Small scale testing of PCD and WC-Co tooling in rock cutting using longitudinal turning

Rock cutting and crushing stands for a considerable part of the world use of Cemented Carbide (CC). CC is preferred due to its hardness while maintaining high fracture toughness. However, new cutting tool materials are developed allowing increased efficiency whilst minimizing the use of critical raw material such as tungsten and cobalt. One material showing promising capabilities is Polycrystalline Diamond (PCD). Field testing of new wear resistant tool materials are known to be notoriously difficult due to issues controlling the test environment. To further support the development of new and more wear resistant tool materials there is a need for an improved methodology of laboratory testing of rock cutting. In this work a test rig was developed and testing methodology was validated, when using cutting tool inserts with standard shapes, such as round double sided general purpose insert RNGN and dome shaped buttons while machining and crushing bars of red granite by longitudinal turning using a standard lathe. Optical microscopy, 3D data of Volume Difference Measurements and SEM were used for analyzing tool wear. Different grades of CC showed similar wear mechanisms irrespectively of tool geometry. The PCD grade did not show similar wear mechanisms, but did outperform CC grade in regard to wear resistance.