2019 №01 (06) DOI of Article
2019 №01 (02)

Electrometallurgy Today 2019 #01
SEM, 2019, #1, 11-16 pages

Journal                    Sovremennaya Elektrometallurgiya
Publisher                International Association «Welding»
ISSN                      2415-8445 (print)
Issue                       № 1, 2019 (February)
Pages                      11-16
Features of structure formation in the precision alloy 29NK in ESR with a portion ingot formation

I.V. Protokovilov, A. T. Nazarchuk, D.A. Petrov, V.B. Porohonko
E.O. Paton Electric Welding Institute of the NAS of Ukraine. 11 Kazimir Malevich Str., 03150, Kyiv, Ukraine. E-mail: office@paton.kiev.ua

The results of studying the features of structure formation in the ingots of the precision alloy 29NK are given, produced by electroslag remelting with a portion formation. The ingots with a diameter of 84 and 120 mm were melted by remelting consumable electrodes in a chamber electroslag furnace in a pulsed mode, providing the periodicity of processes of melting and crystallization of metal. This was achieved due to cyclical variation of electric voltage on the pool from the operating values to the values at which the melting of the electrode stopped. It is shown that a rational choice of electric supply modes during pulses and pauses of metal melting allows maintaining the stability of electroslag process and a good quality of the formation of the side surface of the ingot. At the same time, additional possibilities are opened for controlling the structure formation in the ESR metal with producing ingots having a dense structure, without porosity, inclusions, large columnar crystals and a zone of counter crystallization along the axis of the ingot. Ref. 8, Tabl. 1, Fig. 4.
Key words: electroslag remelting; precision alloys; kovar; ingot; portion formation; crystallization; macrostructure
Received:                12.11.18
Published:               19.02.19
1. GOST 10994–74: Precision alloys. Grades. Intergovernmental standard [in Russian].
2. (1983) Precision alloys: Refer. Book. Ed. by B.V. Molotilov. Moscow, Metallurgiya [in Russian].
3. Gritsianov, Yu.A., Putimtsev, B.N., Molotilov, B.V. (1975) Metallurgy of precision alloys. Moscow, Metallurgiya [in Russian].
4. Golikov, I.N., Maslenkov, O.B. (1977) Dendritic segregation in steels and alloys. Moscow, Metallurgiya [in Russian].
5. Medovar, B.I., Tsykulenko, A.K., Shevtsov, V.L. et al. (1986) Metallurgy of electroslag process. Ed. by B.E. Paton. Kiev, Naukova Dumka [in Russian].
6. Medovar, B.I., Tsykulenko, A.K., Dyachenko, D.M. (1990) Quality of electroslag metal. Ed. by B.E. Paton, B.I. Medovar. Kiev, Naukova Dumka [in Russian].
7. Mitchell, A. (2008) Solidification of metal in remelting processes. Advances in Electrometallurgy, 2, 3–11.
8. (2016) Selection of optimal flux — guarantee of success in electroslag remelting. https://www.wacker.com/cms/media/publications/downloads/632_RU.pdf