Metalurgija 47 (1) 1

Z A G R E B
January / March
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Metalurgija - Journal for Theory and Practice in Metellurgy

Metallurgy 47 (72) pages
pdf - 18016 kB

ISSN 1334-2576 UDC:669+621.7+51/54(05)=163.42=111 METABK: 47 (1) 1 - 72 (2008)

Original Scientific Paper

M. Godec,
B. Šuštaršič,
M. Jenko

A high-magnification EBSD mapping analysis of Fe-Si-B powder particles
abstract, article page 9 - 12 pdf - 1272 kB

J. Slota,
E. Spišák

Determination of flow stress by the hydraulic bulge test
abstract, article page 13 - 17 pdf - 856 kB

M. Buršák,
I. Mamuzić,
J. Michel’

Contribution to evaluation of mechanical properties during impact loading
abstract, article page 19 - 23 pdf - 782 kB

S. Bockus,
J. Vilys, V. Ciuplys,
A. Ciuplys

Distribution of residual stresses in near-surface layer of carbon steel at monotonic tension loading
abstract, article page 25 - 28 pdf - 579 kB

D. Hršak,
G. Sučik,
L. Lazić

The thermophysical properties of serpentinite
abstract, article page 29 - 31 pdf - 993 kB

J. Dvořáček,
R. Sousedíková,
L. Domaracká

Industrial enterprises bankruptcy forecasting
abstract, article page 33 - 36 pdf - 485 kB

V. Stoyka,
F. Kovac,
Y. Sidor

Effect of second phase particles topology on the onset temperature of abnormal grain growth in Fe - 3%Si steels
abstract, article page 37 - 41 pdf - 1207 kB

The effect of mechanical reclamation on the wear of silica sand grains
abstract, article page 43 - 45 pdf - 693 kB

D. Blažević,
M. Ikonić,
T. Mikac

Algorithm for prevention of molten steel sticking onto mold in continous casting process
abstract, article page 47 - 50 pdf - 996 kB

Failures of dies for die-casting of aluminium alloys
abstract, article page 51 - 55 pdf - 1078 kB

N. P. Rudnitsky,
I. Mamuzić

Strength of anisotropic nickel-mesh composite materials
abstract, article page 57 - 59 pdf - 463 kB

Social and ethical challenges for metallurgical companies
abstract, article page 61 - 63 pdf - 805 kB

Š. Molokáč,
L. Grega, P. Rybár

MRI device - alternative for electrical energy storage
abstract, article page 65 - 68 pdf - 2214 kB

R. Celin,
D. Kmetič

Cracks in a roller-bearing
abstract, article page 69 - 72 pdf - 1534 kB

List of reviewers of the artilcles published in journal Metalurgija in 2007
article page 64 pdf - 413 kB

Original Scientific Paper

M. Godec, B. Šuštaršič, M. Jenko - A high-magnification EBSD mapping analysis of Fe-Si-B powder particles

We produced amorphous Fe-Si-B soft-magnetic powder using water atomisation. During annealing the powder particles developed a nanocrystalline structure, and annealing at over 700°C led to the formation of ferrite and boride phases. Here we present a high-magnification electron backscatter diffraction (EBSD) mapping analysis of the powder particles, in combination with a field-emission-gun scanning electron microscopy (FEGSEM) analysis. Some of the problems associated with the preparation of the powder particles for the EBSD analysis as well as the drift problems occurring during the EBSD mapping are reported.
pdf - 1272 kB

J. Slota, E. Spišák - Determination of flow stress by the hydraulic bulge test

In sheet metal forming operations the mechanical properties of the sheet metal (stress-strain curve, flow stress) greatly influence metal flow and product quality. Accurate determination of the stress-strain relationship is important in process simulation by finite element method. In this paper the sheet thickness gradation in different points of the hemisphere formed in the bulge test is analysed, both theoretically and experimentally. A precise determination of sheet thickness at the pole is very important in the precise determination of stress-strain relationship. The use of the hydraulic bulge test for estimation of flow stress under biaxial stress-strain state is discussed.
pdf - 856 kB

M. Buršák, I. Mamuzić, J. Michel’ - Contribution to evaluation of mechanical properties during impact loading

The paper analyzes the influence of the impact rate of up to 120 ms^-1 with a constant energy on the relative compression of high-grade unalloyed steels, Cu and Zn, and the evaluation of energy consumed during the impact bending test at the impact rate of up to 80 ms^-1. Based on the experiments made, relationships for the prediction of the influence of the strain rate within the range of 10-^-3- 2.5.10³ s^-1 on the mechanical properties of high-grade unalloyed steels with the yield point of 210 - 450 MPa and microalloyed steels with the yield point of 300 - 600 MPa are presented.
pdf - 782 kB

