CN-121994907-A - Steel pipe end magnetic leakage defectoscope

CN121994907ACN 121994907 ACN121994907 ACN 121994907ACN-121994907-A

Abstract

The invention relates to the technical field of nondestructive testing of steel pipes, in particular to a steel pipe end magnetic leakage flaw detector. The magnetic flux leakage flaw detector at the end of the steel pipe comprises a frame, wherein a magnetizing coil and a probe system are slidably arranged on the frame, a translation driving mechanism is arranged on the frame, the probe system comprises a probe, a probe lifting driving mechanism and a probe rotation driving mechanism, a magnetic conduction pipe system is further arranged on the frame, the magnetic conduction pipe system comprises a magnetic conduction pipe, a magnetic conduction pipe lifting driving mechanism and a magnetic conduction pipe translation driving mechanism, the magnetic conduction pipe is positioned in front of the magnetizing coil and is positioned on the same straight line with the centers of the magnetizing coil and the probe, and the magnetic conduction pipe and the measured steel pipe are in equal diameter so as to be butted at the end of the measured steel pipe. The magnetic conduction pipe is excited first, then the detected steel pipe is excited, and when the coil reaches the end of the detected steel pipe, the end of the detected steel pipe is saturated and magnetized, so that the dead zone of steel pipe end detection is eliminated, the interference of the magnetic pole effect of the steel pipe end on the detection signal is eliminated, and the detection of the defect of the steel pipe end is realized.

Inventors

ZHANG XIAOJIAN
ZOU ZHENGHUI
LIU XINWEI
CHEN XINBING
ZHANG HUA
HUANG SHIYONG

Assignees

中国石油化工股份有限公司
中国石油化工股份有限公司中原油田分公司

Dates

Publication Date: 20260508
Application Date: 20241101

Claims (10)

1. The magnetic leakage flaw detector for the end part of the steel pipe is characterized by comprising a frame, wherein a magnetizing coil and a probe system are slidably arranged on the frame along the front-back direction, a translation driving mechanism for driving the magnetizing coil and the probe system to move forwards and backwards is arranged on the frame, the probe system comprises a probe, a probe lifting driving mechanism for driving the probe to lift and fall and a probe rotating driving mechanism for driving the probe to rotate, the probe is used for extending into the steel pipe and being attached to the inner wall surface of the steel pipe to detect a defect part, a magnetic conduction pipe system is further arranged on the frame, the magnetic conduction pipe system comprises a magnetic conduction pipe, a magnetic conduction pipe lifting driving mechanism for driving the magnetic conduction pipe to lift and a magnetic conduction pipe translation driving mechanism for driving the magnetic conduction pipe to move forwards and backwards, the magnetic conduction pipe is positioned in front of the magnetizing coil and on the same straight line with the center of the magnetizing coil and the probe, and the magnetic conduction pipe and the probe are equal in diameter with the steel pipe to be abutted to the end part of the steel pipe to be detected.
2. The steel pipe end leakage flux inspection machine according to claim 1, wherein the lifting action part of the magnetic conduction pipe lifting driving mechanism is connected with a supporting rod extending forwards and backwards, the supporting rod is provided with a clamping structure, and the magnetic conduction pipe is clamped and fixed in the clamping structure.
3. The steel pipe end leakage magnetic flaw detector according to claim 2, wherein the clamping structure is a hoop, and the support rod is connected to the edge of the hoop and is located radially outside the magnetic conductive pipe.
4. The apparatus of claim 2, wherein the clamping structure is detachably connected to the support bar.
5. The steel pipe end magnetic leakage flaw detector according to claim 2, wherein the magnetic conduction pipe system further comprises a fixing seat, the fixing seat is fixedly arranged on the frame, the magnetic conduction pipe translation driving mechanism comprises a magnetic conduction pipe driving motor and a sliding block in transmission connection with the magnetic conduction pipe driving motor, a sliding groove extending forwards and backwards is arranged on the fixing seat, the sliding block is slidably arranged in the sliding groove, and the magnetic conduction pipe lifting driving mechanism is arranged on the sliding block.
6. The apparatus of claim 5, wherein the lifting drive mechanism comprises a screw nut mechanism connected to the slider, the moving nut of the screw nut mechanism is connected to the support rod, one of the support rod and the slider is fixedly connected to a guide sleeve extending up and down, the other is fixedly connected to a guide rod, and the guide rod is slidably mounted in the guide sleeve.
7. The apparatus of claim 6, wherein a jackscrew is disposed between the rotating screw and the traveling nut of the screw-nut mechanism.
8. The machine of claim 1-7, wherein the probe comprises a cylindrical shell, a guiding head for guiding the probe to insert into the steel pipe is arranged at the front end of the cylindrical shell, and a strip-shaped magnetic probe unit is elastically and floatingly arranged on the outer peripheral surface of the cylindrical shell along the radial direction and is used for being attached to the inner wall of the steel pipe to be tested.
9. The machine of claim 8, wherein rollers are arranged in rows along the axial direction of the columnar shell between two adjacent strip-shaped magnetic probe units on the peripheral surface of the columnar shell, and the rows of rollers and the strip-shaped magnetic probe units are sequentially arranged alternately at equal intervals along the circumferential direction of the columnar shell.
10. A steel pipe end magnetic leakage flaw detector according to any one of claims 1-7 is characterized in that a slide rail extending back and forth is arranged on the frame, a sliding block is arranged in the slide rail in a sliding mode, and a magnetizing coil and a probe system are fixedly arranged on the sliding block.

