the material and the wall thickness of the pipeline to be detected, whether a cladding layer is coated or not, the thickness of the cladding layer and the sensor assembly selected in the step S1, wherein the frequency of the electromagnetic signal is between 1 and 32HZ, and the voltage value is between 2 and 20V;

s3: placing the sensor assembly selected in the step S1 on the outer surface of the pipeline to be detected or the outer surface of the coating layer, sending the electromagnetic signal selected in the step S2 by adopting a medium-low frequency electromagnetic generating system, continuously moving the sensor assembly, and collecting a detection signal of the pipeline to be detected, wherein the detection signal comprises an induced voltage value attenuated along with time and a step-counting positioning value which are generated in the conduction process of an electromagnet;

s4: the detection signal in the step S2 is preprocessed by the medium-low frequency electromagnetic generation system and then transmitted to the data processing terminal through bluetooth or a cable;

s5: the data processing terminal performs batch processing on data and extracts characteristic values related to wall thickness, and the method comprises the following steps:

s5.1, each piece of preprocessed detection position data received by the data processing terminal comprises 20-31 time windows distributed according to time; each time window comprises a response time T and a corresponding induction voltage value V; removing the first 0-5 time windows;

s5.2, calculating the response time T of each residual time window and the natural logarithm value of the induction voltage V;

s5.3, calculating the slope K value of a fitting straight line of the response time T and the natural logarithm value of the induced voltage V of each two or three adjacent groups of time windows;

s5.4, comparing the slope K values obtained in the step S5.3, and selecting a maximum K value Kmax;

s5.5, selecting the response time T and the induction voltage V corresponding to the last time window corresponding to Kmax, and selecting the data of the time window and the data of the first three time windows as a selection interval;

s5.6, calculating the ' response time T, the natural logarithm value ' of the induction voltage V ' of the four time windows of the selection interval to fit the slope of the straight line, and solving the absolute value of the slope, wherein the absolute value of the slope is the characteristic value S;

s6: calculating a value of the wall thickness of the ferromagnetic material using the characteristic value S obtained in step S5, the steps including:

s6.1, measuring the standard test blocks with different wall thicknesses to obtain a group of characteristic values corresponding to known wall thickness values;

s6.2, fitting the known wall thickness value and the characteristic value in the step S6.1 to obtain a relational expression of the wall thickness and the characteristic value;

s6.3, substituting the characteristic value obtained in the step S5.5 into the relational expression in the step S6.2 to obtain the wall thickness value of the corresponding position;

s7: obtaining a wall thickness value of a certain point of the pipeline to be measured by using an ultrasonic thickness gauge, and comparing the wall thickness value with the wall thickness value obtained in the step S6.3 to obtain a calibration coefficient;

s8: and displaying the real-time imaging result of the detection position and the wall thickness.

A ferromagnetic material wall thickness defect scanning device comprises a medium-low frequency electromagnetic eddy current host, a sensor assembly, a data processing terminal and a cable, wherein the medium-low frequency electromagnetic eddy current host is used for transmitting electromagnetic signals to the sensor assembly and receiving feedback signals; the sensor assembly is used for acquiring a detection signal of a detection part of a ferromagnetic pipeline or equipment to be detected and sending the detection signal to the data processing terminal through the medium-low frequency electromagnetic eddy current host; and the data processing terminal is used for processing the detection signal, extracting the characteristic value of the wall thickness of the ferromagnetic pipeline or equipment in the detection signal and displaying the real-time imaging result of the wall thickness value of the ferromagnetic pipeline or equipment.

The data processing terminal is a common computer or a tablet computer system comprising a data processing module and a display module, and is connected with the medium-low frequency electromagnetic eddy current host through Bluetooth or a cable.

And an electromagnetic signal transmitting module, a signal acquisition module and a signal preprocessing module are arranged in the medium-low frequency electromagnetic eddy current host.

The sensor assembly is connected with the medium-low frequency electromagnetic eddy current host through a cable, and the data processing terminal is connected with the host through Bluetooth or the cable.

