Because of the unique property of EMATs that they generate and detect ultrasound inside the target material, they are eminently suitable for inspection of products/components moving past on a production line where physical contact is not an option. In addition, EMATs are tolerant of high temperature environments and can be used on hot metal products.
Sonemat have developed a novel ultrasonic fill level inspection system for liquid level in metal walled containers. Using only two side wall transducers an accurate measure of the level of liquid can be obtained. This is suitable for online application.
In the metals industry, early detection of flaws in the product is of paramount importance in order to avoid high costs if a metal product is rejected further downstream. Because EMATs are non-contact, they are suitable for working at high temperatures (up to 800
°C) with only simple water cooling.
Hot pipes can be inspected to ensure regular wall thickness ultrasonically. By using a novel laser-EMAT hybrid configuration, optimum performance can be achieved on pipes as hot as 1000 °C.
EMATs do not require a couplant fluid to inspect metals, and are tolerant of surface corrosion and coatings. This leads to quicker inspections and thus lower costs than conventional ultrasonic inspection in many applications.
Shear wave EMATs can be used to accurately detect wall thinning in pipe. Using Sonemat's GS2020 EMAT adaptor box, this can be done with conventional flaw detectors, so there is no need to re-train operators.
Automated Pipeline Inspection
Sonemat has been instrumental in developing EMAT Technology’s Automated Pipe Inspection system for large scale gas/oil pipeline.
Because EMATs are not physically in contact with the material under test, measurement distortion due to such effects as mass loading are negligible compared with conventionally coupled ultrasound. This can make EMATs easier to use for precision measurements in certain applications.
By measuring variations in the elastic modulus of sheet metal, the crystallographic texture can be inferred. This gives an important tool for quality and process control at the cold rolling stage of strip production. Changes in the important Lankford or plastic strain parameters, as well as microstructural changes due to annealing and cold working, are related to the measured texture. The nature of EMATs suits them to rapid, non-contact scans of a section of sheet, with texture parameters determined in less than a minute (compared with hours using conventional texture measurement systems such as X-ray diffraction). This allows rapid feedback to the rolling mill of any parameters causing undesired product
EMATs can be used to detect coating thicknesses on metals with accuracy down to the micron level by measuring the shift in the resonant frequency of a coated metal plate. Since the EMAT does not physically touch the plate it does not affect the resonant frequency due to mass loading from the transducer or couplant.