Thermal characterization of the chip-tool interface when using coated turning inserts

This paper reports some interesting results of extensive experimental investigations of the thermal interactions between the coating/substrate and the moving surface of the chip when turning a medium carbon steel and an austenitic stainless steel. Both flat-faced and grooved inserts coated with TiC, TiC/TiN and TiC/Al2O3/TiN were tested. A standard K-type thermocouple embedded in the workpiece was used to convert measured efm's to the interfacial temperatures. In addition, the chip-rake contact length and the contact area were determined by using computer processing of scanned contact images. As a result of the investigation some coating structures were recommended for high speed machining of the work materials used.