Title: Investigation of microstructure and material properties for 18 different graphitic cast iron model materials with focus on Compacted Graphite Iron (CGI)

Authors: Varun Nayyar; Henrik Svensson; Mathias König; Anders Berglund; Lars Nyborg

Addresses: Department of Materials and Manufacturing Technology, Chalmers University of Technology, Hörsalsvägen 7B, SE-41296 Gothenburg, Sweden ' Swerea SWECAST AB, P.O. Box 2033, SE-550 02 Jönköping, Sweden ' UTMB – Basic Engine, Materials Technology, Scania CV AB, SE-151 87 Södertälje, Sweden ' Department of Production Engineering, KTH Royal Institute of Technology, Brinellvägen 68, SE-100 44 Stockholm, Sweden ' Department of Materials and Manufacturing Technology, Chalmers University of Technology, Hörsalsvägen 7B, SE-41296 Gothenburg, Sweden

Abstract: The higher mechanical strength of Compacted Graphite Iron (CGI) than Flake Graphite Iron (FGI) makes it very useful material for several commercial components. The knowledge of microstructure and hence the mechanical properties and machinability is very important for the CGI to used efficiently in manufacturing. The complex geometry of cast components makes it difficult to produce adequate microstructure in the whole component. Adequate material properties can be achieved by having good knowledge about the correlations between the casted geometry, graphite morphology and pearlite content. In the presented paper, 18 different model materials have been analysed extensively, concerning the effect of chemical composition, solidification and cooling rate on the nodularity, pearlite content, interlamellar spacing in pearlite, hardness and mechanical properties. Later, the cutting force measurement tests were performed on some of the materials and it was found that the forces have a strong positive correlation with pearlite content and the tensile strength of the materials.

Keywords: CGI; compacted graphite iron; microstructure; mechanical properties; vermicular graphite; nodularity; pearlite content; tensile testing; hardness testing; interlamellar spacing; machinability; cast iron model materials; chemical composition; solidification rate; cooling rate; cutting force; tensile strength.

DOI: 10.1504/IJMMP.2013.057065

International Journal of Microstructure and Materials Properties, 2013 Vol.8 No.4/5, pp.262 - 282

Published online: 07 Oct 2013 *

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