Based upon experimental observations the authors have shown in the previous studies that the orientations of orthotropy axes of anisotropic sheet metals are subjected to change during tensile loading at angles to the rolling direction. To predict the rotations of orthotropy axes under general plane stress conditions, a simple phenomenological model is proposed which accounts for the effect of work hardening. Predictions from the model are compared against the experiments for 0%, 3%, and 6% of 1st tensile prestrains in the rolling direction and 2nd tensile prestrains at 30$^{circ}$, 45$^{circ}$ and 60$^{circ}$ to the 1st prestrains axis. The model showed good agreements with the experimental observations. A new interpretation of the experimental data is suggested regarding the rotations of orthotropy axes.