EMAT (Electromagnetic Ultrasonic Transduction), is an NDT inspection technique using ultrasonic wave technology. EMAT is based on a combination of US patents: one for the Ultrasonic Transducer, patented in 1969 by James R. Houck, Henry V. Bohm, and Bruce W. Maxfield; and another for the Meander Coil, patented in 1974 by Robert B. Thompson, George A. Alers, and Marion A. Tennison. Although experiments were first conducted during the 1970s, it wasn’t until the 1990s when the first commercial applications of EMAT were successfully performed.
Recent advancements in technology and equipment have enabled the transformation of the EMAT tool into an effective and diverse NDT inspection technique. EMAT can be used to inspect pipe contact points (pipe supports), tank inspections (floor, walls and roof), soil to air inspections, weld inspections and many more.
Several advantages of EMAT:EMAT-Guided-Wave-Inspections2
• Works without need of contact or liquid coupling
• Works at high temperatures up to 1000°F
• Enables generation of various wave types:
SH (shear horizontally polarized)
LH (longitudinal horizontally polarized)
SH plate waves
• Pipes do not need to be cleaned
• Rapidly inspects full volume of pipe without having to access entire circumference
• High speed screening for corrosion in pipes, vessels and tanks
• Internal & external inspection performed simultaneously
Advanced Corrosion Technologies & Training’s EMAT inspection technique can be used on exotic alloys such as Hastaloy furnace tubes and is ideal for many types of corrosion detection applications. Speed and accuracy of EMAT is superior to other automated systems. ACTT has been performing EMAT inspections since the late 1990’s.