Про механізм засвоєння карбіду кремнію розплавом залізовуглецевого напівпродукту при виробництві сталі в кисневих конвертерах

• Дата: 2023
• Автор: Бондар, В. І.
• Формат: Стаття
• Мова: Українська
• Опубліковано: Physico-technological Institute of Metals and Alloys 2023
• Теми: великоваговий конвертер; залізовуглецевий напівпродукт; попереднє розкислення; карбід кремнію; механізм засвоєння; ступінь засвоєння
• Онлайн доступ: https://www.metalsandcasting.com/index.php/mcu/article/view/80
• Назва журналу: Metal and Casting of Ukraine

The article is devoted to the elucidation of the mechanism of assimilation of silicon carbide by iron-carbon intermediate product, which is produced in heavy-duty oxygen converters with top blowing. The thermodynamics of the process of assimilation of silicon carbide in various conditions of steel production has been studied enough, but the mechanism of assimilation of silicon carbide by the melt is not explained. The material containing silicon carbide is introduced as one of the deoxidizers for preliminary deoxidation when tapping the iron-carbon intermediate product into the ladle. To achieve this goal, it was taken into account that during tapping, a significant part of the oxidizing converter slag also gets into the ladle. A set of the latest data on the physicochemical properties of silicon carbide was also taken into account. Thanks to the successfully carried out stages of research, significant results have been obtained that confirm the mechanism of assimilation of silicon carbide by the melt. The most important role in this is played by the presence of oxidizing slag, which randomly falls into the ladle during the release of iron-carbon intermediate product in a tangible amount. The presence of silicon carbide in the "iron-carbon intermediate product – slag" system ensures the gradual transformation of the oxidizing slag into a refining reducing slag over time. For the first time, a hypothesis was formulated that explains the mechanism of assimilation by a liquid system "carbon intermediate – slag", accompanied by equations of homogeneous chemical transformations that occur in this case in an oxide melt. The correctness of the stated provisions on the mechanism of assimilation of silicon carbide is confirmed by the values of the coefficients of assimilation of silicon and other elements – deoxidizers, namely manganese, aluminum and carbon. This information was obtained by calculation based on the protocol data of more than 900 real heats produced during January 2019 on a 350 t top-blown converter. Thanks to the successful algorithm of the differential approach to the analysis of melts, it was found, in particular, that the degree of assimilation of deoxidizing elements depends on the manganese content in the steel being melted. In general, this study allowed us to draw a number of practical conclusions regarding the possibility of reducing the consumption of deoxidizing elements. The most important is the conclusion about the possibility of removing the expensive element – aluminum from the deoxidizing mixture. This is very important, proceeding from the problem of overgrowing of submersible nozzles of machines for continuous casting of billets with refractory inclusions. It is recommended to use aluminum only for out-of-furnace treatment in a ladle furnace. The proportion of ferroalloys containing manganese and silicon can also be significantly reduced. In this case, it is expedient to determine the most advantageous decrease in the amount of introduced ferroalloys. This will reduce the cost of steel produced by optimizing the consumption of ferroalloys while maintaining steel quality indicators.