Magnetostrictive Sensors Detect Corrosion of Insulated Piping Systems

Engineers and scientists at Southwest Research Institute (SwRI) in San Antonio, Texas, may have found a cost-effective and practical method of detecting ID and OD corrosion of insulated piping systems.

SwRI uses magnetostrictive sensors (MsS) which are electromagnetic coils that produce magnetic fields in carbon steel pipes. When these coils are excited with alternating current, the changing magnetic fields in the pipe cause small changes in the physical dimensions of the pipe. This phenomenon is the magnetostrictive effect and it can be used to transmit elastic waves in frequencies up to a few hundred kHz. These elastic waves can examine the entire cross-sectional area of a pipe and are sensitive to very small OD and ID crack and corrosion defects.