ALLOYING ELEMENTS MACROSEGREGATION IN 6XXX ALUMINUM ALLOY BILLETS OBTAINED BY CONTINUOUS CASTING WITH ELECTROMAGNETIC STIRRING

1 KOWAL Radosław
Co-authors:
1 MAMALA Andrzej 1 ŚCIĘŻOR Wojciech 1 KWAŚNIEWSKI Paweł 1 GRZEBINOGA Justyna 1 JURKIEWICZ Bartosz 1 FRANCZAK Krystian
Institution:
1 AGH University of Science and Technology, Faculty of Non - Ferrous Metals, Department of Metal Working and Physical Metallurgy of Non- Ferrous Metals, Mickiewicza Av. 30, 30-059 Cracow, Poland, EU, rakow@agh.edu.pl
Conference:
26th International Conference on Metallurgy and Materials, Hotel Voronez I, Brno, Czech Republic, EU, May 24th - 26th 2017
Proceedings:
Proceedings 26th International Conference on Metallurgy and Materials
Pages:
1475-1480
ISBN:
978-80-87294-79-6
ISSN:
2694-9296
Published:
9th January 2018
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
11 views / 10 downloads
Abstract

An important scientific and utilitarian challenge is to provide repeatability of the chemical composition in volume of billets, which guarantee the uniform yield stress during hot metal forming processes. During real billet manufacturing processes the segregation of chemical composition is observed. It depends on the type of alloy, solidification process conditions, and technological factors. This segregation can occur in the microscale (microsegregation) or in the macroscale (macrosegregation). The microsegregation can be reduced by the homogenisation but macrosegregation is an indelible defect. An effective way to reduce macrosegregation is electromagnetic stirring of liquid metal before solidification. The effectiveness of this mixing depends on the position of the stirring coil in relation to the solidification area.The paper presents the impact of selected continuous casting process parameters (casting speed, cooling medium flow in the primary cooling) on the alloying elements macrosegregation in the billets. Additionally macrostructures of billets were reported and electrical conductivity of material as an alternative measure of the alloying elements content was done. The distribution of alloying elements on the billet diameter shows a maximum set asymmetrically relative to the axis of the billet (horizontal casting). Variation of the silicon content is greater than for the magnesium. Changing the conditions of the mould primary cooling – increase the flow of cooling medium results in a decrease of solidification zone distance from the mixing coil and causes mainly the reduction of magnesium macrosegregation.

Keywords: Macrosegregation, aluminum alloy, continuous casting, electromagnetic stirring
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