The sensor assembly consists of a transmitting coil, a receiving coil and a pedometer, wherein the pedometer is an incremental pedometer or a dotting type pedometer; the sensor assembly is arranged on the outer surface of the pipeline to be detected or the outer surface of the coating and continuously moves; the pedometer is used for positioning the detection position.

The invention has the advantages and beneficial effects that:

the invention discloses a ferromagnetic material wall thickness defect scanning device and a scanning method; the scanning device can continuously scan the wall thickness of the ferromagnetic pipeline and equipment without removing a coating layer comprising a heat-insulating layer and a protective layer and without surface treatment, can meet the detection requirements of different pipe diameters, and can quickly scan the corrosion defects inside and outside the ferromagnetic pipeline or equipment at the temperature of 500 ℃. The system is combined with a dotting and step-counting device in the sensor assembly, the position of the defect can be roughly determined, and the corrosion defect position in the ferromagnetic material pipeline and equipment can be quickly, directly and accurately positioned. Compared with the original method (algorithm), the scanning method has the advantages of shorter calculation time and lower method complexity.

Drawings

FIG. 1 is a schematic structural diagram of a system for scanning defects of wall thickness of ferromagnetic material;

FIG. 2 is a schematic representation of wall thickness detection curves in a log-log coordinate system;

FIG. 3 is a graphical representation of the log-log slope of different wall thickness measurements;

FIG. 4 is a standard wall thickness fitting curve and formula;

fig. 5 is an example of a wall thickness measurement image.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and examples.

As shown in fig. 1 to 5, a ferromagnetic material wall thickness defect scanning method includes the following steps:

s1: selecting a proper sensor assembly according to the material and the pipe diameter of the pipeline to be detected, whether a coating layer is coated, the thickness of the coating layer and the like;

s2: selecting a proper excitation electromagnetic signal according to the material and the wall thickness of the pipeline to be detected, whether a cladding layer is coated or not, the thickness of the cladding layer and the sensor assembly selected in the step S1, wherein the frequency of the electromagnetic signal is between 1 and 32HZ, and the voltage value is between 2 and 20V;

s3: placing the sensor assembly selected in the step S1 on the outer surface (or the outer surface of a coating layer) of the pipeline to be detected, sending the electromagnetic signal selected in the step S2 by adopting a medium-low frequency electromagnetic generation system, continuously moving the sensor assembly, and collecting a detection signal of the pipeline to be detected, wherein the detection signal comprises an induced voltage value attenuated along with time and a step-counting positioning value which are generated in the conduction process of an electromagnet;

s4: the detection signal in the step S2 is preprocessed by the medium-low frequency electromagnetic generation system and then transmitted to the data processing terminal through bluetooth or a cable;

s5: the data processing terminal performs batch processing on data and extracts characteristic values related to wall thickness, and the method comprises the following steps:

s5.1, each piece of preprocessed detection position data received by the data processing terminal comprises 20-31 time windows distributed according to time (each time window comprises response time T and a corresponding induced voltage value V), and the first 0-5 time windows are removed;

s5.2, calculating the ln (response time T) and the ln (induced voltage V) of the rest time windows;

s5.3, calculating the slope K value of a fitting straight line of two or three adjacent groups of time windows 'ln (response time T) and ln (induced voltage V)';

s5.4, comparing the slope K values obtained in the step S5.3, and selecting a maximum K value Kmax;

s5.5, selecting the response time T and the induction voltage V corresponding to the last time window corresponding to Kmax, and selecting the data of the time window and the data of the first three time windows as a selection interval;

s5.6, calculating the slope of a 'response time T, ln (induced voltage V)' fitting straight line of four time windows in the selection interval, and calculating the absolute value of the slope, wherein the absolute value of the slope is the characteristic value S;

s6: calculating a value of the wall thickness of the ferromagnetic material using the characteristic value S obtained in step S5, the steps including:

s6.1, measuring the standard test blocks with different wall thicknesses to obtain a group of characteristic values corresponding to known wall thickness values;

s6.2, fitting the known wall thickness value and the characteristic value in the step S6.1 to obtain a relational expression of the wall thickness and the characteristic value;

s6.3, substituting the characteristic value obtained in the step S5.5 into the relational expression in the step S6.2 to obtain the wall thickness value of the corresponding position;

s7: obtaining a wall thickness value of a certain point of the pipeline to be measured by using an ultrasonic thickness gauge, and comparing the wall thickness value with the wall thickness value obtained in the step S6.3 to obtain a calibration coefficient;

s8: and displaying the real-time imaging result of the detection position and the wall thickness.

