Nondestructive characterization of microstructure and mechanical properties of intercritically annealed dual-phase steel by magnetic Barkhausen noise technique

Detection of microstructural changes is a great importance matter in production line of steel parts. To implement such a task, many destructive tests are involved in industries. Current work examines the effects of different microstructures and mechanical properties on the magnetic Barkhausen noise technique as a suitable alternative testing method. In this study, different dual-phase steels with different martensite percentages were manufactured using various intercritical annealing temperatures from 750 to 850 °C. The results concerning magnetic Barkhausen noise were discussed in terms of position, height and shape of Barkhausen noise profiles, taking into account the effect of different percentages of martensite. Since this method is nondestructive after calibration, some beneficial relations for nondestructive characterization of microstructure as well as mechanical properties of any unknown dual-phase steel sample were achieved. Additionally, the feasibility of using the magnetic Barkhausen noise to detect microstructural changes during tempering of dual-phase steels was evaluated. The results revealed this magnetic method had a high potential to be used as a reliable nondestructive tool to detect microstructural changes occurring during manufacturing of dual-phase steels.