OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 6 No. 2 2024 Technological possibilities of cold or hot die forging of powder products can be successfully realized in the presence of scientific, design and technological generalized results, the use of which will provide the required quality and properties of the obtained materials, density distribution by volume, durability and cost of tooling [9–12]. This makes it necessary to determine the stress-strain state during cold or hot die forging of powder blanks of different configurations and materials. One of the ways to solve boundary value problems in the theory and technology of hot and cold die forging of powder products is to determine the kinematic parameters in characteristic cross-sections of blanks at different stages of its forming in order to establish the relationship between the strain component and stresses, as well as to identify the allowable values of strains, nucleation and development of cracks during die forging [13–17]. Various simulation models and programs can be used for this purpose [18, 19]. The purpose of the work is to study the influence of tool design, lubricant composition and method of manufacturing sintered blanks from corrosion-resistant steel powders on the kinetics of forming during cold die forging of spherical sliding bearing parts. Research methods One of the design options of the non-separable spherical sliding bearing is shown in (Fig. 1). The manufacturing technology of such sliding bearings, often used in aviation industry, is not described in the publications available to us. However, some requirements for it have been formulated: reliable operation in various conditions under the action of high radial and axial loads, minimum wear and friction coefficient, predictable operational life and others. Such friction units are made of corrosion-resistant steels with the use of special lubricants. Inner rings of the bearing unit are made of steel AISI 52100, after maintenance its hardness is HRC 58–61. The outer ring is made of powders of corrosion-resistant steels 304L-AW100 of “Höganäs” (Sweden) and 0.12C-18Cr-10Ni-Ti of domestic production, as well as components and ligatures (Table 1). To study the mechanical and technological properties of porous blanks, circular (GOST 26529–85 and GOST 18227–98) and prismatic (GOST 1497–84) tensile test specimens were made. Specimens for research were pressed on a hydraulic press HPM–60L in a cylindrical mold with a floating matrix under pressure from 200 to 800 MPa. Part of the pressings was sintered in a laboratory furnace with carbide-silicon heaters in dissociated ammonia, another part was sintered at 1,150 ºC for 1.5–2 hours in a vacuum electric furnace VSl–16–22–U. a b Fig. 1. Spherical sliding bearing: a – sections of friction unit; b – maximum rotation angle of the inner bearing
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