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Evaluation of Wear Mechanisms of Graphites Used for Crystallisers for Continuous Casting

Brudny Anna, Kulasa Joanna, Juszczyk Barbara, Myalski Jerzy, Roskosz Stanisław, Wycisk R., Kwaśniewski Paweł, Strzępek Paweł, Poręba Marek

Archives of Foundry Engineering

2022

Vol. 22, iss. 4

109--115

This paper presents the results of research concerning the evaluation of tribological properties of graphite materials used, among others, for crystallisers for continuous casting of non-ferrous metals and their alloys. Graphite materials differing not only in their physical properties but also in the technology of their production were selected from a wide range of commercially available products. Wear resistance investigations of the tested graphite materials were carried out on a pin-on-disc tribometer under technically dry friction conditions on a sliding distance of 1000 m. A constant load but variable speed was used in the tests. The mean value of the coefficient of friction and the wear of the material were determined based on the tribological tests carried out. It was observed that as the speed increases, the average value of the coefficient of friction decreases, while the wear increases. A microstructural analysis of the wear track showed that the friction mechanism depends mainly on the graphite formation technology, which is related to the microstructure of the tested materials, and to a lesser extent to their physical and mechanical properties. Varying the speed values made it possible to trace changes in the wear mechanism, on the basis of which it is possible to predict the durability and reliability of graphite crystalliser operation.

Research of mechanical and electrical properties of Cu–Sc and Cu–Zr alloys

Franczak Krystian, Kwaśniewski Paweł, Kiesiewicz Grzegorz, Zasadzińska Małgorzata, Jurkiewicz Bartosz, Strzępek Paweł, Rdzawski Zbigniew

Archives of Civil and Mechanical Engineering

2020

Vol. 20, no. 1

390--404

The research paper presents the impact of the scandium additive and various conditions of the heat treatment on copper mechanical, electrical and heat resistance properties. The performed research works included manufacturing of CuSc0.15 and CuSc0.3 alloys through metallurgical synthesis with the use of induction furnace and following crystallization in graphite crucibles at ambient temperature. Additionally, a CuZr0.15 alloy was produced as a reference material for previously syn-thesized Cu–Sc alloys. During research, the selection of heat treatment for the produced materials was conducted in order to obtain the highest mechanical–electrical properties ratio. Materials obtained in such a way were next subjected to thermal resistance tests. Parameters of thermal resistance test included temperatures from the range of 200–700 °C and 1 h of anneal-ing time. The research has shown that CuSc0.15 and CuSc0.3 alloys have higher heat resistance after their precipitation hardening compared to the Cu–Zr alloy. The paper also presents microstructural research of the produced materials, which showed that alloying elements precipitates are mainly localized at the grain boundaries of the material structure.

Analysis of the strengthening and recrystallization of electrolytic copper (Cu-ETP) and oxygen free copper (Cu-OF)

Zasadzińska Małgorzata, Knych Tadeusz, Strzępek Paweł, Jurkiewicz Bartosz, Franczak Krystian

Archives of Civil and Mechanical Engineering

2019

Vol. 19, no. 1

186--193

The research paper studies the strengthening and the kinetics of recrystallization of ETP copper and OF copper. This research covers a wide scope of strain hardening specific for the manufacturing of microwires (true strain of the order of 5) and the range of temperatures and times of the recrystallization process referring to the real life conditions occurring in advanced technologies of microwires’ manufacturing. As a result of the performed tests, it was established that the recrystallization temperature of ETP copper is lower than the recrystallization temperature of OF copper regardless of the recrystallization time as the recrystallisation effect can be achieved after about 10–30 s regardless of the copper grade.