Study of the Dependence of the Lateral Pressure Coefficient on the Compaction Pressure during Pressing of Powder Materia
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TECHNOLOGY OF PRODUCTION STUDY OF THE DEPENDENCE OF THE LATERAL PRESSURE COEFFICIENT ON THE COMPACTION PRESSURE DURING PRESSING OF POWDER MATERIALS A. E. Prokhorovskii,1 V. Yu. Arkhangelskii,1 M. V. Emel’yanov,1 V. M. Klevleev,2 and I. A. Kuznetsova2
UDC 621.777.01
The article describes a method and associated equipment for determining the coefficient of lateral pressure when pressing and ejecting pyrotechnic elements depending on the compaction pressure. The dependence between the force parameters of loading, the coefficient of lateral pressure and the density of powder materials during pressing is experimentally confirmed. The results can be used to determine the parameters that comprise the passport characteristics of products made of pressed powders. Keywords: pressing, lateral pressure coefficient, density, experimental method.
A vital characteristic of the pressing (compaction) of powder materials is the lateral pressure coefficient ξ – the ratio of the radial (lateral) pressure σ r to the axial (normal) compaction pressure σ Z (at ξ ≤ 1) [1]. The theory and practice of compaction suggest that the lateral pressure coefficient increases with an increase in the compact density; however, the correlation varies for different materials: the higher the plasticity of the material, the stronger the relation of ξ to the compaction pressure. For low-plasticity and brittle materials, the coefficient ξ increases at low pressures, remaining constant at pressures above 200 MPa. The lateral pressure coefficient also depends on the size and shape of particles, the state of their surface, the chemical purity of the powder, as well as the compaction speed, decreasing along the height of compactings during single-action pressing [1–3]. It was also found that in the elastic region, ξ is primarily a function of the internal and external friction coefficients of a bulk material [4]. Thus, the lateral pressure coefficient depends on many factors, whose separate consideration presents difficulties. In addition, taking the dependence of the coefficient ξ on the compaction pressure into account offers a rational choice of compaction parameters, as well as helping to predict the compaction quality. Theoretical Justification of the Method for Calculating the Dependence of the Lateral Pressure Coefficient on the Compaction Pressure Due to the variety of material properties, conditions of the technological process, and methods for processing measurement results, there are a number of compaction equations in current use [5]. One of the best known of these is the Kunin–Yurchenko equation[1]: 1 2
Research Institute of Applied Chemistry, Sergiyev Posad, Moscow Region, Russia; e-mail: [email protected]. Moscow Polytechnic University, Russia; e-mail: [email protected].
Translated from Khimicheskoe i Neftegazovoe Mashinostroenie, Vol. 56, No. 7, pp. 33−35, July, 2020. 0009-2355/20/0708-0569
© 2020
Springer Science+Business Media, LLC
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A. E. PROKHOROVSKII, V. YU. ARKHANGELSKII, M. V. EMEL’YANOV, V. M. KLEVLEEV,
⎛ k ⎞ ρ = ρ
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