Eddy current probe having one yoke within another yoke for increased inspection depth, sensitivity and discrimination

摘要

Defects such as corrosion located on either the inner diameter or outer diameter of a covered metal component are detected through eddy current inspection. At least two concentric magnetizing yokes are held fixed with respect to each other and are scanned over the cover of the component. A magnetic flux sensor on the leg of each yoke detects changes in the magnetic flux that penetrates at different depth regions in the covered metal component, depending on the relative postion of each magnetizing yoke.