Primary Austenite Morphology and Tensile Strength in CGI for Different C Contents, Cooling Conditions and Nodularity

Abstract

AbstractCompacted 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.