Effect of degeneracy in graphite particle aspect ratio (AR) on some mechanicalproperties of as-cast spheroidal graphite iron (SGI)-compacted graphite iron(CGI) cast iron series

Statement of the Problem: Spheroidal Graphite Iron (SGI) and Compacted Graphite Iron (CGI) castings and their derivatives have proven to be the cost-effective materials of choice and/or potential alternatives to other conventional/competing materials (e.g. malleable iron, steel, aluminum, etc., castings) and manufacturing processes (forging, machining, fabrication, etc.) in many automotive and industrial applications, with either an outright improvement in service performance or lower production cost or both. A range of un-alloyed SGI-CGI iron grades were produced in a series of systematic iron-melt treatments with a special Ca-CaC2-Mg master alloy. Data sets are presented and analyzed to gauge the effect of variation in graphite particle Aspect Ratio (AR) range in an as-cast SGI-CGI iron series ranging from ASTM type I (fully spheroidal) to ASTM types II-III-IV (mixture of spheroidal and compacted/vermicular graphite forms) on some of their selected mechanical properties. Findings: It was observed that generally, properties relating to strength and ductility progressively decrease as the proportion of non-nodular graphite (AR≤0.65) increases.