1. Ultrasonic testing:
When the ultrasonic wave propagates in the tested material, the changes of the material's acoustic characteristics and internal tissues have a certain impact on the propagation of the ultrasonic wave. By detecting the degree and condition of the ultrasonic wave, we can understand the changes of the material performance and structure.
2. Ray detection:
Radiation detection uses the difference in the amount of radiation transmitted through the normal part and the defect, resulting in the difference in blackness on the film.
3. Penetration test:
Penetration test is to use the capillary action of liquid to infiltrate the penetrant into the opening defects on the surface of the solid material, and then use the developer to suck the penetrant into the surface to show the existence of defects.
4. Magnetic particle detection:
Magnetic particle detection is to use the magnetic flux leakage at the defect to attract the magnetic powder to form a magnetic mark to provide a defect display. It can detect surface and subsurface defects. The nature of the defect is easy to identify. Paint and plating surfaces do not affect the detection sensitivity.
5. Eddy current testing:
Eddy current testing mainly uses the eddy current induced in the workpiece by the ferromagnetic coil to analyze the internal quality of the workpiece. It can detect the surface and near-surface defects of various conductive materials. It is usually difficult to control the parameters, and the test results are difficult to interpret. It must be a conductive crack, and the length of the defect can be measured indirectly.