Metalurgija 47 (2) 73

Z A G R E B
April / June
2 0 0 8

Metalurgija - Journal for Theory and Practice in Metellurgy

Metallurgy 47 (2) 73 - 144
pdf - 9747 kB

ISSN 1334-2576 UDC:669+621.7+51/54(05)=163.42=111 METABK: 47 (2) 73 - 144 (2008)

Original Scientific Paper

F. Tehovnik,
B. Arzenšek,
B. Arh

Tensile tests on stainless steels in temperature range 800 to 1200°C
abstract, article page 75 - 79 pdf - 1463 kB

M. Čudina,
J. Prezelj
I. Polajnar

Use of audible sound for on-line monitoring of gas metal arc welding process
abstract, article page 81 - 85 pdf - 874 kB

M. Duđner,
S. Aračić,
I. Samarždić

Impact energy analysis of HSLA specimens after simulated welding thermal cycle
abstract, article page 87 - 91 pdf - 1866 kB

K. Šimunović,
M. Franz,
G. Marić

Investigation and estimation of residual stress in flame sprayed and fused NiCrBSi coating
abstract, article page 93 - 97 pdf - 612 kB

N. I. Grechaniuk,
I. Mamuzić,
R. V. Minakova

Peculiarities of the structure, its deformation and destruction of condensed Cu-Mo-Zr-Y composite material of commercial purity
abstract, article page 99 - 102 pdf - 1826 kB

R. Lujić,
T. Šarić,
G. Šimunović

Application of genetic algorithm to the technological operations scheduling problem
abstract, article page 103 - 107 pdf - 994 kB

M. Sokić, I. Ilić,
D. Živković
N. Vučković

Investigation of mechanism and kinetics of chalcopyrite concentrate oxidation process
abstract, article page 109 - 113 pdf - 831 kB

I. Naglič,
A. Smolej
M. Dobešrek

Remelting of aluminium with the addition of AlTi5B1 and AlTi3C0,15 grain refiners
abstract, article page 115 - 118 pdf - 743 kB

DJ. Mandrino, M. Godec,
A. Kocijan, M. Lamut,
M. Torkar, M. Jenko

Oxide and nitride protective layers formed on stainless steel by thermal treatment: SEM, AES, WDS and corrosion measurements
abstract, article page 119 - 123 pdf - 1109 kB

V. Bačová,
D. Jankura,
D. Draganovská

Influence of cyclic heat stress on the properties of plasma-sprayed ceramic coatings
abstract, article page 125 - 128 pdf - 1179 kB

E. Kormaníková,
I. Mamuzić

Buckling analysis of a laminate plate
abstract, article page 129 - 132 pdf - 650 kB

F. Trebuňa, F. Šimcák,
J. Bocko, P. Šarga,
P. Trebuňa, M. Pástor,
J. Mihok

Quantification of residual stresses in the weld by the hole-drilling method
abstract, article page 133 - 137 pdf - 1434 kB

J. Črnko, P. Jelić,
M. Kundak, L. Lazić

Technological indicators of operation of the rotating-hearth furnace in conditions of discontinued production
abstract, article page 139 - 141 pdf - 458 kB

Concentration on knowledge and change management at metallurgical company
abstract, article page 142 - 144 pdf - 643 kB

Original Scientific Paper

F. Tehovnik, B. Arzenšek, B. Arh - Tensile tests on stainless steels in temperature range 800 to 1200°C

On different austenitic stainless steels tensile tests were carried out in the hot working temperature range for 800 to 1200şC. The effects of δ ferrite on recrystallisation, of σ phase on deformability and the effect of temperature on recovery, recrystallisation and grain growth were established.
pdf - 1463 kB

M. Čudina, J. Prezelj, I. Polajnar - Use of audible sound for on-line monitoring of gas metal arc welding process

In this paper sound generated during the gas-metal arc welding process was studded. Experimental analyses of the acoustic signals have shown that there are two main noise-generating mechanisms, first having impulse form is arc extinction and arc ignition; the second is the arc itself acting as an ionization sound source. The sound signal is used for assessing and monitoring of the welding process, and for prediction of welding process stability and quality. A new algorithm based on the measured welding current was established for the calculation of emitted sound during the welding process. The comparisons have shown that the calculated values are in good agreement with the measured values.
pdf - 874 kB

M. Duđner, S. Aračić, I. Samarždić - Impact energy analysis of HSLA specimens after simulated welding thermal cycle

This paper presents impact energy results of specimens made from high strength fine grained steel TStE 420 after thermal cycle simulation. These results are obtained by examining Charpy specimens. Metallographic analysis is performed, hardness is measured and total impact energy is divided into ductile and brittle components.
pdf - 1866 kB

K. Šimunović, M. Franz, G. Marić - Investigation and estimation of residual stress in flame sprayed and fused NiCrBSi coatings

