EDDY-CURRENT TESTING OF CAST-IRON BRAKE DISKS

With the goal of optimizing hardness control of grey cast iron parts using eddy currents, we have isolated the physical and metallurgical variables conditioning the response to an eddy current probe and hardness respectively. A simulation program has allowed us to judge the effects of the various properties on the surface and in the core of disks on the viability of measures made from the surface. Moreover, an appropriate representation in the impedance plane has made it easier to obtain a parameter that may be directly linked to the hardness of parts from standards while eliminating the <<lift-off>> effect. Finally, considerations were made for the frequency of the operation depending on whether cast or machined parts are examined.