MT flaw detection, magnetic particle flaw detection:
By magnetizing the ferromagnetic pipeline equipment, a leakage magnetic field is generated on the pipeline surface and near-surface discontinuities, and the magnetic powder applied to the pipeline surface is adsorbed, thereby showing the location, size, shape and severity of the discontinuity. Determine whether there are defects in the pipeline equipment. It is often used for surface and near-surface defect detection of pressure pipelines themselves and welds at joints. When using magnetic particle flaw detection technology for detection, the detection pipeline needs to be magnetized longitudinally and transversely at the same time to effectively ensure all-round detection.
Advantages: It is the most effective detection method for the surface of carbon steel and alloy steel pipelines with strict requirements;
Disadvantages: From the perspective of technical operability, the detection technology is difficult to operate, complex, low in efficiency, and requires high technical skills.
It is often used as a means of non-destructive testing of the pipe surface, pipe port, weld surface, and fillet weld of China Railway’s magnetic pressure pipelines (chemical project pipes A335P22, A335P11, SA106B, A333 Gr.6, Gr.8; 20#, Q345D/E - GB9948/GB6479 pipeline pipes L245N L360NL360Q L415Q, etc.), but it is not suitable for non-magnetic materials such as nickel-based alloys and stainless steel.
