The paper presents the issue of synthetic cast iron production in the electric induction furnace exclusively on the steel scrap base. Silicon

carbide and synthetic graphite were used as carburizers. The carburizers were introduced with solid charge or added on the liquid metal

surface. The chemical analysis of the produced cast iron, the carburization efficiency and microstructure features were presented in the

paper. It was stated that ferrosilicon can be replaced by silicon carbide during the synthetic cast iron melting process. However, due to its

chemical composition (30% C and 70% Si) which causes significant silicon content in iron increase, the carbon deficit can be partly

compensated by the carburizer introduction. Moreover it was shown that the best carbon and silicon assimilation rate is obtained where the

silicon carbide is being introduced together with solid charge. When it is thrown onto liquid alloy surface the efficiency of the process is

almost two times less and the melting process lasts dozen minutes long. The microstructure of the cast iron produced with the silicon

carbide shows more bulky graphite flakes than inside the microstructure of cast iron produced on the pig iron base.

This paper presents the problems related to smelting gray and ductile cast iron. Special attention is paid to the metallurgical quality of cast iron. It depends on the type of furnace, charge materials and the special combination of charge, overheating and holding temperature, melting time, modification and spheroidization method. The evaluation of metallurgical quality has been performed by using derivativethermal analysis (DTA). During the smelting process and secondary metallurgy, the ITACA system was used allowing to obtain information on alloy characteristic temperatures (Tliquidus, TeMin, TeMax, Tsolidus), VPS value, recalescence value, IGQ coefficient, nucleation gauge, porosity etc. The results of investigations and calculations are displayed in the form of graphs and dependencies. It has been shown that the derivative-thermal analysis (DTA) is an effective complement of chemical analysis and it has been found that both the increase in temperature and metal holding time have a negative impact on the metallurgical quality of liquid metal. The metallurgical quality can be improved by using proper composition of charge materials and modifiers.

The paper presents the test results of molding compounds, sand casting molds and their analysis. The subject of testing was compound containing furan resins prepared according to the following recipe: matrix – regenerate 90% + fresh sand – 10%, furan resin – 1.10% by weight, hardener – 0.40% by weight. The impact of adhesive type and its quantity (Quan = 0.90, 1.1 and 1.5%) on the strength indexes of molding compound subject to densification was analyzed. The publication presents the test results: tensile strength Rm, compressive strength Rc and flexural strength Rg, as well as compound permeability as function of its density. The analysis also covers the impact of density level on mold strength and the distribution of density level along the mold height.

Based on the test results, it was found that the best method to obtain high strength molds made from compounds with chemical adhesives was to densify it by vibrating the system: match plate – molding flask – compound filling the mold. The effectiveness of this densification method depends on the amplitude and frequency of vibrations.