Peculiarities of the Fe-C melt carburization process and the effect produced on it by the type of carburizers

Abstract

One of the ways to improve the competitiveness of domestic steel and machine-building products and transition to a carbon-free economy is to develop synthetic pig iron production technology. Synthetic pig iron production ensures the efficiency and quality of foundry operations. The replacement of expensive casting and remolding cast irons with steel scrap reduces the cost of casting production and allows for the use of higher quality materials free of harmful impurities and inclusions. However, their use in the charge results in the need for melt carburizing. In this case, the melt carburizing process plays an important role in the multi-link chain of casting production. In this situation, it is of particular importance to choose a carburizer that will ensure the quality of the final product and reduce production costs. This task was solved in this work on the basis of studying the processes of carburization of Fe-C melt and determining the requirements for the quality of carburizers and determining the technological parameters of their production in units with an electrothermal fluidized bed. The analysis of studies of carburization of Fe-C melt by different types of carburizers has identified the main factors that affect the carburization process and the quality of synthetic cast iron castings: technological parameters (melt temperature, degree of mixing, initial melt composition), characteristics of carburizers (ash content and its composition, sulfur content, nitrogen content, crystal structure). Based on the results of experimental studies, the requirements for the optimal parameters of synthetic cast iron carburizers were formulated: the content of ash and gases should be as low as possible, the crystal structure should include 80-90% of graphitized materials with a crystallinity of more than 100 A when producing cast irons with lamellar graphite. This made it possible to determine the main technological parameters for the production of carburetors based on domestic raw materials (anthracite of the Donetsk deposit): heat treatment temperature 2400-2700°C, treatment time 10 minutes.