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EMAT Pipe Corrosion Detection

Non-contact emat scans allow rapid assessment of corrosion in piping, including normally inaccessible areas under pipe supports.

Brief Description

Electromagnetic Acoustic Transducers induce ultrasonic waves in metals without the need for an acoustic coupling medium. The MBI system is designed for detection and grading of corrosion in piping and under pipe supports in particular.

Although emat probes sit on the pipe surface, they are dry coupled and relatively unaffected by coatings and light surface rusting. The system operates by transmitting Lamb waves around the pipe circumference. The probes are held in a fixed orientation and carried along the pipe by a motor driven scanner with an encoder to track its position. Ultrasonic (thickness) data is recorded and displayed by a computer for evaluation on the spot and off-line review.

Capabilities

• Uses non-contact probes that work through most standard coatings and light surface rusting. 
• Can scan up to 500 m of pipe per day depending on requirements and conditions.
• 100% coverage, detects ID and OD corrosion under pipe supports and similar inaccessible places.
• Can detect wall losses of 10% or more depending on requirements and conditions.
• Primarily used in the inspection of carbon steel low alloy pipe work, although it is possible to apply the technique to high alloy stainless steels.
• Diameter range: 4" to 24" with development ongoing for other sizes.

Limitations

• Needs a consistent surface, heavy coatings and scale degrade performance. 
• Need access to the full pipe run for positioning and operation of the scanner.
• Internal coatings and viscous fluids may affect performance.

Preparation

• Generally no requirement for surface preparation.

Services Required

• Adequate provision for personnel and equipment access.