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Metal cutting puts extreme demands on the tool and tool material through conditions of high forces, high contact pressures, high temperatures, and intense chemical attack by difficult to cut work materials. In addition, the tool geometry and cutting conditions in terms of sharp edges, cyclic engagement and presence of cutting fluid will add to the severity. Most often cutting tools are used close to their ultimate resistance against these loads, especially to the limiting thermal and mechanical stresses. . | 1 Wear mechanisms of HSS cutting tools Wear mechanisms of HSS cutting tools by Sture Hogmark Uppsala University The Ângstrỏm Laboratory Sweden Mikael Olsson Dalarna University Sweden 1. Introduction Metal cutting puts extreme demands on the tool and tool material through conditions of high forces high contact pressures high temperatures and intense chemical attack by difficult to cut work materials. In addition the tool geometry and cutting conditions in terms of sharp edges cyclic engagement and presence of cutting fluid will add to the severity. Most often cutting tools are used close to their ultimate resistance against these loads especially to the limiting thermal and mechanical stresses. In spite of the increasing use of high performance tool materials such as CVD and PVD coated cemented carbides cermets ceramics cubic boron nitride and diamond high speed steels HSS are still frequently used in tools for metal cutting applications. The relatively high toughness and the possibility of economic manufacturing of tools with complicated geometries still justify the use of HSS in many cutting operations. The introduction of powder metallurgical grades in combination with Electro Slag Heating ESH and Physical Vapour Deposition PVD coating technologies has further improved the performance of HSS cutting tools. Since the successful introduction of the PVD-TiN-coating in the late 70 ies the academic research on HSS metal cutting tools has been concentrated to developing even better coating materials and techniques for their deposition. This paper is a brief overview of the mechanisms of wear of HSS cutting tools and includes illustrations from both uncoated and coated tools. More details on the metal cutting process the mechanisms of tool degradation and the properties of HSS materials and their coatings are found in Refs 1-10 . 2. The cutting process in brief To understand the wear mechanisms in metal cutting it is necessary to have a brief understanding of the severe
