Journal of Casting & Materials Engineering
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ISSN 2543-9901
Issue Date
2018
Volume
Vol. 2
Number
No. 1
Description
Journal Volume
Projects
Pages
Articles
Analysis of cooling curves of nodular cast iron
(AGH University of Science and Technology Press, 2018) Bartošová, Marianna; Pribulová, Alena; Futáš, Peter; Eperješi, Štefan
The solidification of cast iron is a complex process with characterized entrance and marginal conditions. Thermal analysis is one of the processes that allows us to observe the solidification of alloys. There is a possibility of gaining information about the melted cast iron quality and predicting the final properties of the cast by evaluating the scanned cooling curves by solidification (stable and metastable system). This article deals with the study and analysis of cooling curves taken from production conditions of a foundry during ductile cast iron production. The aim is to discover the reproduction and reliability of the thermal analysis results of cast iron. The study of the progress of the cooling curves and their first derivation to follow the reactions of the curves to changing factors in the production process.
Study on inhibition of N80 carbon steel in 0.5M KCl solution saturated with CO2 by Gum Arabic
(AGH University of Science and Technology Press, 2018) Palumbo, Gaetano; Banaś, Jacek
The effect of Gum Arabic (GA) on the corrosion of an N80 carbon steel pipeline in a $CO_{2}$-saturated chloride (0.5M KCl) solution was investigated through AC impedance and polarization curves. Potentiodynamic measurements showed that the corrosion current density decreased in the presence of inhibitors and that the inhibitor acts like a mixed-type inhibitor, with anodic predominance. The Nyquist diagrams showed an increase in polarization resistance values in the presence of the inhibitor, thus increasing inhibition efficiency. At higher temperatures, the inhibition efficiency decreased, implying that the inhibition action of GA occurred via the physical adsorption process. The activation parameters of the corrosion process such as activation energies, $E_{\alpha}$ , and the heat of adsorption, $Q_{ads}$ , were calculated, respectively, by the obtained corrosion rate and inhibition efficiency at different temperatures. At higher temperatures, the increase in activation energy combined with the negative levels of the heat of adsorption further supported the physical adsorption nature of the process.
Metallurgical processing of Al-Si alloys with increased iron content using sodium, strontium, and tellurium
(AGH University of Science and Technology Press, 2018) Pokusová, Marcela; Berta, Igor; Murgašová, Marta
This paper presents the results of research focused on the processing of the hypoeutectic Al-Si alloy with an increased iron content of 1.75 wt.%. The physical-metallurgical method was used to eliminate the undesirable effect of the iron rich b-phase on the mechanical properties of the casting material using liquid metal modification by strontium, sodium, and tellurium. The chemical composition of an experimental material didn't contain any elements for the solid-solution strengthening of a matrix, therefore, the presented results can document the capabilities of modifying the ?-phase under a minimum influence on the properties of the basic Al-Si system.
Comparison among different constitutive equations on investigating tensile plastic behavior and microstructure in austempered ductile iron
(AGH University of Science and Technology Press, 2018) Angella, Giuliano; Zanardi, Franco
The capabilities of different constitutive equations of approximating the tensile flow curves and correlating plastic behavior with the microstructure were investigated in austempered ductile iron ADI 1050. In a previous paper, the microstructure evolution of ADI 1050 during austempering was investigated through quenching the ADI 1050 after 14 increasing austempering times to room temperature. The 14 samples were tensile tested and two classes of constitutive equations were examined in the present paper. The Hollomon-type constitutive equations approximated all of the tensile flow curves of ADI 1050 very well but failed in correlating the plastic behavior with microstructure evolution. Voce-type constitutive equations approximated the tensile flow curves only at high stresses very well but could correlate the plastic behavior with the microstructure evolution of ADI 1050 during austempering excellently. The reason of this success was rationalized in terms of the physical basis of Voce-type equations, while Hollomon-type equations are empirical.
Microstructural characterization and mechanical behavior of copper matrix composites reinforced by B4C and sea shell powder
(AGH University of Science and Technology Press, 2018) Sankar, Mathiazhagan; Pushpanathan, D. Peter; Myszka, Dawid; Devaneyan, Pradeep S.
This paper investigates the microstructural and mechanical properties of copper metal matrix composites reinforced with B$_{4}$C and crushed sea shell particles (fabricated using powder metallurgy). In powder form, copper is widely used in structural applications. Copper also possesses very good electrical and thermal conductivity, ductility, and corrosion resistance. B$_{4}$C is the third-hardest-known material that also possesses excellent toughness and wear resistance. Sea shells are readily available along coastal areas. Therefore, an attempt has been made in this work to investigate the feasibility of its utilization in powder metallurgy. Two batches of samples were prepared. In the first batch, the percentage of boron carbide and copper powder were varied, and seashell powder was not included. In the second batch, the percentages of B$_{4}$C, copper, and sea shell powder were varied in order to assess the change effected by the sea shell material. The sintered samples of both batches were subjected to microstructural characterization to ascertain the homogeneous distribution of the reinforcements. The microhardness and wear resistance of all of the fabricated samples were assessed. The results confirmed that the inclusion of 2% sea shell powder (by weight) with 10% boron carbide improved the wear resistance and hardness of the composite.