Arhat R. Improvement of the technology of manufacturing of cylindrical parts by drawing with a stage-by-stage stretching of the workpiece flange with corrugations

The thesis is aimed at solving an important scientific and technical task of the development and improvement of the technological processes of drawing cylindrical parts from sheet blanks to ensure the economy of material and energy resources. A mathematical model of distribution of deformations and stresses on the drawing edge of the die has been developed, which made it possible to more accurately take into account the friction forces between the workpiece and the tool during the drawing without clamping as well as to identify the main factors of the process that influence the distribution of the stress field in the deformation zone. A method of calculating the intervals of stamping without clamping on the basis of the solution of the Bessel equation is developed. This made it possible to determine the critical thickness of the workpiece, in which the loss of stability with the appearance of folds begins, and to identify the factors of the technological process that affect the wavelength in the flange. In this case, consideration is given to the initial anisotropy, as well as to the strengthening of the metal of the workpiece. A new method of drawing with stage-by-stage sketching of a flange of a workpiece with corrugations on the basis of the Bauschinger effect is proposed, an experimental confirmation and implementation of this method is obtained. A method of calculating the reverse stroke length of the punch, a method for determining the geometric sizes of the blanks and the order of the stage-by-stage technological calculations for a new method of drawing are developed.