Home

D. Živković,
D. Manasijević
Ž. Živković,
Lj. Balanović

Calorimetric Investigation of Liquid Ga-Me (Me = Sn, Zn)
Alloys Using Oelsen Method
abstract, article page 71 - 75 pdf - 189 kB

U. Rotnik, M. Marolt,
G. Manojlović,
L. Vehovar, S. Božić

The Influence of Hydrogen in Solid Solutions of Spring Steel
abstract, article page 77 - 82 pdf - 143 kB

V. V. Chygyryns’kyy,
I. Mamuzić,
G. V. Bergeman

Analysis of the State of Stress and Strain of a Medium
under Conditions of Inhomogeneous Plastic Flow
abstract, article page 87 - 91 pdf - 93 kB

D. Živković, D. Manasijević, Ž. Živković, Lj. Balanović - Calorimetric Investigation of Liquid Ga-Me (Me = Sn, Zn) Alloys Using Oelsen Method

     The results of calorimetric investigation of binary, liquid Ga-Me (Sn, Zn) alloys are presented in this paper. According to constructed space enthalpy diagram and enthalpy isotherm diagram, activities, activity coefficients and other partial and integral molar quantities were determined at different temperatures. Also, comparison was made with existing literature data. pdf-189 kB

U. Rotnik, M. Marolt, G. Manojlović, L. Vehovar, S. Božić - The Influence of Hydrogen in Solid Solutions of Spring Steel

     This paper is concerned with the question of the brittle cracking of spring steel, which can occur already in the early stages of steel processing, i.e. during rolling, during the mechanical cutting of rolled profiles, or during any other type of mechanical manipulation where the harmful effect of remaining hydrogen has been observed. In order to investigate this question in greater depth, mechanical tests and fractographic analyses of the fracture surfaces were performed on cathodically hydrogenated test specimens of two types of spring steel, with and without alloyed nitrogen, in order to determine the critical concentration of hydrogen below which a relatively ductile fracture surface occurs, with good resistance to brittle cracking, and above which hydrogen embrittlement occurs. pdf -143 kB

B. Kosec, L. Kosec, G. Čevnik, P. Fajfar, M. Gojić, I. Anžel - Analysis of Interface at Explosive Welded Plates from Low-Carbon Steel and Titanium

     On the basis of experimentally obtained data, it was established that a very thin layer of a melt is generated at the explosive welding of two metals at the bond interface within which impurities flow at the bond during melting. Rapid cooling after the collision generates an alloy of different structure and very small grains of an average thickness approximately 1 to 2 mm. The generation of such an amorphous layer in the bond area has been noticed with various metal combinations and represents a fundamental mechanism of explosive welding of metals. Using the metallographic analysis, the development of the vortices which were formed by the explosive welding of low-carbon steel and titanium plates is described in the paper. pdf - 123 kB

V. V. Chygyryns’kyy, I. Mamuzić, G. V. Bergeman - Analysis of the State of Stress and Strain of a Medium under Conditions of Inhomogeneous Plastic Flow

     Under conditions of a complex state of stress of a medium a solution for a plane problem in the theory of plasticity was obtained for a complex medium being hardened in view of the temperature factor. Analytical relationships which have been obtained allow to predict mechanical characteristics of metal in zone of deformation. pdf-93 kB

G. Sučik, T. Kuffa, D. Hršak - The Use of Diatomaceous Earth in Preparation of SiAlON Powder

     In this paper the SiAlON powder was prepared by carbothermal reduction and nitridation of diatomaceous earth. The origin of raw material was deposit Lučenec, in the central region of Slovak Republic. The aim was investigate potential use of this natural source as a main precursor for production of low-cost SiAlONs by carbothermal reduction and nitridation. pdf - 137 kB

M. Kupková, M. Kupka - Theoretical Bounds on the Electrical Conductivity of Sintered Materials and their Relation to Bounds on the Young’s Modulus

    The constraints to the effective electrical conductivity were derived as function of distribution of material electrical conductivity throughout the sample. If the sample consists only of homogeneous isotropic matrix and pores, the constraints to effective electrical conductivity take the form very similar to the constraints derived previously for the effective Young’s modulus of porous materials. The differences occurring in expressions are due to the fact that elastic properties of an isotropic matrix material are characterized by two quantities, e.g. Young’s modulus and Poisson’s ratio, while the conductivity is characterized only by one quantity. But regardless of the small differences, in the both cases the key role in determining the properties is played by the minimum load-bearing cross section of the sample considered. pdf-105 kB

