We assess the degree of graphitisation of the material in question. A high-quality graphite recarburiser should contain over 95% graphite carbon. If the processing temperature exceeds 2700 degrees, the sulfur content is 0.02-0.05%, the nitrogen content is 100-200ppm, and the price is 7000-9000 yuan per ton. A graphite recarburiser with a calcination temperature of 2000-2700 degrees is also referred to as a semi-graphitised recarburiser. The product contains 0.1-0.5% sulfur and 300-800ppm nitrogen, with a price range of 3000-4000 yuan.
It is crucial to ensure the quality of the graphite recarburiser for casting is of the highest standard, as this will directly impact the ability to melt grey iron in an electric furnace. It is not uncommon for factories to utilise inexpensive graphite recarburisers for casting purposes, however, this can occasionally result in quality issues, such as the formation of pores. Pore defects are more prevalent in high-quality grey cast iron with low carbon and silicon content.
Ductile iron castings have minimal porosity. Despite the use of magnesium and rare earths, porosity persists. The use of a low-grade graphite recarburiser has an adverse effect on ductile iron, resulting in the contamination of graphite balls and the matrix with sulfur and other impurities. The use of a low-grade graphite recarburiser for casting is a cost-effective solution for these plants. This is an unprofitable venture.
The primary method for evaluating a graphitised recarburiser is through nitrogen content analysis. It is important to note that there are two distinct types of graphitisation: good and bad. The temperature and time of calcination play a crucial role in determining the degree of graphitisation achieved. An incomplete graphitised carburising machine will have a high sulphur and nitrogen content. This type of machine is sometimes referred to as a semi-graphitised recarburiser. It offers a cost-effective alternative to a fully graphite recarburiser, which typically costs 7,000 or 8,000 yuan.
