A system for monitoring wall thickness variations of seamless steel pipes

Abstract

The present application relates to the technical field of steel pipe detection, and discloses a monitoring system for wall thickness change of seamless steel pipe, comprising a detection driving assembly, which comprises a mounting frame, a through hole with a circular structure reserved on the mounting frame for steel pipe passing, a connecting seat fixed on one side of the mounting frame, a driving mechanism I fixed on the connecting seat, a bearing frame fixed on the output end of the driving mechanism I, a sliding guide mechanism fixed on the mounting frame and fixed with the bearing frame, and a support fixed on the bearing frame. The present application can analyze and judge the degree and area of wall thickness change, realize reliable detection of wall thickness change of the inner and outer walls of the steel pipe, improve the sensitivity of detecting the expanded magnetic field caused by wall thickness change, facilitate monitoring of smaller wall thickness change, automatically adjust the position of the wall thickness monitoring device, ensure that steel pipes of different diameters can be detected, realize comprehensive wall thickness change monitoring of steel pipes passing at high speed, and fill the blank of the same detection by other detection methods and devices.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel pipe detection, and particularly relates to a wall thickness change monitoring system for seamless steel pipes. BACKGROUND

[0002] At present, in the steel pipe high-speed continuous rolling line at home and abroad, the seamless steel pipes with a length of more than 100 m are rolled in dozens of seconds in most cases. According to the rolling process of the steel pipe, the concentricity between the outer mold and the mandrel of the high-speed rolled steel pipe is difficult to completely coincide, which will lead to uneven wall thickness of the finished steel pipe; in serious cases, it even exceeds the safety regulations. Once such steel pipes are mistakenly used in the industrial system for bearing high-pressure oil and gas, it will cause major accidents and disasters. The wall thickness of the pressure-bearing seamless steel pipe is strictly regulated in the relevant fields at home and abroad, and the maximum wall thickness change of the steel pipe cannot exceed the regulation, for example, the maximum wall thickness change of the steel pipe cannot exceed 5%, 10% or 12.5% of the nominal wall thickness of the steel pipe. The methods for detecting the wall thickness of the steel pipe at home and abroad include ultrasonic method, ray method and the like, and the detection equipment based on these methods is various, but none of them can meet the requirement of comprehensive wall thickness monitoring of the passing steel pipe under the condition that the steel pipe is passing at high speed. For example, the ultrasonic detection device can only scan the outer wall of the steel pipe in a straight line or a spiral line, and the remaining spiral line part is a missed detection area. Meanwhile, during the detection process, grease or clean water is needed as a coupling agent between the probe and the steel pipe, and the detection speed is difficult to meet the requirement of about 2000 mm / s or faster along the axial direction of the steel pipe. As for the ray method, the speed cannot meet the requirement because of the film imaging or computer image segmentation processing. Therefore, the wall thickness change monitoring system for seamless steel pipes is proposed. SUMMARY

[0003] To solve the technical problems in the prior art, the present application provides a wall thickness change monitoring system for seamless steel pipes.

[0004] The present application adopts the following technical scheme: a wall thickness change monitoring system for seamless steel pipes, comprising:

[0005] A detection driving assembly, comprising a mounting frame, a through hole for the steel pipe to pass through in a circular structure preformed on the mounting frame, a connecting seat fixed on one side of the mounting frame, a driving mechanism I fixed on the connecting seat, a bearing frame fixed on the output end of the driving mechanism I, a sliding guide mechanism fixed on the mounting frame and fixed with the bearing frame, a support fixed on the bearing frame, a sensor mounting frame hinged on the end of the bearing frame, and a driving mechanism II hinged on the other end of the sensor mounting frame and hinged with the support;

[0006] A sensor assembly, comprising two groups of guide plates fixed with the sensor mounting frame, a bus bar fixed between the two groups of guide plates, a gap reserved between the two groups of bus bars, and a sensing element fixed with the bus bar installed inside the gap.

[0007] As a further improvement of the above-mentioned scheme, the guide plate and the bus plate are both circular arc structures, and the length of the bus plate gradually decreases in the direction from the guide plate to the bus plate.

[0008] As a further improvement of the above-mentioned scheme, the sensing element is composed of a plurality of magnetoresistive bridges connected in series, and the sensing element is provided with two groups of wiring terminals.

