Magnetic Particle Testing is useful during localized inspections of weld areas and specific areas of high stress or fatique loading. Magnetic testing provides the ability to locate shallow sub-surface defects. A major advantage for magnetic testing is portability and speed of testing. Magnetic particle testing is used to detect cracks and other discontinuities near the surface of ferromagnetic materials. Applications include tank walls, tank bottoms and welds. These testing are used when the part material is magnetized. Magnetic particle testing is limited to parts made of iron, steel or allied materials.
Magnetic pig passage indicator is a device, which is used to detect the presence of a pig at a particular point in piggable piping system. Their magnetic sensors allow them to be non-intrusive, but the pig must be equipped with an embedded magnet. They permit local indication of the pig's presence, or can serve as a remote sensor for a computer-operated/monitored system.
Magnetic Pigs are designed as a magnetic circuit with sufficient field strength in order to saturate the wall of the pipeline through which it is traveling. The magnetic pig is comprised of a steel body, which is attached with a magnetic section, four urethane cups or discs, urethane spacers, a nose plate designed to take shock and a rear locking plate. Magnetic pigs are used more frequently to inspect pipelines for corrosion.