Evaluation of mechanical properties of magnetic materials using a non-destructive method

A magnetic-based nondestructive evaluation (NDE) method, which employs Bark hausen effect and measurement of hysteresis loops, is developed and used to correlate the magnetic and mechanical properties in ultra low carbon (ULC) steel. The NDE test equipment offers the capability to detect small deviat ions from linearity that occur in the stress-strain curve well below the 0. 2% offset strain. Results show that three properties extracted from the exp erimental results, jumpsum and jumpsum rate (derived from the Barkhausen sp ectrum), and differential permeability (derived from the B-H loops), vary s ensitively with small deformations well below the 0.2% offset strain in ULC steels; however coercivity is a slowly varying function of small applied s trains.