Microstructural influence on machinability of wheel hubs in ductile cast iron

Paper i proceeding, 2009

In the present study metal cutting machinability of ductile cast iron of grade 500-7 is investigated experimentally. Machinability will vary in this material, as in most materials, due to variations in microstructure. The purpose of this study has been to analyse and quantify these variations and to compare and incorporate them with industrial findings on variations. Therefore a specific part, wheel hubs for heavy trucks was chosen as study object. Findings from production and real wheel hubs were used for background material as well as in analysing and discussing the results. In the experimental part of the study, a cylindrical test geometry was chosen and test specimens were cast. Subsequently their microstructure was thoroughly analysed and tool life tests were performed. Tests were performed at industrial-like cutting data and with a state-of-the-art insert material. The results show that tool life will vary with a factor 2 within the hardness variation allowed for grade 500-7. Hardness was also shown to be a good indicator of tool life. Discrepancies due to carbide content and pearlite morphology are also quantified and discussed.