Influence of microstructure on the abrasive edge wear of WC-Co hardmetals

Abrasive wear of the tool edge is a damage observed in various industrial applications. Although, the abrasive wear of flat specimens has been investigated thoroughly, still there are some challenges in the understanding of edge wear micromechanisms. In the present research, edge wear of coarse WC-6,9,14 wt.%Co and ultrafine/nano WC-5,6,9 wt.%Co hardmetals was examined using edge-on-disc abrasion test using P800 SiC abrasive paper. The specimens had an edge angle of 90 degrees and were abraded in a direction perpendicular to the edge line. Experimental results demonstrated that Co content and WC grain size influenced wear resistance of the edge remarkably. Increase in Co content resulted in decrease of wear resistance in the coarse and in the ultrafine grades. Comparing to the ultrafine grades of the same Co content, the coarse grades demonstrated higher wear rates at the beginning of sliding, but lower wear rates at the final stages. This behaviour was associated with a transition of pullout of WC grains at the beginning to a binder removal followed by WC grains detachment at final stages. The ultrafine grades showed ploughing wear over all the sliding distances. (C) 2007 Elsevier B.V. All rights reserved.