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1
Content available Influence of Structural Parameters - the Shape of Graphite and Matrix on Change of Ultrasonic Wave Propagation Rate and Value of Attenuation in Graphitic Cast Irons
Belan Juraj, Tillová Eva, Uhríčik Milan, Pastierovičová Lucia
Production Engineering Archives
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2023
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Vol. 29, Iss. 1
23--27
EN
Despite the tendency of the current industry, especially the automotive industry, it is to use modern, light and super-strong materials based on Al or HSLA steels, the application of classic materials such as cast iron still makes sense, especially concerning price and excellent castability. The article presents one of the possible ways of using the ultrasonic non-destructive method in quality control and simpli-fication of the identification of the type of cast iron concerning the change of parameters of ultrasound propagation in materials. The main criteria for assessing the quality and determining the type of graphite cast iron were considered to be the rate of propagation of ultrasound - cL and the value of attenuation , which vary depending on the shape of the graphite and matrix. Graphitic cast irons with different graphite shapes (lamellar, vermicular, and globular shapes) and a matrix with different ferrite/perlite ratios were used as experimental material. Along with the ultrasonic tests, a metallographic analysis was also performed to quantify the microstructure of cast irons.
2
Content available Study of Si morphology in AlSi21CuNiMg cast alloy using col our and deep etching
Tillová Eva, Chalupová Mária, Kuchariková Lenka, Bonek Mirosław, Uhríčik Milan, Pastierovičová Lucia
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2023
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Vol. 71, nr 2
art. no. e144618
EN
The effect of possible modification and refining effect of Al-Cu-P-based pre-alloy combined with Fe on the microstructure and the silicon morphology change in hypereutectic Al-Si cast alloy was studied. The samples in the as-cast state were observed by optical and scanning electron microscopy with energy-dispersive X-ray spectroscopy. The 3D morphology of both primary and eutectic silicon was observed by using colour and deep etching in detail. The results showed that the AlCu19P1.4 pre-alloy (1.07 wt.%) combined with the addition of Fe (0.02 wt.%) has a significant effect on the change of the amount, size and morphology of primary Si. This is significantly refined and changes the shape from a coarse irregular star-shaped, polyhedral, or plate-like shape to a fine polyhedral shape. The average size of the primary Si is reduced by about of 78 % from 135 μm to 28 μm and the number of primary Si particles increased from 7.4 to 237. No change in the morphology of the eutectic Si was observed; a refinement of the structure from a coarse needle/plate-like to a fine plate-like structure was seen. The depth etching method using HCl was very effective in the study of the 3D silicon morphology observed, which could be observed in detail without the presence of artefacts.
3
Content available Fatigue Resistance and Other Utility Properties of NiMn-Type of Austenitic Nodular Cast Iron
Vaško Alan, Uhríčik Milan, Kaňa Václav
Archives of Metallurgy and Materials
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2023
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Vol. 68, iss. 2
563--569
EN
The aim of this paper is to evaluate the fatigue resistance of austenitic nodular cast iron and to compare it with other types of nodular cast irons. The austenitic nodular cast iron, used for the experiments, was alloyed by 13% nickel and 7% manganese (EN-GJSA-XNiMn13-7) to obtain an austenitic matrix. The microstructure was studied using light metallographic microscopy. Mechanical properties were investigated by tensile test, impact bending test and Brinell hardness test. Fatigue tests were carried out at sinusoidal cyclic push-pull loading at ambient temperature. The results of fatigue tests were compared with the fatigue properties of ferrite-pearlitic nodular cast iron and pearlite-ferritic nodular cast iron. Experimental results show that NiMn-type of austenitic nodular cast iron has lower tensile strength and hardness, but higher elongation and absorbed energy than the compared types of nodular cast iron. However, austenitic nodular cast iron has lower fatigue limit.
