In the common setup for pipeline inspection, MsS guided wave probes consist of ferromagnetic strips (0.15 mm thick) and ribbon cables (less than 4 mm thick) as shown in the figure.
The thin probes can be applied to a pipe having a 25-mm or higher clearance between pipes. The MsS guided wave probe can generate longitudinal, torsional, and flexural modes
by adjusting strip conditioning, strip size, and bias magnetization direction relative to AC magnetic field direction.
There are two types of MsS guided wave probes for pipeline inspection: Encircling probe and sector probe. The encircling MsS probes continuously covers the whole circumference (360°)
of the pipe and strongly generate a torsional wave mode with a short dead zone.
Thus, encircling MsS GWUT probe allow for an inspection of up to 500 feet in each direction in aboveground painted pipes in good condition with a defect detection sensitivity of
approximately 2-3% of the total pipe wall cross section.