P. Rybár, H. Hamrák, M . Rybárová - An Application of a High-Temperature and High-Pressure Reactor - Part II

    A prototype of a high-temperature and high-pressure reactor generating on oxygen-hydrogen flame used for gravity separation of multiple mineral components is already in its fourth year of development. This equipment, appliyed in a high temperature range, will be able to treat the waste of some industrial technologies, which are of multiple component nature. [Metalurgija 41 (2002) 3, 139 - 142]. The results of the project received by the february of 2003 are listed in this article. pdf-313 kB

J. Ďurove, M. Maras, P. Vavrek, J. Daňko - Stability Calculation of Underground Chambers Formed by Salt Leaching

    The stability problem of caverns in the connection with the intention of their secondary utilisation is in more general way formulated as the task: to solve the stability of underground opening at which a breaking of surrounding rocks by occurs exceeding the limit of the tensile strength induced by secondary stresses. pdf -93 kB

M. Buršák, I. Mamuzić, M . Mihalikova - Influence of Blasting on Mechanical Properties of Steel Sheet

     The paper analyses the influence of blasting conditions on the properties of steel sheet RSt 37-2 having the gauge of 3 mm. Due to blasting, the surface roughness increases by an order and the surface strain hardening takes place to the depth of ca 0.06 mm, which results in compressive stress on the sheet surface. The above-mentioned changes, among others, increase the yield point and decrease the fatigue life in the tension-zero cycle. The increase of the yield point and the decrease of the fatigue life are more significant if the diameter of the blasting medium (within the tested interval from 0,56 to 0,9 mm) and the impact angle (30 to 75°) are greater at the air pressure of 0,4 to 0,5 MPa. pdf - 164 kB

A. Mockovčiaková, B. Pandula, B. M. Labaš, F. Krepelka - Fractal Geometry and Impulse Dynamic Method Applied at Evaluation of Disturbance of Rocks

     In this paper the fractal geometry, interpreting the size effect was used for evaluation of disturbance of samples of rocks. Fractal geometry offers a possibility to describe the non-regular structure of natural objects by fractal dimension, from which it is possible e.g. to estimate the measure of rock disturbance. The micro-disturbance of rock samples was compared with the results of ultrasonic pulsing method, where the disturbance indexes IQ were calculated from the velocities of exciting ultrasonic waves spreading through the rock medium. pdf -97 kB

I. Lesso, J. Futo, J. Krepelka, B. Pandula, A. Mockovčiaková - Control with Acoustic Method of Disintegration of Rocks by Rotary Drilling

     The contribution describes the technical and algorithmic solution of the optimization of rotary drilling. The global optimization criteria express the minimum specific energy on drilling and the maximum speed of drilling. The article presents the first results of research on the utilization of acoustic methods in indirect measurement of criterion function by optimizing these processes. pdf - 252 kB

M. Kundak, J. Črnko, L. Lazić, M. Dazgić - Possibility of Successful Business Making of Welded Steel Tubes Rolling Mill in Marketing Conditions

     Taking statistically-documentary basis as a starting point and applying adequate mathematical methods, numerical functional relations between total annual production and single production expenses, i.e. average total production expenses are defined. Functional relation between both of them with different number of employees compared to the average number of employees in the analysed period of time is also defined. pdf-270 kB

A. Eksi, M. K. Kulekci - Hardness and Densification Behaviour of Copper and Bronze Powders Compacted with Uniaxial Die and Cold Isostatic Pressing Processes

     In this study hardness and densification behaviour of copper and bronze powders under wet bag cold isostatic and uniaxial die pressing processes are examined. In uniaxial pressing the specimens were compacted up to a pressure of 800 MPa. Cold isostatic pressing (CIP) resulted in better densification for both of the studied powder materials. Attained densities were 94 % for copper and 82 % for bronze powders. In uniaxial die pressing greater pressurisation was needed to attain the same densification that obtained with CIP. The microhardness of both of the studied materials were measured before and after pressing processes. Higher pressure resulted in dislocation and strain hardening and increased hardness of powders. pdf - 245 kB

M. Oruč, H. Babahmetović, D. Pihura - Resistance to Atmospheric Corrosion of Low-Carbon Steel Grade WT St 37-2

     Examination of low-carbon steel resistant to atmospheric corrosion has been actualized as a problem for a large number of years. Indeed, these steels have large importance for civil engineering structures, which will be exposed to changeable atmospheric conditions in next decades or centuries. Since the pollution of atmosphere is more evident nowadays, i.e. more aggressive, the importance of such examination is very significant. This is important for the selection of more suitable materials, as well as for the safety of structures, including the realisation of essential economic effects. pdf -241 kB