Effect of Cutting Speed on Chipping and Wear of the SiAlON Ceramic Tool in Dry Finish Turning of the Precipitation Hardenable IN100 Aerospace Superalloy

abstract

Inconel 100 (IN100) aerospace superalloy is used in manufacturing aero-engine components that operate at intermediate temperatures. It is considered to be a hard-to-cut material. Chipping of the tool edge is one of the major failure mechanisms of ceramic tools in finish cutting of superalloys, which causes a sudden breakage of the cutting edge during machining. Cutting temperature significantly depends on cutting speed. Varying the cutting speed will affect the frictional action during the machining operations. However, proper selection of the cutting variables, especially the cutting speed, can prevent chipping occurrence. In this work, the influence of controlling the cutting speed on the chipping formation in dry finish turning of IN100 aerospace superalloy using SiAlON ceramic tool has been investigated. Scanning electron microscope (SEM)/energy dispersing spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and three-dimensional wear measurements were used to make the investigations of the worn tool edges. It was found that variations of the cutting speeds in a certain range resulted in the generation of different lubricious and protective tribo-films. The presence of these tribo-films at the cutting region proved essential to prevent chipping of the cutting tool edge and to improve its wear resistance during finish turning of age-hardened IN 100 using SiAlON ceramic tools. Chip compression ratio and calculated values of the coefficient of friction at the tool–chip interface confirmed these results.