Dekhtyar'ov V. Development of the tool calibration methods at cold pilger rolling of precision tubes with variable on length of the working cone caliber type

The dissertation is devoted to definition of regularities metal forming depending on the form of the cross profile of the pass groove on length of the work cone and development of the method of calculation of the deforming tool. Methods of calibration of the tool which provide obtaining tubes of the raised dimensional accuracy are developed. Regularities of development of metal forming at cold pilger rolling of tubes for different types of the cross profile of the pass groove have been obtained. The account of metal forming at calculation of geometry of deforming tool allows to minimise stretching stresses and to raise accuracy of tubes. The method of calibration of the tool with variable type of the cross profile of the pass groove on length of a working cone is developed. The calibration of the tool with curvilinear generatrix the groove and mandrel was also developed taking into account yield stress change on length of deformation zone and the scale factor which allows to reduce value of vertical forces on 5 - 12 % and value of an axial thrust on 10 - 35 % that provides raise of accuracy of tubes.