This study, in the area of non-destructive testing and measuring technology, shows that it is possible to inspect and determine the mechanical properties and micro structure of a material using electro-magnetic technique. The goal has been to on-line determine material properties like residual stress distributions, variations in tensile strength and fatigue strength in a material. In the project the latest in materials inspection using electro-magnetic methods combined with statistic modelling is used. The project has shown that these new methods can non-destructively determine the mechanical properties of a material or a machine detail. It is believed that this measuring technique has a clear place in industry.