Wear of ceramic tools in hard machining

Purpose: The principle purpose of this investigation is to recognize the wear phenomenon of the mixed ceramic tips against 60 HRC alloy steel specimens in dry and hard turning operations. This knowledge allows optimal machining chains to be planned by the manufacturing engineers. Design/methodology/approach: 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. Findings: It was found that 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. Research limitations/implications: 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. Practical implications: In this study both microscopic and microstructural aspects of ceramic tool wear were taken into consideration. Moreover, the development of the crater and flank wear and the associated wear mechanisms were identified. Originality/value: In particular, two types of transfer layer formation with different morphologies occurring at the rake-chip interface are distinguished.