FIELD: physics. SUBSTANCE: invention relates to determination of physical and mechanical properties of materials. Method comprises testing samples with cylindrical working part of length l of solid circular cross section with radius r for torsion in one direction. Tests are carried out at constant temperature value of working part of sample θ, and during testing method includes measuring values of swirling angle of sample ϕ, as well as torque values M, under action of which plastic deformation of working part of sample is carried out, at the beginning of test up to arbitrary moment of time t* values of twisting angle are monotonously increased, and starting from moment of time t*, providing condition, where ξu is true strain rate, εu - true degree of deformation, for which value of twisting angle is changed by exponential dependence