Kosilov M. Improvement of forging technology of the hollow forgings with variable wall thickness by step tool enlarging

Object of research - the enlarging process of the hollow forgings with variable wall thickness. The purpose of the work is to increase the mechanical properties and reduce energy and metal costs in the manufacture of forgings with variable wall thickness by developing new energy and resource-saving technological processes of deformation based on the use of a stepping tool during enlarging. Research methods – the finite element method for determining the deformed state, the method of physical modeling and the method of similarity for performing experimental investigations, the regression analysis for processing experimental results, the macroscopic method for the study of macrostructure, the method of grain counting for the study of microstructure. Theoretical and practical results - new scientifically grounded developments in the field of technologies and equipment for large-scale forging production processes is obtained on the basis of the enlarging process, which together provide the solution of an important scientific and technical task - the expansion of the nomenclature and the improvement of the quality of large ring forgings of responsible designation through the creation of new technological regimes forging on the basis of the received regularities of change of the deformed state of ring forging. Novelty - on the basis of the finite element method quantitative estimates of the strained state of ring forging with a one-sided projection, depending on the geometric parameters of the workpiece, degree of deformation and deformation schemes, have allowed to establish rational modes of realization of the studied rolling processes; on the basis of theoretical and experimental analysis of the enlarging process by the profiled tool, the character of the step-by-step change in the stress-strain state was determined, which made it possible to establish a dangerous transition zone near the base of the projection, which may lead to the formation of a ring clamp, for the elimination of which the form of the working tool with a rational angle of the step transition is proposed. Introduction - new technological processes and a step-shaped tool for slipping have been tested and accepted for implementation in production, which is confirmed by an act. Scope - treatment of metals by pressure.