Operating Parameters of Electric Pulse Activation for Internal Tapping-Screw Operations and its Justification

Abstract

The processes of intensification of thread-cutting opera-tions by electric current have been known since the 70s of the last century. Internal threading operations are associated with the mechanism of plastic deformation, and, accordingly, with high values of forces and torques. This reduces the reliability of the process and requires additional measures to reduce power ten-sion. The use of the energy of short stimulating current pulses makes it possible to solve such problems due to the so-called electro-plastic effect (EPE). It is manifested due to additional stresses that cause an increase in the plasticity of metals in the presence of an electric potential and a temperature field in the de-formation center. At present, there is still no clear understanding of the phys-ical processes that determine the change in the VAT of a metal when an electric current is passed. The article presents an analysis of information in this area, which allows us to establish a number of physical phenomena, which are formed into three theories that explain the essence of EPE in metals: electron-dislocation interaction, joule heating, and magnetoplasticity. A description of experiments and equipment for electro-pulse stimulation of the threading operation is presented. The author offers a number of indicators that evaluate the possibilities of electric pulse action on the formation of internal threads when rolling threads, screwing thread-pressing parts, etc. A system of calculated coefficients evaluating the efficiency of the pulse current, its parameters and modes is established.