Дослідження фізико-хімічних процесів в системі твердий силікокальцій–рідкий чавун

• Дата: 2023
• Автори: Бубликов, В. Б., Бачинський, Ю. Д., Нестерук, О. П.
• Формат: Стаття
• Мова: Ukrainian
• Опубліковано: National Academy of Sciences of Ukraine, Physical-Technological Institute of Metals and Alloys of NAS of Ukraine 2023
• Теми: чавун; плавлення; модифікування; силікокальцій; фазовий склад
• Онлайн доступ: https://plit-periodical.org.ua/index.php/plit/article/view/research-physic-chemical-processes-system-solid-silicocalcium-li
• Назва журналу: Casting Processes

Physico-Technological Institute of Metals and Alloys of the National Academy of Seience of Ukraine (Kyiv, Ukraine) Received 16.12.2021 UDK 669.131.7:669.891:669.017.3:669.046.548.2 The situation with resources requires the creation of new high-performance modifiers with adjustable dissolution kinetics. Improving of melt modifying efficiency and production of high-strength cast iron details with optimal strength and ductility meets the today requirements. In high-strength cast iron technologies, along with its chemical composition, microstructure and phase composition of modifying alloys, as well as conditions and their dissolution rate in iron-carbon melt are among the main factors determining the stability and efficiency of modifying processes. In this work the results of the study of silicocalcium phase composition and microstructure changes in the process of physicochemical interaction with molten cast iron are presented. The study showed that the main constituent of the original silicocalcium SiCa30 microstructure is calcium disilicide CaSi2, in which predominantly needle-shaped crystals of silicon Si and leboite FeSi2 are evenly distributed. It is experimentally established that the surface of the silicocalcium samples residue after extraction from the melt is covered with a reaction layer formed by physicochemical interaction in the system «solid silicocalcium – liquid cast iron» and in which the transfer of chemical elements is going on: silicon and calcium goes from silicocalcium to cast iron, and iron – from liquid cast iron to silicocalcium. There is a combination of two components in the reaction layer area adjacent to the silicocalcium – round shape silicon-containing phases with a high content of calcium (71.16 wt.% Ca, i.e. Ca2Si phase) in the amount of 45.36 % or iron (62.34 wt. % Fe, i.e. phase FeSi) in the amount of 54.64 % with congruent melting points of 1314 and 1410 0C, respectively, which may adversely affect on the modifying process stability and efficiency. The reaction layer weight depends on the cast iron melt temperature and sample holding time there. The experimentally determined rate of weight change of SiCa30 samples during their holding in liquid cast iron with temperatures of 1400 and 1450 0C is in the range of 1.0-1.2 g/sec which is 1.5-2.0 times less than in ferrosilicon FeSi75 (1.5-2.4 g/sec) and 2.3-3.0 times less than in ferrosilicon-magnesium master alloy Mg7-FeSi (2.3-3.6 g/sec). 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