Compacted graphite iron (CGI) is a good option for the blocks and cylinder heads in heavy duty engines due to their well-balanced thermal and mechanical properties. In this work, a remelting technique has been utilized for the production of CGI with different nodularity (10 and 20%), C contents (CE=3.5, 3.8, 4.2) and under different solidification and cooling rates. The employed experimental parameters had a sizeable influence on the morphology and fraction of the inter-dendritic structure and resulted in ultimate tensile strength (UTS) that ranged from 335 to 456 MPa and 371 to 521 MPa for the 10 and 20% nodularity, respectively. The results show that the UTS is linearly related to the solidification time and the microstructural parameter that express the scale length of the inter-dendritic region. Different CE and nodularity provide different relationships between UTS, solidification time and microstructure. Finally, an empirical model has been developed for the prediction of the UTS.
This paper is an invited submission to IJMC selected from presentations at the 7th Keith Millis Symposium on Ductile Iron held October 18–20, 2023, at the Crown Plaza Atlanta Perimeter at Ravinia, Atlanta, GA. It is published in the IJMC by permission of the DIS (Ductile Iron Society).