S. Bockus, J. Vilys, V. Ciuplys, A. Ciuplys - Distribution of residual stresses in near-surface layer of carbon steel at monotonic tension loading

The task of our research was to investigate the character of distribution, magnitude and sign of residual stresses in cross-section of a sample in micro-yield, yield and strain hardening stages of monotonic deformation. The analysis of the obtained experimental data shows the peculiarity of micro-plastic flow near a free surface of a solid body and its rather significant influence on the general character and kinetics of macroscopic deformation of metals.
pdf - 579 kB

D. Hršak, G. Sučik, L. Lazić - The thermophysical properties of serpentinite

In this article serpentinite from Banovina, Croatia, was studied. The antigorite is main mineral constituent of that rock. The dilatation curve shows that the first contraction of sample is coursed by dehydratation of antigorite at nearly 660°C. In spite of this, the second contraction of sample, which begines at nearly 860°C, is incident with olivine phase formation. The morphology of the serpentinite before and after thermal treatment was observed with the optical microscope. Image of serpentinite before thermal treatment is characterized by inclusions of olivine as primary mineral left as residue in process of serpentinization. Image of serpentinite after thermal treatment was changed by water disappear. The first thermal treated and than milled serpentinite has better properties than the first milled and than thermally treated serpentinite.
pdf - 993 kB

J. Dvořáček, R. Sousedíková, L. Domaracká - Industrial enterprises bankruptcy forecasting

This paper addresses problems of bankruptcy prediction. It has been oriented by past and recent situations in the Czech Republic. A brief overview of authors from abroad, who have been involved in investigations of this subject, is given. The circulation of capital is described inclusive intrusive factors that disturb capital's circulation hampering economic functioning of corporate businesses, which may lead to their final demise. A set of indicators has been specified that reflect the circulation of capital, and which provide for employing a statistical process - discriminate analysis - that links the probability of a corporate business default to these indicators.
pdf - 485 kB

V. Stoyka, F. Kovac, Y. Sidor - Effect of second phase particles topology on the onset temperature of abnormal grain growth in Fe - 3%Si steels

The relations between regimes of dynamic annealing, state of secondary particles system and the onset temperature of abnormal grain growth are investigated. Two distinguish types of Fe-3%Si grain-oriented steels, after one and two stage cold rolling, were studied. The second phase particles remain unaffected in first type of steel during the heat treatment. Vice versa, the increased density of second phases was observed after annealing in the second type of the investigated materials. It is shown that start/onset of abnormal grain growth strongly depends on both volume fraction of second phase particles and annealing temperature. Texture and magnetic properties of the investigated samples are investigated within the current study.
pdf - 1207 kB

M. Łucarz - The effect of mechanical reclamation on the wear of silica sand grains

The wear effect of silica sands is usually joined with many foundry processes during the fresh sand preparation. The significant effect of silica grains destruction by means of crushing, abrasion and attrition is caused by most of mechanical reclamation treatments, which leads to a higher sand consumption. The experimental reclaimer was equipped with two different peripheral rings, which enabled both impact and impact-free way of the reclamation treatment of silica grains. In each case the duration of treatment and the rotational speed as well as the number of reclamation cycles were changed and effects were checked by multiple sieve analyses of the sand.
pdf - 693 kB

D. Blažević, M. Ikonić, T. Mikac - Algorithm for prevention of molten steel sticking onto mold in continous casting process

In continuous casting steel production a significant loss reduction - in terms of scrap material, time and money - can be achieved by developing an appropriate algorithm for the prevention of molten steel sticking onto mould. The logic of such algorithm should be simple and manageable to ensure its practical implementation on a computer system via the usage of thermo sensors. This suggests that both the algorithm and the automated data collection can be implemented by means of applicative software. Despite its simplicity, the algorithm should accurately trace physical phenomena in molten steel.
pdf - 996 kB

B. Kosec - Failures of dies for die-casting of aluminium alloys

Die-casting dies for casting of aluminum alloys fail because of a great number of different and simultaneously operating factors. Material selection, die design, and thermal stress fatigue generated by the cyclic working process (heat checking), as well as to low and inhomogeneous initial die temperature contribute to the failures and cracks formation on/in dies for die-casting of aluminium alloys. In the frame of the presented investigation work the intensity and homogeneity of the temperature fields on the working surface of the testing die were checked through thermographic measurements, and failures and cracks on the working surface of the die were analysed with non-destructive metallographic examination methods.
pdf - 1078 kB

N. P. Rudnitsky, I. Mamuzić - Strength of anisotropic nickel-mesh composite materials

The authors studied the characteristics of strength of filtering composite materials reinforced by a two-layer nickel mesh with a coating depending on the cutting-out angle. The anisotropy of the characteristics of strength is shown to be the closest to the Ashkenazy phenomenological strength criterion in the form of a fourth degree polynomial, which describes the ultimate strength vs net cut-out angle limiting curve.
pdf - 463 kB

