In the process of recarburizer casting, several critical issues warrant careful consideration. If these issues are not adequately addressed, the quality of the casting may deteriorate, resulting in defects such as porosity and shrinkage.
The selection of an appropriate recarburizer is paramount for successful casting outcomes. Utilizing the correct recarburizer in the appropriate furnace can yield favorable results. It is important to note that the nitrogen content varies among different brands of recarburizers; therefore, selecting a low-nitrogen recarburizer is advisable, as it can also mitigate the presence of harmful substances. The titanium content in molten iron is typically low, which minimizes nitrogen consumption. However, an increase in nitrogen content can lead to the formation of numerous pores and other defects, necessitating the identification of a recarburizer with superior graphitization properties. Failure to do so may result in a low absorption rate, sluggishness, slag formation, and the introduction of harmful elements that adversely affect the quality of molten iron. The timing of recarburizer addition is also crucial; it can be introduced during the early, middle, or late stages of casting, and may be added concurrently with steel scrap. Late-stage addition can serve a pre-treatment function, potentially enhancing the formation of graphite cores. However, it is essential to avoid excessive addition of low-sulfur and low-nitrogen recarburizers at this stage.
