Z A G R E B
July / September
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Original Scientific Paper
Preliminary Note
Review
Review Paper
Professional Paper
ARCHIVE 1996 - 2009
48
year issue
Metalurgija - Journal for Theory and Practice in Metellurgy
Metallurgy 48 (3) 141 - 212
PDF - 11293 kB
ISSN 1334-2576    UDC:669+621.7+51/54(05)=163.42=111     METABK: 48 (3) 141 - 212 (2009)
Authors
Original Scientific Paper
T. Merder, J. Pieprzyca,
M. Warzecha
Numerical modeling of steel flow in the six-strand tundish with different flow control devices
abstract, article page 143 - 146 PDF - 600 kB
I. Naglič, A. Smolej,
M. Doberšek
The influence of alloying elements in aluminium on the grain refinement with ALTI5B1
abstract, article page 147 - 150 PDF - 92 kB
V. Soare, C. Gurgu,
I. Surcel, M. Burada,
V. I. Soare
Electrochemical process for the manufacturing of titanium alloy matrix composites
abstract, article page 151 - 155 PDF - 939 kB
S. Dobatkin, J. Zrnik,
I. Mamuzić
Mechanical and service properties of low carbon steels processed by severe plastic deformation
abstract, article page 157 - 160 PDF - 765 kB
A. Demir, R. Samur,
I. Kiliçaslan
Investigation of the coatings applied onto brake discs on disc-brake pad pair
abstract, article page 161 - 166 PDF - 1225 kB
J. Štaba, M. Buršák
Complex approach mechanical properties and formability assessment of selected deep-drawing steels
abstract, article page 167 - 170 PDF - 346 kB
Home
Preliminary Note
D. Kakaš, L. Kovačević,
P. Terek, D. Krumes,
Z. Kolumbić
Use of SEM and EDS analysis in the investigation of Al-Si-Cu piston alloy cast porosity
abstract, article page 171 - 174 PDF - 1710 kB
M. Saternus, J. Botor
Physical model of aluminium refining process in URC-7000
abstract, article page 175 - 179 PDF - 1354 kB
I. Samardžić, I. Kladarić,
Š. Klarić
The influence of welding parameters on weld characteristics in electric arc stud welding
abstract, article page 181 - 185 PDF - 808 kB
K. Grigorovich,
G. Burkhanov, S. Shibaev,
A. Dalmatov, I. Belyaev,
N. Kolchugina
Fractional gas analysis procedure for determining the contents of oxide and nitride phases in ALNICO alloys
abstract, article page 187 - 191 PDF - 298 kB
Top of Page
Review Paper
M. Kundak, L. Lazić,
J. Črnko
CO2 emissions in the steel industry
abstract, article page 193 - 197 PDF - 511 kB
M. Perinić, M. Ikonić,
S. Maričić
Die casting process assessment using single minute exchange of dies (SMED) method
abstract, article page 199 - 202 PDF - 964 kB
A. Varga, M. Tatič, L. Lazić
Application of roof radiant burners in large pusher-type furnaces
abstract, article page 203 - 207 PDF - 575 kB
Home
Professional Paper
R. Lenort, D. Staš,
A. Samolejová
Capacity planning in operations producing heavy plate cut shapes
abstract, article page 209 - 211 PDF - 84 kB
Top of Page
Original Scientific Paper

T. Merder, J. Pieprzyca, M. Warzecha - Numerical modeling of steel flow in the six-strand tundish with different flow control devices

     Numerical modelling have been extensively used to study the fluid flow phenomena taking place in continuous casting tundish. The paper presents the results of steel flow researches done on tundishs with a capacity of 22 Mg, with different flow control devices. The tundish is a "trough"-type designed for the continuous casting of slabs intended for small cross-section rolled products. In effect of mathematical calculations liquid steel velocity, turbulence intensity, turbulent kinetic energy and temperature distributions have been obtained. Calculations were passed by commercial computer program FLUENT.
 PDF - 600 kB

I. Naglič, A. Smolej, M. Doberšek - The influence of alloying elements in aluminium on the grain refinement with ALTI5B1

     This work deals with the influence of alloying elements in aluminium on the grain refinement with various additions of AlTi5B1. Grain-refinement tests were made at a cooling rate of 15 °C/s. The results revealed that in both aluminium and an Al-Fe alloy the grain size decreases with increasing additions of the AlTi5B1 grain refiner. We found that for the same boron content the grain size was smaller in the case of the Al-Fe alloy. The difference in the grain sizes for the same content of boron was approximately 15 _m; this is considerably smaller than the difference between the grain sizes in samples with the same difference of growth-restricting factor made at slower cooling rates.
 PDF - 92 kB

