In the process of recarburizer casting, there are several critical issues that must be given 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 judicious selection of a suitable recarburizer is of paramount importance to ensure the success of the casting process. The utilization of an appropriate recarburizer in a compatible furnace is instrumental in ensuring optimal outcomes. It is noteworthy that the nitrogen content of recarburizers can vary significantly among brands, necessitating the selection of a low-nitrogen recarburizer to mitigate the presence of potentially 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. The timing of the addition of the recarburizer can influence the quality of the resultant cast metal. For instance, adding the recarburizer late in the casting process can enhance the formation of graphite cores. However, it is imperative to exercise caution and avoid excessive addition of low-sulfur and low-nitrogen recarburizers at this stage.