A ferromagnetic material wall thickness defect scanning device comprises a medium-low frequency electromagnetic eddy current host, a sensor assembly, a data processing terminal and a cable, wherein the medium-low frequency electromagnetic eddy current host is used for transmitting electromagnetic signals to the sensor assembly and receiving feedback signals; the sensor assembly is used for acquiring a detection signal of a detection part of a ferromagnetic pipeline or equipment to be detected and sending the detection signal to the data processing terminal through the medium-low frequency electromagnetic eddy current host; and the data processing terminal is used for processing the detection signal, extracting the characteristic value of the wall thickness of the ferromagnetic pipeline or equipment in the detection signal and displaying the real-time imaging result of the wall thickness value of the ferromagnetic pipeline or equipment.

The data processing terminal is a common computer or a tablet computer system comprising a data processing module and a display module, and is connected with the medium-low frequency electromagnetic eddy current host through Bluetooth or a cable.

And an electromagnetic signal transmitting module, a signal acquisition module and a signal preprocessing module are arranged in the medium-low frequency electromagnetic eddy current host.

The sensor assembly is connected with the medium-low frequency electromagnetic eddy current host through a cable, and the data processing terminal is connected with the host through Bluetooth or the cable.

The sensor assembly consists of a transmitting coil, a receiving coil and a pedometer, wherein the pedometer is an incremental pedometer or a dotting type pedometer; the sensor assembly is arranged on the outer surface of the pipeline to be detected or the outer surface of the coating and continuously moves; the pedometer is used for positioning the detection position.

The principle on which the method is based is as follows:

fig. 3 is a graph of pulsed eddy current testing of ferromagnetic material (2/4/6/8 mm) of different wall thickness in a log-log coordinate system, where the black curve is the empty test curve. The power function appears as a straight line in a log-log coordinate system, and the exponential function still appears as a curve in the log-log coordinate system. As can be seen from fig. 3, the air measurement data satisfies a power function relationship, that is, the attenuation rule of the pulsed eddy current signal in the air satisfies the power function relationship. As can be seen from fig. 3, the pulsed eddy current signal can be divided into three stages when penetrating ferromagnetic materials with different thicknesses, the first stage satisfies a power function relationship, and the signal curves of different wall thicknesses are basically overlapped; the second stage meets the exponential function relationship, and the thicker the wall thickness, the later the second stage appears; the third stage meets the power function rule and is overlapped with the aerial survey curve, and the transition position from the second stage to the third stage is a transition point of a signal penetrating through the ferromagnetic material; this transition point appears as the point of maximum slope change in the log-log coordinate system. Similar to the above-mentioned inflection point, the induced voltage value, the time and the slope between adjacent points of the transition point have a certain relationship with the wall thickness value, and can be used as a pulse eddy current detection method to calculate the characteristic value of the wall thickness. The transition point is represented as a point with the largest slope change in a log-log coordinate system, and as shown in fig. 4, the position of the characteristic value is calculated by solving the maximum value of the log-log slope between two adjacent induced voltage values of each detection point. In the process that the pulse eddy current signal penetrates through the ferromagnetic material, the second stage meets the exponential function relationship, the exponential function is represented as a straight line in a single-logarithmic coordinate system, the slopes of the second stage of the ferromagnetic material with different wall thicknesses are different, and the slope of the second stage meets the power function relationship with the wall thickness, and the slope of the second stage is used as a characteristic value. The slope values of the first induction voltage values of the position in a single logarithmic coordinate system, namely characteristic values, can be obtained through the obtained characteristic value positions; the wall thickness of the ferromagnetic material can be obtained according to the relation between the characteristic value and the wall thickness.