Development of metalworking fluid for compacted graphite iron (cgi) machining using advanced tools

Principal investigator: Fei Ren

University: Temple University

Industry partners: Quaker Houghton

Compact graphite iron (CGI) has been considered to replace widely used grey cast iron in many automotive applications such as exhaust manifolds, cylinder heads, and engine blocks. The higher strength of CGI can lead to weight reduction and higher operation pressure, which in turn can improve the overall efficiency and reduce the emission. However, the manufacturing of CGI components faces many challenges due to its low machinability because of its unique microstructure and chemical composition. For example, excessive wear has been observed in recent years when PCBN (polycrystalline cubic boron nitride) tools were used to manufacture CGI parts using high-speed machining. Therefore, understanding the mechanisms responsible for the wear of the tools and optimizing the machining protocols are essential to the development of low-cost manufacturing technologies of CGI components and successful market deployment of this high-strength material in the automotive industry.

Preliminary work performed by the industrial partner of this project, Quaker Houghton, indicated that the tool wear associated with the machining of CGI could be reduced by using certain lubricants. It is hypothesized that certain constituents in the lubricants, such as sulfur, might react and form a protective layer on the tool surface. To test this hypothesis, researchers at Temple University and Quaker Houghton will collaborate to conduct a series of experiments to study the high-speed machinability of CGI using PCBN tools under different lubrication conditions. The microstructural and chemical evolution at the tool surface will be examined, and the mechanical properties of the machined surface will be investigated. It is expected that this work will lead to a deep understanding of the effect of lubricant composition and machining parameters on the PCBN tool degradation, which can in turn assist the development of novel lubricants for high-speed machining of CGI.