Role of Lanthanum in Graphite Nucleation in Grey Cast Iron

Abstract:

Specific investigations concerning La-contributions in graphite nucleation process in Ca,Al,La-FeSi inoculated grey cast irons were performed by using a scanning electron microscopy (SEM, EDS). It was re-confirmed that complex (Mn,X)S compounds act as major nucleation sites for graphite flakes. La was mainly concentrated in the first formed oxide-based micro-inclusions (similarly to Al), but also at an important level in the shell of (Mn,X)S compounds (accompanying Ca). It is assumed that La forms micro-inclusions later than Al, as La-reached phase surrounded Al-reached phase. Complex Al-La small micro-inclusions, as possible better nucleation sites for (Mn,X)S compounds and La-Ca presence in the shell/body of these sulphides, possible better nucleation sites for flake graphite, appear to be the peculiar effects of ferrosilicon based inoculants, which include these active elements, promoting type-A graphite, inclusively in low S-grey iron.

• Periodical: Key Engineering Materials (Volume 457)
• Pages: 19-24
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.457.19
• Online since: December 2010
• Authors: Iulian Riposan, Mihai Chisamera, Stelian Stan, Eduard Stefan, Cathrine Hartung
• Keywords: Aluminum (Al), CA, Graphite Nucleus, Gray Iron, La, Manganese Sulphide, Mn, Oxide, S Role

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