[0009] As a further improvement of the above-mentioned scheme, the guide plate and the bus plate are both integrally formed by using high-permeability material.

[0010] As a further improvement of the above-mentioned scheme, the driving mechanism one and the driving mechanism two are any one of a pneumatic cylinder, a hydraulic rod and a push rod motor.

[0011] As a further improvement of the above-mentioned scheme, the sliding guide mechanism adopts a sliding rail and sliding block mechanism.

[0012] As a further improvement of the above-mentioned scheme, the sensor mounting rack is reserved with a mounting groove for mounting a sensor assembly.

[0013] Compared with the prior art, the present application has the following advantages:

[0014] 1. The present application forms an expanding magnetic field on the outer surface of the steel pipe at the wall thickness thinning part under the magnetic shielding effect of the seamless steel pipe; the tangential component Hpx of the expanding magnetic field strength has a maximum peak on the surface of the steel pipe, and the normal component Hpy perpendicular to the surface of the steel pipe changes sign and has a zero value at the midpoint; the Hpx and Hpy information can be comprehensively detected to analyze and judge the degree and area of the wall thickness change.

[0015] 2. The present application guides the Hpx and Hpy of the expanding magnetic field formed on the outer surface of the steel pipe into the sensor, so that the sensor obtains all the information of the wall thickness of the steel pipe, and realizes reliable detection of the wall thickness change of the inner and outer walls of the steel pipe; the sensor composed of a plurality of high-sensitivity magnetoresistance bridges connected in series improves the sensitivity of the detection of the expanding magnetic field caused by the wall thickness change, and facilitates the monitoring of smaller wall thickness changes.

[0016] 3. The present application divides the even number of sensor devices into two columns staggered to ensure that they comprehensively cover more than 360 degrees of the circumference of the steel pipe; the position of the wall thickness monitoring device is automatically adjusted to ensure that steel pipes of different diameters can be detected; the wall thickness change monitoring device for the seamless steel pipe passing at high speed realizes comprehensive wall thickness change monitoring of the steel pipe passing at a speed of about 2000 mm / s, and fills the gap in the same detection by other detection methods and devices. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1A structural schematic diagram of a wall thickness change monitoring system for seamless steel pipes provided by the present application;

[0018] Figure 2 A structural schematic diagram provided by the present application;

[0019] Figure 3 A steel pipe detection principle schematic diagram provided by the present application;

[0020] Figure 4 A steel pipe detection principle analysis schematic diagram provided by the present application.

[0021] Main symbol explanation:

[0022] 1 mounting frame, 2 through hole, 3 connecting seat, 4 driving mechanism one, 5 bearing frame, 6 guiding mechanism, 7 support, 8 sensor mounting frame, 9 sensor assembly, 91 guide plate, 92 bus plate, 93 gap, 94 sensing element. DETAILED DESCRIPTION

[0023] In the following, the present application will be further described in conjunction with the drawings and specific embodiments, and it should be noted that, without conflict, the following described embodiments or technical features can be combined to form new embodiments.

[0024] Embodiment 1:

[0025] Please combine Figures 1-2 The wall thickness change monitoring system for seamless steel pipes of the present embodiment comprises:

[0026] The detection driving assembly comprises a mounting frame 1, a through hole 2 for the steel pipe to pass through in a circular structure reserved on the mounting frame 1, a connecting seat 3 fixed on one side of the mounting frame 1, a driving mechanism one 4 fixed on the connecting seat 3, a bearing frame 5 fixed on the output end of the driving mechanism one 4, a sliding guiding mechanism 6 fixed on the mounting frame 1 and fixed with the bearing frame 5, a support 7 fixed on the bearing frame 5, a sensor mounting frame 8 hinged on the end of the bearing frame 5, and a driving mechanism two 10 hinged on the other end of the sensor mounting frame 8 and hinged with the support 7.

[0027] The sensor assembly 9 comprises two groups of guide plates 91 fixed with the sensor mounting frame 8, a bus plate 92 fixed between the two groups of guide plates 91, a gap 93 reserved between the two groups of bus plates 92, and a sensing element 94 fixed with the bus plate 92 inside the gap 93.

