Кафедра обробки металів тиском (ДМетІ)

Permanent URI for this community

http://crust.ust.edu.ua/handle/123456789/14630
UK: Кафедра обробки металів тиском ім. акад. О.П.Чекмарьова (Дніпровський металургійний інститут, ДМетІ) EN: Department of Metal Forming (DMetI)

Browse

Browsing Кафедра обробки металів тиском (ДМетІ) by Author "Bobukh, Oleksandr"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Estimation of Glass Lubricant Viscosity for Hot Extrusion of Cr-Ni Steel and Ni Alloy Tubes
    (Dnipro University of Technology, 2022) Medvedev, Michael; Shyfrin, Yevgen; Frolov, Yaroslav; Bobukh, Oleksandr
    ENG: Purpose. Estimation of optimal viscosity of a glass lubricant for chromium-nickel steel tube extrusion depending on the deformation resistance, chemical composition of metal and the temperature, degree and rate of deformation. Methodology. To determine the force conditions for tube extrusion, a complex factor of deformation resistance was used, which consists in estimating the value of deformation resistance under the basic process parameters of extrusion plants and its refinement depending on the deviations of heating temperature and wall thickness of billets as well as the degree and rate of deformation from the base conditions. Findings. The dependence of basic values of deformation resistance on the percentage of alloying elements (Ni + Cr) in steels has been found. With the addition of hardening alloying elements (Mo, W, V, Nb) into the alloy steel, its deformation resistance increases in proportion to their percentage. Analytical expressions for calculating the base values of deformation resistance for different extrusion plants have been obtained. Originality. For the first time, the principles governing estimation of the optimal viscosity of glass lubricants based on the chemical composition of steel to be formed, its temperature and the degree and rate of deformation of the blank, thickness of the lubricating layer and geometric dimensions of the tool (die) in hot extrusion of tubes have been established. Practical value. The use of the results of calculation according to the developed method will make it possible to increase the surface quality of tubes manufactured by extrusion and reduce the volume of their subsequent machining.
  • Thumbnail Image
    Item
    Roll Bonding of Al-Based Composite Reinforced with C10 Steel Expanded Mesh Inlay
    (MDPI, Switzerland, 2021) Frolov, Yaroslav; Nosko, Maxim; Samsonenko, Andrii A.; Bobukh, Oleksandr; Remez, Oleg
    ENG: The most complex issue related to the design of high efficiency composite materials is the behavior of the reinforcing component during the bonding process. This study presents numerical and experimental investigations of the shape change in the reinforcing inlay in an aluminum-steel mesh-aluminum composite during roll-bonding. A flat composite material consisting of two outer strips of an EN AW 1050 alloy and an inlay of expanded C10 steel mesh was obtained via hot roll bonding with nominal rolling reductions of 20%, 30%, 40% and 50% at a temperature of 500 °C. The experimental procedure was carried out using two separate rolling mills with diameters equal to 135 and 200 mm, respectively. A computer simulation of the roll bonding was performed using the finite element software QForm 9.0.10 by Micas Simulations Limited, Oxford, UK. The distortion of the mesh evaluated via the change in angle between its strands was described using computer tomography scanning. The dependence of the absorbed impact energy of the roll bonded composite on the parameters of the deformation zone was found. The results of the numerical simulation of the steel mesh shape change during roll bonding concur with the data from micro-CT scans of the composites. The diameter of rolls applied during the roll bonding, along with rolling reduction and temperature, have an influence on the resulting mechanical properties, i.e., the absorbed bending energy. Generally, the composites with reinforcement exhibit up to 20% higher impact energy in comparison with the non-reinforced composites. View Full-Text.