For thermally sprayed coatings, beside good wear and corrosion resistance there is also a need for a good coating/substrate adhesion, reduced porosity and reduced level of residual stresses. Residual stresses that occur in the substrate/coating system are very significant because their relaxation can cause different coating failures. In this paper, different approaches to investigation of residual stresses in thermally sprayed coatings, have been presented. An analytical model (authors Tsui and Clyne) was used to estimate the distribution of residual stresses in flame sprayed and fused NiCrBSi coatings. These data can be used as input data for the numerical model.
pdf - 612 kB

N. I. Grechaniuk, I. Mamuzić, R. V. Minakova - Peculiarities of the structure, its deformation and destruction of condensed Cu-Mo-Zr-Y composite material of commercial purity

The peculiarities of the morphology and structure defects of composite material in the Cu-Mo-Zr-Y system produced from commercially pure raw materials using method of electron-beam evaporation/condensation have been studied. The features of deformation and destruction of the composite have been investigated alongside with its mechanical properties and their change under action of structure defects.
pdf - 1826 kB

R. Lujić, T. Šarić, G. Šimunović - Application of genetic algorithm to the technological operations scheduling problem

The basic enterprise task is to satisfy customer requirements: due date, price and quality. Based on experiences from engineers practice of work in Croatian enterprises it could be concluded that enterprises are not able to fulfil obligations to the customer in a way of due dates. One of the basic reasons lies in inappropriate scheduling model that has not had possibility to make plan variants. The paper shows how genetic algorithm could be successfully applied in scheduling model to solve the problem of plan variant. As a basic selection in the paper 3-tournament steady-state selection has been applied.
pdf - 994 kB

M. Sokić, I. Ilić, D. Živković, N. Vučković - Investigation of mechanism and kinetics of chalcopyrite concentrate oxidation process

The oxidation process of chalcopyrite concentrate "Rudnik" (Serbia) was investigated by DTA-TG measurements under air conditions in the temperature range of 298 - 1173 K, as well as by XRD analysis of the oxidation products at 723, 873 and 1173 K. Based on the results obtained, the mechanism of chalcopyrite concentrate oxidation process was given, contributing to the understanding of the successive chemical reactions accompanying the formation of intermediate products. The kinetic study of the investigated process was done according to the methods of Kissinger and Ozawa, which enabled determination of the activation energy values of the chemical reactions proceeding during the chacopyrite concentrate oxidation.
pdf - 831 kB

I. Naglič, A. Smolej, M. Dobešrek - Remelting of aluminium with the addition of AlTi5B1 and AlTi3C0,15 grain refiners

It was found that concentration of boron in aluminium with the addition of AlTi5B1 grain refiner is decreasing during remelting as a consequence of TiB2 particles settling down due to gravity. TiB2₂ particles remained in aluminium after four remelts shows lower effect of grain refinement compared to non-remelted samples with the same TiB₂ content. It was also found that TiC particles are still present in aluminium with the addition of AlTi3C0,15 grain refiner after four remelts and they probably participate in nucleation of α-Al grains.
pdf - 743 kB

DJ. Mandrino, M. Godec, A. Kocijan, M. Lamut, M. Torkar, M. Jenko - Oxide and nitride protective layers formed on stainless steel by thermal treatment: SEM, AES, WDS and corrosion measurements

Protective oxide and/or nitride layers on AISI 321 stainless steel were prepared by thermal treatment in air and two controlled atmospheres in a laboratory simulation of an actual technological procedure. Samples' surface was imaged by Scanning Electron Microscopy (SEM), elemental composition of the substrates was checked by Wavelength Dispersive Spectroscopy (WDS) and depth profiles of the samples were measured by Auger Electron Spectroscopy (AES). Since protective layer thicknesses were found to be of the order of hundreds of nanometers an attempt was made to obtain some fast averaged information about layers composition by Wavelength Dispersive Spectroscopy (WDS) with appropriately adjusted primary beam energy. Electrochemical corrosion testing was also performed on samples.
pdf - 1109 kB

V. Bačová, D. Jankura, D. Draganovská - Influence of cyclic heat stress on the properties of plasma-sprayed ceramic coatings

The paper analyzes the contemporary knowledge by the blasting as the optimal technology for creation of the substrate surface. At the same time, the study support the evaluation of the character of the blasted surface related to the adhesion of the post-applied coatings. Moreover, the study deals with the creation and the characteristics of the ceramic oxide coatings especially used in the conditions of the thermo cyclic loading. In the end of the study, there is analysis of structural changes and crack propagation in the process of the thermal loading at the coatings based on Al₂O₃ and ZrSiO₄, which indicates the convenience of investigated coatings for concrete loading conditions.
pdf - 1179 kB

E. Kormaníková, I. Mamuzić - Buckling analysis of a laminate plate

The paper deals with a modeling of laminate plates and with their buckling analysis. To predict the inception of buckling for plates in plane resultant forces must be included. The buckling analysis is made by the help of finite element method in program COSMOS/M. For rectangular laminate plate consisting of 4 layers with symmetric and antisymmetric stacking sequence a buckling analysis is carried out. In the illustrative example there are depicted buckling modes for symmetric laminates [30/-30]_s, [45/-45]_s, [60/-60]_s, [90/-90]_s and results of the buckling analysis for the symmetric and antisymmetric laminates.
pdf - 650 kB