Description

Steel pipe end magnetic leakage defectoscope Technical Field The invention relates to the technical field of nondestructive testing of steel pipes, in particular to a steel pipe end magnetic leakage flaw detector. Background After the steel pipe is manufactured, the steel pipe needs to be detected to determine whether defects exist, and the magnetic leakage flaw detection technology has the advantages of high detection speed, high precision, easiness in automation and the like, and is widely applied to nondestructive detection of the steel pipe. The magnetic leakage flaw detection device is a double-coil magnetizer which is commonly used at present and is provided with two magnetizing coils, a probe array is arranged between the two magnetizing coils, a magnetic sensor is arranged in the probe, so that a steel pipe passes through the double-coil magnetizer at high speed, the steel pipe is magnetized through the magnetizing coils to form a saturated magnetic field, the probe is contacted with the outer surface of the steel pipe to be detected, magnetic lines of force of a defect-free part are converged and cannot be refracted to an outer surface space, magnetic resistance of a defect part is large, the magnetic lines of force can be refracted from a defective interface to the outer surface space to form a leakage magnetic field, and whether defects exist is detected by picking up the leakage magnetic field. The existing double-coil magnetizer has a steel pipe end detection blind area when in use, and is concretely characterized in that (1) an end effect is generated at the steel pipe end, when the steel pipe end just starts to enter a magnetizing coil, the magnetizing coil is added with a steel pipe as an iron core, the coil gradually becomes a coil with the iron core from an electrified hollow coil, so that the impedance of the coil is increased, at the moment, the magnetizing circuit current under the action of a voltage-stabilizing direct current power supply is reduced, the magnetic field of the magnetizing coil weakens, magnetic force lines cannot be effectively gathered at the steel pipe end to form a saturated magnetic field, the end of the steel pipe is insufficient in magnetization, the leakage magnetic field generated by a defect part is very small, the required magnetization intensity is not detected, so that a detection blind area is generated, and (2) after the steel pipe end continuously passes through the magnetizing coil, a magnetic pole effect is formed at the steel pipe end, a strong magnetic field is generated, a great interference is generated on a probe detected at the steel pipe end, a positive deviation occurs on a detection signal datum line, so that the leakage magnetic field generated by the defect part cannot be picked up, so that the leakage detection is generated, and the detection is mostly the steel pipe end is mainly stressed, and for some steel pipes in special use scenes, such as oil pipes and sleeves used in the field, in order to improve the end intensity, the steel pipe end is usually thickened, and the end part is provided with a thickened, and has a taper structure, and the surface is not suitable for the taper detection area. The current solution to the dead zone generated by the end leakage magnetic flaw detection of the steel pipe is divided into two types, namely, the magnetization intensity of the end of the steel pipe is increased, a saturated magnetic field can be generated at the beginning of the magnetization of the end of the steel pipe in an attempt to meet the condition that the end flaw is detected, but because the magnetic permeability of air and ferromagnetic materials has a large order of magnitude difference, even if the magnetization intensity is increased greatly, the effect is very little, the equipment volume and the manufacturing and running cost can be greatly increased, and the signal interference of the end detection can be balanced or eliminated by adopting various filtering methods, but the influence of the end flaw signal reduction caused by the insufficient magnetization cannot be eliminated, so the end detection dead zone of the end leakage magnetic flaw detection of the steel pipe becomes a difficult problem in industry. Disclosure of Invention The invention aims to provide a steel pipe end magnetic leakage flaw detector, which aims to solve the problem that the existing steel pipe magnetic leakage flaw detector has an end detection blind area and cannot detect the defects of the end of a steel pipe. In order to achieve the above purpose, the invention adopts the following technical scheme: the utility model provides a steel pipe end magnetic leakage defectoscope, which comprises a frame, along fore-and-aft direction slidable mounting in the frame have magnetizing coil and probe system, be equipped with in the frame and be used for driving the translation actuating mechanism of magnetizing coil and probe system back-and-forth movement, pro