Influence of chromium content on the dry machining performance of cathodic arc evaporated TiAlN coatings

• Published in: Wear 2003, Vol.254 (1), p.185-194
• Main Authors: Harris, S.G, Doyle, E.D, Vlasveld, A.C, Audy, J, Long, J.M, Quick, D
• Format: Article
• Language: English
• Subjects: Applied sciences; Cathodic arc evaporation; Cutting; Dry machining; Exact sciences and technology; Friction, wear, lubrication; Machine components; Machining. Machinability; Mechanical engineering. Machine design; Metals. Metallurgy; Production techniques; PVD; TiAlCrN; TiAlN; Wear
• ISSN: 0043-1648; 1873-2577
• DOI: 10.1016/S0043-1648(02)00290-9

Physical vapour deposition (PVD) titanium aluminium nitride coated cutting tools are used extensively in global manufacturing for reducing production costs and improving productivity in a number of aggressive metal-cutting operations, namely, dry and high-speed machining. In this investigation, the performance of Ti 1− x Al x N and Ti 1− x− y Al x Cr y N coatings was assessed on Co-HSS twist drills used to machine grey cast iron. The failure criterion for drills was defined as a critical sized flank wear land at the outer corners of the drills. Using this criterion, the average tool life of uncoated twist drills was increased by factors of 2.5, 3.0 and 3.0 by Ti 0.59Al 0.41N, Ti 0.27Al 0.19Cr 0.54N and Ti 0.21Al 0.14Cr 0.65N coatings, respectively. Notwithstanding the similar increase in average tool life, the Ti 1− x− y Al x Cr y N coatings produced more consistent results than the Ti 1− x Al x N coated drills with standard deviations of 67, 3 and 19 holes, respectively. This result has significant practical implications in manufacturing, since drills are not replaced on an individual basis, but rather on a preset tool change frequency. The present paper discusses the performance of Ti 1− x Al x N and Ti 1− x− y Al x Cr y N coated drills in terms of average and practical drill life and concludes with remarks on the characterisation of PVD coatings and their significance on the performance of Co-HSS twist drills when dry machining grey cast iron.