1. Ultrasonic testing: When ultrasonic waves are transmitted in the tested materials, the changes in the acoustic properties of the materials and the internal tissues have a certain effect on the transmission of ultrasonic waves. After the exploration of the degree and condition of the ultrasonic waves, the changes in material properties and structures are understood.

2. Ray detection: The radio-graphic test uses the difference in the amount of radiation transmitted through the normal part and the defect, and the difference in blackness on the film is formed.

3. Soak detection: Saturation detection is the use of the liquid capillary effect, the penetrating liquid enters the defect of the opening of the surface of the solid material, and then the entered penetrating liquid is sucked to the surface through the developer to show the existence of the defect.

4. Magnetic particle detection: Magnetic particle detection is to use the magnetic flux leakage at the shortcomings to attract the magnetic powder to form magnetic marks to provide the appearance of defects

5. Eddy current testing: Eddy's 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 defects of the appearance and near appearance of various conductive materials. Parameter control is usually difficult.

6. Magnetic leakage detection: Petroleum casing magnetic leakage detection is based on the characteristics of the high permeability of ferromagnetic materials. The quality of petroleum casing in service is detected by measuring the permeability caused by the defects in ferromagnetic materials.

7. Magnetic recall detection: Magnetic memory detection is derived from the connection between the physical nature of metal magnetic phenomena and the process of dislocations. It has many advantages such as high efficiency, low cost, and no need for polishing. It has important application prospects in the industry.