F. Trebuňa, F. Šimčák, J. Bocko, P. Šarga, P. Trebuňa, M. Pástor, J. Mihok - Quantification of residual stresses in the weld by the hole-drilling method

Residual stresses arise in the structures without loading during the technological processes, e.g. casting, rolling, welding, and pressing. In the paper is described the process of quantification of residual stresses by the hole-drilling method. For determination of residual stresses were used the procedures in which are supposed constant or linear distributions of stresses along the hole.
pdf - 1434 kB

J. Črnko, P. Jelić, M. Kundak, L. Lazić - Technological indicators of operation of the rotating-hearth furnace in conditions of discontinued production

Quality heating of the steel charge to be rolled into seamless tubes in the rotating-hearth furnace requires continuous operation of the pilger mill. Interruption of the charging schedule leads to impaired charge heating process. Prolonged heating time causes a rise in the charge temperature above the limit values, and that in turn brings to a larger quantity of scale formed on the charge surface. Final result is loss of metal and overheating of the charge accompanied by increased fuel consumption and lower furnace productivity.
pdf - 458 kB

B. Gajdzik - Concentration on knowledge and change management at metallurgical company

The subject of this paper is an analysis of one of the most crucial aspects of the contemporary business, which is knowledge and change management. Competition on the market is more and more stronger. Knowledge is one of the most precious business resources, it lets companies be more competitive because knowledge inspires to changes. The paper contains examples of knowledge and change management, faced by the largest metallurgical company on the Polish market - Arcelor Mittal.
pdf - 643 kB

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Z A G R E B April / June 2 0 0 8		Original Scientific Paper	Preliminary Note	Review
Z A G R E B April / June 2 0 0 8		Review Paper	Professional Paper	ARCHIVE 1996 - 2008

April / June 2 0 0 8 Top of Page		Original Scientific Paper	Preliminary Note	Review
April / June 2 0 0 8 Top of Page		Review Paper	Professional Paper	ARCHIVE 1996 - 2008

47. year issue	Metalurgija - Journal for Theory and Practice in Metellurgy
Metallurgy 47 (2) 73 - 144 pdf - 9747 kB	ISSN 1334-2576 UDC:669+621.7+51/54(05)=163.42=111 METABK: 47 (2) 73 - 144 (2008)

Authors	Original Scientific Paper
F. Tehovnik, B. Arzenšek, B. Arh	Tensile tests on stainless steels in temperature range 800 to 1200°C abstract, article page 75 - 79 pdf - 1463 kB
M. Čudina, J. Prezelj I. Polajnar	Use of audible sound for on-line monitoring of gas metal arc welding process abstract, article page 81 - 85 pdf - 874 kB
M. Duđner, S. Aračić, I. Samarždić	Impact energy analysis of HSLA specimens after simulated welding thermal cycle abstract, article page 87 - 91 pdf - 1866 kB
K. Šimunović, M. Franz, G. Marić	Investigation and estimation of residual stress in flame sprayed and fused NiCrBSi coating abstract, article page 93 - 97 pdf - 612 kB
N. I. Grechaniuk, I. Mamuzić, R. V. Minakova	Peculiarities of the structure, its deformation and destruction of condensed Cu-Mo-Zr-Y composite material of commercial purity abstract, article page 99 - 102 pdf - 1826 kB
R. Lujić, T. Šarić, G. Šimunović	Application of genetic algorithm to the technological operations scheduling problem abstract, article page 103 - 107 pdf - 994 kB
M. Sokić, I. Ilić, D. Živković N. Vučković	Investigation of mechanism and kinetics of chalcopyrite concentrate oxidation process abstract, article page 109 - 113 pdf - 831 kB
I. Naglič, A. Smolej M. Dobešrek	Remelting of aluminium with the addition of AlTi5B1 and AlTi3C0,15 grain refiners abstract, article page 115 - 118 pdf - 743 kB

Home	Preliminary Note
DJ. Mandrino, M. Godec, A. Kocijan, M. Lamut, M. Torkar, M. Jenko	Oxide and nitride protective layers formed on stainless steel by thermal treatment: SEM, AES, WDS and corrosion measurements abstract, article page 119 - 123 pdf - 1109 kB
V. Bačová, D. Jankura, D. Draganovská	Influence of cyclic heat stress on the properties of plasma-sprayed ceramic coatings abstract, article page 125 - 128 pdf - 1179 kB
E. Kormaníková, I. Mamuzić	Buckling analysis of a laminate plate abstract, article page 129 - 132 pdf - 650 kB
F. Trebuňa, F. Šimcák, J. Bocko, P. Šarga, P. Trebuňa, M. Pástor, J. Mihok	Quantification of residual stresses in the weld by the hole-drilling method abstract, article page 133 - 137 pdf - 1434 kB