Effect of workpiece sulphur content on the degradation of a PCBN tool material

► Degradation of low content PCBN materials is investigated. ► In-depth microscopy methods have been used to illustrate the degradation. ► The impact of workpiece sulphur content on tool degradation is investigated. ► Sulphides protect the tool edge from iron. ► In the absence of sulphides, iron makes into way into the tool material microstructure.