ОЦЕНКА СТЕПЕНИ МОНОТОННОСТИ ДЕФОРМАЦИИ ПРИ БЕЗОПРАВОЧНОМ ВОЛОЧЕНИИ ТРУБ

To determine the of the strain monotonicity in the case of tube sinking of steel pipes, the finite element method, implemented in the deform software module, was used. Calculations have been made for pipes with different thicknesses. the difference was revealed in the results of determining the effective strain and the strain according to von Mises. The conclusion is made about the influence of the method of calculating deformations on these indicators, taking into account the degree of non-monotonicity during drawing. It was found that for thin-walled pipes, radial elongation deformations occur on the inner surface of the pipe, and on the outer surface, the signs of deformations change according to the algorithm: shortening - lengthening - shortening, which is a sign of non-monotonicity; closer to the end of the process, elongation deformations prevail on the inner surface against the background of smaller shortening deformations on the outer surface. For thick-walled pipes, the non-monotonicity of the process is less due to the invariability of the signs of the radial component of the deformation tensor.