Abstract: Duplex stainless steels are a famous group of the stainless steels. Duplex stainless steels
consist of mainly austenitic and ferritic phases, which is resulted by high content of different
alloying elements and low content of carbon. These alloying elements can effect a number of
precipitations at high temperatures. The most important phase of these precipitation is the σ-phase,
what cause rigidity and reduced resistance aganist the corrosion. Several orientation relationships
have been determined between the austenitic, ferritic and σ-phase in duplex stainless steels. In this
paper we tried to verify them by EBSD (electron backscatter diffraction).
Abstract: This paper shows the result of some metallographical examinations that have been
carried out on low-alloyed Cr-Mo-V heat resistant steel. The aim of this research is to present and
compare the advantages and disadvantages of the mainly applied metallographical methods. These
techniques are optical microscopy, scanning electron microscopy, replica method and special
applications of these methods. We have proved that using the investigated methods together gives
much more information about the lifetime of the specimen than using these techniques particularly.
Abstract: In this study the main properties of coated coronary stents are shown, such as recoil,
foreshortening, surface features and failures and the expansion properties. The types and the effects
of active and passive coatings are introduced. The results of our examinations with different coated
coronary stents are shown as well. The quality and the changing of the coatings were examined by
different methods (stereomicroscopy, atomic force microscopy, scanning electron microscopy and
Abstract: It is well known that during sliding friction the properties of rubbing surfaces are
changed owing to transformations caused by applied loads, friction and wear processes. In the last
years many research works were devoted to reveal the properties of the surfaces transformed during
the friction and wear at the Budapest University of Technology and Economics in the Department
of Machine Design. During these investigations the conditions of developing beneficial transformed
surface layers and their operating boundaries were determined by experiments on metal sliding
pairs in laboratory. The conditions of evolving large-scale adhesion junctions, scuffing and seizure
were investigated on heavy-loaded surfaces at slow sliding velocity. During the experiments hard
steel balls slid on dry or lubricated metal disks. Coefficient of friction and wear tracks were
measured and structures and damages of sliding surfaces were evaluated using profilometry, SEM
and normal microscope photographs, and micro-hardness measurement.
Abstract: The aim of the present work is to produce new types of solid nanomaterials for different
purposes (coatings, fillers, foams, bulk pieces, etc.). Technologies such as RS Al flake
production, high energy mechanical milling and high energy rate forming technology (HERF)
for compacting are used. The products are analyzed mainly by XRD, SEM and TEM methods.
It was shown that the new-type of RS Al “flake” material is suitable not only for pigments but
also for powder metallurgical purposes, i.e. Al based nanocomposites.
By choosing suitable parameters for mechanical alloying with the Fritsch Planetary mill 4,
very fine, alloyed and composited nanostructures can be produced (Al-4.5w%Cu-
Dynamic compaction (HERF) using explosive techniques seems to offer a good way for the
compaction of Al (metal) matrix nanostructured composites.
Abstract: Nanostructured Langmuir-Blodgett (LB) films of Stöber-silica nanoparticles have been
prepared on silicon and quartz glass substrates. The deposited layers were investigated using scanning
angle reflectometry and UV-Vis spectroscopy. The reflectivity and the transmittance spectra of the
LB films were evaluated using a model based on thin layer optics. Film thickness and effective
refractive index of the films were determined. From the refractive index values the volume fraction of
the particles in the film was estimated by effective medium approach.
Abstract: Diverse technologies in domestic enamelling production for machining, cutting and
joining process are applied. The experiments presented in this paper focused on the opportunities
of replacement of the drawn tubes built in heat exchangers longitudinal seam pipes produced by
DUNAFERR Co. Ltd. The steel grade which satisfies the requirement of two-side enamelling,
formability and after-fire sag resistance has been investigated. It has been shown that the coldrolled
DC 04 EK-B steel grades stand all demands needed and therefore are able to replace the
imported drawn tubes presently used.
Abstract: The macrosegregation is one of the most recurrent phenomena in continuous steel casting
of slabs. It often impedes the further processing and has detrimental effect on the quality of rolled
strip. The macrosegregation can be explained by the interpretation of unit steps of solidification in
continuous casting slabs as well as on the basis of the interaction of the inclusions at the interface of
solid and liquid phases. Development of solid shell and interaction between growing dendrites and
MnS segregation has been presented. Only the pushing effect could be the real cause of MnS
segregation among the three possible interactive mechanisms. The sulphur print could give
misleading information on sulphur segregation.
Abstract: Three different types of austenitic stainless steel (SUS 304, SUS 304L and SUS 316)
samples were cold formed in order to investigate the effect of cold forming on the grain boundary
structure of the material. SUS 304L and SUS 316 samples were cold rolled, SUS 304 samples were
tensile loaded in different manner at room temperature. Electron back scatter diffraction
measurements have been carried out in order to obtain information about the boundaries of the
treated specimen. The measurements showed that the frequency of the special Σ3n type CSLboundaries
was significantly decreased by increasing the deformation of the samples.
Abstract: It is common for the most reactor pressure vessel (RPV) of light-water reactors used
today, that the RPV made of ferrite-perlitic steel is cladded with an austenitic layer, which well
resists corrosion influence. The cladding is manufactured by welding, the technology (mode of
application, number of layers) is different by each manufacturer. This is the layer which comes into
contact with the working media first, and is of course in cohesive contact with the RPV material.
The aim of this study is to demonstrate the new approach, used for assessing the safety of the
reactors today. This approach plays a decisive role in the lifespan calculation of already operating
nuclear power stations, including the extension of their service period.