Modification and Inoculation of Cast Iron

Comparative Study on the In-Ladle Treatment Techniques for Nodulizing the Iron’s Graphite

“…Ductile iron (nodular graphite iron) has became one of the most important engineering materials, in view of its excellent castability, significantly better mechanical properties and low cost [1][2][3][4][5][6]. Generally, ductile cast iron consist of graphite spheroids dispersed in a matrix.…”

“…The ductile iron can be produced by adding small quantities of magnesium [Mg] to a base cast iron which transforms graphite spheroids instead of flakes [3][4][5][6][7][8][9][10][11][12][13]. Therefore, production of nodular cast iron consists of three basic stages [1][2][3][4][5][6][7][8][9][10][11][12][13]: -Casting of basic cast iron with proper chemical composition, characterised by the high graphitization (nodulizing) ability. This is insured by appropriate high content of carbon and silicon.…”

“…The carbon present in molten iron is normally in flake form, and if the metal solidifies with the carbon in such form [1][2][3]. For a number of years it has been known that flake graphite can be converted to the nodular form by the use of nodulizing agents, which initially were used to treat gray iron as it flowed from the melting furnance or when it was received in the ladle from which castings were poured [1,4].…”

“…Nodulization is a process of controlling the structure and properties by changing the graphite shape from flakes to spheroidal in cast iron during solidification [1][2][3][4][5][6][7][8]. The nodularisers are added in liquid iron to promote the formation of spheroidal or compacted form of graphite, specific for the ductile irons.…”

“…The nodularisers are added in liquid iron to promote the formation of spheroidal or compacted form of graphite, specific for the ductile irons. Therefore, a certain quantity of magnesium is necessary to obtain the graphite in spheroidal or compacted form [1][2][3][4][5][6][7][8][9][10][11][12][13]. The properties of cast iron can be improved by the addition to it of nodulizing elements, commonly magnesium and cerium, or both [1][2][3][4][5][6][7][8][9][10][11][12][13].…”