Electromagnetic Properties Evaluation of High Chromium Ferritic Steel by Eddy-Current Method

In this paper, a pancake-coil impedance model is derived from partial differential equation. Comparing with well established theory by Dodd and Deeds, the presented model is simplified, but can solve the problem that Dodd formula sometimes meets "overflow" error in the case of ferritic steel.In addition, a series of base and heat affected zone (HAZ) materials in different heat treatment conditions are experimentally measured.Then, conductivity and permeability are determined by searching for the accordance with theoretical calculation.