Wear phenomenon in the hard steel machining using ceramic tools

The principle aim of this investigation is to recognize the wear phenomenon of the mixed ceramic tips against 60 HRC steel specimens in dry and hard turning operations. For this purpose both microscopic and microstructural aspects of ceramic tool wear were taken into consideration. Investigations were performed under varying feed rate, constant cutting speed of 100 m/min and small depth of cut of 0.2 mm to perform finishing cuts. Light optical microscopy (LOM), scanning electron microscopy (SEM), BSE technique and X-ray diffraction analysis (XRM) were applied for observations of worn tool surfaces, wear products and the distinction of wear mechanisms occurring. In general, wear mechanisms observed in the machining tests involve abrasion, fracture, plastic flow, material transfer and tribochemical effects which appear depending on the mechanical and thermal conditions generated on the wear zones. In particular, two types of transfer layer formation with different morphologies occurring at the rake-chip interface are distinguished.