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Journal of Materials Engineering and Performance

, Volume 28, Issue 1, pp 278–286 | Cite as

Solidification Characteristics of Silicon-Alloyed Ductile Cast Irons

  • Stelian Stan
  • Iulian Riposan
  • Mihai Chisamera
  • Iuliana Stan
Article
  • 15 Downloads

Abstract

Solidification pattern of three ductile iron compositions [I-2.5%Si; II-4%Si, and III-4%Si-1.6%Mo] is studied, to evaluate the effects of high Si and Mo contents. Inoculation compensates for the negative effect of Mo on eutectic undercooling. The deviation using a sphere as reference of graphite particles is noticeably increased by silicon alloying, when a characteristic of the graphite particles appears have a larger perimeter, resulting in a large category [IV, V and VI forms, ISO 945]. The sphericity shape factor (SSF) considering the real perimeter of particle is recommended in the nodularity evaluation in high-Si ductile iron, instead of the roundness shape factor, involving maximum ferret, presently incorporated in the ISO 945 standard. The higher the minimum acceptable SSF is, the greater difference in nodularity, between conventional and Si-alloyed ductile irons. For more than 4%Si, ductile irons are characterized by a medium-quality graphite phase, with prevalent form V-ISO 945 graphite. A specific inoculant, with a powerful action on the graphite particle compactness, especially to promote VI graphite form, is necessary.

Keywords

ductile iron graphite shape factor inoculation Mg treatment nodularity Si and Si-Mo alloying structure thermal analysis 

Notes

Acknowledgments

This work was partially financed by the grant of the Romanian National Authority for Scientific Research and Innovation, CNCS/CCCDI-UEFISCDI, mobility Grant of the Romanian Ministry of Research and Innovation, CNCS-UEFISCDI, Project Number PN-III-P1-1.1- MC-2018-0207, within PNCDI III. The authors would like to recognize and thank Michael Barstow (Consultant) for reviewing and editing this paper.

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Copyright information

© ASM International 2018

Authors and Affiliations

  • Stelian Stan
    • 1
  • Iulian Riposan
    • 1
  • Mihai Chisamera
    • 1
  • Iuliana Stan
    • 1
  1. 1.Materials Science and Engineering FacultyPOLITEHNICA University of BucharestBucharestRomania

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