PSI - Issue 50

Andrey Polyakov et al. / Procedia Structural Integrity 50 (2023) 228–235 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 5. Dependence of shear resistance value on density.

When tested for radial compression, the powder with the addition of graphite is significantly less strong (at a density of ρ rel  0.84  0.88), which is explained by the lower value of its ultimate shear strength d compared to other samples (Fig 4b). In this case, the parameter d increases with an increase in the density of the briquette, which is due to an increase in the degree of setting of powder particles Tae-Wan Ku et al. (2014), Zhdanovich (1971). Note that, as in the case of axial compression, for powders with zinc and graphite, the value of σ d increases more slowly with increasing density than for other compositions Polyakov (2020). 5. Conclusions Guidelines have been developed on the choice of rational technological parameters for the process of extrusion of bars from powder compositions, which makes it possible to predict the density of bars depending on the initial porosity of the briquette, the elongation coefficient, the taper angle of the matrix, to determine the pressure of extrusion while providing the opportunity after extrusion to obtain a bar suitable for subsequent thermomechanical processing. An algorithm for calculating the technological parameters of the process of extruding bars from powder compositions is proposed, which makes it possible to predict the density of bars depending on the initial porosity of the briquette, the elongation ratio, the taper angle of the matrix, and to determine the extrusion pressure. References Gundermann, P. Overview of the status and trends in the European PM Industry. EURO PM 2015 REIMS. Available at: http://www.europm2015.com/post-event/plenary-presentations/103-the-european-pm-industry-current-status-and-roadmapping-the future/file. Wimbert, L., Arnhold, V., 2014. Powder metallurgy in Germany. International Journal of Powder Metallurgy, no. 2, pp. 67 – 70. Tae-Wan Ku, Beom-Soo Kang, 2014. Tool Design and Experimental Verification for Multi-Stage Cold Forging Process of the Outer Race. Int. J. Precis. Eng. Manuf., vol. 15, no. 9, pp. 1995 – 2004. DOI: 10.1007/s12541-014-0556-x. Plancak, M., Brameley, A. and Osman. F., 1992 Non-conventional cold extrusion. Journal of Materials Processing Technology, vol. 34, p. 465 – 472. DOI: 10.1007/s12289-009-0571-0. Zhdanovich, G M., 1971. Theory of Compaction of Metal Powders, Translated from Teoriya Pressovaniya Metallicheskikh Poroshkov, 1969, pp. 1-262, by the Foreign Technology Division, Wright-Patterson Air Force Base, OH. Zalazinskii, A G., 2000. Plasticheskoe deformirovanie strukturno-neodnorodnykh materialov [Plastic Deformation of Structurally Nonuniform Materials]. Yekaterinburg: Ural. Otd. Ross. Akad. Nauk, 492 p. (In Russian).