Remote field testing (RFT) is an electromagnetic method of nondestructive testing whose main application is finding defects in steel pipes and tubes. The basic RFT probe consists of a transmit coil which sends a signal AC current and emits magnetic field to the detector (or receive coil). The field travels through the pipe wall, and along the pipe. The detector is placed inside the pipe two to three pipe diameters away from the sender and detects the magnetic field that has travelled back in from the outside of the pipe wall (for a total of two through-wall transits). In areas of metal loss, the field arrives at the detector with a faster travel time (greater phase) and greater signal strength (amplitude) due to the reduced path through the steel. Hence the dominant mechanism of RFT is through-transmission.
- Only ferrous tubes can be inspected.
- Detects discontinuities such as corrosion, erosion, wear, pitting and baffles cuts.
- Inspection speed 0.3m/s.
- Productivity 400 tubes per shift (may differ based on site condition).