Study of the Properties of Antifriction Rings under Severe Plastic Deformation

Abstract

The paper studies the properties of brass workpieces for antifriction rings under severe plastic deformation by high-pressure torsion. The evolution of microstructure and mechanical properties of deformed workpieces after six cycles of deformation by high-pressure torsion at 500 °C have been studied. All metallographic studies were performed using modern methods: transmission electron microscopy (TEM) and analysis electron back scatter diffraction patterns (EBSD). The deformation resulted in an ultrafine grained structure with a large number of large-angle boundaries. The strength properties of brass increased compared to the initial state almost by three times, the microhardness also increases by three times, i.e., increased from 820 MPa in the initial state to 2115 MPa after deformation. In this case, the greatest increase in strength properties occurs in the first two cycles of deformation.

Experimental Analysis of the Stress State of a Prestressed Cylindrical Shell with Various Structural Parameters

“…As a result, the structure is facilitated, metal is saved, the technology is simplified and the cost of structures is reduced. The results of the research confirm the possibility of using prestress taking into account the parameters for different cases in a cylindrical shell [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ].…”

“…In any case, the pitch, according to the recommendations of [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ], should be less than the half-wave length— , and it should be selected according to the conditions of the tasks solved by prestressing and a technical and economic comparison of options.…”

“…The works [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ] present the results of studies, including the modeling of shell structures under various static and dynamic loads, where studies were also carried out taking into account the deformations of the shell body (pipelines, reservoirs, cisterns, etc.). In the studies [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ], work was carried out to study the effect of damage and defects in steel wrappings on the stiffness and natural frequencies of prestressed pipes as well as the characteristics of metals. Nonlinear analysis of prestressed round cylindrical shells’ free vibrations was studied, and the simultaneous influence of the prestressed state and the elastic foundation on the eigenfrequencies of shells under various boundary conditions was considered in detail.…”

“…The results of the above works [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ] show the general issues of construction and design of steel structures with and without prestressing shells.…”

Development of a Thermomechanical Treatment Mode for Stainless-Steel Rings

“…In terms of manufacturing process development, this means a tendency to reduce the number of different production steps while using materials as efficiently as possible [ 11 , 12 , 13 , 14 , 15 ]. In terms of material performance, against an increasingly important, lightweight design, high strength with good ductility is of great importance [ 16 , 17 ]. Most manufacturing processes for processing metallic materials cause local or global changes in material properties.…”