A Multi-Element and Frequency Eddy Current (MEF-EC) inspection system has been qualified to monitor surface defects in the production line of steel ingots. Sensors comprising up to 16 elements help to avoid expensive and sensitive to damage scanning systems. A three frequency mix provides quantitative results by numerical filters which are established by correlation mathematics on a statistically representative set of test specimens.

The MEF-EC will become part of couplant free EMAT inspection system. The data representation meets the common principles of ultrasonic inspection for this reason.

First test results demonstrate further advantages of implementation of EC surface inspection. The MEF-EC can find all surface defects in arbitrary alignment to the scan index, there is no need for special cleaning of the surface, and the materials surface state e. g. hardness can be monitored.