[0028] Embodiment 2:

[0029] Combine Figure 2This embodiment, based on Embodiment 1, further improves upon the following: both the guide plate 91 and the busbar 92 are arc-shaped structures, and the length of the busbar 92 gradually decreases along the direction from the guide plate 91 to the busbar 92; the sensing element 94 is composed of several series-connected bridges of magnetoresistance, and the sensing element 94 is provided with two sets of terminals; both the guide plate 91 and the busbar 92 are integrally formed using high-permeability magnetic materials; the drive mechanism 1 4 and the drive mechanism 2 10 are any one of a cylinder, a hydraulic rod, and a push rod motor; the sliding guide mechanism 6 is a slide rail slider mechanism; and the sensor mounting bracket 8 has a reserved mounting slot for mounting the sensor assembly 9.

[0030] Example 3:

[0031] To inspect steel pipes, a steady magnetizing field along their length is applied. After rolling deformation, the ferromagnetic seamless steel pipe, under the combined action of load and magnetizing field, undergoes magnetostrictive reorientation of magnetic domains with orientation and irreversible reorientation at the thinner wall sections. This reorientation not only persists after the working load is removed but is also related to the maximum applied stress. Fixed nodes of magnetic domains appear at these sections, forming a residual magnetic field, thus minimizing the permeability of the ferromagnetic material. Under the magnetic shielding effect of the seamless steel pipe, an expanding magnetic field is formed on the outer surface of the thinner wall sections. The tangential component Hpx of this expanding magnetic field intensity relative to the pipe surface has a maximum peak value, while the normal component Hpy perpendicular to the pipe surface changes sign successively and reaches zero at the midpoint. By comprehensively detecting Hpx and Hpy information, the degree and area of ​​wall thickness variation can be analyzed and determined.

[0032] like Figure 3 The diagram shown illustrates the principle of steel pipe testing, where:

[0033] The left section of a seamless steel pipe contains a thinned portion of the outer wall exceeding the safety standard, while the right section contains a thinned portion of the inner wall. When subjected to an axial external magnetic field, for the portion where the pipe wall thickness meets the standard, the magnetic field is confined within the pipe wall. For the portion where the thickness variation exceeds the standard, the permeability of the ferromagnetic material decreases. Under the magnetic shielding effect of the seamless steel pipe, an expanding magnetic field is formed on the outer surface of the thinned portion. Since the channel for this expanding magnetic field on the outer surface is air, the magnetic resistance increases. A specially designed low-resistance external magnetic circuit, made of soft iron material and conforming to the common surface, is constructed on the outer surface. The expanding magnetic field will pass through this external magnetic circuit and then return to the pipe wall. When a sensor composed of a high-sensitivity magnetoresistive bridge (TMR or GMR) element is installed at the cut-off point of the external magnetic circuit, the Hpx and Hpy information of the expanding magnetic field can be effectively and comprehensively detected. Correlation calculations and analysis can then be used to determine the degree and area of ​​the wall thickness variation. Figure 4 For example, the details are as follows:

[0034] For the steel pipe wall thickness in accordance with the standard provisions of the part, by Figure 4 It is known that:

[0035] Without expansion magnetic field through the sensor device, A, B point and C, D point Hpx and Hpy value is zero or small, the detection results show that the sensor device through the steel pipe area in line with safety standards;

[0036] For the expansion magnetic field through the sensor device, E and F point interval Hpx maximum, the greater the value, the more serious the steel pipe wall thickness thinning, but Hpy value is zero; In D, H point Hpx minimum, and Hpy are opposite to each other, the maximum value is large, which shows that the steel pipe wall thickness thinning interval is covered by the sensor device position.

[0037] Example 4:

[0038] In order to monitor the wall thickness of the steel pipe through the wall thickness monitoring device at high speed, the even number of sensor assemblies 9 are divided into two columns staggered to ensure that they are comprehensive to cover more than 360 degrees of the steel pipe circumference; Each sensor assembly 9 is installed on the sensor mounting frame 8 to automatically adjust the position of the wall thickness monitoring device to ensure that different diameter steel pipes can be detected.

