Numerical simulations and experimental investigation of laser hardening depth investigation via 3MA-eddy current technique

This paper discusses laser hardening depth inspection via the industrial 3MA- eddy current module by combining numerical modeling and experiments. The hardening treatment process leads to difference in microstructure from the surface to the bulk, which engenders various signatures in the eddy current signals, using single frequency Eddy current excitation, it is possible to define a link between the measured quantities and laser hardening depth. The results of finite element simulations confirms that the obtained signals are intrinsically linked to the magnetic properties of the specimen material. From the profile of the eddy current signals versus laser hardening depth, the skin depth is accurately evaluated at the indicated frequency.