With magnetic inspection
Magnetic non-destructive testing can only find defects on the surface and near-surface of magnetic cold-drawn pipes, and only qualitative research can be done on the defects, and the characteristics and depth of related defects can only be determined based on work experience. Magnetic field inspection is to use magnetic field leakage caused by cold-drawn tubes of magnetized magnets to find defects. According to the different methods of accurately measuring magnetic flux leakage, it can be divided into magnetic particle inspection method, magnetic induction electromagnetic coil method and magnetic recording method. During the period, magnetic particle inspection method is widely used.
infiltrate to check
Penetration inspection is to use the physical properties of water absorption and other physical properties of some liquids to find and display defects, including color inspection and fluorescent non-destructive testing, which can be used to inspect the surface of ferromagnetic materials and non-ferromagnetic materials.
NDT
Non-destructive testing is a non-destructive testing method that uses radiation through compounds and the characteristics of attenuation coefficients in compounds to find defects. According to the different rays used in non-destructive testing, it can be divided into three types: X-ray non-destructive testing, gamma non-destructive testing, and higher-energy non-destructive testing. Due to the different methods of revealing defects, each NDT is divided into water ballast method, monitor observation, photographic method and industrial television method. The ray inspection is mainly used to inspect the cracks, incomplete penetration, blow holes, welding scars and other defects inside the cold drawn pipe welding.
Ultrasonic flaw detector
In the transmission of metal composite materials and other uniform chemical substances, ultrasonic waves can be used for the inspection of internal defects due to the formation of vertical surfaces on the web of different chemical substances. Ultrasound can inspect all welding parts raw materials and defects in all parts, and can find the location of defects more comfortably, but it is difficult to identify the characteristics, appearance and size of defects. Therefore, the cold-drawn tube ultrasonic flaw detector is often used in conjunction with radiographic inspection.