Magnetic Barkhausen noise: stress-dependent mechanisms in steel

Angular dependent magnetic Barkhausen noise energy signal measurements were performed on two similar pipeline steel samples up to tensile stresses of 330 MPa. Variations between the stress dependence of the energy signals at five investigated positions were interpreted in terms of the relative proportion of three stress-dependent mechanisms for modifying the magnetic properties of steel. These were; the change in the number and in the orientation of 180° domain walls and the modification of pinning barriers