The magnetic parameters of steel depend on the mutual orientation of the applied magnetic field, the (applied) stress and the crystalline structure. The magnetic anisotropy can be modeled in terms of the magneto-elastic and magneto-crystalline energy distributions. By investigation of the magnetic anisotropic behaviour of steels with respect to stress, a rapid, non-destructive and possibly non-contact measurement of the residual stress can be devised that can find application in manufacturing, machining, forming and life-time assessment of steel and steel components. Reliability, robustness and versatility will constitute the main challenges to further develop these techniques for common industrial applications.