V. Soare, C. Gurgu, I. Surcel, M. Burada, V. I. Soare - Electrochemical process for the manufacturing of titanium alloy matrix composites

      The paper presents a new method for precursors' synthesis of titanium alloys matrix composites through an electrochemical process in molten calcium chloride. The cathode of the cell was made from metallic oxides powders and reinforcement ceramic particles, which were pressed and sintered into disk form and the anode from graphite. The process occurred at 850 °C, in two stages, at 2,7 / 3,2 V: the ionization of the oxygen in oxides and the reduction with calcium formed by electrolysis of calcium oxide fed in the electrolyte. The obtained composite precursors, in a form of metallic sponge, were consolidated by pressing and sintering. Chemical and structural analyses on composites samples were performed.
 PDF - 939 kB

S. Dobatkin, J. Zrnik, I. Mamuzić - Mechanical and service properties of low carbon steels processed by severe plastic deformation

     The structure and properties of the 0,09% C-Mn-Si-Nb-V-Ti, 0,1 %C-Mn-V-Ti and 0,09% C-Mo-V-Nb low-carbon steels were studied after cold equal-channel angular pressing (ECAP). ECAP leads to the formation of partially submicrocrystalline structure with a grain size of 150 - 300 nm. The submicrocrystalline 0,09 %C-Mn-Si-Nb-V-Ti steel compared with the normalized steel is characterized by Re higher more than by a factor of 2 and by the impact toughness higher by a factor of 3,5 at a test temperature of -40°C. The plasticity in this case is somewhat lower. The high-strength state of the submicrocrystalline 0,1% C-Mn-V-Ti and 0,09% C-Mo-V-Nb steels after ECAP is retained up to a test temperature of 500°C. The strength properties at 600°C (i.e. the fire resistance ) of these steels are higher by 20-25 % as compared to those of the undeformed steels. The strength of the 0,09% C-Mo-V-Nb steel at 600°C is substantially higher than that of the 0,1% C-Mn-V-Ti steel.
 PDF - 765 kB

A. Demir, R. Samur, I. Kiliçaslan - Investigation of the coatings applied onto brake discs on disc-brake pad pair

     While braking, according to the severity of it, thermal, metallurgical, constructive and tribological occurrences emerge on the brake disc-pad interface. In this study, NiCr was sprayed as bonding layer onto the discs, one of which was coated with Al2O3-TiO2 by plasma spray and the other was coated with NiCr-Cr3C2 by High Velocity Oxygen Fuel (HVOF). In addition, the discs were tested with inertia dynamometer according to SAE's J2522 testing procedure. The measurements showed that although the pads of the coated discs were exposed to higher braking temperatures, friction coefficient of the disc coated with NiCr- Cr3C2 was obtained 6 % higher compared to the original disc.
 PDF - 1225 kB

J. Štaba, M. Buršák - Complex approach mechanical properties and formability assessment of selected deep-drawing steels

     The paper analyses the properties of deep-drawing sheets of three grades (Re = 320 to 475 MPa), surface-treated with hot-dip galvanizing, made of microalloyed steels. Deformation properties are assessed using tensile tests, technological Erichsen or cupping tests. These characteristics, as well as the behaviour of the surface layer, are also investigated under dynamic conditions (modified Erichsen test using a drop tester), or using flat bending fatigue tests. Using microscopic analysis the deformation properties of the surface layer are evaluated. The results show the compactness of the surface layer, high deformation characteristics, as well as fatigue properties of the investigated deep-drawing materials, suitable for application in the automotive industry.
PDF - 346 kB

Home
Preliminary Note

D. Kakaš, L. Kovačević, P. Terek, D. Krumes, Z. Kolumbić - Use of SEM and EDS analysis in the investigation of Al-Si-Cu piston alloy cast porosity

     Porosity formation was detected in the casting thinnest section in the proximity of the as cast surface and near the wall centerline. In order to investigate the cause of the porosity formation light microscopy was used to define as cast structure. After initial findings SEM and EDS analyses were performed. Based on the results it is possible to define cause of the observed porosity. A number of pores originates from the mould filling stage and entrainment of the oxide films, while others appear due to insufficient feeding during solidification.
PDF - 1710 kB

