The description of installation for the tests of thin-walled tubular models under the conditions of the flat and volumetric stressed states with two- or three-parameter load is given by the pressures of liquid to 1000 MPa. The hypothesis of existence of universal dependence between the intensities of deformations and stresses underwent the experimental check. It communicates about the experiments on the study of the stability of the plastic deformation of isotropic and initially anisotropic metals. Is emphasized the urgency of experimental studies of viscoelastically plastic processes in present development stage of the mechanics solid of body being deformed.