Welding is one of the main technological processes used in the manufacture of various structures in mechanical engineering and construction, and the quality and reliability of the operation of structures largely depend on its quality. Despite significant progress in the development of welding equipment and technologies, defects of various types and sizes can occur in welded joints for various reasons, leading to a decrease in the performance and durability of structures, and sometimes to emergencies. Effective methods of non-destructive testing are used to exclude entry into operation of structures having welded joints with unacceptable defects.