M. Saternus, J. Botor - Physical model of aluminium refining process in URC-7000

     The paper presents short characteristics of the most frequently used reactors for the continuous refining of aluminium and its alloys. Refining depends on the flow rate of refining gas. It influences the shape and size of gas bubbles. So the physical model was created to determine the level of gas bubble dispersion in liquids. Schemes of gas dispersion in liquid metal were presented taking into consideration that the gas flow rate is changing from 2 to 30 dm3/min. The range selection of the flow rate of refining gas value for five patterns of the dispersion (no dispersion, minimum, intimate, uniform and overdispersion) was also done.
PDF - 1354 kB

I. Samardžić, I. Kladarić, Š. Klarić - The influence of welding parameters on weld characteristics in electric arc stud welding

     In this paper the influence of welding parameters on weld geometry during stud welding (Drawn Arc Welding process with ceramic ferrule) on steel plate and pipe is analyzed as a variation of weld penetration. The changes of weld characteristics are also confirmed through measurements of HV0,2 across the weld joint and analysis of hardened zone.
PDF - 808 kB

K. Grigorovich, G. Burkhanov, S. Shibaev, A. Dalmatov, I. Belyaev, N. Kolchugina - Fractional gas analysis procedure for determining the contents of oxide and nitride phases in ALNICO alloys

     Fractional gas analysis procedure for estimating the contents of oxide and nitride inclusions in Alnico alloys produced from wastes of production is developed. The effect of the temperature and time of melt holding before pouring on the content of impurity oxide and nitride inclusions is considered. The content of SiO2 inclusions in Alnico mainly depends on the holding time before pouring and decreases with increasing holding time, whereas the content of Al2O3 inclusions decreases with increasing both temperature and time of holding. The content of TiN inclusions decreases with increasing holding time. As the holding temperature increases, the content of nitride inclusions decreases only with increasing holding time.
PDF - 298 kB

Top of Page
Review Paper

M. Kundak, L. Lazić, J. Črnko - CO2 emissions in the steel industry

     Global CO2 emissions caused by the burning of fossil fuels over the past century are presented. Taking into consideration the total world production of more than 1,3 billion tons of steel, the steel industry produces over two billion tons of CO2. Reductions in CO2 emissions as a result of technological improvements and structural changes in steel production in industrialized countries during the past 40 years are described. Substantial further reductions in those emissions will not be possible using conventional technologies. Instead, a radical cutback may be achieved if, instead of carbon, hydrogen is used for direct iron ore reduction. The cost and the ensuing CO2 generation in the production of hydrogen as a reducing agent from various sources are analysed.
PDF - 511 kB

M. Perinić, M. Ikonić, S. Maričić - Die casting process assessment using single minute exchange of dies (SMED) method

     Die casting process uses high productive level machines. Machine capacity utilization is a key goal in achieving minimum time consumption. Changeover procedure during die casting process is recognized as possible area for reducing time consumption. The SMED method has been improved by additional procedures simultaneously applying the 5S method. Their contribution is evident in recognition of internal and external activities, particularly while transferring internal activities into external ones in as many numbers as possible, by minimizing at the same moment the internal ones. The validity of the method and procedures are verified by an example application of die casting foundry for casting automobile parts. Significant time savings have been achieved with minimum investment.
PDF - 964 kB

A. Varga, M. Tatič, L. Lazić - Application of roof radiant burners in large pusher-type furnaces

     The paper deals with the application of roof flat-flame burners in the pusher-type steel slab reheating furnaces, after furnace reconstruction and replacement of conventional torch burners, with the objective to increase the efficiency of radiative heat transfer from the refractory roof to the charge. Based on observations and on measurements of the construction and process parameters under operating conditions, the advantages and disadvantages of indirectly oriented radiant heat transfer are analysed in relation to the heat transfer in classically fired furnaces.
PDF - 575 kB

Home
Professional Paper
R. Lenort, D. Staš, A. Samolejová - Capacity planning in operations producing heavy plate cut shapes

     The present approach to capacity planning in operations producing heavy metal shapes causes problems in fulfilling the required financial and volume indexes in production, as well as in meeting the work order completion dates. The article represents the methodology for optimal production scheduling in operations producing heavy plate cut shapes, which significantly eliminates the above-mentioned problems. The methodology is based on the application Generalized Assignment Problem (GAP).
PDF - 84 kB

July / September
2 0 0 9
Top of Page
Original Scientific Paper
Preliminary Note
Review
Review Paper
Professional Paper
ARCHIVE 1996 - 2009