Effect of plastic strain on magnetic and mechanical properties of ultralow carbon sheet steel

We have investigated how plastic deformation changes the yield stress and the magnetic properties of an ultralow carbon sheet steel. Plastic strains up to 10% nearly doubled the yield stress from 150 to 290 MPa (22–42 ksi), and the coercive field from 0.17 to 0.31 kA/m (2.1–3.9 Oe). The effects on other magnetic properties, such as the Barkhausen signal and permeability, were also determined. It was found that a single magnetic parameter could be related to the yield stress with residual standard deviations as low as 1 MPa (0.2 ksi). Observations using a high-resolution interference–contrast colloid technique revealed a fine intragrain magnetic domain structure with the walls more effectively pinned in the 10% strained material.