ToFD and Corrosion Mapping

ToFD screening has been developed jointly between Sonomatic and Shell Global Solutions with the objective of providing a method of rapid, yet accurate corrosion mapping.
ToFD is an ultrasonic technique originally developed for crack detection. Unlike conventional Pulse Echo, the transmitter receiver in arrangement in ToFD floods the region between the probes with ultrasound. Crack tips are identified by diffraction but it is also very effective for the detection and sizing of Weld Root Erosion or Corrosion.
Corrosion mapping involves scanning one or more straight beam probes over a prescribed, dual axis scan pattern over a pipe or pressure vessel surface whilst taking thickness measurements. The measurements are converted into digital values which are color-coded to create topographic maps of the vessel or pipe wall thickness profile. Various types of crawler are available, ranging from our ruggedized, track-mounted Nautilus scanner, the magnetic wheeled crawler, Mimic, (bottom right), and our UT corrosion mapping system, MicroMap, with video-tracking of probe position.