The five major conventional nondestructive testing technologies include radiographic testing (RT), ultrasonic testing (UT), magnetic particle testing (MT), penetrant testing (PT) and eddy current testing (ET).
Radiographic testing (RT)
Radiographic testing uses X-rays or gamma rays to penetrate an object, and detects the intensity changes of the transmitted rays to determine whether there are defects inside the object and their location and size. This method does not damage the object being tested and is widely used in the industrial field.
Ultrasonic testing (UT)
Ultrasonic testing uses the principle that ultrasonic waves will reflect when they encounter defects when propagating in an object, and determines the defects inside the object by analyzing the shape of the reflected wave, arrival time and other information. This method does not destroy parts or materials, can be tested directly on site, and is highly efficient.
Magnetic particle testing (MT)
Magnetic particle testing uses the fact that after ferromagnetic materials are magnetized in a magnetic field, defects will attract iron powder to form visible defect displays. This method is often used to check tiny cracks or other defects on the surface of ferromagnetic materials.
Penetrant testing (PT)
Pentnetrant testing uses the principle of capillary action to apply coloring dyes or fluorescent dyes to the surface to be tested. The dyes will penetrate into the surface defects. After removing the excess dyes, the defects are displayed through dyeing or fluorescent reactions.
Eddy current testing (ET)
Eddy current testing uses an alternating electromagnetic field to generate eddy currents in the metal being tested, and determines whether there are defects in the metal material by analyzing the changes in the eddy currents. This method is suitable for conductive materials and is often used for the inspection of equipment such as pipelines and pressure vessels.