B. Gajdzik - Social and ethical challenges for metallurgical companies

The subject of this article is an analysis of one of the most crucial aspects of the contemporary business, which is corporate social responsibility and ethical business. The notion of a socially responsible business signifies the business obligation to contribute to the sustainable economical development by way of working with employees and their families, local communities and the society as a whole in order to improve the quality of their lives. Ethical business means following the principles and standards determining a manner of conducting a given business from the moral point of view. The article contains examples of such challenges that are realised by Arcelor Mittal.
pdf - 805 kB

Š. Molokáč, L. Grega, P. Rybár - MRI device - alternative for electrical energy storage

It is well known, that the electrical energy storage in the large scale is basically difficult process. Such a process is marked by the energy losses, as the conversion of electrical energy into another form, is most frequently for example mechanical, and then back to the primary electrical form. Though, the superconducting magnetic energy storage (SMES) technology offers the energy storage in an unchanged form, which is advantageous primarily in the achieved efficiency. Magnetic resonance imaging (MRI) devices, commonly used in the medical facilities are based on the application of superconducting magnet. After its rejection from operation, there is possibility of using such devices for energy storage purposes. Additionally, such a technology of storage is also ecological.
pdf - 2214 kB

R. Celin, D. Kmetič - Cracks in a roller-bearing

Bearings are among the most important components of electromotors, pumps, compressors and other processing equipment. After 30 years of work some non-destructive and metallographic examinations were carried out on a single-row cylindrical roller-bearing. A non-destructive liquid-penetrant testing revealed crack indications on an inner ring groove. When a sample of the roller-bearing outer ring was cut out for metallographic examination, new cracks were discovered that were not detected by the non-destructive testing. However, with the examination of the non-failed bearing it is possible to obtain useful information that can help us to decide how much of the remaining population of bearings with the same geometry and loading should be examined.
pdf - 1534 kB

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

January / March 2 0 0 8 Top of Page		Original Scientific Paper	Preliminary Note	Review
January / March 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 (72) pages pdf - 18016 kB	ISSN 1334-2576 UDC:669+621.7+51/54(05)=163.42=111 METABK: 47 (1) 1 - 72 (2008)

Authors	Original Scientific Paper
M. Godec, B. Šuštaršič, M. Jenko	A high-magnification EBSD mapping analysis of Fe-Si-B powder particles abstract, article page 9 - 12 pdf - 1272 kB
J. Slota, E. Spišák	Determination of flow stress by the hydraulic bulge test abstract, article page 13 - 17 pdf - 856 kB
M. Buršák, I. Mamuzić, J. Michel’	Contribution to evaluation of mechanical properties during impact loading abstract, article page 19 - 23 pdf - 782 kB
S. Bockus, J. Vilys, V. Ciuplys, A. Ciuplys	Distribution of residual stresses in near-surface layer of carbon steel at monotonic tension loading abstract, article page 25 - 28 pdf - 579 kB
D. Hršak, G. Sučik, L. Lazić	The thermophysical properties of serpentinite abstract, article page 29 - 31 pdf - 993 kB
J. Dvořáček, R. Sousedíková, L. Domaracká	Industrial enterprises bankruptcy forecasting abstract, article page 33 - 36 pdf - 485 kB
V. Stoyka, F. Kovac, Y. Sidor	Effect of second phase particles topology on the onset temperature of abnormal grain growth in Fe - 3%Si steels abstract, article page 37 - 41 pdf - 1207 kB

Home	Preliminary Note
M. Łucarz	The effect of mechanical reclamation on the wear of silica sand grains abstract, article page 43 - 45 pdf - 693 kB
D. Blažević, M. Ikonić, T. Mikac	Algorithm for prevention of molten steel sticking onto mold in continous casting process abstract, article page 47 - 50 pdf - 996 kB
B. Kosec	Failures of dies for die-casting of aluminium alloys abstract, article page 51 - 55 pdf - 1078 kB
N. P. Rudnitsky, I. Mamuzić	Strength of anisotropic nickel-mesh composite materials abstract, article page 57 - 59 pdf - 463 kB

Top of Page	Review Paper
B. Gajdzik	Social and ethical challenges for metallurgical companies abstract, article page 61 - 63 pdf - 805 kB
Š. Molokáč, L. Grega, P. Rybár	MRI device - alternative for electrical energy storage abstract, article page 65 - 68 pdf - 2214 kB

Top of Page	Review
I. Mamuzić	List of reviewers of the artilcles published in journal Metalurgija in 2007 article page 64 pdf - 413 kB