Abstract
Surface rolled sintered gears are expected to be used in automotives. For commercialization of them, a reliable and efficient in-line inspection after rolling is inevitable. The authors have been proposing an eddy current inspection for PM components as a non-destructive, efficient method to be installed in-line. The eddy current depends on the resistivity and the relative permeability of the material to be measured. While those of sintered bodies will be changed by surface rolling as it will accompany with both the densification and the residual stress. In order to use the eddy current method as the inspection of the surface rolled sintered gear, distributions of the resistivity, the relative permeability along with the porosity of the Fe-1.5 Cr-0.2 Mo-0.23 C alloy having 4 different densities, 7.0, 7.25, 7.5 and 7.6, were measured and analyzed.
