Impact of Lubrication for Continuous CGI Cutting

The machinability of compacted graphite iron (CGI), and the performance of selected metalworking fluids were assessed in a turning operation used to simulate the continuous cutting conditions that occur during engine cylinder boring. A turning operation was performed on the outside surface of both CGI and gray iron test cylinders. Testing involved the use of tungsten carbide cutting inserts at cutting speeds of 250 m/min, and polycrystalline boron nitride (PCBN) cutting inserts at cutting speeds of 700 m/min. Two metalworking fluids were tested, which included one considered to be standard for conventional cast iron machining, (Fluid 37), and one (Quakercool 7020-CG) engineered specifically for use in machining CGI. In addition to fluid lubricated machining, machining was also done under dry conditions.