An original experimental facility for studying the physical properties of materials during elastic-plastic deformation along two axes has been created. The facility has no ferromagnetic parts in the working area, thus enabling us to make more accurate magnetic measurements. Biaxial deformation is simulated by the finite element method in order to optimize the geometry of the specimen and to determine the stress state in the central zone of the specimen. Test experiments on the effect of biaxial tension on the coercive force of the 12G2S are performed.