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Open access

J. Falkus

Abstract

This paper presents research on the mould slag formed on the basis of two mould fluxes. In the conducted industrial experiments, slag was sampled in equal time intervals between adding subsequent portions of mould flux. The research focused on the an evaluation of the stability of slag parameters by assessing the change in its liquidus temperature. It was shown that a mould flux needs to be assessed individually taking into account the casting process parameters and the steel cast grade.

Open access

Z. Sarajan

). [4] O. Lashkari, R. Ghomashchi, Rheological behavior of semi-solid Al-Si alloys: Effect of morphology. Materials Science and Engineering A 454-455 , 30-36 (2007). [5] M. Mansoor, N. Ejaz, A. Tauqi, Second phase structure effect to the failure of an Al-Si casting. Engineering Failure Analysis 16 , 1549-1553 (2009). [6] L. Zheng, M. Wei-min, Z. Zheng-duo, Effect of pouring temperature on semi-solid slurry of A356 A1 alloy prepared by weak electromagnetic stirring. Trans. Nonferrous Met. SOC. China 16 , 71-76 (2006). [7] O. Lashkari, R. Ghomashchi

Open access

D. Leśniak, M. Dziki, J. Zasadziński and W. Libura

. Richert, W. Libura, W.Z. Misiołek , Modeling of Temperature-Speed Parameters in Aluminium Extrusion, Proc. 5th Aluminium Extrusion Technology Seminar, p. 385-393, Chicago 1992.

Open access

D. Kalisz and S. Rzadkosz

Abstract

The study was carried out computer simulations of the formation process of AlN precipitates in the solidification of steel. The chemical composition of steel and non-metallic inclusions formed was determined using the commercial software FactSage. Calculated amount of precipitates formed during cooling of steel between the liquidus and solidus temperatures under conditions of thermodynamic equilibrium. In parallel, the computations were performed using your own computer program. It was found that aluminum nitride is formed at the final stage of solidification, and the condition of its formation is low oxygen content in steel.

Open access

D. Kalisz

Abstract

This paper deals with the mathematical modeling of physicochemical properties of mold slag such as: viscosity, surface tension, temperature liquidus, basicity. Computer simulation of slag viscosity was made by the Nakamoto structural model. The effect of addition CaF2 to the mold slag was estimated by using of Urbain model. The results were compared with the results of the experiment. Surface tension for the basic slag composition: CaO - SiO2 - Al2O3 was calculated with using Nakamoto model. The results of calculations indicate that the content of the SiO2 lowers the surface tension, but increase the content of CaO and Al2O3 in the slag increases its value. Calcium fluoride (CaF2) reduces the viscosity of the slag. The increase in temperature reduces the viscosity of the slag, simultaneously increasing the surface tension.

Open access

J. Szajnar, A. Dulska, T. Wróbel and C. Baron

REFERENCES [1] J. Szajnar, A. Walasek, C. Baron, The temperature of the beginning of alloy layer forming process on the steel cast, Archives of Foundry Engineering 13 , Issue special 1, 185-188 (2013). [2] J. Szajnar, A. Walasek, C. Baron, Tribological and corrosive properties of the parts of machines with surface alloy layer, Archives of Metallurgy and Materials 58 , 3, 931-936 (2013). [3] A. Walasek, J. Szajnar, The mechanism of the surface alloy layer creation for cast steel, Archives of Foundry Engineering 12, 1, 115-118 (2012). [4

Open access

A.A. Burbelko, D. Gurgul, M. Królikowski and M. Wróbel

Abstract

Formation of the shrinkage defects in ductile iron castings is far more complicated phenomenon than in other casting alloys. In the paper one of the aspects of formation of porosity in this alloy was considered - changes in cast iron's density during crystallization caused by varying temperature, phase fractions and phase's composition. Computer model, using cellular automata method, for determination of changes in density of ductile iron during crystallization was applied. Simulation of solidification was conducted for 5 Fe-C binarie alloys with ES from 0.9 to 1.1 for the estimation of the eutectic saturation influence on the ductile iron shrinkage and expansion. As a result of calculations it was stated that after undercooling ductile iron below liquidus temperature volumetric changes proceed in three stages: preeutectic shrinkage (minimal in eutectic cast iron), eutectic expansion (maximum value equals to about 1.5% for ES = 1.05) and last shrinkage (about 0.4% in all alloys regardless of ES).

Open access

R. Przeliorz and J. Piątkowski

References [1] Sims, S.T., Stoloff, N.S., Hagel, W.C. (1987). Superalloys II. New York: Ed. John Wiley & Sons. [2] Mikułowski, B. (1997). High temperature cast alloys and Nikel-based superalloys. Cracow: Publication AGH. [3] Zrnik, J., Strunz, P., Vrchovinsky, V., Muransky, O., Novy, Z. & Widenmann, A. (2004). Degradation of creep properties in a long-term thermally exposed nickel base superalloy. Materials Science and Engineering. A 387-389, 728-733. [4] Lee, S.H., Kim, S.W. & Kang, K.H. (2006

Open access

P. Migas and M. Karbowniczek

Interactions between Liquid Slag and Graphite During the Reduction of Metallic Oxides

High global demand for metallic elements such as Fe, Cr, Ti, Mn leads to an intensive technological development of metal recovery. One of the ways is to recover metals from metallurgical slag. The sessile drop method was adopted in order to study the interactions between liquid slag and graphite. Steelmaking slag was used during this research. The slag used included converter slag and slag from chrome steel melting as well as their mixtures with other modifiers. The analysis covered six types of slag in the temperature ranging from 1100°C to 1600°C in the argon atmosphere. In the course of research mass spectrometry and scanning microscope were used. The following were set for the examined samples during the reduction process: liquidus temperature and the nature of interactions (wettability or its lack). It was observed that the volume of slag samples dynamically changed in the course of the reduction of metallic oxides.

Open access

J. Pieprzyca, Z. Kudliński and T. Merder

Abstract

The formation of the cast strands’ primary structure is a very complex process in terms of the thermodynamics and physicochemical. It occurs during solidification and crystallization of the liquid steel in the crystallizer and in the secondary cooling zone of the CC device. On the basis of the experience gained in the industry and knowledge arising from theory of metals and alloys solidification it can be concluded, that substantial influence on the shape of cast strands primary structure have the temperature of overheating of the liquid steel above liquidus temperature and solidification velocity. A proper control of those casting parameters allows to obtain the cast strands with desired primary structure. In the one and two-way symmetric devices regulation like this is not problematic, in the multi-way devices - specially in the asymmetric - causes a series of problems. In those devices can occur a major temperature difference in each outlet zone of the tundish working space caused by i.e. the distance length diversity of liquid steel stream from the inlet to each outlet and by disadvantageous layout of liquid steel flow zones (turbulent flow zone, plug flow and dead zones) in working area of tundish. Particularly high values of those diversity can be expected in the asymmetric tundishes.

The article presents results of laboratory research - model and industrial regarding impact of the liquid steel overheating temperature, but also heterogeneity of the temperature fields in the tundish on primary structure of the cast strands.