ORIGINAL ARTICLE Tool wear analysis in the machining of hardened steels Álisson Rocha Machado 1,2 & Anselmo Eduardo Diniz 3 Received: 6 February 2017 /Accepted: 24 April 2017 # Springer-Verlag London 2017 Abstract The machinability of a material can be assessed using many output parameters of the machining process, tool life being undoubtedly the most common. Tool life depends mainly on the tool wear rate, which in turn is very dependent on the prevailing wear mechanisms. It is therefore very impor- tant to study and analyze correctly the possible wear mecha- nisms on the rake and flank faces of the tool. When machining materials with high hardness, usually over 35 HRC, the diffi- culties are enormous because of the high cutting forces and heat generated, causing rapid tool wear and short tool life. When the hardness exceeds 45 HRC, the difficulties are even worse because the chips change from continuous to serrated types formed by localized shearing, increasing forces and tem- peratures even further. To tackle these adversities, ceramic and ultra-hard (CBN) tool materials are normally used, although other materials are also suitable. In interrupted cutting, for example, cemented carbides are frequently used. Wear mech- anism analysis in hard machining is thus of particular impor- tance. This article analyzes the tool wear mechanisms that occur in the machining of several hardened steels during con- tinuous and interrupted cutting. All the analyses were performed after the tools have reached the stipulated end of the tool life criteria. Different types of tool material, such as cubic boron nitride, ceramics, and PVD-coated carbide inserts applied in turning and milling operations had their wear mech- anisms analyzed. The main goal of this work was not to com- pare the tool lives of the conditions tried but to provide a greater understanding of tool wear phenomena and thus con- tribute to the development of tools with improved properties. Most of the worn tools had their wear region analyzed using a scanning electronic microscope (SEM) with the help of energy dispersive spectroscopy (EDS) technique. The wear analysis performed using the pictures taken in the SEM/EDS system was based on the main literature of this field of knowledge. Keywords Machining of hardened steels . Tool wear mechanisms . Continuous and interrupted cuttings . CBN, ceramic, and cemented carbide tools 1 Introduction Cutting tools usually wear because they are in contact with the chip and workpiece. They can also suffer damages to the cut- ting edges. The main wear/damage mechanisms are attrition, diffusion, abrasion, chipping, cracks, and breakage caused by shocks between workpiece and tool cutting edge and thermal and mechanical variations at the tool tip [1]. Attrition wear can be defined as the cyclical adhesion of workpiece/chip material to, and removal of particles from, the tool. During this process, microscopic tool particles are torn from the tool and dragged along with the flow of the work material. According to Trent and Wright [2], attrition usually occurs at low cutting speeds, but Diniz et al. [3] observed attri- tion when machining AISI 1045 steel even at high cutting speeds (490 and 570 m/min). Other conditions for attrition to * Álisson Rocha Machado alisson.machado@ufu.br; alisson.rocha@pucpr.br Anselmo Eduardo Diniz anselmo@fem.unicamp.br 1 LEPU/FEMEC, Federal University of Uberlândia, Uberlândia, MG 38400-902, Brazil 2 Graduate Program in Mechanical Engineering, Pontifícia Universidade Católica do Paraná – PUC-PR, Curitiba, PR 80215-901, Brazil 3 College of Mechanical Engineering, University of Campinas (UNICAMP), Campinas, Brazil Int J Adv Manuf Technol DOI 10.1007/s00170-017-0455-2