Study of the expansion process taking into account the contact interaction of the deforming tool and pipe

Abstract

The elements of the press expander head and the process of pipes expansion are described. The requirements for pipes before and after expansion in accordance with the standards are given. The methods of research on the section of the hydromechanical expander of the J-C-O-E (TESA) 1420 line are presented. Mathematical modeling is carried out in the DEFORM software package, taking into account prehistory loading. On the basis of the experimental study and numerical analysis, the reasons for the occurrence of deviations from roundness, excess of ovality and the perimeter of pipes before and after expansion are determined. The nature of the distribution of stresses and deformations in the process of eliminating ovality in the contact and non-contact sections of pipes and press expander tools are determined. The most loaded areas during the expansion of thick-walled and thin-walled pipes are revealed, and a method for calculating the deformation force is proposed, taking into account the initial curvature of the deformable shell. A method for expanding pipes is presented, taking into account the uneven distribution of mechanical properties and deviation in geometric parameters, perimeter and length of the pipe.