Metallurgical Quality of Cast Iron Made from Steel Scrap and Possibilities of Its Improvement

Abstract

In the field of metallurgy, there are many factors that influence the final quality of cast iron. These are mainly charge materials, chemical composition and metallurgical preparation up to the final casting process. Even small deviations from metallurgical processing lead to fluctuations in melt quality and the occurrence of casting defects. Charge materials have a significant impact on the quality of cast iron, especially steel scrap, which is increasingly used from an economic and ecological point of view, especially when melting cast iron in electric furnaces. Cast iron produced from a higher proportion of steel scrap in the charge has a higher hardness and tensile strength. On the other side, these cast irons have a higher tendency of chillout, brittleness, shrinkage, pearlitic microstructure, stresses and higher purity due to the difference in hardness at different wall thicknesses of the castings. It is the high hardness that is the problem in the final machining of castings. These negative properties are recorded mainly in heavy thick-walled castings with a higher tensile strength and hardness. This negative effect is mainly due to the nitrogen content in the steel scrap. Based on this knowledge, operating melts were realized in the foundry’s operating conditions. The influence of steel scrap in the charge and the possibility of eliminating its negative effects on the properties of cast iron were investigated.

Experimental Study of a Representative Sample to Determine the Chemical Composition of Cast Iron

“…Optical emission spectrometers are now more efficient, user-friendly, and precise. Foundries, which have already started profiting from the improvement in OES technology, can carry out the more accurate analyses required by stricter customer specifications for chemical analysis and make progress in their continuing efforts to acquire ISO 9000 and QS 9000 certification [ 4 , 5 ].…”

Increasing the Efficiency of Synthetic Iron Production by the Use of New Kit Lining

“…When operating these furnaces, their high reliability, ease of maintenance, and high resistance to the acid lining, reaching 300-350 melts, have been observed. Synthetic cast iron smelting in ICFs allows for the deep thermal treatment, refining, modification, and alloying of liquid metal and the production of alloys with predetermined properties superior to cast iron obtained by the wax smelting method [6][7][8][9]. In addition, induction melting contributes to the destruction of the imperfect structure of initial charge materials.…”