Definition
Electromagnetic Inspection — Electromagnetic inspection is a nondestructive method that scans the full length of a drill pipe or tubular tube body with magnetic flux and eddy-current sensors to detect wall loss, pitting, cracks and other defects as the pipe passes through the inspection unit.
Also known as: EMI, electromagnetic inspection, electromagnetic tube inspection
What EMI detects
Electromagnetic inspection (EMI) is the primary volumetric method for inspecting the tube body of drill pipe and tubing. As the pipe is fed through the EMI unit, it is magnetized and scanned by two complementary sensor systems: flux-leakage sensors that respond to abrupt features such as cracks, pits and slip cuts, and eddy-current or wall-monitor channels that respond to gradual wall thinning and grade changes.
EMI covers the full length and circumference of the tube quickly, flagging areas of concern that are then confirmed and measured by ultrasonic wall gauging. It is a cornerstone of drill-pipe classification under DS-1 and API RP 7G-2.
What EMI evaluates
- Wall loss and remaining body wall — for Premium and Class 2 grading.
- Transverse and longitudinal defects — cracks, cuts and pitting.
- Grade verification — detecting mixed or off-grade joints.
Because EMI relies on magnetization, it applies to ferromagnetic tubes; it is complemented by MPI on connections and by ultrasonics for precise wall measurement.
Why it matters for rentals
Full-length EMI to a defined standard is what lets a rental provider certify a joint as Premium or Class 2. See our drill pipe and quality program, or contact us for inspection certificates.