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What should you do after the elbow corrodes? How can you detect that it is corroded? After the elbow is corroded, it usually shows that the pipe wall of the elbow becomes thinner, and local pitting appear.
At present, the widely used elbow corrosion detection methods at home and abroad are magnetic flux leakage and ultrasonic testing.
(1) Ultrasonic Testing
Ultrasonic testing uses the principle of wave pulse reflection to measure the thickness of the pipe wall after corrosion. During testing, the probe emits ultrasonic pulses vertically to the inner wall of the elbow. The probe first receives the reflected pulses from the internal surface of the pipe wall, and then the ultrasonic probe receives the reflected pulses from the external surface of the pipe wall. The distance between the pulses from the external surface and the reflected pulses from the internal surface reflects the thickness of the pipe wall.
(2) Magnetic Flux Leakage
The basic principle of magnetic flux leakage is based on the high permeability of ferromagnetic materials. The permeability of elbow corrosion defects is far less than that of an elbow, and the elbow is magnetized under the action of the external magnetic field. When there is no defect in an elbow, most of magnetic lines pass through steel pipes, and then magnetic lines are evenly distributed; When there are defects in the elbow, the magnetic lines bend and some of them leak out of the steel pipe surface. The existence of defects can be judged by the leakage flux escaping from the surface of magnetized elbow.
According to the user's conditions, the quality control items of materials can be increased, such as magnetic particle inspection, ultrasound, penetration, but this should be negotiated between the manufacturer and the user, and it should be indicated in the contract, and both parties should voluntarily increase the item.
At present, the widely used elbow corrosion detection methods at home and abroad are magnetic flux leakage and ultrasonic testing.
(1) Ultrasonic Testing
Ultrasonic testing uses the principle of wave pulse reflection to measure the thickness of the pipe wall after corrosion. During testing, the probe emits ultrasonic pulses vertically to the inner wall of the elbow. The probe first receives the reflected pulses from the internal surface of the pipe wall, and then the ultrasonic probe receives the reflected pulses from the external surface of the pipe wall. The distance between the pulses from the external surface and the reflected pulses from the internal surface reflects the thickness of the pipe wall.
(2) Magnetic Flux Leakage
The basic principle of magnetic flux leakage is based on the high permeability of ferromagnetic materials. The permeability of elbow corrosion defects is far less than that of an elbow, and the elbow is magnetized under the action of the external magnetic field. When there is no defect in an elbow, most of magnetic lines pass through steel pipes, and then magnetic lines are evenly distributed; When there are defects in the elbow, the magnetic lines bend and some of them leak out of the steel pipe surface. The existence of defects can be judged by the leakage flux escaping from the surface of magnetized elbow.
According to the user's conditions, the quality control items of materials can be increased, such as magnetic particle inspection, ultrasound, penetration, but this should be negotiated between the manufacturer and the user, and it should be indicated in the contract, and both parties should voluntarily increase the item.
