Polycrystalline cubic boron nitride (pcBN) is a very promising tool material for turning martensitic stainless steels at high cutting speeds (vc > 200 m/min). The competitive advantage of pcBN over cemented carbide increases as the cutting speed is increased. Changing the speed might lead to a shift in the wear balance and hence the knowledge about tool wear below vc = 200 m/min might not be applicable at vc = 600 m/min. The coatings designed for the lower speed range might also not be performing in the same way at higher speeds. This paper investigates the wear mechanism of uncoated and (Ti,Al)N coated pcBN tools when turning 17–4 PH in a hardened condition at speeds vc = 200–600 m/min. Both scanning and transmission electron microscopy are used to study the worn tools. The in-depth analysis reveals that adhesive wear is only active at low speeds. Increasing the speed does however lead to more wear by diffusion and oxidation. The cBN is preferentially worn out, leaving the TiC binder at the tool-chip interface. Oxidation results in the accelerated wear of the pcBN but also in the formation of metal oxides within the adhered build up layer. The (Ti,Al)N coating does not significantly extend the tool life within this speed range, but it suppresses the adhesive wear mechanism preventing premature tool failure.

中文翻译：

---

关于无涂层和涂层 pcBN 刀具在 17-4 PH 马氏体不锈钢车削过程中的磨损机制


多晶立方氮化硼 （pcBN） 是一种非常有前途的刀具材料，用于以高切削速度 （vc > 200 m/min） 车削马氏体不锈钢。随着切削速度的提高，pcBN 相对于硬质合金的竞争优势也随之增加。改变速度可能会导致磨损平衡发生变化，因此，当 vc = 600 m/min 时，有关刀具磨损低于 vc = 200 m/min 的知识可能不适用于 vc = 600 m/min。为较低速度范围设计的涂层在较高速度下的性能也可能不同。本文研究了无涂层和 （Ti，Al）N 涂层 pcBN 刀具在硬化条件下以 vc = 200-600 m/min 的速度车削 17-4 PH 时的磨损机制。扫描和透射电子显微镜都用于研究磨损的工具。深入分析表明，粘着磨损仅在低速时有效。然而，提高速度确实会导致更多的扩散和氧化磨损。cBN 优先磨损，将 TiC 粘合剂留在工具芯片界面处。氧化导致 pcBN 加速磨损，但也会导致在粘附的构建层内形成金属氧化物。在此速度范围内，（Ti，Al）N 涂层不会显著延长刀具寿命，但它抑制了粘附磨损机制，防止刀具过早失效。