[0039] For example, to detect small diameter steel pipe with diameter of about 30 mm, generally only two sensor devices staggered above and below are needed, which can automatically adjust the position of their sensor devices through program control servo motor, and the driving mechanism one 4 and the driving mechanism two 10 adopt push rod motor, when the steel pipe passes through the through hole 2 position, the driving mechanism one 4 and the driving mechanism two 10 are controlled to press down the sensor assembly 9 and adhere to the outer surface of the steel pipe;

[0040] For example, to detect large diameter steel pipe with diameter of about 340 mm, 16 sensor assemblies 9 staggered above and below can be used, by adjusting the position of the 16 sensor assemblies 9, when the steel pipe passes through the through hole position, the 16 driving mechanism one 4 and the driving mechanism two 10 are controlled to press down the sensor assembly 9 and adhere to the outer surface of the steel pipe;

[0041] For example, to detect super large diameter steel pipe with diameter of about 508 mm, 32 sensor assemblies 9 staggered above and below can be used, by automatically adjusting the position of the 32 sensor devices through program control servo motor, when the steel pipe passes through the sensor device position, the 32 driving mechanism one 4 and the driving mechanism two 10 are controlled to press down the sensor assembly 9 and adhere to the outer surface of the steel pipe.

[0042] The present application forms an expanding magnetic field on the outer surface of the steel pipe at the wall thickness thinning position under the magnetic shielding of the seamless steel pipe; the tangential component Hpx of the expanding magnetic field strength has a maximum peak on the surface of the steel pipe, and the normal component Hpy perpendicular to the surface of the steel pipe changes sign successively and has a zero value at the midpoint; the Hpx and Hpy information of the expanding magnetic field formed on the outer surface of the steel pipe is guided into the sensor, so that the sensor obtains all the information of the wall thickness of the steel pipe, and reliable detection of the wall thickness change of the inner and outer walls of the steel pipe is realized; the sensor composed of several high-sensitivity magnetoresistance bridges in series improves the sensitivity of the expanding magnetic field caused by the wall thickness change, and facilitates the monitoring of smaller wall thickness changes; an even number of sensor devices are divided into two staggered rows to ensure that they comprehensively cover more than 360 degrees of the circumference of the steel pipe; the position of the wall thickness monitoring device is automatically adjusted to ensure that steel pipes of different diameters can be detected; the wall thickness change monitoring device for the high-speed passing seamless steel pipe realizes comprehensive wall thickness change monitoring of the steel pipe passing at a speed of about 2000 mm / s; and fills the gap in the same detection that other detection methods and devices cannot achieve.

[0043] The above embodiments are only preferred embodiments of the present application, and cannot be used to limit the scope of protection of the present application. Any non-essential changes and substitutions made by those skilled in the art on the basis of the present application are within the scope of the present application.

Claims

1. A monitoring system for wall thickness variation in seamless steel pipes, characterized in that, include: The detection drive assembly includes a mounting frame, a circular structure reserved on the mounting frame for a steel pipe to pass through a through hole, a connecting seat fixed to one side of the mounting frame, a drive mechanism one fixed to the connecting seat, a support frame fixed to the output end of the drive mechanism one, a sliding guide mechanism fixed to the mounting frame and to the support frame, a bracket fixed to the support frame, a sensor mounting frame hinged to one end of the support frame, and a drive mechanism two hinged to the other end of the sensor mounting frame and to the bracket. The sensor assembly includes two sets of guide plates fixed to the sensor mounting bracket, a busbar fixed between the two sets of guide plates, a gap between the two sets of busbars, and a sensing element fixed to the busbar installed inside the gap.

2. The monitoring system for wall thickness variation of seamless steel pipes as described in claim 1, characterized in that, Both the guide plate and the busbar are arc-shaped structures, and the length of the busbar gradually decreases along the direction from the guide plate to the busbar.

3. The monitoring system for wall thickness variation of seamless steel pipes as described in claim 1, characterized in that, The sensing element is composed of several magnetoresistive bridges connected in series, and the sensing element is provided with two sets of terminals.

4. The monitoring system for wall thickness variation of seamless steel pipes as described in claim 1, characterized in that, Both the guide plate and the busbar are integrally formed using high magnetic permeability material.

5. The monitoring system for wall thickness variation of seamless steel pipes as described in claim 1, characterized in that, The drive mechanism one and drive mechanism two adopt any one of the following: cylinder, hydraulic rod and push rod motor.

6. The monitoring system for wall thickness variation of seamless steel pipes as described in claim 1, characterized in that, The sliding guide mechanism adopts a slide rail slider mechanism.

7. The monitoring system for wall thickness variation of seamless steel pipes as described in claim 1, characterized in that, The sensor mounting bracket has reserved mounting slots for installing sensor components.

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