What methods can be used to inspect stainless steel welded pipes

There are many inspection methods for stainless steel welded pipes, among which physical methods are also commonly used inspection methods. Physical inspection is a method of measurement or inspection using some physical phenomena. The inspection of internal defects of materials or stainless steel welded pipes generally adopts the method of non-destructive testing. The current non-destructive testing includes magnetic testing, ultrasonic testing, radiographic testing, penetrant testing, etc.
Magnetic test
Magnetic flaw detection can only find defects on the surface and near the surface of magnetic stainless steel welded pipes, and can only do quantitative analysis on defects, and the nature and depth of defects can only be estimated based on experience. Magnetic inspection is to use the magnetic flux leakage generated by the magnetization of ferromagnetic stainless steel welded pipe to find defects. According to the different methods of measuring magnetic flux leakage, it can be divided into magnetic powder method, magnetic induction method and magnetic recording method, among which the magnetic powder method is widely used.
penetration testing

Penetrant inspection uses the permeability and other physical properties of certain liquids to find and display defects, including coloring inspection and fluorescent flaw detection, which can be used to inspect defects on the surface of ferromagnetic and non-ferromagnetic materials.

Radiographic testing
Radiographic flaw detection is a flaw detection method that uses the characteristics of rays that can penetrate substances and have attenuation in substances to find defects. According to the different rays used in flaw detection, it can be divided into three types: X-ray flaw detection, γ-ray flaw detection, and high-energy ray flaw detection. Due to the different methods of displaying defects, each type of ray inspection is divided into ionization method, fluorescent screen observation method, photographic method and industrial television method. Radiographic inspection is mainly used to inspect defects such as cracks, incomplete penetration, pores, and slag inclusions inside the welds of stainless steel welded pipes.
Ultrasonic flaw detection
Ultrasonic waves can be used in the inspection of internal defects due to the reflection on the interface of different media in the propagation of metal and other homogeneous media. Ultrasound can inspect any weldment material, any defect in any part, and can detect the defect position more sensitively, but it is difficult to determine the nature, shape and size of the defect. Therefore, ultrasonic flaw detection of stainless steel welded pipes is often used in conjunction with radiographic inspection.