Casting structure change caused by magnetic field

• Autorzy: Szajnar, J.
• Języki publikacji: EN

Abstrakty

EN

Purpose: In this work problems of crystallization process for pure metal and alloy castings solidifying under forced convection resulting from use of rotational or rotational reversing magnetic field are presented. Design/methodology/approach: Influence of changes caused by forced convection in solidification conditions on columnar crystals zone and its limitation was studied. Obtained results show that magnetic field changes thermal and concentration conditions. Both conditions are connected with magnetic field induction B, that is with liquid metal velocity Vcm ahead of crystallization front. Examples of magnetic field application for casting structure change are shown. Findings: Model of columnar to equiaxed structure transition was based on modified concentration stability criterion of crystallization front, in which measurements of alloy addition concentration along ingot radius were incorporated. Gradient-kinetic conditions were evaluated with use of computer simulation of solidification process. Crystallization conditions at the interface enabled tracking of solidification process for actual casting from its surface to its axis. It was then possible to analyze relation between thermal and concentration conditions in time of solidification and to determine position of crystallization front stability loss, which after some simplifications can be considered as the columnar crystals zone width. Research limitations/implications: Experimental results confirmed justness of introduced model. In analysis also simulation results were used describing liquid metal flow ahead of crystallization front for different types of the interface showing qualitative relations between crystallization front geometry and structure changes. Practical implications: Relations are proposed, which can be used for columnar crystals zone width taking into account nominal concentration of alloy addition Co, forced by magnetic field liquid metal velocity Vcm and thermal conditions represented by pouring temperature Tzal, thermal gradient at the crystallization front at the moment of forced convection termination GT or difference in temperature on casting cross section delta T. Originality/value: This paper is a result of several studies conducted in Foundry Department since many years and connected of physical factors (ultrasonic vibrations, electromagnetic field) influence on crystallization process of static and continuous castings.

Słowa kluczowe

PL

konwekcja wymuszona; pole magnetyczne; symulacja; stężenie pierwiastków; stężenie miedzi; przekształcenia struktury

EN

forced convection; magnetic field; simulation; copper concentration; structure transformation

• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2007
• Tom: Vol. 24, nr 1
• Strony: 297-306
• Opis fizyczny: Bibliogr. 44 poz., fot., rys.

Twórcy

autor

Szajnar, J.

• Division of Foundry, Institute of Engineering Materials and Biomaterials, Silesian University of Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland,

Bibliografia

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