Online magnetic nondestructive evaluation (NDE) of dual-phase (DP) steels is made on bands submitted to high multiaxial stress. Extraction of microstructural information from the measurement requires separating the effect of stress and microstructure. Coupled magnetomechanical micromagnetic modeling is relevant for that purpose. In this paper, the magnetic behavior of a DP steel under biaxial stress is carried out and compared with the modeling. It is shown that the discrepancies observed between experiments and model can be explained by the 2-D assumption.