Research on strategies to improve measurement of coating thickness in hemispherical steel shells for an inclined eddy current sensor.

The thickness of anti-corrosive layer coated in the inner surface of steel oil containers is very important to prevent the containers from corrosion. To make the measurement accurate, some effective means are needed, especially for the eddy current sensor inclining or deviating over the curved inner surface of the containers. By using an electromagnetic field simulation method with high accuracy, the distorted signals and the measure precision of lift-off were analyzed. Then, some correction measures were proposed according to the characteristics of testing signals due to the sensor's inclination or deviation. Simulation results confirmed their effectiveness for enhancing the measure precision. The conclusions can give an effective theoretical guide to the centering and verticality controlling of the sensor in practice. [ABSTRACT FROM AUTHOR]