4
Content available remote Odporność na korozję austenitycznej stali nierdzewnej poddanej chemicznej obróbce w różnych temperaturach
Zatkalíková Viera, Iwaniak Aleksander, Markovičová Lenka, Uhríčik Milan, Hanusová Patrícia
Przemysł Chemiczny
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2020
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T. 99, nr 6
844--847
PL
Austenityczna stal nierdzewna jest uważana za materiał o doskonałej odporności na korozję i akceptowalnych właściwościach mechanicznych, zalecany do różnych zastosowań konstrukcyjnych, przemysłowych i biomedycznych. W agresywnych środowiskach chlorkowych jest ona podatna na miejscową korozję wżerową. Oceniono odporność na korozję stali nierdzewnej typu AISI 316Ti o powierzchni pasywowanej kwasem azotowym w kwasowym 1 M roztworze jonów chlorkowych w temp. 22-80°C. Ocenę tę oparto na wynikach ekspozycyjnych testów zanurzeniowych i wynikach elektrochemicznej spektroskopii impedancyjnej (EIS).
EN
Com. Ti-stabilized Cr-Ni-Mo austenitic stainless steel was passivated with HNO₃ soln. and then studied for pitting corrosion in 5% FeCl₃ soln. (pH 1.2) by 24-hours std. immersion test and in 0.9 M NaCl + 0.1 M HCl soln. (pH 1.1) by electrochem. impedance spectroscopy (EIS test) at 22- 80°C. The pits were significantly bigger at 22°C than those at 50°C but the distribution of pitting was markedly lower. The polarization resistance decreased with increasing the temp. The quality of the surface passive film was several times lower at 80°C than at the lower temp.
5
Content available Multiaxial fatigue experimental analysis of 6063-T66 aluminum alloy of the base material and the welded material
Uhríčik Milan, Kopas Peter, Palček Peter, Oršulová Tatiana, Hanusová Patrícia
Quality Production Improvement - QPI
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2019
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Vol. 1, Iss. 1
334--341
EN
This article deals with determining of fatigue lifetime of aluminum alloy 6063-T66 during by multiaxial cyclic loading. The experiments deal with the testing of specimens for identification of the strain-life behavior of material, the modeling of combined loading and determining the number of cycles to fracture in the region of low-cycle fatigue. Fatigue tests under constant amplitude loading were performed in a standard electromechanical machine with a suitable gripping system. Based on the experimental results the fatigue design curves are compared to the fatigue data from the base material and the welded material and also multiaxial fatigue models, which are able to predict fatigue life at different loads.
6
Content available Comparison of temperature dependence of internal damping of selected magnesium alloys
Oršulová Tatiana, Palček Peter, Uhríčik Milan
Production Engineering Archives
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2019
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Vol. 22
7--10
EN
The research is focused on the study of the temperature dependence of the internal damping of selected magnesium alloys with different contents of aluminium - AZ31 and AZ61. These alloys are currently widely used in various types of industry, mainly in the automotive industry. It belongs to a group of materials called HIDAMETS because they have excellent damping properties. The internal damping of the samples was measured on a unique ultrasonic device constructed at Žilina University in Žilina. Specimens were measured at baseline in the temperature range from 25 °C to 400 °C. Changes in internal damping caused by varying aluminium contents in investigated alloys were noted. As the aluminium content increases, maximum internal damping is achieved due to the formation, growth and subsequent dissolution of the continuous precipitate in the microstructure.
7
Content available Modeling of multiaxial state of stress and determine the fatigue lifetime for aluminum alloy during cyclic loadingunder in-and-out of phase shift Φ = 0° and Φ = 90
Uhríčik Milan, Kopas Peter, Sága Milan
Studia i Materiały Informatyki Stosowanej
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2011
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nr 5
9--13
EN
This article deals with determining of fatigue lifetime of structural materials during by multiaxial cyclic loading. The theoretical part deals with the fatigue and with the criterions for evaluation of multiaxial fatigue lifetime. The experimental part deals with modeling of combined bending - torsion loading and determining the number of cycles to fracture in region low-cycle and high-cycle fatigue and also during of loading with the sinusoidal wave form under in phase Φ = 0° and out phase Φ = 90°.
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