Tamotsu Fukatsu

Micro-grained cemented carbide with high strength

Abstract The present work is concerned with further improvement of the strength of ultra-fine grained cemented carbide. It has been reported already that the strength of the alloy is strongly affected by its structural defects, e.g. pores, Co pools, extraordinary coarse carbide grains or impurity compounds. In this work, the effects of carbide grain growth inhibitors. Co contents and impurities of starting powders on the strength of the alloy have been investigated in relation to the structural defects appearing on the fracture surface of transverse-ruptured specimens. The results obtained showed that the amount of impurities of starting powders most closely affected the strength of the alloy, and an extremely high-strength cemented carbide having transverse-rupture strength of over 500 kgf/mm2 was obtained by using highly purified WC powder.

Effects of TiC Content and Grain Size on Cutting Performance of Al2O3-TiC Ceramic Tools

Al2O3-TiC ceramic tools having 10–50 mass% TiC and different grain sizes were prepared by hot-pressing, and the cutting performance of these toots was studied. The tools having the highest TiC content and the finest TiC grain she showed the largest flank wear (VB) in turning grey cast iron, and the smallest VB in turning ductile cast iron. The tools having 30% TiC content and the finest TiC grain size showed superior resistance to flaking and optimum cutting performance in turning allayed tool steel. Presented at the 45th Annual Meeting In Denver. Colorado May 7–10, 5990