Method to minimize the radial displacement dependency of an eddy-current based cross-sectional area measurement of hot-rolled rod and wire

Abstract

The cross-sectional area of hot-rolled rod and wire must be measured to meet tight tolerances and high requirements of customers. An eddy-current based method utilizes a pass-through coil as a sensor element. It can measure the cross-sectional area by using the almost linear relationship between the coil reactance and the cross-sectional area of the rolled material. The lateral movement of the rod inside the coil causes deviations in the measured cross-section which must be minimized. This work outlines a successful approach for measuring the rod position within the coil using two differential pickup coils and minimizing the deviation using a simple algorithm.