Effect of bismuth and rare earth elements on graphite structure in different section thicknesses of spheroidal graphite cast iron castings

Scientific paper - Original scientific paper

• Author: Zoran Glavaš
• Author: Anita Štrkalj
• Author: Krešimir Maldini
• Author: Franjo Kozina
• Author's institution: University of Zagreb; Faculty of Metallurgy; (Department of Process Metallurgy); (Laboratory of chemistry (basic, inorganic, physical))
• Author's institution: University of Zagreb; Faculty of Metallurgy; (Department of Process Metallurgy); (Laboratory of Iron, Steel and Founding)
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Metallurgy; Process Metallurgy

Abstract (english)

Effects of additions of 0.00064, 0.001 and 0.0042 wt.% Bi on the graphite structure in the section thicknesses of 3, 12, 25, 38, 50, 75 and 100 mm of spheroidal graphite cast iron castings containing 2.11 wt.% Si and rare earth (RE) elements (Ce + La + Nd + Pr + Sm + Gd) in the range from 0.00297 to 0.00337 wt.% were analyzed in this paper. Addition of Bi was not necessary for obtaining high nodule count and nodularity higher than 80% in section thicknesses of 3, 12 and 25 mm. RE elements showed a beneficial effect on the nodule count and nodularity in these sections. Nodularity was below 80% in section thicknesses of 38 , 50, 75 and 100 mm when Bi was not added. Detrimental effect of RE elements on graphite morphology in these sections was neutral- ized by adequate addition of Bi. Addition of 0.001 wt.% Bi (ratio of RE/Bi = 3.27) was enough to achieve nodularity above 80% in the section thickness of 38 mm. Nodularity was increased above 80% in section thicknesses of 50, 75 and 100 mm by addition of 0.0042 wt.% Bi (ratio of RE/Bi = 0.78). At the same time, Bi significantly increased the nodule count. Nodularity above 80% and the high nodule count in the section thicknesses of 75 and 100 mm were also achieved by using an external metallic chill in the mold. In this case, addition of Bi was not required.

• Keywords (english): spheroidal graphite cast iron casting; graphite structure; bismuth; rare earth elements; microstructure
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Archives of metallurgy and materials
• Numbering: vol. 63, no. 3, pp. 1547-1553
• p-ISSN: 1733-3490
• e-ISSN: 2300-1909
• DOI: https://doi.org/10.24425/123846
• URN:NBN: urn:nbn:hr:115:114595
• Publication: 2018
• Document URL: http://bib.irb.hr/963306
• Type of resource: Text
• Access conditions: Closed access
• Created on: 2019-07-09 07:50:35