Electromagnetic Acoustic Transducer (EMAT) testing is a form of ultrasonic testing. Like other ultrasonic tests, it is a non-destructive test, relying on acoustical wavelengths to detect flaws or identify material properties.
EMAT testing is used on carbon steel and exotic alloys, using the magnetic properties of these materials to create wavelengths that can detect areas of corrosion, and inspect and scan surfaces much more quickly than conventional ultrasound.
Advantages Of EMAT Testing
Faster scans are just one of the advantages of EMAT testing. This method of examination and testing is extremely diverse and can be used in both online and offline applications. Additional advantages include:
- High Speed Screening reduces the amount of time it takes to scan an area, improving testing efficiencies.
- Lightweight Systems are extremely portable.
- No couplant requirement reduces the amount of supplies needed at each exam site, makes deployment easier, and eliminates errors that can occur with couplant variation.
- 100% coverage. EMAT testing can be used on rough surfaces and coated areas since it is unaffected by coatings, roughness and oxidation.
- Easily repeatable tests mean subsequent measurements can be taken to ensure accuracy.
- Operates under a diverse number of operating conditions. Since liquid couplant is not required, EMATs can be used in dry, hot, or cold conditions without risking the validity of the results.
- Enhanced signals provide stronger readings and results.
- Shear waves can be generated without mechanical pressure or couplants that could impede readings.
- Frequency specificity is easily achieved thanks to the antenna-like coils. This helps technicians select the wave mode most appropriate for interpretation.
How EMATs Work
Electromagnetic Acoustic Transducers use interacting magnetic fields to test objects and materials. Electrical coils are placed atop the material to be tested where they generate a high frequency field. The high frequency field interacts with either a static or a low frequency field generated by magnets. This interaction creates a disturbance in acoustic wavelengths that can be picked up by the electric coil and relayed to a computer software system that reads and analyzes the results. The sound is actually generated inside the material or object being inspected, rather than in the transducer, which leads to more accurate readings.
Examining The Inaccessible
Some of the biggest challenges in oil and gas inspections are getting to the object or material that needs to be inspected. EMAT testing reduces this challenge by utilizing acoustic wavelengths that can be sent in multiple directions from a more easily accessible location. This is made possible by the fact that EMATs do not need liquid couplant in order to transmit the wavelengths. This makes it possible to examine inaccessible sections of pipeline or structures, even in harsh environments, thus ensuring 100% inspection coverage.
EMAT Testing And Inspection At Amerapex
Amerapex utilizes the latest advances in EMAT testing to inspect a wide variety of materials and structures including:
- CML assignment
- Pipeline Direct Assessments
- Weld Inspections
- Point of contact / Hangers / Pipe Support Inspection
- Fired and Unfired Furnaces / Heater Tube Inspections
- Tank Inspections (Shell, Floor and Roof)
- Flare Stacks
- 100% Piping system Inspection (Pipe, Elbows, Reducers, etc.)
- Dead End Piping
To learn more about EMAT testing and other NDT inspection services from our Houston-based company, contact us at 1-713-263-0900.