Commonly used non-destructive testing methods include radiographic testing (RT for short), ultrasonic testing (UT for short), magnetic particle testing (MT for short) and penetration testing (PT for short), which are known as the four conventional testing methods. These four methods are the most commonly used nondestructive testing methods for manufacturing quality inspection and in-service inspection of pressure class special equipment.
Among them, RT and UT are mainly used to detect internal defects of specimens, and MT and PT are mainly used to detect surface defects of specimens. Other non-destructive testing methods used for pressurised special equipment include eddy current testing (ET for short), acoustic emission testing (AE for short) and so on.
There are many types of rays, among which X-rays, γ-rays and neutron rays are easy to penetrate the material. These three types of rays are used for NDT, of which X-rays and γ-rays are often used in the defect detection of welding seams of pressurised equipment and other industrial products and structural materials, while neutron rays are only used in some special occasions. Ray detection is an important professional category of industrial non-destructive testing. The main application is the detection of macro-geometric defects within the specimen (flaw detection).
