Study of the Solidification Structure of Compacted Graphite Cast Iron

LOPEZ, MARCOS; G. RIVERA; J. MASSONE; ROBERTO E. BOERI

INTERNATIONAL JOURNAL OF CAST METALS RESEARCH

MANEY PUBLISHING

Lugar: London; Año: 2016 vol. 29 p. 266 - 271

1364-0461

This investigation focuses on the study of the solidification mechanism of compacted graphite cast iron (CGI). The solidification macrostructure was revealed in cast samples using a special technique. The microstructure was revealed by colour etching. The results were compared with earlier investigations of spheroidal (SGI) and lamellar (LGI) graphite irons, and show that, similarly to other free graphite cast irons, the solidification of CGI is dominated by the presence of relatively large grains of austenite that can be observed with bare eyes. The samples show a typical ingot structure, containing columnar and equiaxed grains, with a narrow columnar to equiaxed transition. The microstructure analysis showed that the grains are formed by a dendritic substructure and a large number of eutectic colonies. Microsegregation is located inside the grains, mostly between secondary dendrite arms. Meanwhile, the growth mechanism during solidification of CGI resembles that of LGI, but not the mechanism of SGI.