Wyniki wyszukiwania - BazTech

1

Investigations of stress and strain state of aluminum alloys during a hot extrusion and patterns of structure and feature formation

Aghbalyan Suren G., Bagdasaryan Vazgen, Vasilyan Gayane A., Wyczółkowski Rafał

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

|

2024

|

Vol. 33, No. 1

3--16

EN

This paper investigates the stress and strain state as well as formation processes of structure and features of aluminum alloys during the hot extrusion. It has been shown that during the hot extrusion the ring layers of an extruded element experience not only longitudinal and transverse deformations, but also a slip. The slip increases from inner layers to the surface layer. The tensile principal stresses and the sum of slip deformations also increase. It has been also demonstrated that at the exit of the pressing part the tensile principal stresses have different directions, forming an angle with extruder axis, which also increases towards the surface. In conclusion, it has been stated that the main radial and circumferential deformations act as restraining deformations.

2

Correlations for the thermal conductivity of selected steel grades as a function of temperature in the range of 0–800◦C

Wyczółkowski Rafał, Strychalska Dominika, Bagdasaryan Vazgen

Archives of Thermodynamics

|

2022

|

Vol. 43, no 3

29--45

EN

Reliable knowledge of thermo-physical properties of materials is essential for the interpretation of solidification behaviour, forming, heat treatment and joining of metallic systems. It is also a precondition for precise simulation calculations of technological processes. Numerical calculations usually require the knowledge of temperature dependencies of three basic thermo-physical properties: thermal conductivity, heat capacity and density. The objective of this work is to find a correlation that fits the thermal conductivity of selected steel grades as a function of temperature (within the range of 0–800◦C) and carbon content (within the range of 0.1–0.6%). The starting point for the analysis are the experimental data on thermal conductivity taken from literature. Using the method of least squares it was possible to fit an equation which allows calculating the thermal conductivity of steel depending on the temperature and carbon content. Two kinds of equations have been analyzed: a linear one (a linear model) and a second degree polynomial (a non-linear model). The thermal conductivity obtained by linear and nonlinear models varies on average from the measured values by 3% and 2.6% respectively.

3

Stationary heat conduction in a solid with functionally graded thermal properties

Bagdasaryan Vazgen, Szołucha Jan

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

|

2019

|

Vol. 28, No. 4

539--546

EN

In the paper the solutions for stationary heat conduction in a two dimensional composite with functionally graded heat properties were obtained. Numerical solutions for the taken boundary conditions are shown for several types of changes of composite’s thermal conductivity. The solutions were obtained with the use of the finite-difference method.