Monitoring the State of Stainless Steel under Cyclic Deformation by the Acoustic and Eddy Current Methods

The effect of the amplitude of deformation on the intensity of the change of the elastic and magnetic properties of austenitic stainless steel 12Kh18N10T was studied. It is shown that the application of a combination of eddy current and ultrasound measurements makes it possible to evaluate the state of this steel grade under fatigue failure, and the results of such measurements are provided. The proposed technique for measuring ultrasound parameters made it possible to record the changes of the structural state of the material under fatigue failure long before crack formation. The eddy current method was used in order to determine the volume fraction of martensite possessing ferromagnetic properties. An algorithm is presented for estimating the number of cycle loadings and the operating time of metastable austenitic steel 12Kh18N10T based on ultrasound and eddy current measurements.